U.S. patent application number 09/730327 was filed with the patent office on 2002-08-08 for reaction advantage anti-collision systems and methods.
Invention is credited to Rast, Rodger H..
Application Number | 20020105423 09/730327 |
Document ID | / |
Family ID | 24934867 |
Filed Date | 2002-08-08 |
United States Patent
Application |
20020105423 |
Kind Code |
A1 |
Rast, Rodger H. |
August 8, 2002 |
Reaction advantage anti-collision systems and methods
Abstract
A vehicle anti-collision system and method for is disclosed
which provides drivers with additional time in which to react to
significant roadway events which often precede accidents. The
simplest implementation of the system and method (Phase I) employs
a brake pedal mounted sensor packet for determining how hard a
driver is braking. Hard braking information is relayed to
approaching drivers by means of the reverse lights of the vehicle.
Additional implementation phases (II through IV) are described
wherein event information is communicated between vehicles over a
communications link. Furthermore, additional vehicle information,
such as an impact, swerving, emergency light activation, and
roadway hazards may be communicated to approaching drivers by the
communications link whereby drivers need not see the vehicle that
has slammed on its brakes, or otherwise has created or responded to
an event, in order to avoid an accident.
Inventors: |
Rast, Rodger H.; (Rancho
Cordova, CA) |
Correspondence
Address: |
Rastar Corporation
Suite L
11292 Coloma Rd.
Gold River
CA
95670
US
|
Family ID: |
24934867 |
Appl. No.: |
09/730327 |
Filed: |
December 5, 2000 |
Current U.S.
Class: |
340/479 ;
340/467 |
Current CPC
Class: |
G08G 1/162 20130101;
B60Q 1/44 20130101 |
Class at
Publication: |
340/479 ;
340/467 |
International
Class: |
B60Q 001/44 |
Claims
What is claimed is:
1. An anti-collision system for use within a motorized vehicle,
comprising: (a) means for sensing the urgency with which the brakes
of said vehicle are being activated and generating a signal in
response thereto; and (b) means for rearwardly communicating
sufficiently urgent levels of braking to other drivers in response
to said signal crossing a predetermined threshold.
2. An anti-collision system as recited in claim 1, wherein the
means for sensing the urgency of said brake activation comprises a
pressure sensor responsive to the pressure with which the brake is
being applied.
3. An anti-collision system as recited in claim 1, wherein the
means for sensing the urgency of said brake activation comprises an
acceleration sensor responsive to the acceleration to which the
brake pedal is being subjected.
4. An anti-collision system as recited in claim 1, wherein the
means for rearwardly communicating urgent levels of braking to
other drivers comprises a visual indicator which is capable of
being seen from behind said vehicle.
5. An anti-collision system as recited in claim 1, wherein the
means for rearwardly communicating urgent levels of braking to
other drivers comprises a remote communications link, such as
radio-frequency, operably coupled to a visual indicator within the
vehicles of the other drivers, upon which urgent levels of braking
of said first vehicle are capable of being displayed.
6. An anti-collision system for reducing the probability of
rear-end vehicular collisions between a first vehicle and vehicles
following said first vehicle, comprising: (a) a sensor configured
for attachment to the braking system of said first vehicle and
configured to generate a signal in response to the rapidity with
which the brakes are applied by the driver of said first vehicle;
and (b) a controller operably connected to receive said signal from
said sensor and configured to activate an event indicator upon said
signal crossing a predetermined threshold, said event indicator
configured for recognition by drivers within one or more of said
following vehicles.
7. An anti-collision system as recited in claim 6, wherein the
rapidity of brake application is characterized by said sensor in
response to changes in applied brake pedal pressure.
8. An anti-collision system as recited in claim 6, wherein said
sensor is mounted to the brake pedal.
9. An anti-collision system as recited in claim 6, wherein said
sensor is mounted within the linkages connecting to the brake
pedal.
10. An anti-collision system as recited in claim 6, wherein the
rapidity of brake application is characterized by said sensor in
response to brake pedal accelerations.
11. An anti-collision system as recited in claim 6, wherein the
event indicator comprises a light source.
12. An anti-collision system as recited in claim 11, wherein the
light source is modulated on and off by said controller to increase
recognition by the drivers of the other vehicles.
13. An anti-collision system as recited in claim 11, wherein the
event indicator comprises the reverse lights of said first
vehicle.
14. An anti-collision system as recited in claim 6, further
comprising a communications link operably connected with said
controller, through which the event indicator located on another,
second, vehicle is capable of being activated by the transmission
of an event signal by said controller through said communications
link.
15. An anti-collision system as recited in claim 14, wherein the
communications link is configured with a communications protocol in
which senders and receivers are synchronized to the order of event
occurrence.
16. An anti-collision system as recited in claim 14, wherein said
communications link comprises a transmitter operably connected to
said controller and capable of generating an event signal to
remotely activate an event indicator contained within vehicles
following said first vehicle.
17. An anti-collision system as recited in claim 16, wherein the
transmitter is oriented substantially for rearward projection from
said first vehicle such that the associated event signal generated
by said first vehicle is directed for reception by vehicles
following said first vehicle.
18. An anti-collision system as recited in claim 16, wherein the
controller is configured to provide event signal communication of a
single event as periodic transmissions wherein short-term
short-term signal interference with other of said anti-collision
systems is prevented.
19. An anti-collision system as recited in claim 18, wherein the
period between transmissions within the periodic transmission of an
event signal is temporally offset such that event signals generated
from other of said vehicles in response to a simultaneous event are
not subject to continued interference with one another, but are
shifted apart so as not to continue overlapping.
20. An anti-collision system as recited in claim 19, wherein the
temporal offset is restricted to allow event transmission within
slotted intervals which are based on an event being generated,
wherein event transmissions synchronize themselves in relation to
an event being generated.
21. An anti-collision system as recited in claim 14, wherein said
controller is configured to encode severity data within the event
signal.
22. An anti-collision system as recited in claim 14, wherein said
controller is configured to encode identification data allowing
event signals generated from different vehicles to be distinguished
from one another.
23. An anti-collision system as recited in claim 14, wherein said
communications link comprises a receiver operably connected to said
controller, the combination responsive to an event signal generated
by another of said anti-collision systems, or a device so
configured to transmit signals of that format, and capable of
activating an event indicator for recognition by the driver of said
first vehicle.
24. An anti-collision system as recited in claim 23, wherein said
combination of receiver and operably connected controller is
configured to provide for selective regeneration of received
signals which are retransmitted to additional vehicles.
25. An anti-collision system as recited in claim 24, wherein the
selective regeneration is controlled by the transmission of a
regeneration limiter value encoded within the transmitted event
signal.
26. An anti-collision system as recited in claim 25, wherein the
regeneration is controlled by a count value encoded into the event
signal as the regeneration limiter, said count value set to a first
value upon first transmission from said first vehicle and is
subsequently altered by a system responsive to said first
transmission within an additional vehicle, wherein the system is
configured to further regenerate the signal until the count value
reaches a final value whereupon receipt of the event signal with
the final count value prevents further event signal
regeneration.
27. An anti-collision system as recited in claim 24, wherein the
controller is configured to provide for selective regeneration in
response to the severity of the event being communicated.
28. An anti-collision system as recited in claim 14, further
comprising a crash detection sensor operably connected to said
controller and configured to generate a crash event in response to
detection of a crash.
29. An anti-collision system as recited in claim 28, wherein said
crash detection sensor comprises an acceleration sensor capable of
sensing levels of acceleration commensurate with impact
collisions.
30. An anti-collision system as recited in claim 28, wherein said
crash detection sensor comprises a signal generated by airbag
circuitry within the vehicle which is activated in response to
airbag deployment.
31. An anti-collision system as recited in claim 14, further
comprising a swerve sensor operably connected to said controller,
said swerve sensor generating a swerve signal which is capable of
initiating event signal generation by said controller in response
to a sufficient amount of detected swerve and of conditioning the
response of the controller.
32. An anti-collision system as recited in claim 14, further
comprising a direction sensor operably connected to said controller
such that a direction of travel for said first vehicle may be
encoded within event signals being communicated.
33. An anti-collision system as recited in claim 14, wherein the
event indicator located in the second vehicle provides a visual
indication to the driver of said second vehicle, such as a visual
indication on the dashboard.
34. An anti-collision system as recited in claim 14, wherein the
event indicator located in the second vehicle provides an audio
alert to the driver of said second vehicle.
35. An anti-collision system as recited in claim 14, wherein the
event indicator located in the second vehicle is responsive to the
severity level encoded within the event signal such that feedback
may be provided to the driver of said second vehicle by the event
indicator whereupon the driver is alerted to the severity of the
event which has taken place.
36. An anti-collision system as recited in claim 14, wherein the
event indicator is configured for indicating roadway condition
messages which are received as event signals from roadside devices
and emergency vehicles equipped to generate roadway condition event
signals.
37. An anti-collision system as recited in claim 36, wherein the
event indicator configured for indicating roadway condition
messages is a visual display comprising at least one array of
display elements adapted for displaying text and/or graphics.
38. An anti-collision system as recited in claim 37, wherein the
visual display further comprises a compass display capable of
displaying vehicle heading.
39. An anti-collision system as recited in claim 14, further
comprising a speed sensor connected to the said controller, wherein
event signal generation is fully or partially responsive to the
output of the speed sensor, such that braking activity which occurs
within slow moving vehicles, as in parking lots adjacent to a
roadway, does not unnecessarily alert drivers on the roadway.
40. An anti-collision system as recited in claim 14, further
comprising a GPS positioning system connected to said controller
for enhancing event qualification by embedding position data within
the transmitted event signals and for qualifying received event
signals by comparing the position of the vehicle issuing the event
with the vehicle within which the event signal has been
received.
41. An anti-collision system as recited in claim 14, further
comprising a range detection device operably connected to said
controller and capable of determining the distance to the vehicle
being followed such that the controller may detect impending crash
situations and respond to events in a manner consistent with the
amount of following distance that exists.
42. An anti-collision system as recited in claim 14, wherein the
communication link is configured for transmitting event signals
which are capable of being received within a properly configured
call box unit, or similarly configured receiver, that is configured
to receive event signals and communicate significant event
information over a communication channel to personnel, such as may
be dispatched to the scene.
43. An anti-collision system as recited in claim 42, further
comprising a wireless telephone connected to the controller and
which is capable of automatically dialing out a predetermined
emergency number and providing speakerphone capability so that the
status of occupants can be determined by emergency personnel, the
automatic dialing being triggered by an event of sufficient
severity, such as a crash of the vehicle to which the wireless
telephone is installed.
44. An anti-collision system as recited in claim 14, wherein upon
receipt of an event signal over the communications link the
controller is capable of generating a signal to the cruise control
for releasing the pressure on the accelerator pedal, so that the
car can begin to decelerate immediately upon receipt of the event
signal.
45. An anti-collision system as recited in claim 14, further
comprising an error detection circuit which monitors the operation
of said controller and is capable of shutting down portions, or the
entire, circuit of the controller in response to detected
errors.
46. An anti-collision system as recited in claim 45, wherein the
error detection unit connected to said controller further comprises
status inputs and digital memory within which vehicle status
information is logged until such time as the vehicle containing
said controller is involved in a crash, whereupon the data which
has been logged may be accessed to determine vehicle conditions
prior to the crash.
47. An anti-collision system as recited in claim 14, further
comprising an automatic mute circuit connected to said controller
and capable of muting the audio output of the sound system of said
vehicle in response to the controller receiving an event signal of
sufficient severity, such that the driver can be alerted to
approaching emergency vehicles which are generating an event signal
and to severe roadway conditions requiring the driver's full
attention.
48. An anti-collision system as recited in claim 14, further
comprising an automatic braking mechanism connected to said
controller which is capable of activating the vehicle's brakes,
wherein said controller is configured for activating the automatic
braking mechanism detecting a sufficient alert condition.
49. An anti-collision system as recited in claim 6, further
comprising an accelerator pedal sense input to said controller,
wherein said controller is capable of discerning the level of
acceleration to which the vehicle is subject, an d can additionally
discern changes to acceleration, such as an abrupt release of
accelerator pedal pressure which may be indicative of a process of
hard braking, said controller being configured for conditioning
outputs, such as hard braking indicators, communication links, and
mechanisms for automatically engaging the brakes in response
thereto.
50. An anti-collision system as recited in claim 6, further
comprising a light signal controller which is in wired electrical
connection with said controller and itself connects to a plurality
of vehicle lights, wherein the light signal controller responds to
signals from the controller by activating and deactivating selected
lights within said vehicle, such that the use of the light signal
controller eliminates the necessity of providing individual wiring
to each of the plurality of vehicle lights.
51. An anti-collision system as recited in claim 50, wherein the
light signal controller is integrated within a light module
containing a plurality of elements, such as individual LEDs whose
state of activity is selectively controlled by the light signal
controller.
52. An anti-collision system as recited in claim 6, wherein said
pressure transducer is a load cell whose output is generated across
a Wien bridge.
53. A method of decreasing response time for a driver following a
braking vehicle, so as to decrease the number of rear-end vehicle
collisions, comprising: early detection of brake pedal activation,
prior to brake engagement; and activation of an alerting signal so
that drivers following said braking vehicle are provided with
additional time to respond to the braking action.
54. A method as recited in claim 53, further comprising:
ascertaining the amount of braking action that the driver is
attempting to apply; and activating an alert signal in response to
the detection of hard braking, the alert signal being separately
distinguishable from a conventional braking indication, so that
drivers following said vehicle are warned of that the driver is
attempting to brake hard.
55. In a roadside call box which is capable of providing
communication between its roadway location and emergency personnel,
wherein the improvement comprises: (a) a receiver capable of
registering event signals generated by the transmitters within
vehicles that are experiencing or responding to roadway events; (b)
a control circuit operatively connected to said receiver, wherein
the control circuit is capable of activating an appropriate outcall
to emergency personnel when the registered event signal is of
sufficient severity; and (c) an encoder capable of converting the
information about the received event signals into a signal
compatible with the outcall circuitry of the call box, such as a
voice signal, so that the event signal information is communicated
to emergency personnel that may then respond to the roadside events
which have been registered.
56. A method of decreasing response time for a driver following a
braking vehicle, so as to decrease the number of rear-end vehicle
collisions, comprising: ascertaining the amount of braking action
that the driver is attempting to apply; and activating an alert
signal in response to the detection of hard braking, the alert
signal being separately distinguishable from a conventional braking
indication, so that drivers following said vehicle are warned that
the driver is attempting to brake hard.
57. A method as recited in claim 56, wherein the separately
distinguishable alert signal comprises is a rear facing
illumination source.
58. A method as recited in claim 57, wherein the illumination
source is the reverse indicator light of the vehicle.
59. A method as recited in claim 58, wherein modulation of the
reverse indicator light is selected as a further indicator of the
hard braking condition.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable
REFERENCE TO A MICROFICHE APPENDIX
[0003] Not Applicable
BACKGROUND OF THE INVENTION
[0004] 1 Field of the Invention
[0005] This invention pertains generally to vehicle safety devices
and more particularly to a system and method for reducing vehicular
rear-end collisions by the early sensing of events such as hard
brake pedal activation and the communication of the said events to
approaching vehicle so as to provide a reaction time advantage to
drivers therein.
[0006] 2. Description of the Background Art
[0007] Rear-end collisions on our highways are a major cause of
serious injury. The incidence of rear-ends collisions has risen
rapidly as our highway systems get increasingly congested. The bulk
of these rear end collisions could be avoided, it is estimated by
the National Highway Traffic Safety Administration (NHTSA) that
about 88% of rear end collisions in the United States are caused by
vehicles following too closely, and/or coupled with driver
inattention. Further, it is estimated that rear-end collisions
represent approximately 28% of all vehicle collisions nationwide.
Rear-end collisions account for 36% of fatal and injury collisions
in the state of California.
[0008] Drivers have been admonished and given a variety of
guidelines for following distance, however, these have done little
to alter driving habits. Drivers on the highway are often jockeying
for position, and some feel that when attempting to follow at a
"safe distance", the space just quickly fills with one or more
vehicles. Unfortunately, when vehicles closely follow one another
there is often insufficient time for a driver to respond to a
situation and come to a stop prior to rear-ending the vehicle
ahead. In existing vehicles, drivers are unable to gain sufficient
information relating to the action of drivers and conditions
farther up the road. Drivers may watch brake lights come on and go
off again as they try to see what is occurring farther up the road.
Often the view up ahead is obscured, or completely blocked, by the
vehicle ahead, leaving the driver reliant on being extremely alert
and having fast reaction times. Unfortunately drivers are also
relying on luck which can run out at any time when the person ahead
unexpected "slams" on the brakes. Under actual driving conditions,
by the time a driver recognizes a "situation" they often have
insufficient time to slow, or stop, in order to prevent colliding
with another vehicle. Coming to a stop from highway speeds can
require 3-4 seconds during which over 200 hundred feet of highway
may be traversed. At highway speeds, every {fraction
(1/100)}.sup.th of a second that a driver delays in applying their
brakes can translate to another foot of highway. The energy for
these additional feet are often absorbed by the rear end of another
vehicle. In many cases significant injuries may be prevented by
decreasing reaction times by a few hundred milliseconds.
[0009] Another source of major rear-end accidents occurs within
multi-car "pile-ups", where at times, over a hundred vehicles have
been known to crash in a chain-reaction of rear-end collisions.
These "pile-ups" are generally attributable to low visibility
conditions which further reduce driver reaction time; by the time
the problem is visually seen, there is not enough time to react at
the speed being driven and another car is added to the pile of
wreckage with additional lives often being lost.
[0010] Drivers have been continually admonished not to tailgate.
Drivers know that they should not follow any closer than one car
length for every 10 miles per hour of speed. Many drivers are also
cognizant of the guidelines for driving in reduced visibility.
Unfortunately under actual driving situations these driving
guidelines appear to be widely ignored by drivers. Drivers push
along trying to rely on their wits and reactions to save them from
getting into an accident. Yet, given the wrong set of circumstances
they will simply not be able to stop in time. Driver attitudes have
been mentioned here because the success of any system or method
attempting to reduce highway mortality must take driver attitudes
and driving patterns into account. The rule of "one car length per
10 mph" is a simple system that technically works--however it
totally ignores prevailing highway conditions and driver attitudes,
and therefore is largely being ignored. More recently drivers have
been directed to follow the "3 second rule", wherein drivers should
follow the car ahead no less than 3 seconds. Again, the 3 second
rule--if followed--would save lives. Unfortunately, drivers rarely
follow such guidelines. Any system and method that is to have a
wide range effect to lower the collision rate will be required to
do so under prevailing highway conditions and driver attitudes.
[0011] Presently, the only alert provided by vehicles to
approaching traffic is the brake light. It is interesting to note
how the size and intensity of brake lights has increased over the
years. In order to enhance recognition and driver response, brake
lights have been made larger and brighter, while auxiliary deck
mounted brake lights have been incorporated within vehicles. So
important is quick recognition of braking that in fact it is a
standard policy among numerous insurance companies to provide
discounts for vehicles which incorporate the additional centrally
mounted brake light. However, due to the still limited information
conveyed, and coupled with the constant on/off flicking of brakes
in traffic, a driver's reaction to seeing the brake lights come on
one more time is rarely one of jumping to engage their own brakes.
However, in many cases that reaction would be the only one capable
of preventing an accident.
[0012] Numerous concepts have been considered for reducing rear-end
collisions. The thought of computer driven automobiles, which
control their own speed has perhaps been around since the advent of
the first microcomputers. Programs at various automobile
manufacturers, and universities have been testing elements of the
concept for a number of years. However, wresting control of a
vehicle from the driver is an approach that not only ignores driver
attitudes, but ignores the complex dynamics that exist with highway
driving. Recognizing the distance of objects or close vehicles on
the road is already a function that the driver performs; drivers
know how close they are, they just don't know when the driver ahead
will "slam" on the brakes or swerve suddenly.
[0013] A huge variety of technical solutions can be arrived at
which would theoretically reduce traffic accidents, however, in
order to reduce actual traffic accidents any system or method needs
to gain widespread use on the highway system. The system or method,
therefore, needs to be designed with regard to the difficulties
involved with gaining widespread acceptance and standardization.
Any system or method that is to be successful at reducing traffic
fatalities and injuries should in addition take into account
present vehicle designs, the current highway infrastructure, the
design differences between various manufactured vehicles, design
cost, manufacturer liability, the cost of testing, reliability
concerns, and implementation cost. Additionally, the results from
the system or method should be capable of being progressively
achieved. Implementations that can not be achieved in progressive
steps, can require too large of a commitment from consumers,
manufacturers, and government regulators.
[0014] As can be seen, therefore, the development of a system and
method capable of sufficiently reducing driver reaction time could
save thousands of lives, and eliminate or reduce untold injuries.
Unfortunately, getting any system or method into widespread use is
a complex issue. A safety system directed at widespread adoption
must take into account actual highway driving patterns while it
must be reliable and yet capable of inexpensive deployment.
[0015] So far societies' best implemented solutions involve
accepting crashes and then protecting drivers with better restraint
systems, crumple zones, and airbags. These protection solutions are
wonderful for unavoidable accidents, yet statistics indicate that a
vast majority of accidents can be avoided. These accidents can be
avoided if enough reaction time advantage can be provided to
drivers. The rear-end vehicle collision reduction system of the
present invention is directed at providing solutions which provide
this reaction time advantage while attempting to take into account
the needs and attitudes of drivers, manufacturers and government
regulators.
BRIEF SUMMARY OF THE INVENTION
[0016] The present invention provides drivers with a "reaction
advantage" based on providing additional "event" information to
approaching drivers. The systems and methods described herein are
generally divided into four implementation phases, along with
additional aspects, wherein each successive phase provides
additional "reaction advantage" to the driver. The safety system
according to the present invention described herein is referred to
as a "reaction advantage anti-collision system", and may also be
referred to as a "RAAC system", "anti-collision system, or simply
as "system" in accordance the specific context. It will be
appreciated that the numerous aspects of the present invention,
which will be described in relation to the RAAC system, may be
alternatively subdivided for incorporation within various
integrated, or non-integrated, vehicle systems without departing
from the principles of the invention herein.
[0017] One premise of all phases of the invention is that the
majority of rear-end collisions result when an "event" or trigger
condition occurs that approaching drivers are unaware of. To
provide a "reaction advantage" the RAAC system communicates this
event condition immediately to an approaching driver. The described
inventive method and system seeks to provide an apparatus that
reduces the incidence of rear-end collisions without relying on
either drivers to actively change their driving patterns, or
technology to do the "thinking" for drivers.
[0018] Is it possible to reduce the level of rear-end collisions
without increasing the distance between vehicles? To answer that
question another question may be considered: How does the
Thunderbird.TM. aerobatic team of the United States Air Force,
which often travel at over 500 mph in tight formation within a few
feet of one another, prevent "rear-enders" and collisions. The
answer being that each team member knows at all times what the
other team members are doing. Each member maintains radio
communication and the leader communicates each and every move prior
to execution. If vehicles on the highway communicate their
intentions to other drivers early in the cycle of response (such as
braking or swerving) then drivers approaching from the rear would
have more time to react and thereby avoid an accident. However,
present day safety system have largely ignored systems which
collect and diseminate information, in favor of systems which
attempt to take the driver out of the control loop. This aspect of
creating a safe driving environment has been largely ignored by
safety systems to date.
[0019] Conventional vehicle signals are used to indicate "status",
such as to answer the question are the brakes on or off, or to
attempt to directly react to changes in the environment, such as
vehicle following radars. Within the present system it has been
recognized that if drivers knew the actual intentions of other
drivers up ahead, they would have sufficient time to react. The
system elements and methods described herein provide as based on
the broad concept of anticipating the intentions or actions of
drivers up ahead. Numerous embodiments and aspects are described
herein which communicate this additional information to the driver
thereby providing the driver with a reaction advantage.
[0020] In general, the system and method is required to solve two
problems. Firstly, a method(s) is needed of detecting driver
"intentions", and secondly a method(s) is needed of relaying that
information under both normal conditions and under conditions when
distance vision is impaired by other vehicles, or by weather such
as fog. To instantiate the situations wherein many accidents arise,
the following are provided by way of example as hypothetical
driving scenarios wherein these problems need to be solved:
[0021] Normal Visibility-visualize driving along in traffic on a
clear day, vehicles are slowing and speeding up, brake lights
coming on and going off. Brake lights on the sports car ahead light
up again, and you slowly ease off of the accelerator.
Unfortunately, almost a half second later, as the smoke starts
reeling off the car's tires, you realize too late that the driver
ahead has slammed on his brakes, and as the front end of your car
merges with the rear of the sports car, you wish you had applied
the brakes just a fraction of a second sooner. Accidents of this
nature are a daily occurrence.
[0022] Reduced Visibility-visualize driving in fog on the highway,
vehicles are jostling back and forth around you and you can see the
car ahead, yet nothing ahead of that, but a white veil of fog. The
drive is basically dull and boring as you cruise along. You enter a
denser fog as you see the car just ahead braking, your foot starts
for the brake pedal as you now see the car ahead impact a pile of
vehicles, . . . You can't stop! Each year huge "pileups" occur on
the freeways due to a lack of reaction time caused in part by the
low visibility.
[0023] Heavy Traffic--visualize driving in heavy traffic where you
can't see past the car ahead of you. Unfortunately unbeknownst to
you the traffic up ahead has stopped suddenly--you find out just in
time to slow from 60 to 25 before creasing the bumper of that SUV
blocking the view of the brake lights up ahead. It should be
appreciated that the vehicle up ahead often totally blocks the view
of the road and concomitantly prevents us from seeing the status of
the brake lights and positional status of cars ahead. Although
vehicles up ahead may be braking heavily, our first indication is
often delayed until the brakes of the vehicle directly in front of
us are applied.
[0024] These accident scenarios and numerous others are common
reaction-time related events on highways and freeways.
Unfortunately, short of being neurally connected to one another
there is no way of truly detecting "intentions" prior to some form
of action or execution. However, obtaining earlier comprehensive
information regarding actions and execution "events" can allow the
driver to react and apply the brakes earlier. The rear-end
collision reduction system of the present invention performs this
detection and alert function to thereby provide drivers with
additional time to react to dangerous roadway events in any weather
and/or traffic situation. The system design seeks to alert drivers
at the earliest time possible of dangerous events ahead. The
imperative of generating an alert with minimum delay will be
appreciated in that with each {fraction (1/100)} of a second of
delay can translate to a foot or more of roadway. A system which
provides the driver with even an extra 20 to 200 milliseconds to
react to an event ahead can appreciably reduce the risk of rear-end
collision.
[0025] The RAAC system contains various levels of circuitry, which
are primarily considered to be integrated within a "hard braking
controller" (HBC). Each level of circuitry implementation
contributes more reaction time advantage to drivers. The RAAC
system circuitry implementation is described with regard to four
evolutionary adoption phases; from simple systems providing small
amounts of reaction advantage to more sophisticated systems capable
of providing relatively large amounts of reaction advantage. The
RMC system can be implemented at any of these four phases, along
with permutations and combinations thereof. Understanding the
levels of advantages conferred by each of these four phases leads
to an increased awareness of the underlying principles of the
invention. The following descriptions detail the functional
enhancement gained with each of the four phases, along with various
additional inventive aspects.
HBC Phase I Hard Braking Sensor and Indicator Light
[0026] This first level of protection within the RAAC system
provides an additional visual indicator to approaching drivers when
the brakes of a vehicle are applied forcefully. In its simplest
configuration an additional brake pedal pressure sensor is coupled
to a hard braking controller (HBC), and a hard braking indicator.
The hard braking (brake slamming) sensor senses hard braking by
measuring the amount of pressure applied at the brake pedal, along
with pressure changes and optionally the acceleration of the pedal
itself.
[0027] The pedal pressure can be sensed in a variety of locations
starting at the brake pedal surface and leading back to the brake
cylinder itself. The method of pressure sensing generally preferred
herein employs sensing of pressure on the brake pedal itself, due
to its direct and immediate response, and the consideration that a
single sense unit design can then be manufactured to work with all
vehicles. There are wide variations in the brake pedal actuation
structures on vehicles which would need to be taken into account
for pressure sensors mounted farther back in the brake linkage
system. Additionally, there are delays inherent in the mechanical
brake linkages with regard to sensing pressure. So a sensor on the
pedal itself can discern that hard braking is occurring before
sensors based on pressure increases at later linkage portions.
Attempts to sense activation by the relative amount of pedal
depression, although simpler to implement, unfortunately require
that the system be very sensitive to minute movements near the end
of the pedal travel. This form of sensing further requires that the
system be adjusted for every set of brakes and that the system be
adjusted regularly because the operation of the brakes will vary
over time which will otherwise invalidate the sensor readings.
Sensing of the pedal pressure represents an accurate and direct
measure of the extent of braking and is therefore preferred. The
threshold level of these signals may be set for a particular model
of vehicle and need not be adjusted thereafter. Additional
embodiments of alternate pressure sensors are also described.
[0028] In addition to the pressure sensor, an acceleration sensor
is employed to enhance the early detection of hard-braking events
by sensing the quick transition movement of a pedal prior to
pressure buildup. It should be understood that many brake linkages
employ a pedal biasing mechanism, such as a spring, wherein pedal
pressure will be roughly equal to the biasing force until the pedal
has been depressed sufficiently to begin brake activation.
[0029] The HBC constantly measures and correlates all sensor data
to detect at the earliest instant if the driver is attempting to
slam on the brakes. If a hard braking event is detected, then the
HBC activates a hard-braking indicator to immediately warn traffic
approaching from behind that the vehicle is in the process of a
panic stop.
[0030] In visual uncongested traffic conditions, a hard braking
light can provide an easily recognizable clue to the braking action
of the vehicle directly ahead. As a driver we rarely get excited
when the brake lights come on in front of us--in fact at times it
barely registers, as many drivers vascillate on and off the brakes,
while others ride their brakes constantly. So when brake lights
come on we often intentionally delay or just move slowly by easing
off the accelerator. As drivers we can be easily taken by surprise
when the vehicle directly ahead actually is stopping suddenly. A
driver often will not recognize the need for brake application
until they notice that the vehicle ahead is decelerating rapidly,
or skidding; over a second of possible reaction time may have been
lost by this time. Yet a hard braking indicator that is activated
only when a vehicle slams on its brakes, is better able to jolt us
into heading to the brake pedal quickly without delay.
[0031] Indicators of many varieties may be used as a hard braking
indicator. Rows of LEDs, for instance, can be configured as an
indicator, or separate illuminated sections may be added. Additive
approaches such as these, however, require changing existing
vehicle designs and driver intuitions. Therefore, the preferred
embodiment of the invention employs the existing reverse (backup)
light of a vehicle, in a second role as a hard braking indicator.
This use is immediately intuitive to drivers, since in relation to
a constant speed, the act of stopping hard is a rearward
acceleration. People are conditioned to think of vehicles whose
reverse lights are on as being in reverse coming towards them. To
increase recognition of the light, the reverse light is modulated
(flickered) under hard braking. Use of the double duty reverse
signal is not expected to cause any driver confusion--turn signals
are already used for the double duty purpose of signaling
emergencies, and the general populace understands immediately what
is being signaled when both turn signal lights are flashing.
[0032] In addition, a forward brake light indicator detection
(FBLID) system is described that may be utilized in combination
with the aforementioned hard-braking controller, or as a separate
unit to provide a reaction advantage. In typical congested traffic
situations, a driver is often totally reliant on their following
distance, and luck, for safety as they can not see the road
conditions beyond vehicle ahead. A driver often is relegated to
waiting until the driver just ahead hits their brakes before they
themselves may react to the event. It will be readily understood
that gaining the ability to see even one more car ahead would at
least double the time available for reacting to the event. If the
vehicle ahead were invisible, there would be little difficulty in
stopping within the limited space. The FBLID system is a simple
device that provide the advantage of letting a driver "see" up past
the car ahead. In a general sense the FBLID relays the brake light
indicator status of those vehicles ahead "through" a vehicle to the
vehicle which is following that vehicle. The driver whose vehicle
is equipped with an FBLID system is less likely to be rear ended
because the FBLID system will alert the driver behind you at the
same time you yourself see the brake lights ahead. In particular,
the FBLID comprises a forward mounted brake light indicator
detection circuit that senses sudden changes in the intensity of
red light which correspond to brake application. One or more narrow
forward paths of light is sensed by the system. Since intensity is
a function of the square of the distance it will be readily
appreciated that the system automatically has greater sensitivity
to the vehicle directly ahead than to vehicles in other lanes, or
light reflections. The detector circuit for the FBLID is configured
to sense changes in red light intensity that occur within its field
of view and not from red lights that move in or out of its field of
view. Upon detecting that brake lights in the vehicle ahead have
activated, the FBLID generates a signal that is used to activate a
rearward indicator, such as the reverse lights, and as a result the
braking indication has been passed rearwardly "through" a vehicle.
The FBLID may be utilized with any of the phases of the hard
braking controller described herein, or in conjunction with other
safety system, or as a separate safety system. When utilized with
the Phase I hard-braking controller, the FBLID senses that brake
lights up ahead have been activated, the unit generates a signal to
the HBC which in turn activates the hard-braking indicator, such as
the reverse lights of the vehicle. Therefore, as the brake lights
for a leading first vehicle activate, a second vehicle directly
behind the first vehicle will see the brakes lights immediately. It
will take an alert driver of the second vehicle about one second to
see the lights and activate their own braking system. The driver of
vehicle three would traditionally lose that one second of reaction
time if they can not see the brake lights of the first vehicle and
must wait for the response from the second vehicle. The FBLID
system of vehicle two, however, senses the brake light activation
of vehicle one, and immediately activates either the rear brake
lights, backup light, or a hard braking indicator. Vehicle three as
a result receives a braking indication, generated by the FBLID,
within a few milliseconds after the brake lights of vehicle one
activates--the added reaction advantage could be from one-half
second on up depending on the level of alertness of the driver
ahead. The advantages that can accrue as a result of reduced
injuries, and vehicular damage should be easily appreciated as the
result is somewhat equivalent to doubling the following distance
between each vehicle on the congested roadway. The FBLID may be
utilized as a separate system unit, sans HBC controller, wherein
the FBLID unit controls the state of the brake light,
reverse-light, or a hard-braking indicator. The FBLID is simple to
implement and yet it provides a one-vehicle reaction advantage that
is especially applicable to congested traffic situations.
[0033] In another inventive aspect described near the end of the
specification, an forward looking audio correlation (FLAC) system
is utilized within a vehicle in conjunction with the RAAC system,
another safety system, or as an individual system. The FLAC system
receives and analyzes audio from vehicles up ahead to detect if any
event conditions exist, such as braking, hard braking, or
accidents. Upon detecting one or more event conditions, the driver
is alerted by audio or visual indication, so that they may react
early. The FLAC system is preferably implemented with an audio
detector mounted near the front of the vehicle, preferable near the
bottom, and is configured to maximize the reception of sounds
associated with brake application, especially hard brake
application. The sounds are analyzed within a signal processing
circuit which is capable of discriminating numerous audio events,
and alerting the driver, for instance by providing audio output of
the sound over a separate speaker or the vehicles audio system.
[0034] Therefore, HBC Phase I along with the FBLID system and FLAC
system are simple to implement systems which provides a visual
alert signal to drivers that the vehicle immediately ahead is
decelerating quickly.
HBC Phase II Non-visual Event Signaling and Alerts
[0035] Phase II level of RAAC system implementation adds a signal
link between vehicles, wherein events, such as vehicle crashes,
vehicle brakes being slammed on, and vehicles quickly swerving, are
communicated to approaching vehicles. Drivers are alerted even if
the vehicle that is slamming on its brakes, swerving, or involved
in an accident can not be seen. The hard braking sensor and HBC, as
described above, are used along with a rearward projecting
transmitter and a forward collecting receiver which together
implement a coded messaging scheme for communicating events. It
will be appreciated that numerous wide band communication
techniques currently exist for short range communication, for
instance, according to the Blue Tooth communication standard.
Furthermore, short range RF communication can be implemented at
very moderate cost with modular transmitters and receivers
currently being available for under five dollars, with further
reductions possible. To further enhance event detection, an input
from a swerve sensor is preferably utilized to detect when a
vehicle makes an abrupt swerve. Additionally, the HBC is capable of
receiving input from: electronic speedometer, turn sensor,
emergency flashers, headlight switch, a driver selectable
sensitivity selector, and an electronic compass. These additional
inputs further qualify events to minimize unnecessary alerts from
the HBC. Also the preferred implementation of the HBC, incorporates
a crash sensor which allows approaching drivers to be warned when a
vehicle has been involved in an accident (impact). In order that
the signal associated with a particular event, such as a crash, be
rearwardly communicated a long enough distance, receiving vehicles
in certain circumstances perform a limited regeneration of the
original event signal. The signal is therefore repeated a
controlled number of times. Therefore, upon severe events such as
hard braking, brake slamming, and crashes; vehicles approaching the
event are notified immediately upon occurrence of the event such
that they may brake early.
[0036] Vehicles receive the event signal transmissions which are
converted to audible and/or visual alert indications so that the
driver may immediately engage the brakes. The communication of an
event signal alerts approaching vehicles even when they are unable
to see the vehicle that has crashed or slammed on its brakes.
Therefore, the driver receives early warning alerts, regardless of
the prevalent weather or traffic condition. It is anticipated that
numerous highway accidents can then be avoided because drivers in
approaching vehicles get extra time to react, . . . "a reaction
advantage", so that they may properly respond to the event.
[0037] Additionally, a high power transmitter generating HBC
protocol based signals can be used by emergency vehicles to alert
drivers ahead to pull over, even when those drivers cannot yet hear
or see the emergency vehicle. Also the transmit/receive protocol,
when implemented within roadside call boxes, is capable of
providing immediate accident information to dispatchers when
accidents occur on the roadway and can disseminate downloaded
roadway information about traffic conditions that exist up
ahead.
[0038] The road side call boxes may be further augmented with
circuitry, and a simple traffic detection system is described,
referred to as a roadway audio status system, which does not
necessarily rely on vehicles being equipped with Phase II or higher
HBC units. Call box circuitry is described which is capable of
quickly assessing various traffic pattern parameters, such as the
number of vehicles per unit of time, the speed (average, maximum,
median, and so forth), in addition to sensing accidents occurring
near that area of the roadway. The circuitry may be implemented
within the roadside call boxes or within alternative device
periodically disbursed along the side of a roadway.
[0039] In summary, roadside systems may be adapted to generate
additional safety information, while the aforementioned HBC Phase
II system provides a large "reaction advantage" to drivers in low
visibility situations caused by weather, such as fog, and when
obstructions such as other vehicles in heavy traffic, or actual
physical obstructions impair forward visibility. Therefore, HBC
Phase II provides a major benefit with "blind" operation wherein
approaching drivers are alerted to upcoming dangers in any traffic
or weather condition.
HBC Phase III Full Position Data and Communication
[0040] The HBC at this Phase III level of the RAAC system are
augmented by additional information sources and functions which
increase utility. Data from an electronic global positioning system
can provide position data on incidents. Upon experiencing an event,
the GPS data is transmitted along with the other event information.
The GPS data is additionally used by a vehicle mounted phone system
implementing an enhanced 911 (E911) service, wherein an automatic
emergency call is generated when the crash sensor is activated,
wherein the 911 call preferably provides location and severity
information and can allow direct and immediate communication
between the vehicle occupant (if still conscious) and the emergency
911 dispatcher within a Public Safety Answering Point (PSAP). (FCC
has mandated an Oct. 1, 2001 deadline for handset based E911
deployment.) If vehicles generally adopt the GPS of phase III, then
the signal transmission power used by the system may be increased
to provide transmission over larger distances, as the GPS location
information provides very selective discrimination of which events
received within an event signal are relevant. The HBC provides for
utilizing GPS position data to calculate the relative position of a
communicated event which may be utilized within vehicle systems
receiving the event signal to determine if the associated event is
of relevance for the subject vehicle. In addition, the system can
be configured to provide the driver with a substantial amount of
control over what event information is displayed and how the
display is to be organized. With the low cost of GPS units, already
in some instances below thirty dollars, many industry leaders
anticipate that the majority of newly manufactured vehicles will
soon contain a GPS unit for navigation purposes in the near
future.
[0041] Additionally, Phase III of the RAAC system provides a method
for communicating additional forms of information between vehicles
and even between the highway itself and the vehicles traveling upon
it. With GPS positioning information available, a virtual highway
network is created wherein information about accident events,
congestion details, roadwork, and emergency vehicles can all be
communicated automatically.
[0042] HBC Phase IlIl therefore extends functionality and driver
convenience while providing additional communications.
HBC Phase IV Partial Response Automation
[0043] The HBC at this level is augmented with inputs for a
"tailgate" distance selector, a distance sensor, and an output for
an assisted braking solenoid. Upon receipt of a significant event
signal, the Phase IV HBC has sufficient information to determine
with reasonably high accuracy the probability of the driver being
able to stop in time to prevent an accident. The HBC provides a
driver selectable level of early braking assistance based on this
information and may thereby engage the brakes automatically if
imminent danger exists. Once the driver reasonably engages the
pedal, the system disengages the assisted braking solenoid.
Assisted braking can get the brakes engaged in those critical early
milliseconds after an event from up ahead has been detected; yet
does not wrest control of the braking or driving process from the
driver. Should the HBC Phase IV system be in error and engage the
brakes in a situation when unwarranted, the driver will only
experience a slight temporary slowing of the vehicle, and will not
be harmed or unduly inconvenienced.
[0044] HBC Phase IV therefore is a first step in automating driver
response based on event conditions occurring ahead.
HBC Phase V Full Response Automation
[0045] The implementation of a phase V fully automated response
system is not described in detail within this application. In a
phase V system, however, the HBC determines the parameters of
driving while automatically controlling variables such as vehicle
speed, and braking, as well as possibly the steering of the vehicle
to its destination. A Phase V system is a logical extension of the
described HBC from Phase IV, and will benefit from the information
and statistics collected from widespread adoption of Phases I
through IV.
[0046] Phase I Visual early warning benefits can be immediately
realized as drivers are provided with a reaction advantage.
[0047] FBLID--Forward brake light detection
[0048] FLAC--Forward looking audio correlation
[0049] Phase II "Blind" event sensing benefits can begin to be
realized as a standard is established and widespread deployment
begins.
[0050] Phase III Position related enhancement benefits can be
realized, wherein both the specificity of event conditions and the
utility thereof are improved.
[0051] Phase IV Reaction automation benefits begin to be
realized.
[0052] An object of the invention is to reduce fatalities and
injuries by providing added "reaction time" to events such as
brakes slamming on, abrupt swerving, or a collision.
[0053] Another object of the invention is to provide a system and
method for reducing rear-end collisions that may be implemented
inexpensively without the need of redesigning vehicles and without
requiring additional exterior vehicle modifications.
[0054] Another object of the invention is to provide a system which
requires negligible maintenance or periodic calibration.
[0055] Another object of the invention is to provide a system whose
implementation is directed toward current new vehicle designs
wherein largely digital communication paths (Digital, SPI serial,
CAN) are replacing analog signals.
[0056] Another object of the invention is to provide a system and
method of reducing rear-end collisions wherein standardization is
easily and inexpensively achieved and a variety of implementation
levels/stages available to allow for a gradual implementation phase
in if necessary.
[0057] Another object of the invention is to provide a system whose
implementation does not incur a liability burden to vehicle
manufacturers, wherein vehicle operation on system errors defaults
to conventional operation, i.e. a systems breakdown becomes
similarly equivalent to having one tail-light burned-out.
[0058] Another object of the invention is to provide a system and
method for reducing rear-end collisions that requires no highway
infrastructure changes.
[0059] Another object of the invention is to provide a system and
method for reducing rear-end collisions that does not require
drivers to adopt a new set of driving habits, or to learn new
technology.
[0060] Another object of the invention is to provide a system and
method for reducing rear-end collisions upon which enhanced safety
features may be built.
[0061] Another object of the invention is to provide an easily
recognized indication to alert drivers approaching from behind that
the driver of a first vehicle is braking heavily.
[0062] Another object of the invention is to provide a system which
rapidly communicates to approaching drivers when the brakes have
been applied by a vehicle directly ahead.
[0063] Another object of the invention is to provide driver alerts
in response to events that occur farther up the road beyond what
can be seen immediately ahead.
[0064] Another object of the invention is to qualify the
communication of event signals which provide driver alerts based on
driving conditions; so that signals are only generated when
conditions warrant.
[0065] Another object of the invention is to provide for event
signal regeneration by vehicles in which an event is not occurring,
so that the communication of event signals can be provided to all
vehicles within a reasonable proximity despite vehicle
communication path obstructions.
[0066] Another object of the invention is to provide this reaction
time advantage despite conditions of reduced visibility (fog, rain,
snow or traffic).
[0067] Another object of the invention is to provide the reaction
advantage by means of visual and audio alerts to drivers
approaching a possibly dangerous event.
[0068] Another object of the invention is to provide a system
wherein the same elements may be incorporated into any vehicle
regardless of the type of braking system and other equipment
employed.
[0069] Another object of the invention is to provide a system which
can be easily retrofitted to existing vehicles.
[0070] Another object of the invention is to provide a brake pedal
sensing system that does not require adjustment to a particular set
of brakes, or during the life of those brakes.
[0071] Another object of the invention is to encode information
into generated event signals that may be used by HBC units within
vehicles under driver control to allow the discrimination of event
signal allowed to produces driver alerts.
[0072] Another object of the invention is to automatically limit
driver alerts based on the information encoded within an event
signal as determined by location and/or direction so that drivers
are not alerted in cases wherein the event occurs on the other side
of the freeway or is otherwise not pertinent to the driver.
[0073] Another object of the invention is to provide event signal
regeneration wherein vehicles not directly receiving the initial
event signal still receive an alert from a vehicle that received
the event and retransmitted it.
[0074] Another object of the invention is to limit the regeneration
of event signal transmissions to a reasonable distance and group of
vehicles that actually need to respond to the event.
[0075] Another object of the invention is to allow airbag
deployment to be used to trigger a "crash" event.
[0076] Another object of the invention is to provide a system that
allows approaching emergency vehicles to alert drivers from beyond
the range of hearing or sight in crowded traffic to pull aside.
[0077] Another object of the invention is to provide call box
support wherein call boxes are configured to directly receive
vehicle "crash" event signals so that emergency crews can be
quickly dispatched to an accident location for which they will
already know the number of vehicles and extent of the accident.
[0078] Another object of the invention is to provide call box
circuitry which is capable of monitoring roadway condition as
discerned by way of received audio.
[0079] Another object of the invention is to supports multiple
levels of event signals that include: Crash, Slamming brakes, Hard
braking, Emergency vehicle approaching,
Emergency Blinkers
[0080] Another object of the invention is to supports a "road
condition" level of event signal receipt wherein hazardous road
conditions and special alerts may be communicated as a series of
event signal data packets which can be annunciated and/or displayed
to the driver.
[0081] Another object of the invention is to support automatic
extended 911 service, wherein upon a crash of sufficient intensity
vehicle systems and relevant conditions verify that a crash has
occurred wherein a 911 call is automatically generated wherein the
car sends data to the 911 dispatcher and the dispatcher can talk
and listen to the passengers within the vehicle.
[0082] Another object of the invention is to provide levels of
system error sensing--If HBC unit malfunctions monitor notifies
driver, and tries to reasonably correct situation, or disables the
HBC.
[0083] Another object of the invention is to provide autoassist
braking for "early reaction" brake activation in dangerous event
situations.
[0084] Another object of the invention is to generate an audio
alert that can be heard and therefore reacted to when a car sound
system is turned up to a high volume, yet not unduly disturb
drivers in a low noise environment.
[0085] Another object of the invention is to provide a platform for
the addition of extendable safety and convenience features.
[0086] Further objects and advantages of the invention will be
brought out in the following portions of the specification, wherein
the detailed description is for the purpose of fully disclosing
preferred embodiments of the invention without placing limitations
thereon.
BRIEF DESCRIPTION OF THE DRAWINGS
[0087] The invention will be more fully understood by reference to
the following drawings which are for illustrative purposes
only:
[0088] FIG. 1 is a side view of the pressure sensor module
according to an embodiment of the present invention and shown
attached to a brake pedal to which pressure from a drivers foot is
being applied.
[0089] FIG. 2 is a rear-view of a representative vehicle showing
the location of the tail-light clusters.
[0090] FIG. 3 is a simplified wiring diagram of a simple HBC (phase
II) module and pressure sensing module according to an embodiment
of the present invention shown being electrically connected within
a vehicle.
[0091] FIG. 4 is a schematic of a pedal sensor module according to
an aspect of the present invention.
[0092] FIG. 5 is a schematic which exemplifies the internal
circuits within an HBC according to an embodiment of the present
invention, showing the various inputs and outputs for implementing
a Phase IV rear-end collision reduction system.
[0093] FIG. 6 is a diagram of the regeneration levels used for
regeneration of event signals within phase II, III, and IV
according to an aspect of the present invention.
[0094] FIG. 7 is a representative bit string header for an event
signal packet according to an aspect of the present invention.
[0095] FIG. 8 is a simplified flowchart for the main loop of the
HBC firmware according to an embodiment of the present
invention.
[0096] FIG. 9 is a simplified schematic for the ISR_Tick routine as
used within the firmware of the HBC according to an embodiment of
the present invention.
[0097] FIG. 10 is a simplified schematic of representative main
loop firmware for the processor within the event signal receiver
according to an embodiment of the present invention.
[0098] FIG. 11 is a simplified schematic of representative "tick"
interrupt firmware for the processor within the event signal
receiver according to an embodiment of the present invention.
[0099] FIG. 12 is an alternate pressure sensing device for sensing
pedal pressure being applied by the driver according to an aspect
of the present invention.
[0100] FIG. 13 is a diagram representing one method of sensing
steering actions according to an embodiment of the present
invention showing a sensor for registering what may be classified
at highway speeds as a "swerve".
[0101] FIG. 14 is a side view of a rotational sensor with
engagement wheel as shown in FIG. 13 for sensing steering wheel
movements.
[0102] FIG. 15 is a front view of the rotational sensor of FIG.
14.
[0103] FIG. 16 is a schematic of the rotational potentiometer as
shown in FIG. 14 providing a swerve signal to the HBC.
[0104] FIG. 17 is a block diagram of an enhanced monitor circuit
according to an aspect of the present invention showing inputs and
outputs.
[0105] FIG. 18 is a schematic of a circuit for sensing emergency
flasher activation within a vehicle according to an aspect of the
present invention.
[0106] FIG. 19 is a schematic of a circuit for sensing and
communicating speed data to the HBC according to an aspect of the
present invention.
[0107] FIG. 20 is a schematic for a sound system muting circuit
according to an aspect of the present invention.
[0108] FIG. 21 is an alternate embodiment of pressure sensing,
wherein master cylinder fluid pressure is registered according to
an aspect of the present invention.
[0109] FIG. 22 is a block diagram of an alternate visual display
system according to an aspect of the present invention.
[0110] FIG. 23 is a schematic of a representative compass module
according to an aspect of the present invention shown with
interface to the HBC.
[0111] FIG. 24 is a schematic of a representative GPS unit
configured for connection with the HBC system according to an
aspect of the present invention.
[0112] FIG. 25 is a schematic of a representative sonar ranging
module according to an aspect of the present invention which is
shown configured for connection with the HBC.
[0113] FIG. 26 is a diagram of a representative assisted braking
mechanism according to an aspect of the present invention which is
shown with a drive schematic for connection with the HBC.
[0114] FIG. 27 is a schematic of a representative event signal
transmitter shown with connections for interfacing with the
HBC.
[0115] FIG. 28 is a schematic of a representative event signal
receiver according to an aspect of the present invention shown with
connections for interfacing with the HBC.
[0116] FIG. 29 is a schematic of a forward brake light detection
(FBLID) system according to an aspect of the present invention,
shown with alternative connections to an HBC (Phase I-Phase IV) and
for individual use.
[0117] FIG. 30 is a block diagram of a transceiver using HBC
protocols according to an aspect of the present invention shown
embedded within a road side call box unit.
[0118] FIG. 31 is a block diagram of a roadside audio status system
according to an aspect of the present invention shown detecting
vehicle speeds and conditions on a span of roadway.
[0119] FIG. 32 is a schematic of the roadside audio status system
of FIG. 31, shown sensing traffic conditions based on the tracking
of vehicle audio signatures.
[0120] FIG. 33 is an internal driver alert signal according to one
embodiment of the present invention, shown mounted to the dash.
[0121] FIG. 34 is a close-up front view of the internal driver
alert signal of FIG. 33.
[0122] FIG. 35 is a schematic of a brake light modulation circuit
according to an aspect of the present invention.
[0123] FIG. 36 is a schematic of a light signal controller (LSC)
according to an aspect of the present invention.
[0124] FIG. 37 is a top view of a lighting cluster according to an
aspect of the present invention shown for providing external
vehicle signaling.
[0125] FIG. 38 is a cross-section of the lighting cluster shown in
FIG. 37.
[0126] FIG. 39 is a side view of a forward looking audio
correlation system according to an aspect of the present invention
which is shown mounted within a vehicle.
[0127] FIG. 40 is a block diagram of the circuit for the forward
looking audio correlation system illustrated in FIG. 39.
[0128] FIG. 41 is a schematic of an accelerator pedal sensor
utilized for registering accelerator pedal depression according to
the present invention.
[0129] FIG. 42 is a block schematic of an accelerator pedal
conditioner and event indicator according to the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0130] Referring more specifically to the drawings, for
illustrative purposes, the present invention is embodied in the
apparatus generally shown in FIG. 1 through FIG. 42. It will be
appreciated that the apparatus may vary as to configuration and as
to details of the parts without departing from the basic concepts
as disclosed herein.
[0131] 1. Implementation Considerations
[0132] In order for the rear-end collision reduction system to save
lives and reduce injuries on our highways, it is necessary for it
to be implemented on a large scale involving an increasingly large
percentage of the vehicles on the roadway. To implement a traffic
safety system on a large scale requires implementation standards.
The embodiment described is directed at implementing the system to
fit within a set of roughly four standards designed to simplify
widespread implementation. The embodiment of the HBC described can
be operated in any of the previously described phases, Phase I
through Phase IV, and variations thereof.
[0133] 2. Top Level System Description
[0134] A pedal configured with a sensor for the rear-end collision
reduction system 10 of the current invention is shown in FIG. 1. A
brake actuation arm 12 contains a brake pedal lever 14 that rotates
about a brake lever pivot 16, and a brake pedal 18 with a brake
pedal cover 20. The pedal actuates the brakes of the vehicle by
means of the brake linkage 22 which connects the pedal to a brake
linkage rod 24 that connects with the brake actuation mechanism,
typically hydraulic, of the vehicle. The brake lights of the
vehicle are activated by means of the brake sense switch 26 which
has a plunger 28 that when retracted by movement of the switch
actuation protrusion 30, switches to an ON state whereby current
powers the brake lights. Conventionally, the driver presses the
brake pedal with a foot 32 which moves the brake pedal rearward,
pushing the linkage rod 24 which begins activating the brakes. The
brake sense switch 26 senses the brake pedal movement as the
plunger moves, so that the brake lights (not shown) are
activated.
[0135] An embodiment of the invention is shown in which a hard
braking sensor 34 is attached to the brake pedal 18. Preferably the
sensor 34 is attached to the front of the bare brake pedal and
covered by a brake pedal cover 20, although it may be otherwise
integrated or attached to the pedal. The hard braking sensor 34
contains a pressure transducer which senses applied pressure,
preferably over a large surface area so that pressure applied
anywhere on the pedal will be registered. The pressure transducer
exemplified within this embodiment is a load cell whose output is
generated across an internal Wien bridge. An acceleration sensor is
may be optionally incorporated within the hard braking sensor (HBS)
34. The exemplified hard braking sensor 34 may be mounted to the
brake pedal 18 by any of various means, such as by fasteners,
adhesives, or physical configuration. The wiring 36 from the HBS
can travel through a hole in the pedal face or alternately be
threaded around the pedal. The HBS may alternatively be configured
as a transponder wherein no wiring is required, however, the
present current requirements of the HBS may complicate the
implementation. The pedal cover 20 provides a resilient cushion for
the brake pedal 18 and distributes localized forces onto the
underlying sensor.
[0136] FIG. 2 depicts a small automobile 40 shown with a group of
indicator lights 42 containing a turn signal light 44, a brake
light 46, and a reverse light 48. Additionally an auxiliary brake
light 50 is shown on the rear deck of the back window. The brake
light 46, 50 and the reverse light 48 are shown activated, which
indicates hard braking has been registered by the sensor which
controls light output from the reverse lamps.
[0137] 3. Vehicle Wired with HBC
[0138] A simplified wiring schematic 60 of an embodiment providing
a Phase II implementation of the rear-end collision reduction
system is shown in FIG. 3. Shown in the schematic is a simplified
representation of the system with major elements depicted wherein
numerous minor and qualifying inputs have been left off for the
sake of clarity. This description will first detail the function of
the parts shown in the wiring diagram and then will describe the
functioning of the system in relation to FIG. 3.
[0139] 3.1. System Elements
[0140] The simplified wiring schematic 60 of FIG. 3 shows that the
system is powered by the conventional vehicle electrical system 62,
which is nominally powered by +12 to 14 Volts. The majority of the
items depicted in this figure are conventional vehicle components,
such as: reverse lights 64, brake lights 66, brake actuation arm
68, brake pedal lever 70, brake pedal 72, brake pedal cover 74,
brake lever pivot 76, brake linkage 78, brake linkage rod 80, brake
sense switch 82 with plunger 84, brake light power lead 86, reverse
sense switch 88, and reverse light power lead 90.
[0141] Additionally depicted are components of the rear-end
collision reduction system. For clarity, the hard braking sensor
module 92 is shown separated from the pedal 72 with the pedal cover
74 pulled away. (The sensor module is shown for simplicity without
power and ground connections and with a single wire connection
whereas a serial bus connection is preferred within this
embodiment.) Alternatively, the sensor module may be wireless and
communicate with the hard braking controller by radio or even audio
signals. When installed, the hard braking sensor (HBS) 92 is
preferably firmly attached to the pedal and covered with the pedal
cover 74. Wiring 94 from the HBS module 92 is routed through a
notch in the pedal 72 and routed up along the pedal where it is
fixedly retained by fasteners (not shown). The wiring exits the
pedal and connects with a "Hard Braking Controller" (HBC) 96, which
controls the actions of the rear-end collision reduction system by
receiving and interpreting all inputs and generating outputs in
response to the input. It should be appreciated that although the
described functions and circuitry are in reference to the hard
braking controller, they may be equivalently implemented within or
among other vehicle systems, which include airbag deployment
systems, or vehicle control systems, without departing from the
object of the present invention. The aforementioned functions of
the rear end collision avoidance system have been described in
accord with a Phase I implementation of the system.
[0142] Additional Phase II elements within the system comprise a
remote communication mechanism. The HBC is shown connected via a
serial line 98 to an event signal transmitter module 100, which is
preferably implemented as an RF transmitter. The event signal
transmitter (EST) 100 receives data signals from the HBC 96 which
are modulated and transmitted as radio signals rearwardly to other
vehicles. An event signal receiver (ESR) module 102, which is
preferably implemented as an RF receiver, is also shown for
receiving signals from HBC modules in vehicles traveling up ahead.
A coded signal is received by a signal collector, in this case a
forwardly oriented antenna which is demodulated by ESR 102 with a
coded serial signal being sent via a serial connection 104 to HBC
96. In addition, the HBC module of this embodiment preferably
contains a crash sensor within its circuitry that generates an
extended duration alerting signal upon encountering a high
threshold acceleration event, as would occur only as a result of
vehicular impact. The HBC will be subsequently described in added
detail.
[0143] Annunciators are provided to signal the driver whose vehicle
receives one or more transmissions that indicate a vehicle is
braking hard, or is experiencing another important event. An audio
annunciator 106 emits tones or voice output generated by HBC 96. A
visual annunciator (indicator) 108 consists of a series of lights
(exemplified as LEDs, although any form of display may be utilized)
for displaying the severity or type of hard braking event. A
sensitivity selector 110 allows the driver to select the level of
audio sensitivity to events. Additionally, HBC 96 can generate
indications or annunciations on a variety of output devices such as
display screens, or dashboard instrumentation.
[0144] 3.2. System Functioning
[0145] Briefly returning to FIG. 1, as the driver's foot presses
the brake pedal 18, HBS 34 registers a new pressure value on the
load cell. Returning to FIG. 3, HBS 34 generates a signal to the
HBC 96. The HBC monitors all incoming signals and performs various
tests of the information received to determine what action is to be
taken. If the brake pressure is low and the variation from that low
pressure level is small, then the HBC will keep recording but not
generate any external outputs. If a marked transition occurs, for
instance from NO braking to a distinct level of hard braking, then
the HBC generates an alert indication, such as activating external
lights, or other signals. Within the exemplified embodiment, the
HBC 96 activates the reverse lights 64 by providing power on the
reverse light power wire 90, and HBC 96 continues monitoring. If
the transition immediately subsides (within about 10 mS) then the
reverse light 64 is turned off. It is generally preferred that
non-latched event indications, such as lights, be activated while
an event is being verified, so as to reduce delay. It will be
appreciated that the time required for event verification is
generally of short duration, on the order of ten milliseconds, and
if the event fails verification, the activation should not even be
noticeable. For example, a hard braking event may be defined within
the HBC 96 as a quick rise in brake pedal force which exceeds a
minimum change value or a sustained pressure which exceeds a
minimum pressure value level. When hard braking is detected by HBC
96, the reverse lights 64 are activated and if the pedal pressure
is retained, then the reverse lights 64 can be flickered by means
of the HBC software alternately applying and removing power from
the reverse lights. The flickering of the reverse lights is
expected to increase the attendant response from drivers in
relation to steady-state lighting.
[0146] When the HBC 96 detects and verifies a given threshold level
of hard braking, it additionally activates the EST 100, which is
sent a coded transmission to be broadcast rearwardly of the
vehicle. The coded transmission contains a code indicating the
severity of the hard braking event along with additional
information which may include but is not limited to HBC unit coding
data (i.e. a VIN number encoded within circuit of HBC). The
transmissions from the event signal transmitter are sent according
to a particular timing pattern, described subsequently, so that
event signal receivers barraged by more than one simultaneous
signal can discern the number and severity of levels represented by
the signals generated. The ESR 102 preferably contains a
radio-frequency receiver section whose encoding protocol and
receiving frequency are compatible for the receipt of information
from the transmitter module.
[0147] 4. Hard Braking Controller Sensors and Signals
[0148] This section exemplifies a specific implementation of HBC
and sensor circuits in greater detail. The HBC and sensors
described are generally according to a Phase IV implementation of
the system and include exemplifications of transmission protocols
along with additional signals and controls.
[0149] 4.1. Overview
[0150] FIG. 4 and FIG. 5 are schematics of the HBS and the HBC
respectively. The HBC contained in this schematic exemplifies an
implementation of an HBC that provides Phase IV HBC functionality.
The HBC interprets inputs and generates visual signals, event
signals, and audio alert signals. For the sake of clarity, a number
of signals are shown in FIG. 5 without pull-up resistors and in
some cases line termination resistors. The following sections
describe portions of the HBC within the rear-end collision
reduction system.
[0151] It will be apparent to those of ordinary skill in the
electronic arts, that each of the sense functions, signal
functions, and output functions depicted may be variously
implemented without departing from the principles taught by the
invention.
[0152] 4.2. Pedal Sensor Module
[0153] FIG. 4 is a hard braking sensor (HBS) module 120 according
to a Phase IV implementation according to the present collision
reduction system. The HBS 120 is powered by the vehicle battery
system of nominal 12 to 14 volts into a voltage regulator 122 which
provides power for the sensor module circuitry.
[0154] A pedal activation sensor, such as pressure transducer 124
preferably provides a differential signal output with a Wien
bridge. The pedal pressure sensor utilized within this embodiment
is a load cell with conditioning resistors, an example of which
would be a model ELW-D load cell with a full scale reading of 200
pounds that generates a full-scale voltage output of 250 mV and is
manufactured by Entran Incorporated.TM.. The load cell pedal
pressure sensor 124 is connected to a bridge interface circuit 126.
The bridge interface circuit depicted is a MAX 1458.TM. sensor
interface IC manufactured by Maxim Semiconductor.TM.. The sensor
interface provides internal EPROM based calibration of the load
cell. Control lines 132 allow the functions of the bridge sensor
interface to be controlled.
[0155] The bridge sensor interface 126 provides an analog output
128 which is read by control circuits, which are embodied as a
microcontroller 130. The exemplified microcontroller is a PIC
16C72.TM. manufactured by Microchip Technology Incorporated.TM.,
that includes a RAM, ROM, and an A/D converter.
[0156] An acceleration sensor 134 is shown providing encoded brake
pedal acceleration data to the microcontroller 130. The
acceleration sensor described herein is an ADXL150.TM. manufactured
by Analog Devices.TM. with a full scale G range of 50 G's. The
acceleration sensor provides a pulse-width output wherein the duty
cycle of the output square-wave represents the measured
acceleration. A nominal 50% duty cycle corresponds to 0 Gs.
[0157] The microcontroller 130 is connected to the HBC by an
SPI.TM. interface 138. The SPI interface is a serial interface
allowing simultaneous sending and receiving of serial data. (SPI is
a registered trademark of Motorola Corporation.TM..) The
microcontroller additionally has an IRQ output to the HBC so that
it may alert the HBC to changes that warrant data collection. The
microcontroller 130 also contains calibration lookup data for the
sensors so that corrected data is passed to the HBC, while sensor
modules may additionally be replaced without performing any
recalibration of the HBC module.
[0158] 4.3. HBC Module Overview
[0159] FIG. 5 is a schematic 140 which exemplifies a hard braking
controller (HBC) according to a Phase IV implementation according
to the collision avoidance system of the present invention, which
is capable of integration into a vehicle. It will be obvious to
those of ordinary skill in the art, that incorporation of the
functions herein described for the HBC according to the present
invention, into one or more alternative vehicle systems to perform
similar functions is still anticipated by the HBC description
herein. The embodied HBC 142 is connected via two lines 143 from
the vehicles power system which are fused for safety. The HBC
contains a power supply 144 which preferably provides power to the
circuits within HBC 140. A crash sensor 146 provides for the
sensing of accidents, a microcontroller 148 contains a firmware
program which controls all the HBC functions, and a monitor circuit
150 provides fail-safe operation of the HBC.
[0160] 4.4. HBC Control
[0161] The microcontroller 148 contains the programming which
determines the interpretation of the sensor signal data and the
mapping of that data to the various outputs in the system. Within
this embodiment, the exemplified microprocessor is a PIC
17C756A.TM. which is manufactured by Microchip Technology
Incorporated.TM.. The microprocessor 172 contains 16K of program
memory, 902 bytes of data memory, a 10 input A/D converter, 3 pulse
width modulator outputs, USART controls to support a variety of
serial interfaces. Various processors may be substituted for the
PIC 17C756, and other circuit elements used within this embodiment
while still adhering to the principles taught by the invention.
[0162] 4.5. HBC Signal Types
[0163] HBC 140 inputs and outputs a variety of signal types, with
serial data being often input and output as SPI data within this
embodiment. A common set of serial signals (data in, data out,
clock) are shared among the SPI slaves. When the chip select for an
SPI slave is activated the slave uses the clock edges to clock in
and out a serial bit stream which simultaneously sends out and
brings in a group of 8 data bits. Slaves that can not just be
polled by the master, are provided with an interrupt request line.
When the interrupt request is asserted, the processor ISR routine
retrieves data from the slave. Table 1A and Table 1B exemplify
signals described in this embodiment of a Phase IV HBC within FIG.
5 (which is substantially a superset of Phase I through Phase III
implementations) with the signals arranged by type and shown with
the phase number to which they are considered to be implemented
within the described embodiment.
[0164] 4.6. Driver Alert Signals
[0165] The purpose of the rear-end collision avoidance system and
the contained HBC is to reduce the chances of an accident occurring
as a result of a highway "event". Primarily the system attempts to
achieve this goal by alerting the driver to conditions surrounding
the occurrence of events that occur up ahead. The system is
sensitive to events that result in hard-braking, abrupt swerving,
crashing and additional emergency situations. When such an event
occurs, the driver is alerted by both external and internal alert
mechanisms.
[0166] 4.6.1. External Visual Indicator
[0167] An external visual indicator provides an alert to
approaching drivers. When a driver of a vehicle begins forcefully
applying the brakes, the HBC activates a rearwardly directed
hard-braking indicator. Again referring to FIG. 5, the indicator is
activated by the microcontroller 148, which activates a switching
element illustrated by pass-transistor 165, which provides power to
the hard-braking indicator line 166. The reverse light is preferred
within this embodiment as a hard-braking indicator, its use being
shared with the normal reverse light function. Under hard braking,
and other event conditions the reverse light power within this
embodiment is controlled by the microcontroller and further may
include modulation thereof by periodically turning on and off a
switching device, such as the exemplified pass transistor, to
induce approaching drivers into reacting more readily to the event
alert.
[0168] Upon an event occurrence in front of a subject vehicle being
recognized and signaled rearwardly, vehicles containing receptive
HBC units will generate alerts to their associated drivers. To
provide an additional indicator and to provide an alert to drivers
of older vehicles that do not contain the collision reduction
system, the HBC preferably activates the hard braking indicator
light upon receipt of a hard braking event regardless of whether
the driver of the vehicle has yet applied the brakes. Therefore,
the hard braking indicator light of a vehicle can activate before
the driver of the vehicle responds to the event, thus providing
additional reaction time for the driver.
[0169] A brake light modulation signal 204 is preferably also
provided by the HBC. FIG. 35 shows this signal connected via
circuitry to the brake lights of a vehicle 1650. Vehicle power 1652
(+12 volts) is switched through the conventional brake light switch
1654 which is routed through a pass transistor 1656 (a bipolar
transistor is shown, however a FET transistor and/or other
switching elements may be substituted). The transistor is biased by
resistors 1658 and 1660 and switched on and off by transistor 1662
which is held in the normally active state by the BrkLtMod signal
1666 being held high; therefore when power is gated by the brake
switch 1654 it is provided to brake lights 1668 and any auxiliary
braking indicators 1670. Negative going pulses of the BrkLtMod
signal 1666 cause the brake lights to turn off to allow for
flickering of the brake lights by the HBC when brakes have been
applied. As the pressure level of applied braking increases, the
HBC increases the pulse rate in response to provide a signal in
which the hard braking condition is more readily recognized. The
brake lights can thereby flicker even if the detected brake pedal
pressure level is below the threshold selected for activating the
hard braking indicator light. This brake light control line may be
used in conjunction, or as an alternate to the use of other hard
braking indicators. Additional embodiments of hard braking
indicators are described later.
[0170] 4.6.2. Internal Driver Indicator
[0171] Internal driver alert signals are used to alert the driver
to dangerous event conditions occurring up ahead, such as an
accident, a vehicle slamming on its brakes, a vehicle abruptly
swerving, or other emergency conditions. Signals representing these
dangerous event conditions are received from vehicles up ahead and
received by the vehicle which is then communicated to the driver of
the vehicle. These "alert signals", are in the form of audio tones
or speech from an audio annunciator and/or a combination of
dashboard visual display indicators. Referring again to FIG. 5,
upon registering event conditions, the HBC via a digital output
signal CanCr 180, cancels the setting of the Cruise control, if it
is currently set. This provides an additional warning to the driver
and slightly begins slowing the vehicle.
[0172] Shown also in FIG. 5 is a group of annunciators 184, which
includes visual indicators 186, exemplified as LED lights, and an
audio annunciator 188 with a volume control. The audio is driven by
a PWM output from the microcontroller 148.
[0173] The display represented by the three LEDs provides a simple
display means. The visual indicator, however, can be provided with
various levels of information as provided by the HBC. By selective
modulation of the three LEDs 186 shown in FIG. 5, a number of
conditions can be represented. As it may be desirable to represent
event conditions on a graphic display incorporated within the
vehicle instruments, or within the GPS display, an SPI chip select
signal Disp 190 provides for a serial interface to a display
controller.
[0174] The driver of the vehicle can control the generation of
alert signals through a set of user controls. A sensitivity
selector 192 allows the driver to select the level at which the
system generates audio driver alerts. The HBC will not generate
audio in response to events of lesser importance than the user
setting. The sensitivity selector shown employs a multi-position
detented potentiometer whose voltage output is read by the internal
A/D converter. Alternately a digital microprocessor I/O line can be
used wherein the wiper I/O is pulled to ground by the
microcontroller and then allowed to charge back to logic high via
the potentiometer, wherein the potentiometer setting is determined
by the time to reach a logic high level.
[0175] 4.7. Sound System Muting Circuit
[0176] In order to assure that the driver of the vehicle hears the
HBC alerts, a sound system muting device output is provided 182
(FIG. 5). The HBC provides an output, SSMute, to control muting of
the sound system 182. Muting the sound system during alert
intervals can make it easier for drivers to hear and respond
correctly to the alert. It is preferable that the mute circuit
decrease output power by at least 6 dB to assure recognition of the
alerts. It is anticipated that car stereo manufacturers will
eventually incorporate a mute signal input into the design of the
units, as is currently done with a headlight signal for controlling
sound system display lighting levels. However, since these units do
not now incorporate a mute circuit a separate mute circuit wired
into a sound system 1000 is depicted in FIG. 20. The sound system
1002 has two sets of outputs for left and right channels. The Mute
circuit 1004 is interposed between the sound system 1002 and the
left and right speakers 1006, 1008. The right channel 1010 signal
enters the mute circuit 1004. A solid state relay 1014 is presently
set to normal (non-mute) mode, such that the input signal passes
through to the speaker and current loops back around to the sound
system. However, when the SSMute signal 1005 is active, the
solid-state relay changes state. The speaker is now driven by
current through resistor R.sub.x 1016, while a parallel return path
is established through R.sub.2x. With R.sub.x value set to the
speaker impedance (normally 8 ohms), the power to the speaker is
dropped by 6 dB, while the amplifier of the sound system still sees
the same load impedance. This balanced mute circuit can work with
various amplifiers without risk of damage to the sound system or
the speakers. The left channel contains an identical circuit
responsive to the same received SSMute 1005 control signal.
[0177] 4.8. Event Signals Communicated Between Vehicles
[0178] In order that drivers be alerted to conditions up ahead a
mechanism is provided for communicating events between vehicles.
Vehicles experiencing an event are considered event signal
generators. Numerous events preferably are capable of recognition
within the HBC which by way of example include a vehicle which is
involved in an accident, slams on its brakes, or abruptly swerves.
Upon recognizing a sufficiently important event condition, the HBC
generates an event signal rearwardly. Additionally, a vehicle that
is not directly experiencing an event may regenerate an event
signal from a vehicle up ahead so that the event warning may be
propagated to vehicles farther back from the event.
[0179] When the HBC qualifies an event for generation, output 162
of FIG. 5 is used for sending an alert signal, as a serial data
stream, to an event signal transmitter (EST) module. An SPI serial
bus is used for serial communication in both directions initiated
by the microcontroller 148. FIG. 27 depicts an example circuit 1400
of an EST connected with the SPI bus of the HBC. A microcontroller
1402, in this embodiment a PIC 16C72.TM. manufactured by Microchip
technologies Inc.TM., is used for controlling the RF transmitter
1403. Various transmitters may be utilized without the need of a
microcontroller, however, the use of a microcontroller can assure
that the interface to the EST module is generic wherein RF modules
from various manufacturers may be incorporated without the need to
alter the protocol definitions for the EST module. SPI interface
lines: Data in, Data Out, Clk, and IRQ are supported by the
microcontroller 1402. The IRQ line from the EST allows it to
asynchronously signal the HBC when it needs service, such as when
it has completed sending the data packet. The RF transmitter 1403
exemplified in FIG. 27 is a Linx Technologies.TM. model
TXM-900-HP-II.TM. module, which provides FSK modulation with data
rates to 50 Kbps. The transmitter module receives a data input
signal 1412, and is controlled with a power down signal 1414, and
three frequency setting bits 1416. A clear to send signal 1418,
indicates when a new bit can be sent. RF from the EST module is
directed generally rearwardly by an antenna 1420.
[0180] An event signal receiver (ESR) Input 164 of FIG. 5 receives
alert signals in the form of a serial bit stream, from an event
signal receiver (ESR) module. FIG. 28 exemplifies an ESR circuit
1450 connected with the SPI bus of the HBC. A microcontroller 1452,
in this embodiment a PIC 16C72.TM. manufactured by Microchip
technologies Inc.TM., is used for controlling the RF receiver 1454.
Various transmitters could be used without the need of a
microcontroller, however, the use of a microcontroller can assure
that an ESR module is created with a generic protocol. SPI
interface lines Data in, Data Out, Clk, and IRQ are supported by
the microcontroller 1452. The IRQ line from the ESR allows it to
asynchronously signal the HBC when it needs service, such as when
it has received data. The RF receiver 1454 illustrated within this
embodiment is a Linx Technologies.TM. model RXM-900-HP-II.TM.
module, which is compatible with the transmitter module above.
Received data is output 1464 to the microcontroller 1452. A
received signal strength signal RSSI 1466 is an analog output which
can be used for determining when data is being received. The Rx
module is controlled with a power down signal 1468, and three
frequency setting bits 1470. RF is received by the ESR module by an
antenna 1472 which is forwardly directed from the vehicle. It will
be appreciated that the transmitter and receiver may be implemented
with any form of remote communication mechanism capable of
integrating with the RAAC system.
[0181] 4.9. Forward Brake Light Detection System
[0182] Referring to FIG. 29, a forward brake light detection
(FBLID) system 1475 is exemplified. The system may be utilized in
accord with any of the described phases of implementation (I
through IV) or utilized in with other safety systems or in a
standalone configuration. The FBLID is capable of detecting the
activation of brake lights in front of the vehicle, within which
the FBLID is installed, and immediately rearwardly conveying that
information to drivers following that vehicle. The drivers
following a vehicle, equipped with FBLID technology, is immediately
alerted to brake application by the vehicle, or vehicles, ahead of
the vehicle equipped with FBLID, such that a reaction advantage is
gained that may be equivalent to doubling the following distance.
The vehicle thus equipped with FBLID is, as a result, far less
likely to be involved in a rear end collision than conventional
vehicles. Drivers behind the vehicle containing the FBLID system
may be alerted to the brake light conditions ahead by any of a
number of indication mechanisms. First, a rearward facing indicator
light may be activated on the vehicle with the FBLID system, by way
of example the indicator light may include activating the brake
lights, reverse lights, or a separate visual indicator. Secondly,
the FBLID system can additionally provide an alerting signal by way
of the HBC which is capable of generating a low priority alert
signal that can be received within vehicles that are farther
behind.
[0183] The FBLID system 1475 detects the activation of a brake
light 1476 by receiving light 1478 therefrom. A light collimator
1480 provides for limiting the light input to a selected forward
area directed forward of the subject vehicle. The light collimator
1480 preferably includes a lens 1482 configured with a red color
filter and a gradiation filter. The light collimator 1480 is
coupled to a light detector 1484 capable of registering the
intensity of light incident thereupon. The red filter provides for
filtering out all non-red illumination components, so that only
changes in red light intensity are registered. The gradiation
filter is configured with concentric filtering whereby the
amplitude of illumination is increasingly attenuated moving from
the center of the lens to the exterior of the lens. Vehicles are
moving tranversely in relation to one another, and therefore
incident red vehicle lighting is subject to rapid changes near the
perimeter of the focal area as red light sources enter and exit the
focal area. The use of perimeter filtering reduces the effect of
these motion-effects, so as to more easily distinguish activations
of brake lights instead of the movement of tail lights. It will be
appreciated that a number of light receptors may be utilized to
further aid in discriminating the movement of brake or tail lights
from the activation of a brake light. Furthermore, the use of light
sensor arrays, or camera elements can provide increased
discrimination ability, albeit at an increased cost. The light
detector 1484 is capable of registering light intensity and may be
additionally provided with a filter, or implemented as a filtrode
device (a photodiode containing an integral wavelength-sensitive
filter directly on its input surface). The light detector 1484 is
coupled to a preamplifier 1486 which conditions the signal for a
controller 1488, herein exemplified as a microcontroller having an
internal A/D converter for digitizing the light intensity to allow
digital processing. It would be tempting to augment the light
sensor with an infrared detector, however, the circuit would then
need to distinguish incandescent lighting from the future use of
solid state LED lighting, which is a narrow band light source. The
controller circuit 1488 is shown configured with a ambient light
intensity detector 1490 coupled to another A/D input such that the
controller may adjust processing of the received red light in
accord with the amount of daylight. The FBLID may be connected 1492
to the HBC or used as an input to another safety device, or may be
utilized as a separate system. Utilized as a separate system, the
FBLID exemplified in FIG. 29 is shown configured for flashing the
reverse lights of the vehicle when brake light activation is
detected ahead. The reverse switch 1494 of the vehicle is connected
to the reverse lights 1495 as is a light driver circuit 1496
responsive to an activation signal 1497 from the FBLID 1488. The
FBLID in the illustrated embodiment is therefore able to activate
the reverse lights in response to brake light activations sensed
ahead. It should be appreciated that should the FBLID be used to
activate the brake lights of the vehicle, that a chain reaction
could occur whereby as one vehicle activates its brakes, the FBLID
system on all following vehicles would in turn be activated. It is
therefore preferable that the light activated by the FBLID be a
light source that will not generate a feed-forward signal that is
capable of registering as a brake light activation by a subsequent
FBLID unit. Furthermore, the FBLID is shown with a speed input 1498
so that the FBLID may be conditioned for inactivity at low speeds,
for instance at speeds below 40 mph. Redundant light intensity
detectors are also preferred, wherein the output of the two
detectors should remain equivalent, and if enough difference exists
between their output then the system is disabled and a warning
light activated. It will be appreciated that a forward looking
optical sensor is subject to impacts from bugs an debris and may
need periodic cleaning.
[0184] To increase the accuracy with which FBLID systems may
optically detect the status of braking indicators, the brake lights
of the vehicle are preferably modulated at a predetermined rate,
wherein the FBLID system can more readily discern activated brake
lights from other optical light sources. It will be recognized that
fast brake light modulation, such as at 100 Hz, especially of solid
state indicator lights (i.e. LEDs), is easily detected by the
sensor in the FBLID while being generally undetectable to the human
viewer. Furthermore, the RAAC system (or other safety system)
preferably encodes the intensity of brake activation into the
modulation of the brake light, so that the FBLID is capable of
registering not only that vehicles ahead are braking, but in
addition registers the intensity of the braking being applied. The
HBC of both FIG. 3 and FIG. 5 are shown inclusive of inputs from an
FBLID system. The HBC of FIG. 5 is shown with a brake modulation
signal 204 which may be utilized by an external brake light
switching circuit, such as shown in FIG. 35, to provide the
aforementioned modulation of the brake lights. It will be
appreciated that such modulation may be easily incorporated into
any phase of RAAC system implementation.
[0185] 4.10. Crash Sensor
[0186] In FIG. 5 a crash sensor 146 is incorporated within the hard
braking controller 142. The crash sensor detects a threshold value
of acceleration (generally above 5-10 Gs) and generates a logic
signal in response. It will be recognized that an accident is a
high severity hard braking event that approaching drivers should be
made aware of. When a crash occurs, the G-loading indicative of the
crash is a temporary event, . . . although the crash itself may not
be so temporary. Therefore, in the case of a crash (Severity
Level=HB 1 Crash) the HBC continues to generate a hard braking
signal both visually and by transmitted alert signal for a period
of 5 minutes after the incident. (Providing that vehicle speed is
negligible, stopped.) During this time drivers are alerted by the
alert signal transmissions, which upon receipt audibly indicate
trouble ahead. Alternately, an input from the impact sensor within
the vehicle airbag system (not shown) can be used in place of, or
along with, the internal crash sensor. Data from the pedal-mounted
acceleration sensor is correlated with the crash sensor so that
false crash indications may be eliminated. This is possible since
the pedal mounted acceleration sensor is subject to the same
accelerations as the crash sensor, even without the foot pressures.
A "G" spike will be seen at the output of the pedal sensor upon any
sizeable impact (i.e. sudden deceleration). An error condition is
signaled to the driver if erroneous events are being registered by
the crash sensor.
[0187] 4.11. Headlight Sense Input
[0188] An input 176 of FIG. 5 receives input from the headlight
switch to indicate if headlights are on. The binary voltage levels
to the headlight are translated by a voltage divider and filtered
by a capacitor prior to entering a logic input of the
microcontroller 148 within the HBC 142. The HBC uses the headlight
on/off sense to control the light intensity for the visual driver
alert indicators used by the HBC, such as the LEDs shown, based on
the headlight setting. Furthermore, the headlight condition can be
utilized for establishing additional operating parameters of the
system, while the status of the lights can be registered within the
crash data logging system.
[0189] 4.12. Emergency Flasher Input
[0190] An input 177 of FIG. 5, from the emergency flasher circuits
of the subject vehicle allows external communication of hazards
that the driver considers an emergency, these are embodied herein
as low level events of level HB5. FIG. 18 is a schematic of a
representative vehicle turn signal/emergency flasher circuit 900.
Vehicle power 901 (12 Volts), is used in the powering of a left
front indicator 902, a left rear indicator 904, a right front 906,
and a right rear indicator 908. A left turn signal switch 910
controls power to both left turn lights, while a right turn switch
912 controls power to both right turn lights. A double pole switch
simultaneously controls power to both sets of indicators. A flasher
unit 918 periodically turns on and off. Previously flasher units
were implemented as bimetallic strips wherein current flow through
the combined strip caused heating which resulted in strip
separation and loss of contact. The current flow was therefore
intermittently allowed and the lights flashed when the circuits
were closed. A variety of current flasher implementations exist but
the concept represented can be used or modified by anyone skilled
in the art to provide a signal indicative of emergency flasher
operation. Activating a right turn signal switch 912 causes current
to flow from the power 901 through the flasher circuit 918, through
the switch 912 and through both right turn indicators 906, 908. The
left lights operate similarly. Activating the emergency flasher
switches 914, 916, causes power to flow through both right and left
sets of indicator lights to ground. A voltage divider with two
resistors 919, 920 is placed between the two signal circuits. If a
turn signal is activated then the voltage at the center between the
resistors is about 1/2 the supplied voltage. If the emergency
flasher 918 is activated, then the voltage is almost equal to the
supplied voltage. A Zener diode 922 is used to drop about 1/2 the
applied voltage (6 Volts). If the emergency flashers are activated
then about 1/2 the supply voltage reaches resistor 924 and current
flows out through a length of wire to the HBC side pull down 928
and filter capacitor 930, wherein the voltage of 1/2 the supply is
translated to the an appropriate high voltage for the HBC power
circuit and noise spikes are filtered out. The emergency input
could be fashioned in a variety of ways, for instance another poll
of the switch could be used with a pull-up to the supply voltage on
one side and the pull down at the HBC side.
[0191] 4.13. Reverse Light Input
[0192] A Reverse input 178 of FIG. 5, provides a binary signal from
the reverse light switch of the vehicle which is capable of serving
multiple functions. First, it provides another status input that
can be taken into account by the HBC for qualifying HBC event
signals or controlling the output state of the reverse light
indicators, and secondly the state of this signal can be logged
within an extended monitor circuit. When the reverse signal is
high, the HBC correspondingly sets the HB Ind output to high. The
reverse lights can then be incorporated conventionally, with the
output of the HBC hard braking indicator power coupled in parallel
to the reverse light power signal from the reverse light switch, or
by using a separate reverse sensing sensor which provide the signal
to the HBC which generates the HB Ind output in response to both
conditions.
[0193] 4.14. Brake Light Input
[0194] A Brake input 179 of FIG. 5, provides a binary input from
the brake light switch or alternately a brake light sensor. In a
conventionally wired system, the Brake input provides a check on
HBC functioning. If the Brake input goes active and the pedal
pressure sensor has not sensed pedal activity, then the operation
of the HBC is faulty and the error signal is activated. The HBC
also internally registers the pedal pressure setting at which the
Brake input goes active. This minimum recorded value of pedal
pressure when the Brake input goes active corresponds to the bias
force on the brake pedal system. This bias force is taken into
account in determining medium levels of hard braking. Systems with
higher bias forces will require a higher pressure before any form
of hard braking is indicated by the HBC. In addition, if the HBC is
registering pressures largely in excess of the recorded minimum
recorded value of pedal pressure, but the Brake input signal has
not gone high, then the brake switch or wiring may be faulty. The
HBC will signal a fault condition if this condition continues.
Additionally, the Brake input is logged if an extended monitor
circuit is implemented within the HBC, so that the state of the
brake is recorded with other related data in the event of a
crash.
[0195] 4.15. Vehicle Speed Input
[0196] A speed input 156 of FIG. 5 allows the HBC to interpret all
received signals in relation to the speed of the vehicle. This
allows the system to be more discerning as to the generation of
event signals and driver alerts. Speed signals are typically
already generated for use by electronic control purposes within the
vehicle. FIG. 19 shows speed signal conversion 950 providing serial
speed input to the HBC. A signal from a Hall-effect style speed
sensor 952 is received. The signal is shown as the square wave
pulse train 954. A resistor divider 956, 958 translates the voltage
of the signal that is filtered by capacitor 960. A resultant pulse
train 962 enters a microcontroller 964. The microcontroller is
exemplified as a Microchip Technologies.TM. 12C508.TM., which is a
small 8 pin controller chip. The firmware within the controller 964
calculates the speed of the vehicle based on the received pulse
train. An SPI serial slave interface is also implemented in
firmware so that the controller can receive control information and
send out speed data. A data in line 966 receives data from the HBC.
These can be commands on how to process the information and
constants. One constant sent to the controller is based on the
intervals between the pulses and takes into account the tire sizes.
If tire size is altered, then new calibration data must be entered.
(Calibration data can be determined by the GPS unit over time and
used to recalibrate the tire size value.) Speed data is sent to the
HBC via the data out signal 968 upon HBC request. A request occurs
when the chip select 972 line goes low. One bit is received and
transmitted for each transition of the SClk signal 970. The HBC
could directly use the pulse train, but then the HBC design would
need to be modified for each form of vehicle speed sensing
apparatus being employed. The use of the microcontroller provides
for a generic speed data protocol to the HBC. Furthermore, it is
preferable that two sources of speed data be correlated within the
HBC system, such that errors may be detected.
[0197] 4.16. Vehicle Acceleration Pedal Input
[0198] Related to the aforementioned speed input is an optional
input from the acceleration pedal 175 which may be utilized to
increase reaction advantage. It will be appreciated that a driver
typically operates the brake and accelerator with the same foot,
therefore, prior to a driver applying pressure to the brake pedal
they must first release their foot from the accelerator pedal. The
acceleration pedal sensor input to the hard braking controller 148
senses the amount of accelerator pedal depression, and is capable
of registering changes in the amount of pedal depression. FIG. 41
and FIG. 42 depict an accelerator pedal sensing arrangement capable
of registering the amount of pedal depression. An HBC equipped for
monitoring the accelerator pedal can utilize the data to modify
actions in relation to the other sensors. For example, if the
driver is increasing depressing the accelerator pedal then the
severity of received event conditions may be elevated, since it is
likely the driver has not perceived any such danger, by virtue of
their increasing acceleration. By way of further example, the
system can sense for an abrupt release of pressure, consistent with
a driver removing his/her foot from the accelerator pedal to
activate the brakes, wherein the HBC can generate an alert signal,
such as by activating a hard braking light or transmission. It will
be appreciated that the HBC may utilize the status of acceleration
in a number of ways consistent with providing enhanced reaction
advantage to the driver.
[0199] FIG. 41 exemplifies a sensor 1800 for detecting the amount
of accelerator pedal depression. Any form of accelerator pedal
sensor may be utilized within the present invention to provide the
reaction advantages outlined herein. An accelerator pedal 1802, is
capable of single axis movement for depression and release 1804 is
acted upon by the foot 1806 of the driver. The accelerator pedal is
often hinged 1808. A linkage 1810 is connected at a joint 1812 with
the accelerator pedal and traditionally connected through a joint
1814 with a motion transfer mechanism 1816 whose output is utilized
to control the throttle of the vehicle. The motion transfer
mechanism 1816 is exemplified as an encoder disk with a central
axis 1818 about which the disk rotates in response to accelerator
pedal position changes. A biasing device 1820 biases the transfer
mechanism 1816 toward a state of accelerator pedal release. The
output of motion transfer mechanism 1816 is exemplfied as a linkage
1822 for further connection toward a throttle connection. A sensor
1824 is shown proximal to the disk encoder of the motion transfer
mechanism 1816 for sensing the position of the attached accelerator
pedal 1802. The sensor 1824 may utilize any of various sense
methods, such as Hall effect, optical, resistive, such that the
position and relative change of motion of the accelerator pedal may
be determined and output as a signal 1826. It will be appreciated
that accelerator linkages may be implemented in a wide variety of
formats, and that the linkage shown in FIG. 41 is provided by way
of example to indicate a single method of providing sensing of
accelerator pedal depression. Furthermore, in the near term
vehicles are being comtemplated utilizing electronic throttle
control wherein the accelerator pedal is converted to a position
signal for driving an electrical throttle input, such that no
further need of an output linkage is required.
[0200] FIG. 42 illustrates an accelerator pedal signal conditioner
1830 which is configured for use with an HBC, or optionally as a
standalone system. The signal conditioner 1830 is shown for
connection with the accelerator pedal sensor 1824 by the wiring
1826, which is shown having three leads consistent with a two row
optical or Hall effect encoder. The signal conditioner 1830 is
shown exemplified as a microcontroller so that an intelligent
calibrated output may be provided, such as the serial interface
1832 exemplified within the figure that may be connected to the
HBC, such as line 175 shown in FIG. 5.
[0201] When utilized without an HBC, the acceleration sensor and
conditioner of FIG. 41 and FIG. 42 may provide for a direct
reaction advantage in a number of ways. First, the by sensing for
an abrupt release of accelerator pedal pressure above a given
speed, as registered by speed input 1834, the unit can slightly
begin engaging the brakes. It can be presumed that at highway
speeds, the driver will generally not abruptly yank their foot from
the accelerator pedal unless they are attempting to engage the
brakes. The system can start the process of engaging the brakes
through a brake assist output 1836 which is capable of driving an
activation device, such as solenoid 1838 connected to ground 1840.
The system may also alert drivers behind the vehicle to the
impending quick deceleration by activating a hard braking
indicator, such as reverse lights, through the hard braking signal
(HBS) line 1842. In the case of either HBC use, or use with other
systems or as a standalone system, the sensing of accelerator pedal
position can provide enhanced reaction advantages to the driver of
a vehicle, as well as to those following said driver.
[0202] 4.17. Swerve Sensor Input
[0203] A swerve sensor input 172 of FIG. 5 is shown connecting to
the microcontroller 148 of the HBC 142 so that information
regarding abrupt swerving actions are communicated to approaching
drivers. The sensor data is an analog signal received by an A/D bit
of the HBC. A representative circuit for the swerve sensor is shown
in FIG. 13, FIG. 14, FIG. 15, and FIG. 16. A means of sensing
movement 700 of the steering shaft is shown. A steering wheel 702
coupled to a steering shaft 704 allows the driver to control the
vehicle. A swerve sensor 706 is in mechanical connection with the
steering shaft 704 and contains electrical connections 708 for
interfacing with the HBC. This embodiment of the swerve sensor 720
employs a free-turning potentiometer 722 with an input shaft 724 on
which is mounted an engagement wheel 726. The engagement wheel in
this case has a compliant rubber exterior in contact with the
steering wheel shaft 704. Rotation of the steering shaft is coupled
to the wheel which in turn rotates the potentiometer thereby
altering the output 728. FIG. 15 is the front view of the round
wheel 726. FIG. 16 is a schematic of this simple swerve sensor 730.
A free-turning potentiometer 732 (potentiometer can spin freely any
number of turns) is used with a sense tap that changes with the
angular position of the wheel. With power supplied 734 and a drop
resistor 735, current passes through the potentiometer resistance
732 to ground 736. Potentiometer output 738 provides a voltage
proportional to the position of the steering wheel shaft and
therefore the steering wheel. Numerous alternative sense
arrangements may be configured by anyone skilled in the art. For
example, the potentiometer may be directly replaced with an optical
encoder that provides a digital output. Additionally, Hall effect
sensors may be employed, or a rotational acceleration sensor on the
wheel, or response sensors connected to the mechanism of the
steering box. The yaw movement of the vehicle could be used as
alternate way of sensing vehicle swerving. The swerve would then be
sensed by measuring the sideways acceleration of the vehicle by
means of one or more acceleration sensors. Another axis may be
utilized within either of the acceleration sensors already
incorporated for sensing a crash within the HBC, or for sensing
pedal acceleration within the pedal sense module.
[0204] 4.18. Compass Heading Input
[0205] A compass input 158 in FIG. 5 provides direction of travel
information to the HBC wherein approaching vehicles can be alerted
to the danger selectively based upon their travel direction.
Inexpensive electronic and electronically read mechanical compasses
are reliable and readily available. This embodiment employs the
output of a compass which is encoded in the output signal from the
HBC, so that only vehicles traveling in the same general direction
alert their drivers to the generated event signal. Although the
transmitters and receivers are directionally oriented, this
precaution further reduces the probability that vehicles traveling
in the opposing direction will pick up enough signal intensity to
trigger an unnecessary hard braking alert.
[0206] FIG. 23 exemplifies a compass 1200 shown configured for
connecting to the HBC of the RAAC system. The compass utilized
within this embodiment is a Honeywell.TM. HMR-3000.TM. Electronic
digital compass which uses magneto-resistive sensors for detecting
compass orientation. The compass provides high accuracy (0.5.), an
ability to tolerate tilting, and an RS-232 interface. The compass
1202 has a serial interface 1204 provided by a UART 1206. The UART
shown is manufactured by Maxim Semiconductor.TM. as a MAX3100.TM.,
and it provides an SPI to RS-232 interface. The UART has a crystal
section 1208 to provide the timing needed for the RS-232 interface.
The UART is connected to the HBC via an SPI interface 1210.
[0207] The high accuracy of the compass used herein is not
necessary for providing the rough readings required in quantifying
the direction, as an accuracy of 15. would be sufficient. A simple
compass, such as those currently manufactured within watches and
other inexpensive consumer electronics could alternately be used.
However, the high accuracy of the compass is useful when coupled
with a GPS unit used as a navigation system. Often the direction
information provided by the GPS alone is insufficient to determine
navigation and turning information, but when coupled with high
accuracy compass information, the GPS navigation system can more
easily determine exact vehicle location on the roadway. Therefore
the high accuracy compass used performs double duty.
[0208] 4.19. GPS Coordinate Position Input
[0209] Additionally this embodiment contains a pair of serial data
lines 160 from an optional global positioning system, GPS system.
The position data from the GPS is transmitted as an auxiliary data
packet by the HBC to approaching traffic upon the occurrence of an
event. The coordinate data provided by the GPS allows precise
alerting of drivers relative to location of dangerous events.
Upcoming phase If GPS satellite location service (not to be
confused with phase II HBC) provides distance accuracy within 125
meters, while systems developed using differential GPS can provide
resolution of from 2 to 15 meters. The use of differential GPS
requires the reception of differential error signals from ground
based sources such as those provided by Coast Guard GPS beacons.
Numerous GPS units are being manufactured currently and many of
these contain internal microcontrollers capable of providing serial
output.
[0210] Two serial interfaces are provided for the GPS. A serial
data interface that is accompanied with an IRQ line for timely
receipt of coordinate data, and a serial control channel for
controlling the actions of the GPS. FIG. 24 is a preferred circuit
1250 wherein GPS coordinate data is generated by a Lassen-SK8.TM.
GPS Board 1252 within a starter kit which is manufactured by
Trimble Tracking and Communication Products.TM.. (Lassen-SK8 is a
registered Trademark of Trimble). GPS receives 1.575 GHz signals
from orbiting satellites wherein the received time relationships of
the time-stamped transmissions are used for triangulating the
position of the receiver. The GPS antenna 1254 is a small antenna
mounted on/near a top surface of the vehicle so that minimum signal
impairment occurs. The GPS unit 1252 employs dual-serial channels,
one for control while the other for data output. Since the RS-232
data ports are set for 12 Volt signal levels the serial data lines
are translated to match the HBC unit. Each set of Tx, Rx, CTS, RTS,
signals 1256, 1258 are level translated and buffered by circuits
1260, 1262, so that signal levels match those in use by the HBC.
The RS-232 serial streams are then converted to SPI data by MAX3100
UARTS 1268, 1270 so that SPI control and position data 1272, 1274
can be communicated between the HBC and the GPS.
[0211] Various GPS circuits are available for providing coordinate
data. Widespread inclusion, besides allowing the addition of
numerous features, allows the power level of the transmitted event
signals to be increased because the coordinate data from the GPS
provides a nearly optimum event location qualifier. Additionally,
the GPS provides the basis for additional features such as
emergency 911 call out described below.
[0212] 4.20. Emergency 911 Call Outs
[0213] With the addition of the GPS system, the HBC can register
precise roadway position information. In order to further speed
emergency crews to the scene of an accident, a wireless phone
module 194 of FIG. 5 is connected to the HBC 142. The wireless
phone module is connected with an SPI serial interface. The SPI
serial interface bus 197 is provided along with a pair of module
signals 193 for module selection by HBC and for IRQ generation by
the wireless phone module. The IRQ allows the wireless phone system
upon receiving calls to interrupt the HBC for other signaling
purposes. User I/O devices 196 are connected to the wireless phone
module, in this case a microphone and speaker. The phone transmits
via the antenna 198. When the crash sensor is activated, or the
airbag deployed, the phone generates an emergency 911 call. When
the call is picked up, then the phone module transmits voice data
from the HBC over the phone connection. The annunciator speaker 188
is already driven by the HBC to generate tones or voice, and this
capability is extended with a signal 195 provided to the wireless
phone system, so that specific emergency data may be provided over
the wireless phone as audio tones or voiced info. It is assumed
that the wireless phone module includes at least a DTMF generation
chip, and possibly a modem, so that signals from the HBC, passed
via the serial bus may be more quickly sent to the dispatchers. It
should be noted that the HBC unit also provides the HBC unit ID
number (which may be the VIN number of the vehicle) which is
additionally provided as a voice so that the 911 operators can
record in which vehicle the event has occurred. (And provide a
means of eliminating possible false signals, should the need
arise.) The speaker and microphone 196 within the vehicle are
activated in the case of a crash so that the emergency dispatch
operator may attempt to speak with the driver and occupants to
assess their condition. A special Emergency 911 button 199 is also
provided within the HBC should 911 help be required in other
emergency situations. Preferably the button is provided with a
latched flip open cover to prevent accidental activation. When
pressed, button activation is detected by the HBC which first asks
for a user confirmation via audio or display such as "E911
activated--turn it off unless this is an emergency". Then if it
remains activated, then a call is made wherein the HBC sends
pertinent location and ID information while the microphone and
speaker can be used by dispatch personnel to speak with the
occupants.
[0214] Depending on configuration, the wireless phone with its
microphone and speaker may additionally be used by the driver for
non-emergency phone calls, so that the unit can perform double
duty. The phone module contains a standard plug-in interface to the
system to facilitate replacement when wireless infrastructure
changes warrant updating.
[0215] 4.21. Distance Sensor Input
[0216] A distance sensor input 174 of FIG. 5 is used to provide
information to the HBC about the forward distance to the next
vehicle and the closing speed on that vehicle. The current
implementation employs a 6500 Series.TM. sonar ranging module from
Polaroid.TM.. This front-mounted forward-directed sonar-ranging
module contains a SN28827.TM. circuit from Texas instruments.TM..
The 6500 series module drives an electrostatic transducer from
Polaroid Corporation. The module provides an acoustical ultrasonic
signal at about 50 kHz, whose echo (reflection) is displaced in
time proportional to the distance and the speed of sound under
present atmospheric conditions. The module can sense distance up to
about 35 feet, although the acoustic technique employed can be
extended with improved sensors.
[0217] FIG. 25 is a schematic 1300 of the distance sensing module
set up for connection to the HBC. An ultrasonic transducer 1302 is
used to both send and receive sound ultrasonic sound pressure
waves. The sonar ranging (SR) module 1304 provides the drive and
analog signal correlation circuits. The module provides an INIT
input wherein the start of transmission commences after the INIT
signal 1306 goes high. (input is shown with terminating resistors)
When the SR module has received an echo from the sound transmission
it sets the output ECHO signal 1308 to high. The HBC in this way
can set INIT high and then measure the time until the ECHO signal
goes active.
[0218] In FIG. 5 a pair of microcontroller signals 174 are shown,
an INIT signal is activated and then the time is measured until the
ECHO signal arrives. The time between INIT and ECHO is divided by
approximately 1.78 by the microcontroller firmware to arrive at the
round trip distance in feet. By taking successive measurements, the
approximate closing speed may be calculated in relation to the
vehicle ahead. The distance information, when used with the speed
information is useful for qualifying events in relation to their
relative risk, or danger. For example a hard braking event that
occurs 35 feet ahead at 50 miles per hour may not be regenerated to
additional vehicles since this car and subsequent vehicles should
have adequate reaction time. The "danger" level sense provided by
the distance sensor coupled with a speed sensor allows the HBC to
assist the driver in reacting to the dangerous event.
[0219] 4.22. Assisted Braking with "Tailgate" Control
[0220] A brake assist output BrAssist 168 of FIG. 5 and tailgate
sensitivity adjust 170 are employed so that the HBC may apply
initial pressure to the brakes of a vehicle in cases where an event
occurs ahead and the data received by the HBC indicates that the
driver will/may not be able to react in time. The HBC applies the
brakes until the driver applies a sufficient level of braking
pressure, as measured by the brake pedal pressure sensor. The
release of assisted braking is similar to that employed within a
cruise control device. It will be appreciated that the brake assist
signal, as is the case of many other signals within FIG. 5, are
optional and dependent on the desired implementation phase and
desired features of the subject RAAC system.
[0221] Assisted braking can improve the reaction time of the
driver. Under normal circumstances of use, it is anticipated that
assisted braking will be able to apply the brakes at least a few
hundred milliseconds before the driver. This extra time when the
vehicle is at top speed can dramatically improve the chances of the
vehicle stopping/slowing from highway speeds in time to avoid an
accident. Applying the brakes even 200 mS earlier from a speed of
70 mph allows the vehicle to stop about 20 feet earlier.
[0222] If the HBC determines that the driver will/may not be able
to react quickly enough to an event signal which has been received,
the HBC triggers a braking assist solenoid by activating the brake
assist signal 168 of FIG. 5. The solenoid may be a conventional
electrical solenoid with a winding through which current is applied
to move a plunger which pulls or pushes the brake system into
activation. Brake activation under HBC control can be accomplished
with various alternate actuators, such as electrically activated
hydraulic cylinders, servo motors, or even exotic actuators such as
"muscle wire". The signal driving the braking assist solenoid
within this embodiment is pulse width modulated so that any desired
level of brake activation may be achieved under the control of the
HBC.
[0223] FIG. 26 is a diagram of an assisted braking solenoid 1350
connected to the brake pedal lever. The brake pedal 1352 is
attached to the end of the brake pedal arm 1354 which can rotate
under foot pressure about pivot 1356. Depressing the brake pedal
1352 causes a compression of the brake actuation link 1358 which
engages the vehicle's brakes. An assisted braking linkage 1360 is
also connected to the brake pedal arm 1354, and terminates on one
end as a slidable engagement with a solenoid 1264. In this case the
solenoid 1264 is provided by a cylinder wrapped with a wire coil.
One end of the coil 1364 is at nominal 12 volts while the other end
1366 is connected with a drive circuit. The drive circuit is
exemplified as a transistor 1368 with emitter to ground, base
connected with a resistor 1370, capacitor 1372 to ground, and a
signal input 1374 supplied from the HBC. Activation by the HBC of
the signal 1374 turns on the transistor such that current flows
through the coil of the solenoid whose magnetic field increases
which draws the ferro-magnetic activation rod further into the coil
which thereby activates the brakes to assist the driver.
[0224] In order to determine tailgating danger, the distance
information is correlated with both speed and closure speed
information which is correlated to a driver selected "tailgate"
value. A "tailgate" sensitivity control 170 of FIG. 5 is provided
to allow the driver to set the amount of assistance desired from
the assisted braking device. The tailgate sensitivity adjustment
170 herein is preferably presented to the driver in relation to the
number of car lengths per every 10 mph of speed. The sensitivity
control within this embodiment uses a simple potentiometer whose
wiper value voltage is read by the microcontroller 148 to determine
the setting of the tailgate control. It must be understood that
various means of providing user input can be substituted for the
potentiometer while still adhering tot he inventive principle
outlined.
[0225] Perhaps the majority of drivers have heard that their
following distance should be at least one car length for every 10
mph of vehicle speed. However, in the actual world of commuting, a
large percentage of drivers appear comfortable with values as low
as 10 feet at 60 mph; which is less than 1/6 of a car length per 10
mph. The sensitivity adjustment of this embodiment is set to allow
as low as 1/4 car length per 10 mph and provides a range up to over
1.0 car lengths per 10 mph. A detent position below 1/4 car length
per 10 mph allows the brake assist function to be disabled. It must
be noted that the braking assist solenoid is not activated at the
time when "tailgate" parameters are violated; however a very short
audio alert is generated (depending on driver audio sensitivity
setting) by the HBC when the distance in relation to speed falls
below the tailgate value selected. The brake assist solenoid is
only activated if a hard braking event (HB1, HB2, HB3) occurs
directly ahead, while the tailgate parameter is being violated. The
HBC activates the brake assist solenoid to apply the brakes so that
the vehicle can begin so slow down before the driver reacts to the
alert. It can take drivers as much as one second to get on their
brakes once an event occurs. The time from event recognition to
brake application by the HBC can be performed in under 20-50 mS.
Keeping in mind that highway speeds can often exceed 100
feet/second (70 mph), the time saved may translate to a significant
reduction in collision related destruction.
[0226] 4.23. HBC Monitor Circuit
[0227] The firmware of the microprocessor 148 contains various self
tests to ascertain the functioning of the system. Should the
microprocessor fail, a monitor circuit 150 prevents the false
generation of event signal output. Failure rates of modern
microprocessors are almost insignificant, and the chance of a
microprocessor failing in a mode with only signal generation
affected is even lower. However, the addition of a small
microcontroller to monitor the system is a very inexpensive method
of being certain that invalid, or even malicious, event signals are
not being generated on the roadways. Monitor 150 is connected to a
common SPI serial bus (not shown) having controller inputs 205 and
outputs 206 as shown in Table 2.
[0228] If the monitor detects errors in the generation of signals
by the HBC, it turns on an error indicator 200 and can pull the
Master Clear line of the Microprocessor 201, being held up by a
resistor, down to a low state to thereby hold the microprocessor in
a state of reset. Additionally, an external reset switch 202, can
be toggled to allow service personnel to disable the HBC system. If
monitor 150 detects problems with HBC functioning, it has numerous
options depending on severity. It may signal the HBC by Log IRQ
signal 205 and thereby send it a command packet, such as a
restrictive functioning command. The HBC functions are checked and
the HBC can be set to reduced functionality, or even a state of
passivity, by the monitor circuit. As previously mentioned, monitor
150 may also hold processor 148 in a reset mode if the processor
operations can not be trusted even in a passive mode.
[0229] The HBC is shown with a connection 207 to an FBLID system
according to an aspect of the present invention. The FBLID system
generates a signal to the HBC in response to the optically detected
brake light status of vehicles ahead.
[0230] The HBC is further shown with a connection 208 to a FLAC
system according to an aspect of the present invention. The FLAC
system provides information to the HBC in response to correlated
external audio events, such as brakes squeeling as a result of hard
application. The FLAC thereby extends the reception of event
conditions which have not been transmitted by a Phase II, or
higher, RAAC system; such as may occur prior to the inclusion of
the RAAC system, or similar, in all subject vehicles.
[0231] 5 5. Event Signal Mapping
[0232] 5.1. HB Event Levels
[0233] Within this preferred embodiment seven braking event levels
are delineated. It should be recognized that the present invention
may be implemented with event classifications designed in a variety
of ways with a varying number of levels.
[0234] The highest severity event with regard to this system is
considered to be a crash event. A crash event is considered a level
1 hard braking event (HB1). The seven hard braking levels
exemplified within the present invention are described in Table
3.
[0235] Additionally, it should be understood that in relation to a
particular vehicle, a few of the event levels may be either created
as a generated event or a received event. Differences exist in the
handling of generated events versus received events.
[0236] Causative events are mapped to the event levels shown in a
variety of ways.
[0237] Level HB1 Crash occurs when the vehicle itself experiences
an impact which sets off the crash sensor. It is not determined by
the braking of the vehicle, but one could say it is determined by
the "breaking" of the vehicle, as per an impact. HB1 may also occur
as a received event wherein the vehicle itself receives a message
from another vehicle which has experienced an impact. The crash
sensor is triggered if a sudden deceleration exceeds a certain
level. Braking itself can produce only a nominal force based on
tire adhesion forces which rarely exceeds around 1 G. Impact forces
can be on the order of 50 Gs of deceleration. In this embodiment
the crash sensor activates above 5-10 Gs, although any large value
distinguishable from hard braking can be utilized. The crash sensor
data is checked against the pedal acceleration as it too will show
a sudden acceleration at the time of impact. By correlating the two
sensors, the probability of false alarms is reduced.
[0238] Level HB5 Emergency flashers are similar to the crash event
in that it is generated by a vehicle event unrelated to the extent
of braking. Emergency flashers can be deployed by a driver that has
experienced a roadside condition or at some time after an accident
has occurred. The event is significant to approaching drivers as
they should approach with caution and reduced speed. Obviously a
level HB5 is not as important to safety as an HB1 event. The
emergency flasher event can additionally be received from other
vehicles.
[0239] Level HB4 Emergency vehicles/incidents is a level provided
to allow emergency vehicles traveling on the road which are
equipped with a special transmitter to alert drivers that they are
approaching. Drivers so alerted are to provide a path for the
emergency vehicle. Presently drivers often do not see or hear the
emergency vehicle until it is directly behind them. Consequently,
emergency vehicles are often catastrophically delayed while victims
occasionally die awaiting paramedic attention.
[0240] Levels HB2 Brake Slamming and HB3 Hard Braking provide the
core of the system. These two events can be either generated or
received events. These two events are generated when the level of
braking as perceived by the hard braking controller exceeds certain
thresholds. These may be sensed in a variety of ways involving the
pressure and/or acceleration of the brake pedal.
[0241] Level HB6 Abrupt Swerving is provided since drivers may
respond to certain dangerous roadside conditions by either braking
or swerving. If a large piece of debris is in the road, a lead
driver may abruptly swerve since they can see the object from a
distance. Drivers subsequently arriving at the debris may not have
sufficient time to react. The HBC system in this case would alert
approaching drivers to the swerve hazard ahead.
[0242] Level HB7 Condition reporting is provided to allow large low
priority data packets to be transmitted and received. These
transmissions are encoded with a packet number and a total number
of packets so that sequences of packets can be ordered correctly
for display to the driver. Level HB7 signals are utilized herein
primarily for allowing roadside equipment, such as call boxes or
vehicles of roadside crews, to transmit road condition information
to drivers via their HBC units.
[0243] 5.2. Speed in relation to HB Event
[0244] Speed data is used within the HBC of this embodiment to
minimize unnecessary event signal generation, and unwarranted
internal driver alert signal. Vehicle speed is herein divided into
four representative categories which are shown in Table 4.
[0245] The speed data therefore is used to modify the generation of
event actions related to the speed. For example, it is not
generally necessary for vehicles traveling in parking lots to be
generating alert signals to other drivers. Allowing event signal
generation under any condition would allow surface street
activities in some instances to affect highway traffic. In
addition, the speed data is correlated to the rate at which the
wheel is turned to arrive at a swerve value. Abrupt swerving that
exceeds a set value within the firmware triggers an HB6 alert. For
example at speeds in excess of 45 mph, a turn rate exceeding 1/8
wheel-turn per 100 mS wherein the turn rate continues for a total
of two consecutive intervals may trigger the generation of the HB6
alert. Internal audio driver alerts are also repressed when the
vehicle is stopped or moving slowly in situations where the event
is not considered a dangerous event under present speed and
conditions.
[0246] 5.3. Direction in relation to HB Event
[0247] In order to even further limit the possibility of false
triggering, this embodiment of the present invention employs an
electronic compass heading sensor. The signal from the compass is
used within the HBC to generate a set of 3 direction bits
corresponding to the 8 compass points (N, NE, E, SE, S, SW, W, NW).
Vehicles receiving alerts compare the direction of the vehicle
sending the alert with the direction as generated by their own
compass. Events HB2, HB3, and HB5 are preferably ignored if the
difference between the vehicle directions exceeds 90. Largely this
feature reduces reflective alerts to drivers traveling on a highway
in the opposite direction. Alert signals are generated rearwardly
to front directed receivers, therefore, a natural disposition
favors a given direction of travel. However, signals projected
rearwardly can reflect from vehicle surfaces and be received by
drivers traveling in the opposite direction. Employing the compass
data reduces this possibility.
[0248] 5.4. Interpretation of Pedal Sensor Data
[0249] This embodiment employs both a pedal pressure sensor and an
acceleration sensor for sensing hard braking events. The
interpretation of the sensor data is a complex process that must
take into account a number of factors. Additionally, the
interpretive settings used can vary from one vehicle type to
another, i.e. electronic brakes versus manual brakes. Therefore,
the values discussed are representative values wherein the actual
settings depend on calibrations tests within a given vehicle. In
the current embodiment a set of sub-events are associated with the
sensor information. These events are classified into tables from
which the microcontroller firmware discerns events and produces
action. The microcontroller firmware operates from these event and
action tables in generating control responses. The sub-events could
be both determined and categorized within the firmware itself but
then a different set of firmware would be required for each
instance, wherein a value substitution was required. Within the
embodiment described, values for the event and action tables are
retained as data tables stored within the program data store which
is contained in Flash memory. Manufacturers can then vary the table
data itself to accommodate any desired configuration without the
need of altering and testing the underlying firmware program.
[0250] Table 5 provides a representative table of sensor threshold
levels in which each of the three measured parameters are broken
down into sub-event ranges with thresholds within each range. It
should be noted, that acceleration data is sensed as a positive
value only for positive accelerations, wherein zero and negative
accelerations (which may indicate releasing of the brake pedal) are
ignored.
[0251] An event table whose states are represented in Table 6,
translates the threshold values for the pressure and change in
pressure readings into events. The event table is used when the
current system state is inactive with no hard braking events
signaled. The event "-none-" indicates no hard braking activity,
while the event "-Alert-" indicates that the system must prepare
for a change, the firmware drops extra non-essential activities
(processing of incoming signals) to concentrate on processing
sensor data.
[0252] Similarly, tables preferably contain data for each system
state and set of events to be generated. Table 7 exemplifies events
generated from an HB3 state. The acceleration sensor data is not
shown within the above tables as it is used as a modifier to weight
the event responses. When the acceleration sensor indicates the
pedal is transitioning rapidly (value=High) then if the system is
in a non-active state (no hard braking being signaled) then the
transition is considered to be a non-confirmed indication of hard
braking, wherein the hard braking indicator would be signaled to
following vehicles, but a transmitted signal would not be generated
until a confirmation was found. If the system is already signaling
a hard braking event, then the acceleration data is ignored.
Additionally it must be recognized that the event to be signaled is
also determined by the state of the system and by any signal
receptions from vehicles ahead.
[0253] It will be appreciated by anyone of ordinary skill in the
art that the aforementioned events may be alternatively categorized
and determined without departing from the teachings of the
invention.
[0254] 6. Event Signal Transmission and Receipt
[0255] 6.1. Communicating Events
[0256] As described previously, event signals are utilized for
remotely alerting drivers to possible dangers ahead so that they
may take preventative actions, such as braking, to avoid being
involved in an accident. Event signals within the system are
communicated from event signal transmitter (EST) modules to event
signal receiver (ESR) modules.
[0257] An embodiment of the invention comprises a pair of FSK
modulated radio-frequency data modules for the transmission and
receipt of data between vehicles. The particular RF transmitter and
receiver described are manufactured by Linx Technologies.TM. as
their HP Series.TM. of high-performance digital/analog modules.
This transmitter/receiver pair operates in the high UHF band
(902-928 MHz) and provides serial communication up to 50 Kbps. The
use of high frequency transmissions allows for the use of small
antenna structures which can be easily configured, or shielded, to
provide a directional orientation to the transmitted signal. The
power output of the transmitter is very low, and when coupled to
the small directional antenna, provides a maximum unobstructed
signal reception distance between a transmitter and a receiver of
approximately 1/8 of a mile.
[0258] Numerous methods of providing remote communication may be
alternatively utilized, which by way of example include, discrete
RF solutions, and Blue Tooth communication modules. One of the
alternate RF coding techniques is the use of simple On/Off Keying
(OOK), although it generally provides a lower data rate than other
techniques. Additionally, QPSK, broad-band transmissions, as well
as others can be employed within the system. Although RF signaling
is used in this embodiment data transmissions between vehicles may
be communicated with audio signals (such as ultrasonic), or even
with light signals, such as infrared. It must be realized that
various transmitter/receiver pairs can be substituted within an
embodiment of the invention without departing from the inventive
principles, since any form of transmission and low-level
transmission protocol can be adopted, so long as the event signal
transmitter module can transmit data bits which the event signal
receiver module can register.
[0259] When an event occurs such as a crash, or the slamming of
brakes, an event signal is transmitted to approaching vehicles. On
a crowded freeway the event signal may be attenuated by closely
approaching vehicles. As a result, the event signal may not
propagate sufficiently to alert all drivers to the event so that
they may apply their own brakes. Therefore, an embodiment of the
invention provides for controlled signal regeneration capability,
wherein vehicles receiving event signals selectively retransmit
those signals to allow drivers farther behind to be alerted so they
may start slowing.
[0260] 6.2. Regeneration Limitation
[0261] If each event signal generated by a vehicle were to be
regenerated at the same intensity level by every vehicle within
range, then on a crowded freeway the possibility would exist that
one event signal could be propagated for miles. To eliminate this
possibility, a novel approach is taken with regard to generation of
signals in response to those received. Each event signal
transmission is coded with unit code, severity, and a regeneration
counter. Received transmissions are checked and are regenerated a
maximum number of times as set by the severity of the hard braking
incident. In other words, an event received for a crash will be
regenerated for a larger count than a simple hard braking event. A
crash event within this preferred embodiment regenerates up to five
times, a brake slamming event for two, and a hard braking event for
one. Signals are regenerated with a count value of one less than
the lowest count value being received. The HBC of the vehicle which
originally generated the event, sets the maximum regeneration
count, as the number of levels of regeneration is largely dependent
on the conditions surrounding the event for which a signal is being
generated. It should be kept in mind that the transmissions are
generally line of sight transmission and that a whole series of
vehicles could receive the primary transmission, wherein a whole
series would receive the secondary and so forth. Since a crash
event is a static event the transmission frequency of the coded
signal is sent with longer intervals between each transmission
(generally 200 mS instead of 50 mS), this extra time allows the
receiver to receive a larger number of transmissions.
[0262] FIG. 6 shows a diagram of regeneration levels utilized
within this embodiment of the invention. When a vehicle crashes
into another vehicle, the crash sensor is activated by the high G
forces and a crash event is transmitted. Within this embodiment a
crash signal is regenerated up to a maximum of five times in a set
of five regeneration levels 210 as seen in FIG. 6. The primary
transmission "P" 212 is generated by one of the event generating
vehicles involved in the crash. The system is designed such that
within any event situation, there is but one primary transmission.
The first car to signal an event within a given group is the
primary event generator, whereas subsequent event generators and
regenerators synchronize with the event signals of the primary
generator. The mechanism by which this is accomplished is explained
later. The primary event signal represented by "P" 212 is received
by a number of following vehicles within the reception range of
this primary signal. A certain number of these vehicles will
regenerate the signal as a regeneration level 1 signal 214. Those
behind the level 1 group, which receive the level 1 regeneration
signal, but not the primary signal, can then regenerate the signal
as a level 2 signal 216, those that receive the level 2 signal but
not the primary signal, or level 1 signal, can regenerate the
signal as a level 3 signal 218, and so forth back for up to five
levels. Each HBC only acts to regenerate a single signal which is
the one at the highest level received. In this way unproductive
multiple regenerations are not produced.
[0263] 6.3. Event Signal Data Packet Bits
[0264] It can be seen that the primary signal "P" 212 is shown in
FIG. 6 as a short transmission segment while the remaining
retransmissions are shown as longer blocks of signal. This depicts
the manner in which the regeneration intervals are implemented. The
level 1 regeneration interval 214 is shown in greater detail as
sixteen regeneration channels 224. Regenerated signals and
additional events are signaled within these channels.
[0265] After checking that no other vehicles are in the process of
transmitting an event signal, a vehicle signals an event by
transmitting a packet of event information. Fields and bits
contained within a representative event data packet are represented
in Table 8. The data in an event signal packet is arranged with
higher priority information at the head of the packet. Therefore,
should a packet be cutoff during receipt, the critical information
thus far received can still be used to alert the driver, although
the regeneration of an invalid packet is generally not performed.
The data packet for the primary event generator contains a hard
braking level (HB1-HB5 ) which indicates the severity of the event.
An active event flag signals whether the event is active or
regenerated (always=1 in the primary). The regeneration number
contains a value for the number of times the signal can be
regenerated. A maximum value of five is preferably utilized for
crash events, with a value of two for brake slamming events and a
value of one for hard braking. These are representative values and
can be set to other levels as desired while still adhering to the
inventive principles. An auxiliary data flag is set to one when
additional data is contained within the packet and alerts the
receiver to properly collect this auxiliary data. Slot number is
derived from combining the HBC unit ID number with the present
timestamp, wherein the slot number can vary slightly over short
periods of time. Slot number is used for splitting up prospective
respondents into various slots within a set of regeneration
intervals. A set of direction bits are provided in which the
direction of the vehicle experiencing the event is encoded. The
direction information is used by receiving HBCs to determine if the
event signal is relevant to them. An ID field contains the unique
ID number of the HBC unit. This ID is propagated through all
regenerations so that respondents can determine and react if
another vehicle begins acting as the primary vehicle. An auxiliary
field for containing position data is also shown. This field is
optionally included in the packet if the vehicle generating the
original event signal employs a GPS connected to the HBC. This
auxiliary field may contain other data as well.
[0266] The packet used for passing condition reporting data as HB7
data is in a different format than the normal packet, and is
outlined in Table 9. The structure of the HB7 packet is similar to
a standard packet. A condition report can consist of a number of
associated packets. To assemble these packets into a report for
display to the drivers (or to be spoken by an audio annunciator)
the relative packet number and total number of packets in the
condition report must be known. Therefore a Packet number is added.
The regeneration information was eliminated as HB7 packets are
never regenerated. The ID field was also eliminated as well as the
GPS data field; these fields were replaced with a packet data field
of 64 bits. The data in the packets within this embodiment can be
encoded in two ways. ASCII data can be passed as 8 bit bytes,
wherein a total of 8 bytes are passed per packet. The maximum
number of character which could be sent is then 128 characters.
Also a set of standard condition phrases can be sent by sending an
ASCII control code which is interpreted into a string of ASCII
bytes. For example rather than sending "Roadcrews" working on left
shoulder prior to Watt Ave. exit", a control code is sent which
translates to "Roadcrews working", another control code for "left",
another for "shoulder", and another for "exit", as these are all
common terms used for building condition reports. A standard set of
these control codes are defined for use in the system. A
translation table is retained by the HBC non-volatile memory.
[0267] 6.4. Regeneration Channels, Slots and Regions
[0268] Event signal regeneration occurs in slots within
regeneration levels 210 of FIG. 6. The first signal generated is
considered the primary signal "P" 212, it is the event from which
the approaching drivers need to be alerted. Up to five regeneration
intervals 214, 216, 218, 220, 222 can follow an HB1 event. The
first interval 214 is subdivided into 16 regeneration channels 224.
In the example shown, the 16 regeneration levels begin with a slot
"8" then wrap back to a slot "7". The event signal packet generated
by the primary sender in this example had a slot number of "7"
encoded. The HBC within the vehicles which received this primary
data packet recognize that the event is to be regenerated. If they
all were to regenerate the signal a transmission confusion would
result, therefore, the slots allot respondents an interval in which
to regenerate the signal. Those receiving the transmission
calculate a slot ID from their embedded ID number and a portion of
the timestamp value. The calculation provides a time variance of a
few slots, so that a particular HBC may for example be able to
arrive at slot numbers 4-7, or 11-13 as determined by changes in
the timestamp. This calculated slot number is used to determine the
preferred slot number in which to transmit a regenerated signal. A
prospective responder upon receiving the primary event signal, sets
up a time-base wherein all transmissions are synchronized to slot
sized intervals. Event signal receivers synchronize to the center
of bit sized intervals within the slots. For the example of FIG. 6,
if the slot calculated were 8, then the HBC would check for a clear
transmission channel and then wait until it reached slot 8 to
regenerate the signal. However, the above description is a slight
oversimplification of the embodied process. The slot is actually
further broken down into regions so that various classes of
respondents can be accommodated. First of all, other vehicles may
also be slamming on their own brakes and wish to generate an event
signal. Secondly, the handling of instances of multiple respondents
on the same channel requires accommodation. Slot 12, 226 is shown
broken down 228 into four regions: event region 230, regenerator
region 232, and unused region 234. The actual packet size is shown
236 in relation to the slot which is twice as long. The use of the
regions is determined by the state of the prospective slot user and
the value in the timestamp register of the microcontroller. A
prospective HBC event signal generator after receiving the primary
transmission delays to reach its designated slot value for
transmission and then delays again for a calculated region
interval. The region calculation takes into account the various
factors.
region_delay=(Regen_f* EConst)+(TStamp XOR TConst)
[0269] A hard braking controller within a vehicle experiencing an
event have their Regen_f=0 and can attempt to secure the
transmission channel ahead of HBCs whose vehicles are just wishing
to transmit a regenerated signal. The value of (TStamp XOR TConst)
is a pseudo-random value created from the timestamp that
artificially separates respondents seeking the transmission
channel. So in practice, vehicles that have their own hard braking
event will delay a short random period within the slot, while
checking for other transmissions, and will send at the appropriate
time if the channel is ready. As there are actually two events
occurring here, the HBC will send the highest priority event.
Therefore, if a crash were to occur ahead, and an approaching
vehicle were then to slam on its brakes, the signal passed
rearwardly as the crash signal is the more important signal.
Vehicles whose HBC is trying to regenerate the primary event will
delay within the slot to give active respondents time to secure the
channel, then they delay a short random period within the slot,
while checking for other transmissions, and will send the
regenerated signal at the appropriate time if the channel is
otherwise clear. This embodiment additionally encourages the
transmission of generated events over regenerated events by
transmitting regenerated events at 6 dB lower power. All
respondents desiring to generate a transmission within their own
slot will have started transmission by the time region "U" 234
arrives. If no one is transmitting by the time region "U" is
reached within the slot, then responders unable to transmit during
previous slots, due to other respondents using the channel, can
then secure the channel and use it to respond starting in the "U"
region. All transmissions are started within the first three
intervals of the slot to assure that transmission completes within
the slot and does not spill over into subsequent slots.
[0270] Regeneration at subsequent levels is similar. A prospective
regenerator can fall into, one and only one, of the regeneration
levels. The region which they fall into is determined by the
highest level of transmission received. All prospective
regenerators that received the primary transmission can ONLY
respond as level 1 regenerators. Those that do not receive the
primary signal, but receive a signal from a level 1 regenerator,
then become prospective level 2 regenerators, and so on. This
method provides a maximum depth of signal dispersion for the
particular regeneration count used.
[0271] If an event is still active, such as a hard braking action,
then the primary event signal is regenerated at regular intervals.
Each time the primary event is regenerated, the slot number is
recalculated and bumped. In this example the slot number is
intentionally bumped by five on each iteration of the transmission.
This slot bumping allows reapportioning of the slot numbers so
different slots will come first. Additionally, the calculation
within each prospective respondent will provide a new time delay in
which different respondents within the same slot interval will then
get the chance to transmit. By allowing various respondents within
a group to perform the transmission, the transmission can reach
farther back in the group of vehicles and receipt of the packets
are thereby less prone to obstructive influences.
[0272] One significant case has not been discussed. Vehicle "A"
begins generating an event signal (primary vehicle), such as hard
braking, and within a few milliseconds a vehicle "B", only slightly
farther up the highway than vehicle "A" also begins generating an
event signal. Vehicle "B" does not receive the primary event
signals from vehicle "A", as it is ahead of vehicle "A", and
therefore "B" appears to have a clear communication channel and
sends an event signal packet. The system handles this condition by
allowing the signal from "B" to become the new primary signal.
Other vehicles that have just received the primary packet will
receive this new primary packet which contains a different ID. The
new ID alerts them to the fact that it is a new primary signal, the
old primary sender also received the new primary signal and now
queues up behind the new primary transmission. Vehicles receiving
the alert will alert their drivers but retransmissions are then
based only upon the new primary signal. If a transmission is cut
off, then the alert information is passed to the driver as a visual
or audio alert while any retransmissions to other vehicles must
wait for error free packets. In this way the data within the group
resynchronizes to the lead event generating vehicle and the
approaching vehicles respond and synchronize accordingly.
[0273] 6.4. Start Bit Sequence
[0274] It was mentioned that each prospective respondent waits for
a clear communication channel before sending a signal within its
respective slot and region. FIG. 7 shows a possible start bit
method 240 used for determining if the communication channel is
being used. If no other signals are being received, then a pair of
start bits are transmitted in a specific time relationship. Each
start bit is half the duration of a normal data bit used in
transmissions and therefore the start sequence is identifiable even
when it overlaps transmissions from another signal source. After
transmission of the first pair of half-width bits, a delay interval
occurs during which the transmitter checks for received
transmissions. If no other transmissions are received then another
pair of start bits prefaces the packet of data being sent. The
delay used herein is a variable delay calculated with a constant to
which a limited random number is added. This randomness helps
stagger the responses of respondents whose first start bits are
coincidentally transmitted simultaneously with one another.
Following the data packet is a checksum value that can be used to
validate the entire packet.
[0275] 7. Firmware
[0276] 7.1. Overview
[0277] The firmware within the microcontroller of the embodied HBC
measures hard braking information within the vehicle, keeps track
of the event status of the vehicle, it controls the activation of
hard braking indicators, it receives status from other vehicles, it
sends status to other vehicles, it provides driver alerts, and it
can receive input from the driver about how to process the alerts.
From the discussion of the signal regeneration mechanism it is
apparent that the rear-end collision reduction system is an event
driven real-time system with numerous input and output devices.
[0278] In order to keep costs low and maximize performance and
reliability the firmware of this embodiment is preferably written
in assembler code as a main loop with interrupt service routines
(ISRs) that handle time and event dependent activities. FIG. 8 is a
simplified flowchart representation of the Main loop 300 within the
system. At power on 302 the system initializes all data registers,
memory, and hardware; after which it performs a self-test on its
circuitry 304. A new_status byte is checked 306. If no new status
information has been received (as a result of ISR operation) then
the user input is checked for changes 308. If the user has input a
change, such as changing sensitivity, then the system hardware is
set for this new condition 310. A check for sensor updates is made
312 and if no updates then the Main loop restarts again. The ISRs
process the sensor data to create a set of instantaneous and
averaged values of pressure and acceleration. Large instantaneous
changes can set off a hard braking event immediately, those that
are less severe are averaged over a short period to create data
which is periodically reviewed by the main loop to determine if a
new hard braking state needs to be entered. The measured values are
processed 314 according to tables (described previously) which
determine what actions are to be taken in accord with the measured
results. After checking status 306 and finding a change the main
loop acts upon the status information based upon its current state.
It drops down through a subroutine calling tree, blocks 316 through
342, starting with checking for state HB1 316. If the new state is
to be as hard braking event level 1, i.e. Crash, then upon entry
318 the hard braking indicator is turned on, the driver is alerted,
and the sequence for generating event signals to other drivers
commences. In a similar fashion the other states, blocks 320
through 342, process their own state sequences. When a state
transition occurs, the prior state is always retained as decisions
are often based on the direction in which states are changing. When
event inducing conditions are no longer present then this is also
registered as a change of state which is processed. The main loop
operates as other loop based routines.
[0279] FIG. 9 is an ISR_Tick routine 400. This interrupt is driven
by a periodic interrupt every 50 uS. When the interrupt occurs the
ISR routine is entered 402 and the registers and status are saved
404. Upon each tick interrupt the timestamp, TStamp of the HBC is
incremented 406. This time stamp is used throughout the system for
relating events times. Additionally, a polling loop counter,
PolLpCtr, is decremented. If the polling counter decrements to zero
408 then sensor data is processed. The time for the polling loop is
set to match the basic serial data rate between the HBC and the
event signal transmitter and the event signal receiver. A check for
output signals is made 410 by checking SigOut_F. If the HBC has
sent the previous byte then a new byte is loaded 412 for
transmission to the serially connected event signal transmitter,
and the byte transmission count decremented. A check for last byte
is made 414 and if it is the last byte to be sent, then the
SigOut_F is cleared. Similarly RcvBlock_F is checked 420 to
determine if an event data packet is being received. If it is then
the next byte of it is picked up and stored 422 and the count value
is incremented. A last byte is checked (taking into account the
auxiliary information bit) 424 and the RcvBlock_F is reset 426. A
flag FlagSigRcvd is set to indicate to the main loop that new data
exists for processing. Raw pressure and acceleration data are read
from the sensors 428. An HB3 level is assumed 430 followed by a
check for a large pedal pressure increase 432. ISR exit is made 440
with HB3 level set when any very large pressure increase is
detected which appears to be certainly indicative of a hard braking
level. The acceleration data is next read and processed 434. Again
upon finding a large acceleration increase indicative of a hard
braking event the ISR is exited 442 after register restoration 440.
If neither case occurs then the assumed HB3 level is cleared 438
followed by register restoration 440 and exit 442. It should be
noted that changes of pressure and acceleration are averaged over a
number of these ISR intervals to produce a set of average and peak
related values stored in memory. These stored values are processed
within the Main loop to determine if they indicate the occurrence
of a hard braking event.
[0280] 7.2. Event Signal Receiver Module Firmware
[0281] The start bit logic on the event data packets was briefly
described earlier. The ESR module validates the start sequence of
incoming packets and collects packet data byte by byte which are
sent to the HBC. The HBC determines the meaning of the packets,
while both the ESR and EST are responsive to serial commands from
the HBC. FIG. 10 and FIG. 11 are flowcharts of the firmware within
the event signal receiver such that the general flow of processing
within one of these event signal communication modules can be
understood.
[0282] FIG. 10 exemplifies processing within an ESR main loop 500.
Upon power-up the processor leaves reset state 502 and performs
initializations and self-test 504. If all is normal a serial
message of "On-line" is sent 506 to the HBC, to let it know that
the module is functioning normally. The loop is basically a state
machine for verifying the start bit sequence and processing data to
and from the HBC. An interrupt service routine ISR_Tick 600 is
described below in reference to FIG. 11, collects the bits of the
event data packets. The state, RcvStateCtr, is cleared 508
(re-entry point). A check is made 510 for RcvStateCtr being set for
packet reception (=2). The state is 0, so a check is made on signal
data receipt from the receiver 512, as no data is being received a
check for commands from the HBC is made 514. If no commands from
the HBC then a check to see if the ISR_Tick interrupt has collected
up a byte to be sent to the HBC 518. If no bytes to be sent then
the main loop restarts with the RcvStateCtr check 510. When the
beginning of an event sequence is being received the check for
signal received 512 will cause the initiation of a start bit
sequence check routine. The start bit check comes in two parts, one
during state=0 and a second half during state=1. A check is made
for the second half of start sequence 522. As this is the first
part the timestamp value TStamp is copied to a variable and a
limited polling loop is entered which checks for the signal
transition to a "0", which signals the end of the first "1" bit of
the start sequence. The interrupts are still running keeping the
value for the timestamp updated. When a transition to "0" is
detected, or a timeout occurs, a validity check is performed 530.
If the sequence is invalid then the system clears the RcvStateCtr
508 and continues looking for other events. If the first "1" length
is valid at about 1/2 the interval of a normal bit size, then the
following "0" is checked for duration in the same manner 532, 534.
The second "1" bit is then checked 536, 538. After the second "1"
bit is a variable length period of no signal in which checks are
made by the transmitter to prevent "stepping on" other signals.
This period is checked within the main loop. The check for state
540 determines if this is a first half start verification or a
second. Since it is a first half, the timestamp value is copied and
the receiver state is bumped 542 to RcvStateCtr=1, which indicates
to process the second half next time. The main loop then continues
processing while the timestamp is being incremented. When another
signal is received 512, then the check 522 for RcvStateCtr=1,
causes execution of a verification step for the variable delay 526.
If the variable delay is not within bounds then the receiver state
returns to "0" and main loop entered 508. If the variable delay is
within the bounds then the start bit loop 522 commences to check
the two short "1" bit durations and the intervening short "0" bit.
If the bits are validated then the start sequence has been
completely validated and a data packet should be forthcoming. A
check for state 540, finds RcvStateCtr=1, indicating that the start
sequence has been validated, so the system is setup to process an
incoming data packet 544. The ISR_Tick interrupt service routine
actually processes the data packet, so it is initialized by setting
a BitLpCtrto a timer decrement value to synchronize the bit
collection times with the interrupt rate. The RcvStateCtr is set to
"2" so that the system will not be looking for start bits. The main
polling loop resumes 510 with the state check. The interrupt will
collect bits of data into bytes and set a flag RcvdByte_F when a
byte has been collected into RcvdByte. The main loop is checking
for this condition 518, and if a byte is ready to be sent, it is
sent to the HBC for processing 520. The HBC at any time that the
ESR module is not using the serial line, may sent a command to the
ESR module. The main loop checks for HBC commands 514. Received
commands are picked up, processed in view of ESR state and a
response is collected and sent to the HBC 516. Various status
gathering commands or data setting commands can be received. One
such message informs the ESR module that auxiliary data is to be
picked up within the current packet; the flag Aux_Data_F is
accordingly set for use by the interrupt routine. The ESR module
does not interpret the packet data and so has no manner to
understand if the auxiliary data bit is set. It can be seen in the
main loop that while the interrupt ISR_Tick is gathering bit data
the main loop is bypassing the signal received check, as the ISR is
collecting the data synchronized to a execution loop cycle derived
from the timestamp.
[0283] FIG. 11 exemplifies an interrupt service routine ISR_Tick
600 which is called within the ESR module at intervals set by a
hardware clock. The interrupt keeps the timestamp ticking and can
receive the data bits of event data packets. When the periodic
timer interrupt occurs, the ISR is entered 602. Registers and
status are saved, and the timestamp value TStamp is incremented
604. A polling loop counter is checked for activity 606. If the
polling loop is not active then the ISR is finished, therefore
registers are restored 632 and a return 634 to the Main loop is
performed. The polling loop is only used when data packet bits are
collected. These bits are collected synchronous to the timing of
the start bit sequence which was initialized by the main loop. Once
the start bit sequence is validated (RcvStateCtr=2), and the
BitLpCtr loaded then the ISR will collect the requisite number of
data bits. The check 606 therefore succeeds and the loop counter is
decremented 610, if the check for loop completion fails, then the
ISR is exited 632, 634. If the loop expires then the counter is
reloaded 612 and an event signal data bit is collected 614 and
stored via a bit pointer value into a variable where the collected
byte is built 616. A bit counter, RcvdBitCtr, and a total bit count
for the packet, TtIBitCtr, are incremented to indicate receipt of
one more bits. Checks are made to determine if the packet has been
completed or if auxiliary data needs to be collected. A check 620
on the auxiliary data flag, Aux_Data_F, is made. If no auxiliary
data then the total bits received is checked against the packet
size 622. If all bits still aren't received, then a check is made
for all bits within the byte being received 630. The total check is
performed before the 8 bit check since the packet may be defined on
an off-byte boundary. If 8 bits have not yet been collected then
the ISR is exited 632, 634. If the 8 bits had been collected, then
the built up byte would be stored in RcvdByte and the flag
RcvdByte_F would be set 628 in addition to the clearing of the bit
counter so that the next byte can be collected. If auxiliary data
is being collected then a check against a different total value are
made. If the data packets are expanded, the HBC can dynamically
read a size from within the auxiliary data which determines the
size. The size can be conveyed to the ESR for proper
collection.
[0284] 7.3. Event Signal Transmitter Module Firmware
[0285] The firmware used in the event signal transmitter (EST)
module is similar to that of the receiver. The EST transmitter
receives commands and data packets from the HBC. The EST responds
to HBC commands and transmits event data according to HBC
directives.
[0286] 8. Alternative Embodiments
[0287] 8.1. Alternate Brake Pedal Pressure Sensors
[0288] It must be recognized that a variety of brake pedal pressure
sensing mechanisms can be employed within the rear-end collision
reduction system. Two additional examples are now provided.
[0289] FIG. 12 depicts the incorporation of a strain gauge load
sensor within the activation rod of the braking system 650. The rod
is comprised of two section 652, 654 which are slideably engaged
via a sleeve 656 attached to the proximal end 652. A slide stop pin
with a sensor retention structure 658 retains the sleeve through a
slot in the rod preventing separation of the two halves of the rod
652, 654, while providing a mount for the sensor. A sensor
retention structure 660 is attached to the distal rod end 654,
wherein a load sensor 662 is mounted between the two sections.
Pressure applied to the activation rod creates force across the
load cell that can be registered by the HBC. The use of this brake
pedal pressure sensing embodiment may require manufacturers to
design, test and stock a variety of activation rods for various
vehicles. Additionally, the unit shown does not sense acceleration
of the brake pedal, while it can induce a sense time delay when
compared with the embodiment previously described.
[0290] FIG. 21 depicts an alternate pressure sensor 1100 that
incorporates a liquid/gas pressure transducer 1102 coupled with the
brake master hydraulic cylinder 1104, for sensing the braking force
applied by the driver. The pressure transducer output 1106 can be
measured by the HBC in the same manner as the pedal pressure sensor
described earlier. This hydraulic mechanism of sensing is simpler
to implement, however, it is generally less sensitive to pedal
pressure changes and provides a delayed output in comparison with
direct pedal pressure sensing. In addition, this hydraulic sensing
lacks the accompanying pedal acceleration sensor described
earlier.
[0291] 8.2. Wireless Brake Pedal Pressure Sensors
[0292] The brake pedal pressure measurement unit was previously
described as being connected to the HBC with a set of wires forming
a serial link. Alternately, the pressure sensor can be configured
with a transmitter on which the pressure signal is encoded, and the
HBC would thereby require a receiver for registering the
transmitted pressures. A variety of transmitter receiver pairs
could be considered.
[0293] (1) Audio Output-The pressure sensor could generate a unique
audio signal pattern that is picked up by a microphone in the HBC
and processed using digital filtering within the microcontroller
firmware within the HBC. The audio could be in the normal audio
range of human hearing or ultrasonic frequencies could be used. If
false triggering of the audio were found to be a problem, the
firmware would adopt a learning algorithm in which the sound input
would be correlated to the brake input to store corrective
information so that the system would be able to distinguish other
normally occurring sounds from that of the brake pedal pressure
sensor.
[0294] (2) Radio Frequency--The pressure sensor can incorporate an
RF transmitter wherein the HBC would house an RF receiver. Simple
single chip RF units are available currently at low cost for
transmitting and receiving digital data at low speed. An example of
such a receiver is manufactured by Micrel Semiconductor.TM. which
manufactures a line of single chip receivers, currently
MICRF001.TM. through MICRF033.TM. which provide various RF receiver
rates and functions in package as small as an 8 pin surface
mount.
[0295] In utilizing any form of wireless link, such as those
described, it must be realized that the pressure sensor would
require another form of power, as no wiring connection would then
be provided. The use of battery power by the pedal sensor module
obviates the need of reduced power levels in the sensor, which
suggest providing transmissions from the pedal only when the
pressure level exceeds predetermined thresholds. Maintenance of
such a system is questionable, as vehicle owners may be disinclined
to replace the batteries on the system as a large part of the
benefit is to approaching drivers. Transponder technology may
alternatively be applied to the pedal sensor, however, it use with
presently available circuits would reduce reliability of the unit
and increase costs.
[0296] 8.3. Roadside Condition Reception and Reporting
[0297] 8.3.1. HBC Protocols integrated within a Call Box
[0298] HBC compatible protocols and communication can be
incorporated into equipment to provide additional communication
capability along highways and roads. When the RAAC system according
with the present invention has been widely implemented, a number of
other positive benefits can be easily derived therefrom. Emergency
crews can be summoned more readily to accidents and drivers may be
automatically alerted to various road hazards and conditions
ahead.
[0299] One location in which to implement these features is within
roadside call boxes. Roadside call boxes are self-contained
wireless phones along the highways that allow drivers to call for
help in the case of an emergency or a road-side breakdown. Call
boxes are already being tested for use in collecting traffic data,
which is then uploaded to computers via the wireless phone within
the call box. Portions of the described HBC functionality can be
added to these call boxes to extend functionality.
[0300] FIG. 30 is a block diagram 1500 of a call box shown with
additional HBC related circuitry. The standard call box is powered
by a solar panel 1502 whose output is controlled with a power
controller 1504 which charges a battery 1506 and provides power to
the remainder of the circuits within the call box. An RF section
1508 performs the modulation/demodulation of the voice data to/from
the RF carrier of the wireless system which is broadcast and
received via the antenna 1510. A phone 1514 is connected to the RF
section which provides a microphone and speaker.
[0301] A new set of circuitry 1516 according to the present
invention is thereby added to a conventional call box for extending
the aforementioned functions. A line interface 1520 provides a
phone line interface and a modem to the HBC type functions. A
message control unit 1522 handles conversion of messages to/from
the modem. Events can be generated (HB7 events) from the call box
by passing data to an event encoder 1530 which passes the encoded
data to an output transmitter 1532 whose antenna 1534 projects the
signal generally opposite to the direction of traffic flow. Events
can be collected (ALL events) by a receiver 1538 whose antenna 1536
is directed with the flow of traffic. Event data is decoded 1540
and passed to the message interface.
[0302] Drivers can be alerted to conditions on the roadway very
easily using this system. For instance suppose that the message
"Icy Road near Ice House Exit" was to be generated for drivers
approaching this dangerous roadway condition. A call is made to the
call box by a dispatcher. The call is picked up by the line
interface 1518 and the modem collects ASCII data for "Icy Road near
Ice House Exit". The data is passed to the message control section
1522 which formats it and passes it to the event encoder 1530. The
event encoder 1530 uses HBC protocols to break the message down
into multiple packets for transmission each of which are saved. If
no events are occurring on the highway being monitored by the
receiver section, then the event encoder starts packet sending to
the transmitter 1532. The packets are sequentially sent one by one.
Once all packets are sent, then a delay occurs after which the set
of packets are sent again. Prior to sending each packet, a check
for roadway events is made, so that no low priority packets get in
the way of actual high priority events. Drivers approaching the
call box receive the packets; a small beep alerts the driver as the
message "Icy Road near Ice House Exit" scrolls on a text display on
the console. Alternately, the received packet can be annunciated
with audio by the receiving HBC of the vehicle which contains a
speech synthesizer.
[0303] Emergency crews, Highway patrol and other personnel can be
alerted to roadside conditions by the call box. Imagine a
wheelbarrow has fallen off of a truck and is laying on the freeway.
Cars approaching this debris will be swerving, and many will be
slamming on their brakes. The HBC units of these vehicles will be
correspondingly generating event data. The event data is being
received by the receiver section 1538 in a call box. When a
settable threshold level is reached on events (i.e. 4 hard braking
events within 2 minutes), then the event decoder packages the event
data into an ASCII stream which is passed to the message control
1522. Message control then adds other info (call box number,
location, time) to the message and formats it for transmission. The
modem in the line interface 1520 takes the message and transmits it
via the RF section 1510. Emergency crews are alerted that some
condition exists here on the roadway and nearby units can be
quickly dispatched to remove the debris so as to reduce the chances
of damage or accidents.
[0304] Alternatively, the call box unit can send data to the
dispatchers as a series of voice data. This requires that the call
box contain a speech synthesis and storage ability, such as stored
speech segments for numbers and location, or formant encoding
speech synthesis routines. Dispatchers would be capable of download
new speech segments remotely by calling in and providing a special
DTMF code, wherein speech is encoded 1524 and stored in memory
1526. Receipt of roadside events causes packet info to be collected
by message control 1522. When the threshold is reached, then
message control assembles audio message tokens pointing to speech
segments in memory 1526. The message control section initiates a
call via the line interface which provides the call connection.
Message control then controls the playback from the token stream by
passing pointers to the decoder which extracts and synthesizes the
audio segments which are transmitted out to the dispatcher.
[0305] Various other message encoding formats can be used aside
from voice and digital ASCII via a modem. For example DTMF or MF
coding may be used for passing textual type data.
[0306] The circuitry added to the call box to provide these
functions contains a microcontroller as used within the HBC, a
modem, a phone line interface, an event receiver module, and an
event generator module. The firmware within the HBC microcontroller
is modified to perform the additional control of the modem and line
interface but already contains protocol information and packet
knowledge.
[0307] 8.3.2. Monitoring of Roadway Conditions within a Roadside
Audio Status System
[0308] In another embodiment of an intelligent call box, the call
box is additionally, or alternatively, configured as a roadside
audio status system which is capable of detecting traffic
parameters, roadway conditions and of discerning accidents by the
processing of audio information from the roadway to discern roadway
information. It will be appreciated that the "call box"
functionality described in this section is equally applicable to
other roadside equipment, or vehicles. It has been a long-felt need
to determine the conditions of a section of roadway, such as
vehicle speed, and so forth, for communication and control
purposes. However, the conventional devices for monitoring roadway
conditions teach the use of active systems such as laser systems,
broken beam light sensors, pressure pads, and the like which
consider vehicles as passive devices from which an active energy
source must be reflected and analyzed. These teachings treat the
vehicles decidedly similar to articles, for instance cans of
hairspray moving down an assembly line, while in addition they are
expensive to implement and maintain. The present system eschews the
necessity for active detection in favor of passive audio detection
and realizes that the vehicle is already an active transmitter
which may be passively detected to determine the number of
vehicles, vehicle speed, and even vehicle size and type.
[0309] In general, the technique of the present invention utilizes
audio sensors within a call box, or other roadside contrivance,
which receives and processes the sounds of the vehicles as they
pass to determine road and vehicle parameters. It will be
appreciated that each vehicle on the roadway at any particular
point in time presents a unique signature, or "voice", to the
stationary audio sensor. The system processes the audio to identify
each unique vehicle in its field of audio reception. Vehicles are
"identified" by a set of audio signature characteristics,
sufficient characteristics are preferably extracted to uniquely
identify each subject vehicle, without regard to temporal
displacement. Digital signal processing techniques are utilized for
extracting signatures, and signature analysis itself is well known
in the electronic arts and is widely practiced, such as in relation
to voice print analysis, analyzing radar signatures, and the
signature analysis of submerged vessels. As the signatures are
temporally analyzed, the number of individual vehicle signatures
will be easily discerned, because each engine is at a specific set
of conditions, such as RPM and acceleration, whereby the
differences between vehicles can be detected. If the signal
analysis routine is sufficiently sensitive, it can be determined
how many cylinders are in each engine within the individual
vehicles. This is possible since each firing cylinder produces a
slightly different sound due to slight variation, such as spark
timing, mixture, cylinder condition, and so forth. Additionally, it
will be appreciated that the sound of the vehicle, such as
amplitude, will change as the vehicle position in relation to the
audio sensor changes. Extracting the signature, therefore, provides
a measure of the number of vehicles on the roadway, which may be
augmented by detecting the doppler shift points on the audio
streams being detected. Furthermore, the system is preferably
configured to recognize emergency vehicles with active sirens which
traverse the road, so that emergency vehicle position may be
relayed by the system, along with the detection of impact audio for
the direct discernment of accidents on the roadway.
[0310] Speed may be determined for each identified vehicle by using
at least two coordinated audio sensors. Based solely on the audio
sound being detected, the position of a vehicle is precisely known
as it passes the audio sensor due to the Doppler shift that occurs.
The Doppler effect on the sound received from the vehicle will be
readily recognized by anyone that has ever stood beside a roadway
or a train track; as a vehicle approaches it has a particular sound
frequency with a rising amplitude, as the vehicle passes out
position the sound shifts to a lower frequency and the amplitude
then begins falling off with respect to time. By detecting the
Doppler shift point, the position of each vehicle is known at a
given instant in time with relation to the audio sensor. Speed is
thereby accurately measured by detecting the Doppler shift point
for each particular vehicle at more than one location along the
roadway.
[0311] Referring now to FIG. 31 a section of highway 1551 is shown
with three lanes A, B, and C. A call box 1551, or other apparatus,
is shown alongside the roadway upon which three vehicles 1552,
1553, 1554, are traveling. A microphone 1555 is shown receiving
audio from the roadway in a path 1556. Multiple microphones may be
utilized to improve the detection ability, for instance, by
improving reception, and removing deadspots. A pair of extra
microphones 1557, 1558, is shown, although microphones may be
across the roadway or otherwise disbursed. It will be appreciated
that the microphones should be preferably position at a height of
at least six feet so as to reduce the amount of sound blocking,
wherein a vehicle in a lane near the microphone such as vehicle
1552, blocks the sound from a vehicle, such as 1554, that is in a
lane farther from the microphone. Configuring the audio status
system for attachment to an overpass or overhead lighting could
provide a near optimal angle from which to receive audio generated
by traffic within any lane of the highway.
[0312] A first method of properly registering vehicle velocity
according to the roadside audio status system aspect of the present
invention utilizes coordinated information from widely spaced
microphones. If the accurate registration of speed is desired, a
separated microphone may be utilized so that time between the
locations may be detected. FIG. 31 illustrates a pair of units in
communication with one another, first box B.sub.1, 1551 which
communicates with a secondary status box B.sub.2 1559 having
microphone 1560, and antenna 1561 through which a link is
established with antenna 1562 of the first box 1551. The secondary
box 1559, need not be a call box, but preferably comprises a small
system unit mounted on a sign or other post near the roadway. The
secondary box is optimally located between twenty and one-hundred
feet from the first box and it transmits the collected audio back
to the first box. Each vehicle passing the first box is identified
as per its sound signature. The time of passing the first box is
registered by means of the Doppler shift which takes place in the
audio sound. The first box continues to "track" the various audio
signatures as they continue past the first box, the first box is
continuously receiving the audio from the second unit and
correlates this information with the signatures, thereby extending
the "tracking" for each vehicle. As the vehicles pass the second
box, the Doppler shift is again detected for each vehicle and an
average speed of that vehicle between the boxes can then be
determined. As the second box requires only a microphone,
amplifier, and transmitter it may be powered by a battery, or
alternatively as a transponder circuit, wherein it receives a
signal from the first box that is utilized for power in driving the
transmission back from the second box to the first box.
[0313] A second method of properly registering vehicle speed
utilizes sound modulators at fixed locations along the roadway
which are capable of modulating the audio of the vehicle as
received by the microphone. The intervals registered as a vehicle
traverses these sound modulators is detected within the received
sound pattern. One form of these sound modulators may be created as
spaced grooves cut in the pavement as exemplified by a groove 1564
of FIG. 31. Two sets of parallel grooves are shown with a first
group 1566 on the approach side of the microphone 1560, and a
second group 1567 shown on the departure side of the microphone
1560. The grooves have been shown in connection with the second box
1559 for the sake of figure clarity, however, it should be
recognized that by configuring the roadway in the described manner,
only a single microphone unit is required which would preferably be
associated with the first box, while the adjacent roadway surface
would be configured with the sound modulators. In operation, the
roadside audio status system in this second configuration detects
the additional sound modulation caused by the vehicle traversing
the spaced grooves and is capable of determining additional
information about the vehicle, such as vehicle velocity,
acceleration, braking, approximate weight, and number of axles. The
two separate sets of grooves 1566 and 1567 simplify the process of
determining speed, since the received audio for a traversing
vehicle will contain the audio signature of the vehicle onto which
is imposed two separate bursts of modulation, the interval between
which being related to the known distance between the sets of
grooves to accurately determine vehicle speed. The modulators have
been exemplified as grooves in the pavement, yet they may
alternatively be implemented as paintstrips, channels, or any of
various dimpling or protrusions in the roadway surface. The
modulation of vehicle audio produced by using on-surface horizontal
modulators can be very simply and accurately detected by the
vehicle audio discrimination circuits. However, for use on roads
that may get icy in the winters, thereby obscuring modulation, the
modulators may be alternately implemented as above ground vertical
sound reflectors on the opposite side of the roadway from which the
sound of the vehicle is reflected prior to being received by the
microphone. The vertical posts used to secure the center partition
on the roadway may provide adequate sound reflection so as to pick
up the modulation in the received audio, otherwise other forms of
spaced reflectors may be utilized. A preferred vertical modulator
may consist of parabolic dishes 1568 attached to the center
partition 1569 and focused on the microphone. The discrimination of
vehicle speed from vertical modulators is more complex than with
the use of horizontal modulators because the microphone must
discern the modulation in a reflected, "echo", of far lower sound
energy while it still tracks the original sound. In addition, in
using the vertical reflection modulators, the reflection geometries
and audio reflection distances can come into play.
[0314] The roadside audio status system of the present invention
provides a very inexpensive and low maintenance method of
monitoring traffic flow and status within a section of roadway, and
is preferably capable of determining: number of vehicles, speed of
vehicles (average, high, low, median), level of safety level (based
on amount and severity of brake application), size of vehicles,
number of cylinders, determining number of axles on the vehicles,
sensing emergency vehicles, and sensing accidents. The system can
be calibrated as per sound level, so that the absolute value of the
sound amplitude and characteristics thereof may be used to discern
vehicle characteristics. It will be appreciated that the roadway
status may be maintained at a central station into which numerous
roadside call boxes and other system reports flow.
[0315] Referring now to FIG. 32 is exemplified a circuit 1570 for
use within the roadside audio status system depicted in FIG. 31. A
first microphone 1572 is shown for receiving roadway audio from the
subject vehicles, while a second optional microphone 1574 is shown
which may be utilized to improve signal discrimination. The
microphone(s) outputs are conditioned and amplified by a pre-amp
1576 and digitized by A/D converter 1578 prior to receipt within a
digital signal processor (DSP) circuit 1580. Numerous signal
processing algorithms execute within the DSP unit for discerning
various parameters of the received audio. It will be appreciated
that numerous DSP circuits may be integrated, wherein they may each
be configured to discern a separate metric of the audio stream. By
way of example and not of limitation, a few types of algorithms
which may be executed within the DSP circuit are shown in block
1582 to include: identifying vehicles, detecting the Doppler shift
point, transmission of vehicle arrive time (for use with multiple
boxes), detection of braking, heavy braking, crash detection, along
with road condition detection, and the detection of sounds
associated with the modulators. The DSP circuit is interfaced to a
controller 1584, that orchestrates the functioning within the audio
status system and additionally controls the configuration of the
pre-amplifier 1576, A/D 1578, and the DSP 1580. The controller may
also provide computation functions that relate to the logging, and
calculation therefrom, of parametric data extracted by the DSP
circuit. A block 1586 is shown containing example functions that
may be performed by the controller 1584 which includes the external
communication, speed calculations, logging of data, and maintaining
statistics. The controller is optionally connected with a
transceiver 1588 to allow it to communicate with other call box
units. The controller is shown with a connection "A" 1590 that
preferably interfaces with the message controller 1522 of the call
box as shown in FIG. 30, so that the collected information may be
relayed via the call box circuitry to vehicles as an event
according to the aforementioned communication aspects of the
invention, or by way of the call out functionality inherent within
the call box unit.
[0316] 8.4. Alternate Internal Driver Visual Displays
[0317] The embodiment of the RAAC system previously described in
FIG. 5, was illustrated with a simple set of LED indicators as a
visual display for alerting the driver to events occurring ahead
and the visual indicators should be placed and configured to
function so that roadway alerts are readily seen, understood, and
acted upon. FIG. 33 shows a driver alert signal 1600 containing the
LEDs 186 as shown in FIG. 5 mounted for easy recognition. A
dashboard is shown 1602 with a steering wheel 1604 and rear-view
mirror 1606. The visual alert 1608 is positioned in front of the
driver so that it is near his field of view. Preferably, the visual
alert will appear similar to the auxiliary brake light displays
attached above the rear deck up against many vehicles rear window.
FIG. 34 shows a front view of the alert indicator 1620 with a set
of 3 lighted regions: two red areas 1622, 1624, and a white light
area 1626. These lights or LEDs are modulated on and off according
to the event conditions received by the HBC unit from vehicles up
ahead. The car immediately ahead may not have yet applied the
brakes when this little warning indicator warns the driver of the
possible danger ahead. Red LEDs are activated at low intensity for
low levels of hard braking detection, or emergency flasher
deployment. Red LEDs go to high intensity and white LED is
activated for high levels of brake slamming, while additionally the
white light is modulated on and off for severe events and
crashes.
[0318] To provide additional information to the driver an enhanced
method of visually alerting the driver provides a graphic and
textual display means. An SPI serial channel Disp 190 of FIG. 5 was
provided for connection to a more complete visual display. The HBC
can provide data which may be used with a wide variety of driver
displays. An alternate embodiment of a display 1150 is shown in
FIG. 22. A display controller 1152 is formed by a microcontroller
or a mix of control and discrete electronic circuits. The display
controller 1152 receives an SPI serial input from the HBC (not
shown) which may additionally be used to receive input from other
system circuits. The SPI has a data in line 1154 which is pulled up
to Vcc by a resistor 1156. A data out line 1158, a system clock
1160 with pull-up 1162, and a chip select 1164 with pull-up are
provided. The pull-ups allow devices aside from the HBC to also
send information to the display controller. When the HBC is not
sending data to the display controller it leaves the data in line
1154, synch clock 1160, and chip select 1164 outputs in tri-state
mode. Prior to transmission the chip select is read as an input by
the HBC, if it is not low, then the HBC can pull it low to grab the
serial input at which time it clocks the synch clock signal to
clock the bits of data out and data in. Other controllers wanting
to pass information to the display controller follow the same
procedure.
[0319] The display controller contains memory and an interface to a
set of displays. Shown are a pair of displays where one is used for
graphics and one is used for textual display. A set of multiplexed
signal lines 1168 provides the drive signals for the graphic
display 1170. The small graphic display is currently displaying
representation of the vehicle 1172 with a surrounding compass rose
1174 and a tailgating value. The Value "2/6" shown indicates that
the car is following about 2 car lengths behind another vehicles,
when it should be at least 6 car lengths away. When an event
occurs, the graphics display changes from that of a compass to an
icon or animation which indicates what hard braking event has
occurred. For example a accident up ahead may be shown as an icons
wherein two vehicles are merged as in a rear-end collision. A
textual display 1180 is used to convey general information or
highway information to the driver. A set of multiplexed signal
lines 1180 provides the display signals from the display controller
1152. The text line shown is indicating a roadway condition alert
as provided by a call box roadway condition generator as previously
described. The text line may be used by other vehicle system for a
variety of purposes.
[0320] In addition it must be realized that vehicles can provide a
wide ranging set of displays upon which HBC information can be
displayed. Another example is the use of a moving map style graphic
display to convey additional HBC information (not shown). These
moving maps are often a part of a global positioning system (GPS)
within the vehicle. In order to display event messages on the GPS
moving map, the GPS system must provide for external input, whereas
the HBC then signals the data to the GPS unit for display on the
moving map. Furthermore a variety of additional display formats,
such as a heads up display, may be utilized upon which to display
driver alerts,
[0321] 8.5. Alternate External Hard Braking Visual Indicators
[0322] There are also numerous mechanisms by which the hard braking
information from the HBC can be visually indicated to approaching
drivers besides the use of the existing reverse lights, braking
lights, and auxiliary braking lights modulated by the HBC that have
already been described.
[0323] One or more additional indicator lights may be added to the
vehicle for the display of hard braking event information, as
previously mentioned, however implementation requires that
relatively large vehicle design changes be made and that drivers be
trained to the meaning of the new indicator.
[0324] Existing indicators can be modified to provide enhanced
ability for displaying a visual hard braking indication. A number
of alternative embodiments are described which can be used
alternately or in combination with indicators already
described.
[0325] Additional lights (including LEDs, and incandescent lights)
can be added to existing auxiliary brake lights. These auxiliary
brake lights are centrally located on the rear of a vehicle,
usually on the rear deck inside the window or on the top portion of
the trunk deck. The auxiliary brake lights provide another brake
indication which is easy to see, and often these units contain a
series of lights, such as LEDs which are activated in response to
the brake activation. In some cases the lights are activated
sequentially to increase speedy recognition. Lights of a color
other than red, such as white or light blue, can be added to the
auxiliary braking indicator assembly under the control of the HBC.
A separate group of these lights may be added with a separate power
line connected to the HB Ind signal 166 of FIG. 5. Alternately the
existing wire may be used to provide power and for signaling.
[0326] To independently control a series of illumination sources
within a single indicator without necessitating major vehicle
wiring changes, conventional wiring can be used in conjunction with
a light signal controller (LSC) which is mounted in proximity to
the actual indicator lights on the vehicle. The conventional power
line to the light, whether it be a turn signal, a brake light, an
auxiliary brake light, or a reverse light, is used as a power and
signal bus to a light signal controller (LSC). The power line is
held high except for short negative pulses that form a signal bit
stream to the LSC. (Opposite a traditional light wherein that is
activated by high voltage). The LSC interprets the signals and sets
the lighting accordingly. FIG. 36 depicts an LSC 1700 in this
configuration with the HB Ind signal from the HBC, which by
firmware or external select signal is configured to maintain the
output signal and provide transitions only for the sending of
serial data to the LSC. The HB Ind signal 1702 is shown coming from
the HBC and connected to an LSC 1704 which in turn controls the
activity of the reverse gear light 1706 (normally a white light).
The LSC circuit preferably contains a microcontroller, such as the
Microchip Technologies.TM. 12C508.TM., a power supply and I/O
voltage conversion circuits so that the voltage levels of the
microcontroller are compatible with the voltage levels of the power
line, in this the HB Ind signal with 12-14 volts. Alternatively
special purpose processors can be used that employ voltages already
compatible with the power voltage. A power retention circuit 1710
retains power to the controller when the generation of negative
going signals cause the power to drop for brief bit intervals.
Alternatively the power line, HB Ind in this case can be modulated
by a small signal voltage which is amplified within the LSC.
Although slightly more complicated this has the advantages of
easing LSC power supply design and reduces the emissive power
resulting from swinging large currents. The LSC senses the logic
level on the line 1702 (alternately measures via A/D converted the
voltage and determines which logic level) to capture the serial
signal transmitted by the HBC. Upon receiving the start of a
signal, all indicators are switched off to facilitate the data
transfer. The serial data of the signal indicates what is to be
indicated by the combination of lights, 1706, 1716, 1718. The LSC
upon receiving a signal sets the lights in a static setting
(On/Off), or alternately performs sequencing actions upon the
series of lights. The HB Ind signal is shown 1702 being routed to a
subsequent LSC, which in this case would be the reverse light on
the other side of the vehicle, and then perhaps to the auxiliary
braking indicator. This bus arrangement can connect to a series of
lights used for the same general function. The indicator light 1706
is shown incorporating an optional RF signal generator 1720 to
comprise an event signal transmitter (EST). The incorporation of
the RF transmitter within the bulb, or indicator module is
beneficial as power is continually available at the indicator 1706
and the indicator lamp is positioned within a plastic lens case
through which RF may be transmitted.
[0327] This aforementioned mode of controlling indicators has
numerous benefits over conventional indicator control while it
retains many of the benefits. The same power line from a fuse box
provides a conventional connection that is easy to understand and
troubleshoot. Providing a constant power to the LSC allows active
circuitry to be incorporated in the indicator package. The LSC can
control a series of lights for signaling a single action or
multiple actions. In this case the LSC controls a normal reverse
light and additional LEDs. Within this embodiment the LEDs are
bright Blue LEDs used to flicker along with the hard brake light to
attract extra attention. Alternately any form of lighting can be
controlled as well as various other output devices, such as a sound
generator. The LSC can control various forms of lighting which
include incandescent lights, flash circuits, LEDs or semiconductor
lasers. The LSC circuitry can be provided as a separate module or
fully integrated into a lamp or lamp cluster that may even connect
to the vehicle with the same bayonet style mount as used with
conventional incandescent lights.
[0328] A light cluster containing a group of semiconductor
indicator lights integrated into a bayonet mount are shown in FIG.
37 and FIG. 38. A top view 1750 of FIG. 37 shows a cluster with a
bayonet mount light housing 1752 with a central mounted LED 1754, a
bayonet mounting nub 1756 and a series of LEDs 1758 attached to
extension arms 1760. The extension arms shown are of various
lengths for optical and to facilitate easier removal. The extension
arms are flexible members that carry a pair of conductors to the
LED. As a group these can be flexed into a form similar in size to
a conventional bulb and inserted into a convention bulb socket.
Upon removal, the LED attachment arms automatically flex to allow
easy removal. FIG. 38 shows a cut-away view of the light cluster
1780. The main base of the lamp 1782 is a cylindrical form, whose
outer surface forms one electrical contact, with a rounded sealed
bottom that contains a contact nub 1786 for the other contact. A
printed circuit board containing the circuitry of the LSC 1788 is
shown with attached central LED 1794 and extension arms 1790 that
each terminate in an LED. In this embodiment LEDs are mounted as
die on a flexible circuit which contains the twin conductors. The
flexible circuits are bonded to a resilient plastic extension arm
with the shape as shown. The extension arm assembly then has a
plastic lens formed over its LED and the end of the flex-circuit
and plastic support. A series of these arms are soldered to the LSC
circuit board. The LSC circuit board contains an underside
contactor pin and multiple sidewall contacts to the cylindrical
housing. The assembly is inserted into the cylindrical housing and
is filled with a nonconductive potting compound which secures the
assembly to the housing. A number of variations can be created to
the light cluster without departing from the inventive
principles.
[0329] Another example of the use of an LSC provides adding unique
lighting features to turn signals, brakes or reverse lights for
conventionally wired vehicles. A lighting cluster as shown in FIG.
37 and FIG. 38 and an LSC as shown in FIG. 36 is used in a vehicle
that is not equipped to control the LSC with serial signals. The
LSC in this mode, upon receiving power, enters into its display
routine under firmware control, wherein lights are alternately
turned on and off in various patterns by the controller of the LSC
to create a light display. For example a circular pattern may be
created wherein a pair of opposing radially extended lights are
activated, after 200 mS those lights are turned off and the next
clockwise pair of lights are activated. The light pattern therefore
is seen to swirl around the large center light which is on during
the entire period. The colors of the lights can be varied as well
as the patterns produced.
[0330] 8.6. Use with various Serial Interfaces
[0331] The HBC in the previously described embodiment employed an
SPI serial interface to communicate with the various sensors within
the system. Currently a variety of serial protocols are vying for
acceptance in the automotive field, and any of these standards can
be employed within the HBC for signaling. Currently there are
standards for air-bag sensor busses (higher voltage), and a CAN
signaling protocol which is being adopted in a variety of forms by
various manufacturers, while some auto industry leaders are
proposing a shift to higher voltage systems (i.e. 42 Volts) and new
buses. it must be understood that the system shown can be modified
for use with any serial protocol or implemented by one skilled in
the art to provide the alternate serial interface signaling.
[0332] 8.7. Event Communication
[0333] The previous description of the communication of event
signals referred to the use of a rearward mounted transmitter unit
and a forward mounted receiver unit, however transceivers can be
substituted at either or both locations. The use of single
direction communication is all that is necessary, however, added
functions can be provided at an added cost by using a forward and
reverse transceiver instead.
[0334] 8.8. Enhanced HBC System Monitor
[0335] FIG. 17 is an enhanced HBC monitor 800 that contains crash
data logging. It may be desirable to provide a more in-depth HBC
monitor than the one previously described in FIG. 5 monitor circuit
150. The monitor circuit 800 of FIG. 17 provides in-depth circuit
state monitoring as well as a sensor log. This extended monitor
circuit can be especially useful with regard to a Phase IV
implementation wherein a form of automatic reaction is performed by
the system. When automatic functions are performed (as contrasted
with alert functions) it is especially useful from a manufacturer
standpoint to log the conditions under which the critical actions
took place. General Motors Corporation.TM. has begun to include
simple black boxes for monitoring the status of the airbag systems.
This monitor provides this form of logging whereby system activity
just prior to a crash is recorded. The monitor circuit of this
embodiment preferably employs an identical microcontroller circuit
802 as used within the HBC. A three wire serial Flash memory
circuit 804 is connected to the microcontroller 802 through a Flash
access device 806 which provides dual port access to the Flash
memory 804. HBC condition inputs are shown 810-842 that represent
the internal inputs of the HBC and the outputs provided by the HBC.
A group of four state inputs 850, 852, 854, 856 additionally
receive state information provided by four digital outputs from the
HBC microcontroller (not shown). These inputs to the monitor
provide additional information regarding the operating state of the
HBC so that a more complete log entry is kept. Also a set of inputs
860, 862, 864, 866 is received from the airbag deployment system
and additional safety inputs, so that this data also stored for
correlation along with the HBC collection of data. As with the
simple monitor circuit, an error indicator is provided 870 and an
output that allows the HBC to be held in reset via the Master Clear
signal 872 by this extended monitor circuit.
[0336] The monitor circuit continuously logs data in an internal
buffer. Data is checked continuously for large changes of invalid
HBC conditions. The data is tested to assure correct HBC operation
according to the same tables and criterion used within the HBC.
Data is only recorded to the log when changes to conditions warrant
it, this saves log space. Additionally cumulative changes are
lumped together in a log entry so that the majority of useful
information gets recorded. Each entry contains a relative timestamp
value, so that event relationships may be later gauged. At least 5
seconds of data is contained in the internal log. When the HBC
crash sensor activates, the log is copied to Flash and additional
logging is performed for another 10 seconds. Upon analyzing the
crash, this log may be downloaded via the serial port bits 880,
882, 884 to a collection device. Analyzing the log provides details
on what the vehicle experienced prior to and just after the crash.
This data is similar to what a cockpit recorder provides (black
box), yet is much simpler and less expensive. The information can
prove very useful in post-crash analysis to determine which driver
was at fault, and additionally may be used to squelch invalid
driver assertions of system malfunctions.
[0337] 8.9. Simple Phase I implementation
[0338] A few simple but less robust phase I implementations can be
created less expensively and with lower tooling costs than the
previously described phase I implementation. The following
implementations are perhaps more suitable as an after-market
addition than as a manufactured item.
[0339] (1) Bladder pressure sensor-Herein an air bladder reservoir
is manufactured into the brake pad, with a small pressure hose that
leads from the foot pedal reservoir to a simple HBC containing only
the pressure input and the HB Ind signal output shown in FIG. 5.
The HBC in this case contains a pressure transducer for registering
the pressure applied to the air bladder. Although workable and less
expensive, such a system is difficult to implement reliably.
[0340] (2) Audio output pressure sensor-Herein an air bladder
reservoir is manufactured into the brake pad. The air bladder in
this case contains a valve responsive to pressure above a
predetermined level which corresponds to hard braking (>30
pounds of pedal pressure), which terminates in an audio emitting
mechanism. The pedal pressure sensor can be thought of similarly to
a child's squeak toy, yet with a pressure valve that only allows
activation above a given threshold. When pedal pressure is reduced
after activation the pressure reservoir refills automatically due
to the surrounding structure of the reservoir. The HBC is
configured with a microphone for reception of the squeak sound from
the pressure sensor. The circuitry of the microphone is set as a
bandpass filter set to the squeaker frequency, while the HBC
firmware contains additional digital processing of the squeak
sound. When a correct squeak sound is registered then the hard
braking light is activate. Reliability of this system could be
difficult to achieve due to both the mechanical nature of the
sensed pressure and in trying to discriminate the pedal pressure
"squeaker" sound from other sounds that occur within the vehicle,
such as squeaky pedals.
[0341] 8.10. Forward Looking Audio Correlation System
[0342] FIG. 39 and FIG. 40 exemplify a forward looking audio
correlation (FLAC) system that is capable of being utilized in
combination with the HBC of any phase, in combination with other
vehicle safety systems, or as an individual system. The FLAC system
is similar in numerous respects to the aforementioned roadside
audio status system described for detecting roadway status, such as
from within a roadside call box. The FLAC system utilizes audio
detection of external event, preferentially sensed from a forward
direction, to provide extended sensing of roadway events that the
driver may be otherwise unaware. It will be appreciated that the
implementation of the RAAC system as of Phase II and beyond is
capable of providing extended sensing beyond the capabilities of an
audio system, whereas if all vehicle were simultaneously equipped
with a Phase II system, there would be no need of implementing a
FLAC system. However, as the implementation of the RAAC system may
require a number of years to reach full deployment, it is
beneficial to provide additional capability to protect the subject
driver from accidents, while additionally providing an inexpensive
system that may be independently deployed to reduce traffic
collisions. FIG. 39 shows a FLAC system 1750 exemplified 1750
within a vehicle 1752 with driver 1754 in forward transit. An
acoustic transducer 1756 is preferably directed forward of the
vehicle to receive sounds, such as braking, hard braking, swerving,
transition over an obstruction, tire squeeling, emergency vehicles,
and the sounds of a collision. The acoustic transducer 1756 is
preferably mounted low on the front of the vehicle so as to receive
sounds traveling underneath the vehicles, as would be consistent
with the sounds of tires on the pavement. A processing unit 1760 is
coupled to the transducer 1756 to digitize and process the audio
signals received. The processing unit preferably comprises a DSP
circuit for analyzing the received audio for a set of trigger
conditions indicative of a roadway event to which the driver should
be alerted. Upon detecting such an event the driver 1754 may be
notified by means of an audio output transducer 1764 and/or visual
display 1764. For example an audio beep or voiced annunciation may
be generated to alert the occupant of the condition ahead, such as
"braking ahead". It is preferable, however, and in keeping with one
of the basic tenets of the system, that upon detecting an event,
the driver should be provided with information so that they may
decide the relevance of the data. Therefore, the system preferably
generates audio that includes a quick alerting beep followed by a
sample of the sound, preferably accentuated by the DSP. As the FLAC
system detects an event it preferably generates an audio rendition
of the event to the driver, wherein the critical elements of the
event such as squeeling sounds are accentuated and the
non-important sounds, such as engine sounds are attenuated. FIG. 40
is an embodiment of the FLAC system 1750 showing internal circuit
blocks. To processing unit 1760 are connected acoustic transducer
1756 through a pre-amp circuit 1766 and the output audio
annunciator 1762 along with display 1764. The audio signal is
converted within a A/D converter 1768 and received by a DSP chip,
or circuitry, 1770 wherein the audio is analyzed for event
conditions according to algorithms executing therein. The DSP 1770
can generate output into a memory 1772 for the storage of audio
segments. A microcontroller 1774 performs the overall control of
the FLAC system and is capable of controlling the DSP 1770 and
operating on the memory 1772, such as for retrieving and playing
audio contained therein. The microcontroller 1774 can generate
output through an amplifier 1776 to audio annunciator 1762. It will
be appreciated that FLAC system may be implemented in a variety of
ways using numerous forms of circuits without departing from the
inventive principles contained herein.
[0343] Accordingly, it will be seen that this invention, Reaction
Advantage Anti-Collision Systems and Methods of the present
invention may be implemented in a variety of ways and can provide
various levels of reaction time advantage to drivers which can
translate to a reduction in the number of rear-end collisions which
occur each year. The described systems present drivers with
information which provides a reaction time advantage to the
drivers, while further providing for the blind communication of
dangerous events on the highways. The system may be economically
produced for widespread adoption, while it requires no
infrastructure changes. The systems provide driver information, and
do not attempt to completely control the subject vehicles. It will
be appreciated, therefore, that system errors and failures can lead
only to the loss of driver reaction advantage. Failure modes of the
described system and methods thereby reduce both the liability and
the cost of implementing the described solutions.
[0344] Although the description above contains many specificities,
these should not be construed as limiting the scope of the
invention but as merely providing illustrations of some of the
presently preferred embodiments of this invention. Thus the scope
of this invention should be determined by the appended claims and
their legal equivalents. Therefore, it will be appreciated that the
scope of the present invention fully encompasses other embodiments
which may become obvious to those skilled in the art, and that the
scope of the present invention is accordingly to be limited by
nothing other than the appended claims, in which reference to an
element in the singular is not intended to mean "one and only one"
unless explicitly so stated, but rather "one or more." All
structural, chemical, and functional equivalents to the elements of
the above-described preferred embodiment that are known to those of
ordinary skill in the art are expressly incorporated herein by
reference and are intended to be encompassed by the present claims.
Moreover, it is not necessary for a device or method to address
each and every problem sought to be solved by the present
invention, for it to be encompassed by the present claims.
Furthermore, no element, component, or method step in the present
disclosure is intended to be dedicated to the public regardless of
whether the element, component, or method step is explicitly
recited in the claims. No claim element herein is to be construed
under the provisions of 35 U.S.C. 112, sixth paragraph, unless the
element is expressly recited using the phrase "means for."
1TABLE 1A Hard Braking Controller (HBC) Phase IV - Signals by Type
Signal Name Use Phase SPI Serial Select & IRQ lines: PSense
Pressure & Acc. Sensor data I PSense IRQ Active when large
sensor change I Sig Out Event Signal Output II Sig Out IRQ Output
Complete II Sig In IRQ Event Signal Receipt II Sig In Event Signal
reception II Speed Vehicle Speedometer data II Compass Vehicle
Direction II Disp Display Controller Output II GPS Data GPS
coordinate data input III GPS Dta IRQ GPS data rdy III GPS Control
GPS control setting III WPh Wireless phone data III WPh IRQ
Wireless phone request III SPI Serial - Common lines: Din serial
Data Input to HBC I Dout serial Data Output from HBC I SClk serial
bit Clock I Analog Data: Swerve Sense wheel rotation II Crash Sense
crash impact Gs II Alert Sensitivity Sense user setting II Tailgate
value Sense use setting of tailgate value IV Special Signals: HB
Ind Hard Braking Indicator Power I Reset Reset HBC controller
signal I
[0345]
2 TABLE 1B Signal Name Use Phase Digital Output: Error HBC Error
indicator drive I Disp0 Event indicator bit 0 II Disp1 Event
indicator bit 1 II Disp2 Event indicator bit 2 II Dist Out Distance
Out signal (INIT) II SSMute Sound System Mute II CanCr Cancel
Cruise Setting II Brk Lt Mod Brake Light Modulation II BrAssist
Brake Assist activation IV Digital Input: E. Flash Emergency
Flasher Sense II E. 911 Emergency 911 activation HdLight Headlight
sense II Dist In Distance In signal (ECHO) II
[0346]
3TABLE 2 Monitor Circuit Inputs and Outputs Inputs: Log SPI CS -
Log data rcvd from HBC anytime action performed Log IRQ Monitor can
send cmds to HBC BrAssist Check condition of brake assist HB Ind
Check status of hard braking indicator Sig Out Monitor signals sent
to the event transmitter module Outputs: MCIr Clear/hold in reset
mode, the microprocessor of the HBC ERROR An error indicator
[0347]
4TABLE 3 Hard Braking Events Level Causitive Event HB1 Vehicle
Collision (Crash!) HB2 Slamming Brakes HB3 Hard Braking HB4
Emergency vehicle/incident HB5 Emergency Flashers HB6 Abrupt
Swerving HB7 Condition Report (a serial sequence)
[0348]
5TABLE 4 Speed versus Event Overrides Speed mph Event Generation
Override 0-15 No Events (Except Crash!) 15-30 Visual Indicator Only
30-45 No Regeneration of event signal >45 ALL Functions
[0349]
6TABLE 5 Sensor Threshold Values Meas. Param Value Threshold
Pressure L <2 lbs M 2-10 lbs H 10-20 lbs VH >20 lbs Delta
Press. L <0.05 lb/ms.sup.2 M 0.05-0.10 lb/ms.sup.2 H >0.10
lb/ms.sup.2 Acceleration L <15 microns/ms.sup.2 H >15
microns/ms.sup.2
[0350]
7TABLE 6 Events registered from inactive state P D P Event L L none
L M Alert L H HB3 M L none M M none M H HB3 H L HB3 H M HB2 H H HB2
VH L HB2 VH M HB2 VH H HB2
[0351]
8TABLE 7 Events registered from HB3 state P D P Event L L none L M
Alert L H HB3 M L none M M HB3 M H HB3 H L HB3 H M HB2 H H HB2 VH L
HB2 VH M HB2 VH H HB2
[0352]
9TABLE 8 Event Signal Data Packet Description No. Bits HB Level 3
Active event flag 1 Regen Number 3 Aux. Data Flag 1 Slot number 4
Direction 4 ID number 32 *Aux Position Data 32 Checksum 8
[0353]
10TABLE 9 HB7 Event Signal Data Packet Description No. Bits HB
Level 3 -- 1 Direction 4 Packet Number 4 Total Number of Packets 4
Packet Data 64 Checksum 8
* * * * *