U.S. patent application number 10/249999 was filed with the patent office on 2004-06-17 for adaptive safety system for a bumper-bag equipped vehicle.
This patent application is currently assigned to FORD MOTOR COMPANY. Invention is credited to Barbat, Saeed David, Prakah-Asante, Kwaku O., Rao, Manoharprasad K., Strumolo, Gary Steven.
Application Number | 20040117116 10/249999 |
Document ID | / |
Family ID | 32328759 |
Filed Date | 2004-06-17 |
United States Patent
Application |
20040117116 |
Kind Code |
A1 |
Rao, Manoharprasad K. ; et
al. |
June 17, 2004 |
ADAPTIVE SAFETY SYSTEM FOR A BUMPER-BAG EQUIPPED VEHICLE
Abstract
The present invention provides a safety system control method
for a host automotive vehicle. The method includes providing a
first vehicle safety countermeasure and providing a second vehicle
safety countermeasure operable in a first mode corresponding to the
first vehicle safety countermeasure being inactive and a second
mode corresponding to the first vehicle safety countermeasure being
activated. The method also determines a collision threat with a
target object and selectively activates the first vehicle safety
countermeasure as a function of said collision threat. The second
vehicle safety countermeasure is then activated in the second mode
when the first vehicle safety countermeasure is activated.
Otherwise, the second vehicle safety countermeasure is activated in
the first mode when the first vehicle safety countermeasure is
inactive.
Inventors: |
Rao, Manoharprasad K.;
(Novi, MI) ; Prakah-Asante, Kwaku O.; (Commerce
Township, MI) ; Strumolo, Gary Steven; (Beverly
Hills, MI) ; Barbat, Saeed David; (Farmington Hills,
MI) |
Correspondence
Address: |
KEVIN G. MIERZWA
ARTZ & ARTZ, P.C.
28333 TELEGRAPH ROAD, SUITE 250
SOUTHFIELD
MI
48034
US
|
Assignee: |
FORD MOTOR COMPANY
One Parklane Boulevard 600 Parklane Towers East
Dearborn
MI
|
Family ID: |
32328759 |
Appl. No.: |
10/249999 |
Filed: |
May 27, 2003 |
Current U.S.
Class: |
701/301 ;
340/436; 340/903; 701/45 |
Current CPC
Class: |
B60R 21/0132 20130101;
B60R 21/0156 20141001; B60R 21/0134 20130101; B60R 19/205
20130101 |
Class at
Publication: |
701/301 ;
701/045; 340/903; 340/436 |
International
Class: |
G08G 001/16; B60R
021/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 13, 2002 |
US |
60/432973 |
Claims
1. A safety system control method for a host automotive vehicle
comprising: providing a first vehicle safety countermeasure;
providing a second vehicle safety countermeasure operable in a
first mode corresponding to said first vehicle safety
countermeasure being inactive and a second mode corresponding to
said first vehicle safety countermeasure being activated;
determining a collision threat with a target object; selectively
activating said first vehicle safety countermeasure as a function
of said collision threat; and activating said second vehicle safety
countermeasure in said second mode when said first vehicle safety
countermeasure is activated.
2. A method according to claim 1 further comprising detecting a
crash event and, in response, activating said second vehicle safety
countermeasure in said first mode when said first vehicle safety
countermeasure is inactive.
3. A method according to claim 1 wherein said first vehicle safety
countermeasure comprises an external vehicle airbag.
4. A method according to claim 3 wherein said external vehicle
airbag comprises a front or rear bumper airbag.
5. A method according to claim 1 wherein said second vehicle safety
countermeasure comprises an internal vehicle occupant airbag.
6. A method according to claim 3 wherein said second vehicle safety
countermeasure comprises an internal vehicle occupant airbag.
7. A method according to claim 5 wherein said second mode of the
second vehicle safety countermeasure has a modified response as
compared to said first mode.
8. A method according to claim 1 comprising determining a host
vehicle velocity, and activating said first vehicle countermeasure
when said host vehicle velocity exceeds a threshold velocity value
and when said collision threat exceeds a threshold collision
value.
9. A method according to claim 1 comprising determining a relative
velocity between said host vehicle and said detected object, and
activating said first vehicle countermeasure when said relative
velocity is within a range of threshold relative velocity values
and when said collision threat exceeds a threshold collision
value.
10. A method according to claim 8 comprising determining a relative
velocity between said host vehicle and said detected object, and
activating said first vehicle countermeasure when said relative
velocity is within a range of threshold relative velocity values
and when said collision threat exceeds a threshold collision
value.
11. A method according to claim 1 comprising determining a size of
said target object, and selectively activating said first vehicle
safety countermeasure as a function of said target object size.
12. A method according to claim 8 comprising determining a size of
said target object, and selectively activating said first vehicle
safety countermeasure as a function of said target object size.
13. A method according to claim 9 comprising determining a size of
said target object, and selectively activating said first vehicle
safety countermeasure as a function of said target object size.
14. A method according to claim 10 comprising determining a size of
said target object, and selectively activating said first vehicle
safety countermeasure as a function of said target object size.
15. A safety system control method for a host automotive vehicle
including at least one external vehicle airbag and at least one
internal occupant airbag, the method comprising: determining a
collision threat with a target object; selectively activating said
at least one external vehicle airbag as a function of said
collision threat; and in response to a crash event, activating said
at least one internal occupant airbag in a first mode when said at
least one external vehicle airbag is activated, otherwise,
activating said at least one internal occupant airbag in a second
mode when said at least one external vehicle airbag is
inactive.
16. A method according to claim 15 wherein said at least one
external vehicle airbag comprises a front or rear bumper
airbag.
17. A method according to claim 15 comprising determining a host
vehicle velocity, and activating said at least one external vehicle
airbag when said host vehicle velocity exceeds a threshold velocity
value and when said collision threat exceeds a threshold collision
value.
18. A method according to claim 17 comprising determining a
relative velocity between said host vehicle and said detected
object, and activating said at least one external vehicle airbag
when said relative velocity is within a range of threshold relative
velocity values.
19. A method according to claim 18 comprising determining a size of
said target object, and selectively activating said at least one
external vehicle airbag as a function of said target object
size.
20. A safety system for an automotive vehicle having a pre-crash
sensing system and a countermeasure system comprising: a first
vehicle safety countermeasure; a second vehicle safety
countermeasure operable in a first mode corresponding to said first
vehicle safety countermeasure being inactive and a second mode
corresponding to said first vehicle safety countermeasure being
activated; and a controller coupled to said pre-crash sensing
system and said first and second vehicle safety countermeasures,
said controller determining a collision threat with a target
object, selectively activating said first vehicle safety
countermeasure as a function of said collision threat, and
activating said second vehicle safety countermeasure in said second
mode when said first vehicle safety countermeasure is activated.
Description
BACKGROUND OF INVENTION
[0001] The present invention relates to automotive safety systems
and, more particularly, concerns an adaptive occupant protective
system for vehicles equipped with bumper-bag systems.
[0002] Current vehicle crash safety systems typically employ
accelerometers that measure decelerations acting on the vehicle
body during a crash event. In response to signals from such
accelerometers, airbags or other safety devices are activated. In
certain crash situations, however, it is desirable to provide
information before forces actually act upon the vehicle such as
when a collision is unavoidable. Such systems are commonly known as
collision prediction systems or pre-crash warning systems. Such
remote sensing applications use radar, lidar, or vision-based
technologies for collision avoidance and pre-collision warning
applications.
[0003] With regard to occupant safety systems, in addition to
conventional airbags within the passenger compartment, exterior
airbag systems are also being considered for vehicle applications.
These exterior airbag applications are commonly referred to as
"bumper-bag" applications, when the bags are located along the
exterior of the vehicle near the front or rear bumpers.
[0004] Bumper-bag systems are most effective when they are fully
deployed before actual physical contact with the impacting object.
Accordingly, unlike interior occupant airbags, bumper-bags are most
likely to be deployed in response to pre-crash sensing
information.
[0005] When bumper-bags are deployed in a crash situation, however,
they can change the collision dynamics of the vehicle which would
otherwise occur by acting as an additional energy-absorbing
component and by providing additional collapsible distance. These
changes in the collision dynamics can affect the host vehicle crash
pulse as seen by the accelerometers, the crash duration, the amount
of passenger compartment deformation, and other occupant
injury-producing phenomena.
[0006] Bumper-bag systems, however, are not deployed in all crash
situations. For example, to minimize repair costs, bumper-bags may
not be deployed in relatively low-velocity impact situations. Also,
due to real-time performance limitations of the pre-crash sensing
systems, bumper-bags may not be deployed in crash situations with
very high relative velocities between the impacting and host
vehicle, or when the pre-crash sensing system cannot "see" the
impacting object such as, for example, during a high speed
intersection-type collision.
[0007] Accordingly, it is desirable to optimize the performance of
the occupant safety systems, and the vehicle interior occupant
airbags in particular, under both situations when the bumper-bags
are deployed and are likely to alter the collision dynamics, and
when the bumper-bags have not been deployed and the crash situation
is equivalent to a vehicle without a bumper-bag system. The present
invention is directed towards providing such an adaptive safety
system for bumper-bag equipped vehicles.
SUMMARY OF INVENTION
[0008] An adaptive safety system for bumper-bag equipped vehicles
in accordance with one embodiment of the present invention includes
a safety system control method for a host automotive vehicle. The
method comprises providing a first vehicle safety countermeasure
and providing a second vehicle safety countermeasure operable in a
first mode corresponding to the first vehicle safety countermeasure
being inactive and a second mode corresponding to the first vehicle
safety countermeasure being activated. The method also determines a
collision threat with a target object and selectively activates the
first vehicle safety countermeasure as a function of the collision
threat. The second vehicle safety countermeasure is then activated
in the second mode when the first vehicle safety countermeasure is
activated. Otherwise, the second vehicle safety countermeasure is
activated in the first mode when the first vehicle safety
countermeasure is inactive. The first vehicle safety countermeasure
can be an external vehicle airbag and the second vehicle safety
countermeasure can be in internal occupant airbag.
[0009] In another embodiment, a safety system control method for a
host automotive vehicle including at least one external vehicle
airbag and at least one internal occupant airbag is provided. The
method includes determining a collision threat with a target
object, selectively activating the external vehicle airbag as a
function of the collision threat, and, in response to a crash
event, activating at least one internal occupant airbag in a first
mode when the external vehicle airbag is activated, otherwise,
activating the at least one internal occupant airbag in a second
mode when the external vehicle airbag is inactive.
[0010] In anther embodiment, a safety system for an automotive
vehicle having a pre-crash sensing system is provided. The system
includes a first vehicle safety countermeasure, a second vehicle
safety countermeasure operable in a first mode corresponding to the
first vehicle safety countermeasure being inactive and a second
mode corresponding to the first vehicle safety countermeasure being
activated, and a controller coupled to the pre-crash sensing system
and the first and second vehicle safety countermeasures. The
controller determines a collision threat with a target object,
selectively activates the first vehicle safety countermeasure as a
function of the collision threat, and activates the second vehicle
safety countermeasure in the second mode when the first vehicle
safety countermeasure is activated.
[0011] The present invention is advantageous in that it can provide
improved occupant protection by optimizing the response
characteristics of the occupant safety systems in response to
likely changes in vehicle collision dynamics resulting from
bumper-bag or other countermeasure deployment.
[0012] Other advantages and features of the invention will become
apparent to one of skill in the art upon reading the following
detailed description with reference to the drawings illustrating
features of the invention by way of example.
BRIEF DESCRIPTION OF DRAWINGS
[0013] For a more complete understanding of this invention,
reference should now be made to the embodiments illustrated in
greater detail in the accompanying drawings and described below by
way of examples of the invention.
[0014] In the drawings:
[0015] FIG. 1 is a schematic side view of a bumper-bag equipped
vehicle according to an embodiment of the present invention with
the bumper-bag deployed.
[0016] FIG. 2 is a top view of a bumper-bag equipped vehicle with a
multi-sensor pre-crash sensing system according to an embodiment of
the present invention.
[0017] FIG. 3 is a block diagrammatic view of one example of a
pre-crash sensing system for a bumper-bag equipped vehicle in which
the present invention may be used to advantage.
[0018] FIG. 4 is a graph of a rigid barrier crash pulse for a
vehicle with and without deployment of the bumper-bag system.
[0019] FIG. 5 is a logic flow diagram for an adaptive safety system
for a bumper-bag equipped vehicle according to one embodiment of
the present invention.
[0020] FIG. 6 is a graph of simulated head acceleration for a
vehicle crash at 56 km/h with and without deployment of the
bumper-bag system.
DETAILED DESCRIPTION
[0021] While the present invention is described with respect to an
adaptive safety system for bumper-bag equipped vehicles, the
present invention may be adapted and utilized for other vehicle
safety systems wherein the vehicle crash dynamics may be altered as
a result of deployment of various safety devices such that it is
desirable to modify the behavior of the safety systems acting upon
the vehicle occupant.
[0022] Also, in the following description, various operating
parameters and components are described for one constructed
embodiment. For example, the adaptive safety system of the present
invention is described as being implemented in a vehicle with a
bumper-bag system and including a pre-crash sensing system having
vision and radar-based sensing capabilities. These specific
parameters and components are included as examples and are not
meant to be limiting. In particular, the adaptive safety system is
intended to be readily adaptable to any bumper-bag equipped vehicle
without regard to the particular pre-crash sensing system
employed.
[0023] Referring now to the drawings wherein like reference
numerals are used to identify identical components in the various
views, FIG. 1 illustrates a schematic side view of a bumper-bag
equipped vehicle 50 according to an embodiment of the present
invention with the bumper-bag 13 fully deployed. The adaptive
safety system of the present invention includes a controller 12
which will be described in more detail below. In the example of
FIG. 1, the front bumper-bag 13 is shown fully deployed. The
vehicle 50 may also include a rear bumper-bag and side external
airbags, as well. As can be seen in FIG. 1, when the bumper-bag is
deployed, it provides additional, collapsible frontal distance for
the vehicle 50 with respect to the impacting object. When the
bumper-bag 13 is effectively fully deployed just before physical
contact with an impacting object, it will change the collision
dynamics of the vehicle 50 by acting as an additional energy
absorbing component as well as providing the additional collapsible
frontal distance. To be fully effective, however, it is desirable
that the bumper-bag 13 be fully deployed before physical contact
with the detected impacting object. Accordingly, vehicles with
bumper-bags typically include a pre-crash sensing system to detect
objects before they actually physically contact the vehicle 50.
[0024] Referring now to FIG. 2 there is shown a top view of the
bumper-bag equipped vehicle 50 with a multi-sensor pre-crash
sensing system. The vehicle 50 of FIG. 2 includes a vision system
with a stereo pair of cameras 28, 30 and a radar system 22 with a
wide field-of-view detection zone. Together the vision and radar
systems provide one example of a multi-sensor pre-crash sensing
system for a bumper-bag equipped vehicle in which the present
invention may be used to advantage. The radar system can detect the
presence of an object in its detection zone 52, and obtain distance
and relative velocity information to the detected object with
reference to the host vehicle. The camera system alone can also be
used to detect the presence of the object in its detection zone 53,
and obtain distance, relative velocity and size information for the
detected object with respect to the host vehicle 50. Alternately,
the radar system can be used to detect the presence of the object
and provide distance and relative velocity information, and the
vision system can be used to confirm the distance and relative
velocity information and also provide additional information
regarding the size of the detected object. For pre-crash sensing
applications, it is advantageous to have both radar and
vision-based systems to ensure good performance under all weather
conditions and also to provide redundancy for improved
reliability.
[0025] The host vehicle 50 is illustrated with respect to target
vehicles 54 and 56. Target vehicle 54 is traveling in an opposite
direction to the host vehicle 50. Target vehicle 56 is traveling in
the opposite direction of vehicle 54. The pre-crash sensing systems
have object detection and threat assessment algorithms, which are
well known to people skilled in the art of collision threat
assessment that can differentiate between objects such as. 54,
which are harmlessly passing by, and objects such as 56, which may
cause collision with the host vehicle.
[0026] FIG. 3 is a block diagrammatic view of one example of a
pre-crash sensing system for a bumper-bag equipped vehicle which
includes an adaptive safety system according to the present
invention. The pre-crash sensing system 10 has a controller 12. The
controller 12 is a preferably a microprocessor-based controller
that is coupled to a memory 14 and a timer 16. Memory 14 and timer
16 are illustrated as separate components from that of the
controller 12, however, those skilled in the art will recognize
that memory 14 and timer 16 may be incorporated into controller 12.
Controller 12 may be one component or a collection of individual
control elements. Further, several features of controller 12 can be
implemented in software, however, those skilled in the art will
also recognize that such systems may be implemented in
hardware.
[0027] Memory 14 may comprise various types of memory including
read-only memory, random access memory, electrically erasable
programmable read-only memory, and keep-alive memory. Memory 14 is
used to store various thresholds and parameters as will be further
described below.
[0028] Timer 16 is a timer such as a clock timer of a central
processing unit within controller 12. Timer 16 is capable of timing
the duration of various events as well as counting up or counting
down. For example, based on time, the acceleration of the vehicle
can be determined from a velocity.
[0029] A remote object sensor 18 is coupled to controller 12.
Remote object sensor 18 generates an object signal in the presence
of an object within its field-of-view (FIG. 2). Remote object
sensor 18 may be comprised of one or a number of combinations of
sensors including a radar 22, a lidar 24, and a vision system 26.
Vision system 26 may be comprised of one or more cameras, CCD, or
CMOS-type devices. As illustrated, a first camera 28 and a second
camera 30 may form vision system 26. Both radar 22 and lidar 24 are
capable of sensing the presence and the distance of an object from
the vehicle and may be capable of detecting the object size.
[0030] The camera system is also capable of detecting the object
and the distance of an object from the vehicle. Alternatively,
radar 22 or lidar 24 may be used to detect an object within a
detection zone and vision system 26 may be used to confirm the
presence of the object within the detection zone. The vision system
consisting of camera 1 and camera 2 alone may use established
triangulation technique and other vision based techniques to
determine the presence of an object, the object's distance from the
vehicle, and the relative velocity of the object with respect to
the host vehicle, as well as the size of the object. The object's
size may include information regarding the object area, volume,
height, width, or combinations thereof. Preferably, the cameras are
high-speed cameras operating in excess of 50 Hz. A suitable example
is a CMOS-based high dynamic range camera capable of operating
under widely differing lighting and contrast conditions.
[0031] A receiver 31 may also be included within the object sensor.
Receiver 31 may, however, be a stand-alone device. Receiver 31 is
also coupled to controller 12. Receiver 31 is used to receive
signals from other vehicles or vehicle transponders.
[0032] A vehicle dynamics detector 32 may also be coupled to
controller 12. The vehicle dynamics detector 32 generates a signal
or signals indicative of the dynamic conditions of the vehicle. The
vehicle dynamics detector 32 may comprise various numbers or
combinations of sensors but preferably includes a speed sensor 34,
a yaw rate sensor 36 and a steering wheel angle sensor 38. In
addition, longitudinal acceleration sensor 40 may also be included
in the vehicle dynamics detector 32. The longitudinal acceleration
sensor can provide controller 12 some indication as to the occupant
driving characteristics such as braking or deceleration.
[0033] Speed sensor 34 may be one of a variety of speed sensors
known to those skilled in the art. For example, a suitable speed
sensor may include a sensor at every wheel that is averaged by
controller 12. The controller 12 can control the wheel speeds to
control the speed of the vehicle. Suitable types of speed sensors
34 may include for example, two-wheel sensors such as those
employed on anti-lock brake systems.
[0034] Yaw rate sensor 36 preferably provides the yaw rate of the
vehicle about the center of gravity of the vehicle. The yaw rate
measures the rotational tendency of the vehicle about an axis
normal to the surface of the road. Although the yaw rate sensor 36
is preferably located at the center of gravity, those skilled in
the art will recognize that the yaw rate sensor may be located in
various locations of the vehicle and translated back to the center
of gravity either through calculations at the yaw rate sensor or
through calculations within controller 12 in a known manner.
[0035] Steering wheel angle sensor 38 provides a steering wheel
angle signal to controller 12. The steering wheel angle signal
corresponds to the steering wheel angle of the hand wheel of the
automotive vehicle. The yaw rate sensor 36 and the vehicle speed
sensor 34 or the steering wheel angle sensor 38 alone, or the above
sensors in combination, may be used to indicate the kinematics of
the vehicle as is known in the art.
[0036] Longitudinal acceleration sensor 40 may be a separate sensor
or may be derived. That is, the change in speed over a
predetermined time is defined as the acceleration. Thus, by
measuring speed from speed sensor 34 and time from timer 16, an
approximation of acceleration or deceleration may be obtained. In
vehicles with systems such as yaw control or rollover control, such
a sensor may already be incorporated into the vehicle.
[0037] An impact sensor 49 may comprise one or more accelerometers
located at various positions throughout the vehicle to confirm
impact with an object such as known in the art for deploying
vehicle occupant airbag systems.
[0038] A global positioning system (GPS) 46 may also be coupled to
controller 12. GPS 46 generates a vehicle position of the host
vehicle in response to satellites. Controller 12 may use this
information determining the relative position of the host vehicle
and a target vehicle.
[0039] A transponder 42 may also be coupled to controller 12.
Transponder 42 may generate information from controller 12 and
transmit it to other vehicles upon the reception of a
pre-determined frequency signal from another vehicle. Also,
transponder 42 may always be activated and broadcasting vehicle
information to other vehicles. Transponder 42 and receiver 31 may
be located in a common location and may be integrally formed.
[0040] A braking system sensor 44 may also be coupled to controller
12. Braking system sensor 44 may be a sensor or sensors such as a
brake pedal position sensor or a brake pressure monitor. The brake
system conditions may be used to determine occupant-driving
characteristics and thus provide an improved collision prediction
and, as a result, provide an improved countermeasure deployment
decision.
[0041] Controller 12 is used to control the activation of a
countermeasure system 48. Each countermeasure may have an
individual actuator associated therewith. In that case, controller
12 may direct the individual countermeasure actuator to activate
the particular countermeasure. Various types of countermeasure
systems are evident to those skilled in the art. Examples of a
countermeasure within the countermeasure system include occupant
seatbelt pretensioners, bumper height changing including
nose-dipping, braking, the pre-arming of internal airbags, the
deployment of exterior or internal airbags, pedal control, steering
column positioning, head restraint and knee bolster control.
Preferably, controller 12 is programmed to activate the appropriate
countermeasure in response to the inputs from the various
sensors.
[0042] To the extent that some countermeasure systems, when
activated, are likely to significantly change the vehicle crash
dynamics, the present invention is directed toward optimizing the
performance of those countermeasures acting directly upon the
vehicle occupants. In the following description, the vehicle
bumper-bag system provides an example of a countermeasure which
influences the vehicle crash dynamics and the occupant airbag
system as an example of a countermeasure adaptively controlled in
response to deployment of the vehicle bumper-bag system.
[0043] The influence on vehicle crash dynamics can be seen, for
example, in FIG. 4 which is a graph of a 56 km/h rigid barrier
crash pulse for a vehicle with and without deployment of the
bumper-bag system. As can be seen in FIG. 4, the deployment of the
bumper-bag system minimizes the magnitude of the crash pulse for a
56 Km/h rigid wall frontal impact. The deceleration pulse profile
for the crash simulation with bumper-bags deployed is significantly
different than the deceleration pulse profile without the
bumper-bags deployed. Comparing the two profiles of FIG. 4, it can
be seen that it would be beneficial to coordinate, in particular,
the deployment scheme of the interior occupant airbag system with
the appropriate vehicle crash pulse profile in the crash situation
where the bumper-bag system is deployed as well as in the crash
situation when the bumper-bag system is not deployed.
[0044] FIG. 5 is a logic flow diagram for an adaptive safety system
for a bumper-bag equipped vehicle according to one embodiment of
the present invention. Again, the adaptive safety system is
described with respect to a bumper-bag deployment and the resulting
modification of the interior occupant airbag deployment as a result
thereof. In the broadest sense, however, the present method
determines whether a vehicle safety system will be deployed which
may affect the vehicle crash dynamics and, in response, modifies
the activation characteristics of other vehicle safety systems to
be optimized for the anticipated vehicle impact profile.
[0045] In example of FIG. 5, the logic begins in step 100 wherein
the pre-crash sensing system monitors the sensor field-of-view for
potential objects. If an object is detected by the pre-crash
sensing system in step 102, then the host vehicle velocity
(V.sub.H) is determined in step 104.
[0046] The host vehicle velocity is used in deciding whether to
deploy the bumper-bags. In certain situations, it may not be
desirable to activate the vehicle bumper-bag system. For example,
to minimize repair costs, the bumper-bags may not be deployed for
low relative velocity impacts where they may provide little or no
additional occupant safety improvements yet significantly increase
the cost to repair the vehicle. Low-relative velocities may be, for
example, velocities up to 22 Km/h. Additionally, due to real-time
performance limitations of pre-crash sensing systems, under certain
conditions such as collisions with very high relative velocities or
when the sensing system cannot "see" the impacting object, such as
during a high speed side collision, the bumper-bags may not be
commanded to deploy or may not have time to deploy. Such
high-relative velocities may be, for example, velocities above 72
Km/h. To this end, step 106 determines whether the host vehicle
velocity is above a lower threshold velocity (V.sub.L) such that
the bumper-bag system may be deployed, if desirable. In a similar
manner, the relative velocity (V.sub.R) between the host vehicle
and the detected object is determined, and this value is compared
to the a lower relative velocity limit (V.sub.RL) and an upper
relative velocity limit (V.sub.R) in step 110. Assigning an upper
relative velocity limit helps in improving the reliability of the
bumper-bag system by eliminating unintentional deployments in some
situations. If the host vehicle velocity is above the lower
threshold limit and the relative velocity between the host vehicle
and the detected object is within the range appropriate for
bumper-bag deployment, the logic continues to step 112 wherein the
collision threat between the host vehicle and the detected object
is assessed.
[0047] The collision threat assessment in step 112 can be performed
by any known pre-collision threat assessment schemes including a
multi-sensor pre-crash sensing scheme such as shown in FIGS. 2 and
3.
[0048] If a collision is highly likely, as determined by the
collision threat assessor in step 114, the detected object size is
determined with, for example, the vision system or radar system in
step 116. If the object size is below a threshold value (S.sub.C)
as is determined in step 118, it may not be desirable to activate
the vehicle bumper-bag system. For example, if the detected object
is very low to the ground or otherwise relatively small or very
narrow, such as a pole, the bumper-bag system may be ineffective at
improving the vehicle crash-worthiness. Otherwise, in step 120, the
vehicle bumper-bag system is activated if the detected object is
above the threshold value (S.sub.C) as determined in step 118.
[0049] At this time, in step 122, other vehicle safety
countermeasures may be activated such as those which are
reversible. Reversible safety system countermeasures may include
occupant safety seatbelt motorized pretensioning systems, bumper
height adjustments including nose-dipping, vehicle braking, the
pre-arming of internal occupant airbags, activate steering column
positioning, active head restraint positioning and active knee
bolster control. In that way, if the collision is not confirmed,
for example, by vehicle impact sensors or accelerometers in step
124, the reversible countermeasures can be returned to normal
operating mode. If, however, the collision event is confirmed in
step 124, the activation characteristics of certain countermeasures
are modified to correspond to the altered collision dynamics mode.
In this case, in step 126, the interior occupant airbags are
deployed in accordance with a bumper-bag activated mode. This may
correspond to a delayed deployment in view of the additional
energy-absorbing component and collapsible frontal length provided
by the deployed bumper-bags. Besides delaying the activation of the
interior airbags, the rate of airbag inflation and vent rate of the
airbag may also be modified to optimize the interior airbag
performance for the vehicle collision dynamics corresponding to the
bumper-bag deployment crash situation. If, however, the crash event
is confirmed and the bumper-bag system has not been deployed, then
the interior airbags would be activated in the normal manner. This
would correspond to activating the interior airbag in the same
manner as if the vehicle did not have a bumper-bag system.
[0050] The influence of operating the interior airbags as a
function of the status of the bumper-bag system activation can be
seen in FIG. 6. FIG. 6 shows a graph of simulated resultant head
accelerations for an occupant in a vehicle with and without
bumper-bag deployment in a 56 Km/h rigid wall frontal impact. The
head acceleration of FIG. 6 is for an unbelted vehicle driver. As
can be seen, in the impact situation without the bumper-bag
deployment, the occupant head acceleration reaches approximately 58
Gs at approximately 55 ms after impact. In this situation, the
interior airbags would be deployed in the conventional manner
optimized for normal impact conditions. In the case where the
bumper-bag is deployed, however, the interior airbags would be
optimized for a more gradually increasing and delayed deceleration
profile (see FIG. 4). The trace of FIG. 6 corresponding to the
bumper-bag being deployed prior to or during impact shows how the
interior airbag performance can be improved to better correspond
with the vehicle crash dynamics corresponding to the bumper-bag
being deployed. In this example, for the same impact, the resultant
head acceleration was lowered to approximately 43 Gs and delayed
until approximately 80 ms after impact. Similar improved safety
performance can be expected for driver chest accelerations with and
without bumper-bag deployment.
[0051] From the foregoing, it can be seen that there has been
brought to the art a new and improved adaptive safety system for
bumper-bag equipped vehicles which has advantages over prior
vehicle safety systems. In this regard, the present invention
provides countermeasure deployment for one crash scenario wherein
the bumper-bags are not deployed and the vehicle crash dynamics are
the same as in vehicles without bumper-bags, and a modified
countermeasure deployment scheme for a second crash scenario
wherein the vehicle bumper-bags are properly deployed and
resultingly change the vehicle crash dynamics. While the invention
has been described in connection with one or more embodiments, it
should be understood that the invention is not limited to those
embodiments. On the contrary, the invention covers all
alternatives, modifications, and equivalents as may be included
within the spirit and scope of the appended claims.
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