U.S. patent application number 10/579363 was filed with the patent office on 2007-04-19 for electronic control system and method for an auxiliary device interlock safety system.
Invention is credited to Ronald Goodrich, Keith Heigl.
Application Number | 20070086879 10/579363 |
Document ID | / |
Family ID | 34618931 |
Filed Date | 2007-04-19 |
United States Patent
Application |
20070086879 |
Kind Code |
A1 |
Goodrich; Ronald ; et
al. |
April 19, 2007 |
Electronic control system and method for an auxiliary device
interlock safety system
Abstract
A controller, control system and method for controlling an
auxiliary device comprising a wheelchair lift, ramp, or the like
are provided. An exemplary embodiment of the auxiliary device
controller is microprocessor-based and communicates with a
vehicle's OEM controller for receiving a plurality of sensor
inputs, which originate from OEM and auxiliary sensors, process the
sensor inputs, and control various OEM and auxiliary systems
relative to the sensor inputs to effect a number of safety
interlocks. The controller may operate to coordinate various OEM
and auxiliary subsystems to automate auxiliary device operation to
reduce operator error.
Inventors: |
Goodrich; Ronald;
(Logansport, IN) ; Heigl; Keith; (Winamac,
IN) |
Correspondence
Address: |
MICHAEL BEST & FRIEDRICH LLP
Two Prudential Plaza
180 North Stetson Avenue, Suite 2000
CHICAGO
IL
60601
US
|
Family ID: |
34618931 |
Appl. No.: |
10/579363 |
Filed: |
November 17, 2004 |
PCT Filed: |
November 17, 2004 |
PCT NO: |
PCT/US04/38380 |
371 Date: |
May 16, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60520848 |
Nov 18, 2003 |
|
|
|
Current U.S.
Class: |
414/537 ;
414/539; 414/545; 414/546 |
Current CPC
Class: |
B60P 1/43 20130101; H02H
7/0851 20130101; B60P 1/4471 20130101; A61G 3/061 20130101; A61G
3/062 20130101; A61G 2203/46 20130101; Y10S 414/134 20130101; A61G
2203/38 20130101 |
Class at
Publication: |
414/537 ;
414/539; 414/545; 414/546 |
International
Class: |
B60P 1/00 20060101
B60P001/00; B65F 3/00 20060101 B65F003/00 |
Claims
1. A control system for controlling the operation of an auxiliary
device installed in a vehicle, the system comprising: a controller
communicating with a vehicle controller for monitoring and
controlling operation of an auxiliary device subsystem and a
vehicle subsystem; and a plurality of sensors communicating with
the controller for providing output communications thereto, the
sensors comprising vehicle sensors relative to the vehicle
subsystem and auxiliary sensors relative to the auxiliary device
subsystem.
2. The control system of claim 1 wherein the controller comprises a
microprocessor including auxiliary device control logic to
coordinate operation of the auxiliary device subsystem and vehicle
subsystem relative to one or more output communications from the
sensors.
3. The control system of claim 1 wherein the auxiliary device
comprises a wheelchair ramp.
4. The control system of claim 1 wherein the auxiliary device
comprises a wheelchair lift including a platform having inboard and
outboard rollstops, wherein the rollstops are coupled with the
platform at opposing ends thereof for moving between a generally
vertical barrier orientation and a generally horizontal
orientation.
5. The control system of claim 4 wherein the plurality of sensors
includes an occupancy sensor for detecting an occupancy state of
the platform and sending an output signal indicative of the
occupancy state to the controller, the controller operating to
inhibit stowage of the wheelchair lift if the platform is
occupied.
6. The control system of claim 4 wherein the plurality of sensors
includes an inboard rollstop position sensor for detecting the
orientation of the inboard rollstop and sending an output signal
indicative of the orientation of the inboard rollstop to the
controller, the controller operating to inhibit raising of the
platform if the inboard rollstop is generally horizontal.
7. The control system of claim 4 wherein the plurality of sensors
includes an outboard rollstop position sensor for detecting the
orientation of the outboard rollstop and sending an output signal
indicative of the orientation of the outboard rollstop to the
controller, the controller operating to inhibit movement of the
platform if the outboard rollstop is generally horizontal.
8. The control system of claim 4 wherein the plurality of sensors
includes an outboard rollstop occupancy sensor for detecting the
occupancy state of the outboard rollstop and sending an output
signal indicative of the occupancy state of the outboard rollstop
to the controller, the controller operating to inhibit movement of
the outboard rollstop if the outboard rollstop is occupied.
9. The control system of claim 4 wherein the plurality of sensors
includes an inboard rollstop position sensor for detecting the
orientation of the inboard rollstop and sending an output signal
indicative of the orientation of the inboard rollstop to the
controller, the controller operating to inhibit movement of the
inboard rollstop if the inboard rollstop is occupied.
10. The control system of claim 4 wherein the plurality of sensors
includes: a threshold occupancy sensor for detecting the occupancy
state of a threshold area proximate a vehicle doorway and sending
an output signal indicative of the occupancy state of the threshold
area to the controller; a lift position sensor for detecting an
elevation of the platform and sending an output signal indicative
of the elevation of the platform if other than an elevation of the
threshold area; and wherein the controller is linked with an
indicator that operates to output a warning in response to the
threshold occupancy sensor detecting an occupied state of the
threshold area and a platform elevation other than at the vehicle
threshold elevation.
11. The control system of claim 1 further comprises a lighting
control module in communication with the controller that is
operative to activate an illuminating means for illuminating the
auxiliary device.
12. The control system of claim 4 further comprising a motor
control module linked with the controller for outputting a pulse
width modulated signal that controls the operation of a motor.
13. The control system of claim 12 wherein the plurality of sensors
includes a speed sensor and an acceleration sensor coupled with the
motor for detecting the speed and acceleration, respectively, of
the wheelchair lift, the speed and acceleration sensors each
sending output signals to the controller so that the controller may
cooperate with the lift motor control module to vary the pulse
width modulated signal for enabling speed and acceleration feedback
control of the wheelchair lift.
14. The control system of claim 12 wherein the plurality of sensors
includes an audio sensor for detecting a noise level relative to an
operation of the wheelchair lift, the controller communicating with
the motor control module to vary a speed and acceleration of the
operation, thereby decreasing the noise level within the
vehicle.
15. The control system of claim 4 further comprising an incremental
counter linked with the controller for providing an indication of
the usage of the lift, the counter incrementing relative to a full
operation cycle of the lift.
16. The control system of claim 1 further comprising a user
interface linked with the controller, the user interface comprising
a master power control actuator operative to turn the auxiliary
device on and off.
17. A method for controlling a mobility auxiliary device having an
interlock that prevents an unsafe operation of the auxiliary
device, the method comprising the steps of: receiving a user input
relative to a requested operation of the mobility auxiliary device;
delaying the requested operation of the mobility auxiliary device;
and verifying that conditions of the interlock relative to the
requested operation have been satisfied.
18. The method of claim 17 wherein the verifying step comprises:
receiving an output signal from a sensor relative to the interlock;
and comparing the output signal with a known output signal from the
sensor that is indicative of a safe operating condition.
19. The method of claim 17 further comprising the step of providing
an indication of a state of the interlock.
20. The method of claim 17 further comprising the step of providing
a warning that the conditions of an interlock relative to the
requested operation have not been satisfied.
21. The method of claim 19 wherein the providing step comprises
providing one or more of a visual warning and an audible warning if
the interlock state is active.
22. A control system for controlling the operation of a mobility
access device, the system comprising: a controller for receiving a
user input relative to a requested operation of the mobility access
device; and a plurality of sensors coupled with the mobility access
device, the sensors communicating with the controller for sending
output communications relative to a status of the mobility access
device to the controller.
23. The control system of claim 22 wherein the mobility access
device comprises a wheelchair ramp.
24. The control system of claim 22 wherein the mobility access
device comprises a wheelchair lift including a platform having
inboard and outboard rollstops, wherein the rollstops are coupled
with the platform at opposing ends thereof for moving between a
generally vertical barrier orientation and a generally horizontal
orientation.
25. The control system of claim 24 further comprising an interlock
communicating with the controller to prevent at least a portion of
the requested operation unless one or more conditions relative to
the output communications have been satisfied.
26. The control system of claim 25 wherein the plurality of sensors
includes an occupancy sensor for detecting an occupancy state of
the platform and sending an output signal indicative of the
occupancy state to the controller, the interlock operating to
inhibit stowage of the wheelchair lift if the platform is
occupied.
27. The control system of claim 25 wherein the plurality of sensors
includes an inboard rollstop position sensor for detecting the
orientation of the inboard rollstop and sending an output signal
indicative of the orientation of the inboard rollstop to the
controller, the interlock operating to inhibit raising of the
platform if the inboard rollstop is generally horizontal.
28. The control system of claim 25 wherein the plurality of sensors
includes an outboard rollstop position sensor for detecting the
orientation of the outboard rollstop and sending an output signal
indicative of the orientation of the outboard rollstop to the
controller, the interlock operating to inhibit movement of the
platform if the outboard rollstop is generally horizontal.
29. The control system of claim 25 wherein the plurality of sensors
includes an outboard rollstop occupancy sensor for detecting the
occupancy state of the outboard rollstop and sending an output
signal indicative of the occupancy state of the outboard rollstop
to the controller, the interlock operating to inhibit movement of
the outboard rollstop if the outboard rollstop is occupied.
30. The control system of claim 25 wherein the plurality of sensors
includes an inboard rollstop position sensor for detecting the
orientation of the inboard rollstop and sending an output signal
indicative of the orientation of the inboard rollstop to the
controller, the interlock operating to inhibit movement of the
inboard rollstop if the inboard rollstop is occupied.
31. A controller for operating a wheelchair lift installed in a
vehicle, the wheelchair lift and vehicle each including subsystems
having a plurality of sensors for sensing a state of the
subsystems, the controller comprising: a control circuit having
interlock logic that provides safe operation of the wheelchair lift
relative to one or more states of the subsystems; a first interface
module coupled with the control circuit for providing a plurality
of output signals from the sensors to the control circuit; and a
second interface module coupling an indicator with the control
circuit for providing a wheelchair lift subsystem state.
32. The controller of claim 31 wherein the first interface module
comprises: a communication module linked with a vehicle
communication bus and operative to intercept vehicle communications
between the vehicle controller and a vehicle subsystem, the
communication module relaying an intercepted communication to the
control circuit; and a sensor input module linked with a plurality
of sensors coupled with the wheelchair lift subsystems.
33. The controller of claim 31 wherein the control circuit
comprises a processing unit.
34. The controller of claim 33 wherein the processing unit
comprises a microprocessor.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATION
[0001] This patent application is a continuation-in-part of
copending U.S. patent application Ser. No. 10/142,712, filed May
10, 2002, now allowed, which is a continuation-in-part of
International Patent Application No. PCT/US01/27102, filed Aug. 31,
2001, which claims the benefit of and priority to U.S. Provisional
Patent Application No. 60/229,922, filed Sep. 1, 2000. This
application also claims the benefit of and priority to U.S.
Provisional Patent Application No. 60/520,848, filed Nov. 18,
2003.
FIELD OF THE INVENTION
[0002] The invention relates generally to an electronic control
system. More particularly, the invention relates to an electronic
control system for an auxiliary device, such as a wheelchair lift,
with an interlock safety system.
BACKGROUND OF THE INVENTION
[0003] In the automotive field, the operation of major original
equipment manufacturer (OEM) subsystems, such as the engine,
emissions, transmission, and braking has become computerized, as
have convenience-type features such as power locks, windows,
sliding doors, and the like. Since these OEM subsystems are now
usually controlled, either entirely or in part, by an OEM
controller including a microcomputer, the vehicle may include a
number of sensors that communicate with the OEM controller.
Further, the microcomputer may additionally be programmed with
software to operate various safety features in response to outputs
from the sensors. For example, most modern vehicles are operative
to sense when a driver is wearing a safety belt. If the driver does
not employ their safety belt, the vehicle may provide a warning
such as a visual indication (e.g., dashboard light or message), an
audible indication (e.g., chime or warning sound), or other
indication to notify and/or remind the noncompliant driver of the
unsafe condition.
[0004] In another example, vehicles may also sense when one or more
doors are open or ajar to prevent an occupant from accidentally
falling out of the vehicle when it is in motion. In some instances,
if an open door condition is detected by a door sensor, the OEM
vehicle controller may operate to prevent the driver from shifting
the stationary vehicle out of park or neutral. With ongoing
attempts to make passenger vehicles safer, air bags are employed to
prevent occupant injury during collisions. To this end and in a
further example, crash sensors operate in a vehicle to detect the
instance of a collision and communicate the crash occurrence to the
OEM vehicle controller so that the controller may output a signal
to deploy one or more air bags. Moreover, with the increasing
availability of telematics (e.g., OnStar.RTM.), many vehicles are
operative to automatically notify emergency services of a vehicle
collision almost immediately upon the signal output of a crash
sensor.
[0005] To comply with the Americans with Disabilities Act (ADA),
many public and private vehicles are being equipped with auxiliary
devices such as wheelchair lifts and ramps. Such auxiliary devices
provide access to vehicles such as vans, busses, minivans and the
like for mobility-challenged persons. Control systems for the
foregoing auxiliary devices have generally relied on the assistance
of the auxiliary device operators (often the vehicle driver).
Unfortunately, such auxiliary device control systems have proven to
be generally deficient in providing an adequate level of safety to
an auxiliary device user.
[0006] Several factors have been identified which contribute to
operator error: (1) the lack of familiarity with the controls, (2)
the lack of standardization in the control sequence and types of
controls (e.g., different controls for different lifts), and (3)
the lack of operator training. In addition, even though the user of
the auxiliary device may be fully visible to the operator, the
operator may not be aware of the passenger's presence. This "looked
but did not see" or daydreaming phenomenon is a frequent cause of
motor vehicle collisions. For example, the National Highway
Transportation Safety Administration (NHTSA) Office of Defects
Investigation (ODI) has reported cases in which accidents occurred
on vehicle wheelchair lifts when an operator accidentally tried to
stow a lift with the user still on the lift platform. To this end,
the NHTSA has proposed safety features known in the art as
"interlocks" that are expected to help prevent the auxiliary device
operator from making errors.
[0007] Additionally, lack of routine system maintenance has been
cited as a cause of malfunctions of auxiliary devices. To this end,
the NHTSA has proposed an "operations counter" that records each
complete (i.e., through its entire range of motion) operation of
the auxiliary device. The operations counter, which may provide an
operator or technician with a general indication of the device's
usage and/or age, is only helpful in assisting with identification
of an appropriate maintenance task (e.g., preventative maintenance
procedure) to be performed. For example, the auxiliary device's
hydraulic system should be inspected after a predetermined number
(e.g., 100) of uses.
[0008] To improve auxiliary device safety, auxiliary device
controls are becoming less operator-assisted and more computerized
and automated. Moreover, to enhance the safety of vehicles with
installed auxiliary devices, it would be advantageous to facilitate
communications between the auxiliary device's control system and
the OEM controller. By communicating in this manner, the auxiliary
device control system could operate to communicate with OEM
subsystem elements such as sensors, switches, motors, and the like
to enable a plurality of safety features and interlocks. In view of
the foregoing, there exists a need for an electronic auxiliary
device controller that operates to enable safety interlocks through
coordination of various OEM and auxiliary subsystems, assists in
system diagnostics, and indicates unsafe operating conditions such
as when repair or maintenance is required, and the like.
BRIEF SUMMARY OF THE INVENTION
[0009] An electronic controller, control system and method for
controlling the operation of a vehicle auxiliary device, such as a
wheelchair lift installed in a vehicle, are provided. The control
system includes an electronic controller with a microprocessor or
the like that operates under software control to communicate with a
vehicle's OEM controller and a plurality of sensors, which may be
associated with OEM and auxiliary device subsystems. The auxiliary
device controller processes the sensor communications to determine
the occurrence of an unsafe condition, and prevents the operation
of OEM and auxiliary device subsystems relative to the sensor
communications to enhance the safety of a auxiliary device user.
Additionally, the auxiliary device controller operates to
coordinate various OEM and auxiliary device subsystems to reduce
auxiliary device operator error.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The present invention is described with reference to the
accompanying figures and appendices, which illustrate embodiments
of the present invention. However, it should be noted that the
invention as disclosed in the accompanying figures and appendices
is illustrated by way of example only.
[0011] FIGS. 1A-B illustrate a block diagram of an exemplary
control system for operating a vehicle auxiliary device;
[0012] FIG. 2 is a perspective view of an exemplary auxiliary
device for which the exemplary electronic controller of FIG. 1 may
be employed; and
[0013] FIGS. 3A-1 through 3A-4, 3B-1 through 3B-5 and 3C-1 through
3C-4 illustrate electrical circuit schematic diagrams for one
exemplary embodiment of the electronic controller of FIG. 1.
DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0014] Referring now to the figures, and particularly FIG. 1, a
control system for an auxiliary device is shown. The control system
may include an after-market type controller 100 (i.e., not OEM
equipment) that is provided with an auxiliary device such as a
wheelchair lift or ramp for controlling the auxiliary device. One
exemplary auxiliary device is illustrated in FIG. 2 as a vehicle
wheelchair lift 10, but the auxiliary device may be a wheelchair
ramp or other device that helps a mobility-challenged person enter
and exit a vehicle, building or other structure. As shown in FIG.
2, by way of example, the wheelchair lift 10 is installed in
vehicle V such as a bus, van, or other suitable vehicle. Wheelchair
lift 10 is installed in a doorway D and is bolted or otherwise
fixedly attached to the vehicle floor F. With reference to the axis
shown in FIG. 2, a direction closest to or toward the vehicle V
shall be referred to as inboard (IB), whereas the direction away
from or farthest from the vehicle V shall be referred to as
outboard (OB). The wheelchair lift 10 operates to raise and lower a
platform 12 to help a mobility-challenged individual such as a
person using a wheelchair, scooter, walker or the like to enter and
exit the vehicle V. The individual typically employs the lift 10
with the assistance of an operator who controls the operation of
the lift 10.
[0015] The individual enters the wheelchair lift platform 12 so
that the operator may control the lift 10 to move the platform 12
up and down to transfer the individual between the ground level and
the vehicle doorway D, which is known in the art as the transfer
level or threshold elevation. As shown in FIG. 2, the wheelchair
lift 10 includes several features that help to ensure the safety of
an individual employing the lift 10. The safety features include
but are not limited to graspable handrails 18, an inboard barrier
16, an outboard barrier 14 and side barriers 20. Other safety
features that are not illustrated include a safety belt and a
tie-down or the like known in the art for securing a wheelchair to
the platform 12. Inboard and outboard barriers 16, 14, which are
also known in the art as rollstops, help prevent an individual from
accidentally falling off the inboard and outboard sides of the
platform 12 when the platform is elevated above the ground level.
Further, side barriers 13 cooperate with the barriers 14, 16 to
help prevent an individual from accidentally falling off the right
and left sides of the platform 12. In addition, the inboard barrier
16 serves as a "bridge plate" to allow the individual to safely
move from the platform 12 to the vehicle interior when the platform
12 is raised to the elevated transfer level. Controls for the
wheelchair lift 10 may be located within the vehicle V or outside
of the vehicle V, and are typically operated by the vehicle driver
or operator, but in some cases the user of the auxiliary device may
operate the auxiliary device without assistance. Controls for the
lift may include switches, buttons or the like that are operable to
raise, lower, deploy and stow the platform 12. When the lift 10 is
fully stowed, the platform 12 is typically folded and stored within
vehicle doorway D in a generally vertical orientation.
[0016] Referring now back to FIGS. 1A-B, a control system for an
auxiliary device such as the exemplary wheelchair lift 10 of FIG. 2
is shown. The control system includes a controller 100 comprising a
microprocessor 20 that operates under software control to safely
control the operation of the auxiliary device relative to a
plurality of received inputs including but not limited to control
(i.e., operator) inputs and environmental (i.e., sensor) inputs.
Although the controller 100 is described hereinafter as comprising
a plurality of integrated circuit (IC) chips, particularly a
microprocessor 20, the ICs may be substituted with fewer or
additional ICs that perform substantially similar functions. For
example, the microprocessor 20 may be replaced with a digital
signal processing (DSP) IC or other IC or logic device known in the
art. As shown in FIGS. 1A-B, a sensor input module 22 may be linked
to the microprocessor 20 in order to interface a plurality of
sensors with the controller 100 by aggregating the outputs of the
sensors and relaying the sensor outputs to the microprocessor 20
for analysis and decision-making. As shown, the plurality of
sensors providing outputs to the sensor input module 22 can be
categorized as follows: sensors associated with the outboard
rollstop 14, sensors associated with the inboard rollstop 16,
sensors associated with the platform 12 and sensors associated with
the vehicle V. As can be appreciated, rollstop occupancy sensor
220, rollstop position sensor 221 and rollstop lock sensor 222 are
associated with the outboard rollstop 14 whereas inboard barrier
position sensor 224, inboard barrier lock sensor 225 and inboard
barrier occupancy sensor 226 are associated with the inboard
barrier 16. Further, lift position sensor 223 and platform
occupancy sensor 227 are associated with the platform 12 and
threshold occupancy sensor 228 and door position sensor 229 are
associated with the vehicle V. As known in the art, the sensors
220-229 may be embodied by switches such as contact microswitches
or the like. Alternatively, the sensors 220-229 may be embodied by
known devices that operate to discriminate a state change in the
associated member (e.g., platform 12, rollstops 14, 16, etc.). As
can be appreciated, the sensors 220-229 provide digital or
otherwise discrete outputs.
[0017] Further, a plurality of analog sensors that provide
variable, continuous outputs may provide data to the microprocessor
20 by linking the outputs of the analog sensors to an analog to
digital (A/D) converter 23 that is linked with the microprocessor
20. As shown in FIGS. 1A-B, analog sensors may monitor
environmental aspects of the auxiliary device (e.g., lift 10 and
controller) such as voltage, current, pressure and temperature to
ensure that various OEM and auxiliary device subsystems are
operating within predetermined specifications or parameters. To
this end, the plurality of analog sensors linked with the A/D
converter 23 may include: a lift motor current sensor 230, a lift
supply voltage sensor 231, a controller supply voltage sensor 232,
a rollstop motor current sensor 233, a pressure transducer and a
temperature sensor 236.
[0018] Moreover, microprocessor 20 is linked with the OEM vehicle
controller for receiving outputs from OEM vehicle sensors and other
communications between the OEM vehicle controller and OEM vehicle
subsystems, among other things. To this end and as shown in FIG. 1,
a multiplexed interface module 21 is linked to microprocessor 20
for enabling the microprocessor 20 to communicate with the OEM
controller via the OEM communications bus 30. The interface module
21 may communicate with the OEM controller via known communication
protocols such as CAN, SAE J1850, LIN and the like. In this way,
the microprocessor 20 may operate to intercept an OEM control
signal to delay the execution of an OEM subsystem operation until
the microprocessor 20 is able to query or otherwise process the
output of one or more auxiliary device sensors. Similarly, the
microprocessor 20 may operate to delay the execution of an
auxiliary device subsystem operation until the microprocessor 20 is
able to query or otherwise process the output of one or more OEM
sensors. In one example, the controller may cooperate with the OEM
vehicle controller to ensure safe deployment of the lift 10 when
the vehicle is in a secure state (e.g., transmission in park with
parking brake set and door open). Thus, when a lift user or
operator requests deployment of the lift 10, the controller may
verify the state of a number of OEM subsystems and subsequently
take corrective action to correct an incorrect or unsafe subsystem
state by controlling the subsystem or alternatively inhibiting the
requested deployment and providing a warning or indication. In this
way, the controller may operate to coordinate, streamline or
otherwise automate safe operation of the OEM and auxiliary device
subsystems.
[0019] In response to the aforementioned outputs of sensors
220-229, 230-236, microprocessor 20 may output control, status, or
informational signals. As shown in FIGS. 1A-B, a control output
module 24 is linked to microprocessor 20 to control or actuate
various subsystem elements, such as motors, pumps, valves,
switches, indicators and the like. As shown, the control output
module 24 may be linked or otherwise communicate with: a motor
speed control 240, a hydraulic valve control 241, a system busy
status indicator 242 and audio/visual alarms or indicators 243.
Further, as previously mentioned, since microprocessor 20 is linked
with the OEM vehicle controller via multiplex physical interface
21, the microprocessor 20 also operates to control various OEM
subsystems such as motors for power sliding doors, solenoid
switches and the like.
[0020] Additionally as shown in FIGS. 1A-B, microprocessor 20 is
linked to a user interface module 25 that provides a user or
operator with a means for interacting with the controller 100 for
the purpose of receiving information from or providing inputs to
the microprocessor 20. As can be appreciated, the user interface
module 25 may include a graphical or alphanumeric display that
provides an operator or user with status information, messages,
error messages, diagnostic displays and the like as well as audible
or other sensor indications relative to the status of the auxiliary
device and the vehicle V. As shown, the user interface module 25 is
linked with: a system status indicator 250, an interlock status
indicator 251, an error message indicator 252, a diagnostic display
interface 253, a cycle count indicator 254 and a service interval
indicator 255. System status indicator 250 may provide a display
relative to the controller or auxiliary device environment (e.g.,
voltages, current, etc.) and interlock status indicator 251 may
provide a status display of all lift interlocks which will be
discussed in further detail hereinafter. In connection with
maintenance and troubleshooting of the controller and auxiliary
device, the error message indicator 252 may provide a list of any
and all errors detected by the controller during vehicle V and
auxiliary device operation (e.g., OBDII codes or translations
thereof), the diagnostic display interface 253 may provide a series
of help menus such as an interactive menu-driven interface for
assisting a technician or operator in troubleshooting or otherwise
isolating a fault, the cycle count indicator 254 may display the
number of times the auxiliary device has been used (e.g., how many
complete lift cycles the lift 10 has completed) and the service
interval indicator 255 may display when a predetermined maintenance
task is required relative to the cycle count indicator 254, a
length of time or other determining factor. Further, a service
technician may be able to input information to the controller
indicating that a maintenance task has been completed for record
keeping. Moreover, the controller may also include a diagnostic
interface such as a port or connector that allows a technician to
debug the controller, troubleshoot auxiliary device subsystems and
exercise auxiliary and OEM subsystem components. By connecting a
laptop, dumb terminal, or the like to the diagnostic interface
(e.g., an RS232, 9-pin, subminiature "D" connector with standard
EIA pinout), a technician may access a menu-driven user interface
or the like. Alternatively, a display such as a small LCD may be
included in the interface module 25 or otherwise coupled thereto to
facilitate communications with the diagnostic interface.
[0021] The controller may also include a remote receiver module 27
that is linked to the microprocessor 20 for communicating with
wireless devices that cooperate with the controller to provide
access to or otherwise control the vehicle V and/or auxiliary
device. Remote receiver module 27 may include or otherwise be
coupled with an antenna so that it is operable to receive wireless
signals (e.g., RF, IR, RFID, etc.) from a remote sensor or
transmitter 28. For example transmitter 28 may be a hand controller
that operates the lift 10 to deploy, stow, raise and lower the
platform 12 by sending wireless control signals to the
microprocessor 20 via the receiver module 27. As can be
appreciated, since microprocessor 20 communicates with the OEM
vehicle controller, transmitter 28 may be operable to actuate OEM
subsystem components such as power locks, power sliding doors, a
security alarm and the like in addition to actuating auxiliary
functions such as deploying, raising and lowering a lift, ramp.
[0022] As shown in FIGS. 1A-B, the controller also includes a
lighting control module 26. The lighting control module 26 may
operate to control a light proximate to or coupled with the
auxiliary device for illuminating the auxiliary device or
surrounding environment when needed or desired. As shown, the
lighting control module 26 may receive an output signal from a
light sensor 260 (e.g., a photodetector), which senses low ambient
light conditions in the area of the auxiliary device. In response
to a sensed low ambient light condition, the lighting control
module 26 and microprocessor 20 are operable to output a control
signal to an illumination means 261. The light enabling control
signal may actuate one or more lights, such as spot or flood lights
which thereby illuminate a surface or portion of the auxiliary
device (e.g., platform 12) such as throughout the device's range of
operation. The lights may be located in and/or on the vehicle, or
on the auxiliary device (e.g., lift 10) so that there is
illumination of at least 5 lm/sqft on all portions of the surface
of the platform 12.
[0023] Operation of the exemplary auxiliary device embodied by the
wheelchair lift 10 (FIG. 1) relative to the controller 100 is
hereafter described in detail. The auxiliary device controller 100
comprising the foregoing modules 21-27 operates under software
control of the microprocessor 20 to implement various safety
features. One safety feature of the controller prevents an
individual from falling out of vehicle V through doorway D when the
lift 12 is at an elevation other than the transfer level. To this
end, the controller 100 receives an input via sensor input module
22 from both a threshold sensor 228 and a lift position sensor 223.
The threshold sensor 228 may include a physically actuated switch
such as a pressure sensitive mat or tape, or may alternatively be
an electronic sensing means comprising an infrared, ultrasonic,
optical, or electric field type sensor. When an individual or other
object is sensed in the threshold area, the threshold sensor 228
outputs a signal to the sensor input module 22. The lift position
sensor 223 may include one or more sensors on the lift 10 and/or
vehicle V to determine the position or elevation of the platform 12
with respect to the vehicle floor F. If the platform 12 is
determined by the lift position sensor 223 to be at an elevation
other than the vehicle floor F, the sensor 223 is operable to
output a signal to sensor input module 22. Having received signals
from both sensors 223 and 228, microprocessor 20 may actuate a
visual or audible warning until either the lift platform 12 is
elevated to the vehicle floor level, or the object or individual
exits the threshold area. The microprocessor 20 may actuate audio
and/or visual alarms (e.g., alarms 243) through the control output
module 24. The visual warning may be a flashing red beacon or the
like having a minimum intensity of twenty candela and a frequency
from ten to two Hz, which is installed such that it does not
require more than plus or minus fifteen degrees side-to-side head
rotation as viewed by a user either backing or moving in a forward
direction onto the platform from the interior of the vehicle. An
audible warning produced by audio alarm 243 may be a minimum of
eighty-five dBa, and is between five hundred and three thousand Hz.
Moreover, the lift position sensor 223 may be operable to
discriminate elevation changes of less than or equal to 1 inch
below the vehicle floor F. As is known in the art, the threshold
area may be a rectangular space on the vehicle floor defined by the
edge of the vehicle floor directly adjacent to the platform through
a distance of eighteen inches inboard from the edge across the
vehicle floor.
[0024] Another safety feature of controller 100 disables the lift
10 from operating if a lift user is improperly positioned on the
lift platform 12 before or during a requested lift operation. Such
a safety feature is known as an "interlock" in the art. As
described hereinafter, the controller 100 includes and operates
five interlocks, but fewer or additional interlocks may be
provided. Generally, in operating an interlock, the controller 100
receives a user input requesting the activation of an auxiliary
device function (e.g., raise, lower, stow, deploy), checks the
outputs of one or more sensors relative to the requested function
and allows or prevents the activation of the requested auxiliary
device function. The controller 100 includes a first interlock that
the controller 100 operates to inhibit stowage of the lift 10 when
the platform 12 is occupied by a user or other object. If
microprocessor 20 receives a user or operator request to stow the
lift 10 via a remote transmitter 28 or other user control such as a
hand control within the vehicle, microprocessor 20 queries or
otherwise communicates with platform sensor 227 via sensor input
module 22 to determine the platform occupancy state (i.e., occupied
or unoccupied). Platform sensor 227 may comprise a
pressure-sensitive tape or mat, infrared, ultrasonic, optical, or
electric field sensing means on or near the platform 12 in order to
discriminate the presence of an object thereon. Having received a
lift stow request, microprocessor 20 delays action on the received
request by queuing the request or the like and operates to
determine the occupancy state of the platform 12. If microprocessor
20 determines that platform 12 is occupied, the microprocessor 20
may output a signal via control output module 24 to disable the
lift 10. For example, the microprocessor 20 via control output
module 24 may disable or de-energize a motor driving a hydraulic
pump, inhibit the actuation of one or more hydraulic solenoid
actuated valves 241, or the like. In addition, the microprocessor
20 may indicate an interlock state via interface module 25 and
interlock status display 251, and/or actuation of an audio or
visual alarm 243 via control output module 24. Upon removal of the
platform object, microprocessor 20 may discontinue actuation of the
alarm, and allow stowage of lift 10.
[0025] The controller 100 includes a second interlock that the
controller 100 operates to inhibit movement of the platform 12 up
or down unless the inboard rollstop 16 is deployed. When
microprocessor 20 receives an operator request via remote
transmitter 28 or other user control such as a hand control within
the vehicle to raise or lower the platform 12, the microprocessor
20 may operate to determine the position of the inboard barrier via
inboard barrier position sensor 224, and may further determine if
the inboard barrier is locked in a deployed (i.e., substantially
vertical) position. The inboard barrier position sensor 224 may
include a cam and microswitch arrangement or the like to provide an
indication of the rotational position of the inboard barrier 16,
whereas the inboard barrier lock sensor 225 may include a relay
actuated solenoid switch or the like. Additionally, microprocessor
20 may consider the output of lift position sensor 223 when
comparing the sensed position of the inboard barrier 16 with a
known safe position of the barrier 16. Moreover, to enhance the
safety of the lift and prevent a lift occupant from becoming pinned
between the platform 12 and vehicle V, the controller may inhibit
operation of the lift 10 or provide a visual or audible warning if
microprocessor 20 determines that the inboard barrier 16 is in an
unlocked position via inboard barrier lock sensor 225. As described
above with the first interlock, controller 100 may disable one or
more hydraulic or electrical components of the wheelchair lift
10.
[0026] The controller 100 includes a third interlock that the
controller 100 operates to inhibit deployment of the inboard
rollstop 16 if an object is sensed on the rollstop 16. Since a user
or mobility device may be tipped, tilted or, at worst, thrown off
the lift 10 if the rollstop 16 is moving when occupied (i.e., there
is an object present on the rollstop 16), it is important to check
the occupancy state of the inboard rollstop 16 via an inboard
barrier occupancy sensor 226. Generally, the third interlock is
only applicable when the platform 12 is located at the vehicle
floor level F and the rollstop 16 is in a generally horizontal,
bridging orientation. If the platform 12 is at the vehicle floor
elevation for transferring a user from the vehicle to the ground
elevation, and the user is positioned on a portion of the platform
12 and inboard rollstop 16, microprocessor 20 operates to verify
the output from the inboard barrier occupancy sensor 226 when lift
lowering is requested. Thus, if the inboard barrier 16 is
determined to be occupied, the microprocessor 20 may, as with the
aforementioned interlocks, disable the lowering operation the lift
and trigger an audio or visual warning alarm.
[0027] The controller 100 includes a fourth interlock that the
controller 100 operates, which is somewhat similar to the foregoing
third interlock, but is generally concerned with the occupancy
state of the outboard barrier rollstop 14. Generally, the fourth
interlock is only applicable when the platform 12 is located at the
ground elevation and the rollstop 14 is in a generally horizontal
orientation. If the platform 12 is at the ground elevation, and the
outboard rollstop 14 is in a generally horizontal position, the
outboard barrier 14 may become occupied (i.e., there may be an
object present on the rollstop 14), prior to raising the platform
12. To prevent a user or object from being tipped off the platform
onto the ground, the lift 10 may include various sensors on the
platform 12 or the outboard rollstop 14 which are operable to
determine the outboard rollstop position (sensor 221), the locked
or unlocked state of the outboard rollstop (sensor 222), and the
outboard rollstop occupancy state (sensor 220). As with operation
of the aforementioned interlocks, microprocessor 20 is operable to
receive and process signals from sensors 220, 221, and 222 when a
platform raise operation is requested and disable the lift 10 and
trigger an audio or visual warning alarm if outboard rollstop 14 is
occupied or remains in a generally horizontal position after the
platform 12 has been raised a very small predetermined distance
(e.g., one inch) from the ground elevation. If the platform 12 has
been raised slightly and the rollstop position sensor 221 or lock
sensor 222 indicates that the rollstop 14 remains in a horizontal
orientation, the controller 100 may operate the lift to lower the
platform back to the ground.
[0028] The controller 100 includes a fifth interlock that the
controller 100 operates to inhibit both raising and lowering
movement of the platform 12 unless a wheelchair retention device,
such as the outboard rollstop 14, is deployed (i.e., in a generally
vertical barrier orientation). As with the second interlock
discussed above, when microprocessor 20 receives an operator
request via remote transmitter 28 or other wired operator control
in the vehicle to raise or lower the platform 12, the
microprocessor 20 may determine the position of the outboard
rollstop 14 via rollstop position sensor 221, and may also
determine if the outboard rollstop 14 is locked in a deployed or
substantially vertical position via rollstop lock sensor 222. The
rollstop position sensor 221 may include a cam and microswitch
arrangement or the like to determine the rotational position of the
outboard rollstop 14, whereas the rollstop lock sensor 222 may
include a relay actuated solenoid switch or the like. Additionally,
microprocessor 20 may consider the output of lift position sensor
223 when comparing the sensed position of the outboard rollstop 14
with a known safe position of the rollstop. Preferably, the
controller 100 inhibits the platform 12 from raising more than
three inches above the ground when the platform 12 is occupied and
the outboard rollstop 14 is in a nondeployed (i.e., horizontal)
orientation. For example, the controller, having received a raise
operation request, is operative to determine if the platform 12 is
occupied, the outboard rollstop 14 position, and whether the
outboard rollstop 14 is locked, prior to sensing when the platform
12 has been raised three inches above the ground level or the
lowest deployed platform level.
[0029] In addition to the foregoing described five interlocks that
are generally concerned with providing safe operation of the
auxiliary device, the controller 100 may provide other
interlock-type safety features that require the controller 100 to
interact, control or otherwise communicate with one or more OEM
subsystems. For example, the microprocessor 20 may inhibit
deployment of the lift 10 if the vehicle door is closed or not
fully open. In a further example, the microprocessor 20 may prevent
the user from closing the vehicle door if the lift 10 is
deployed.
[0030] In addition to the aforementioned safety features,
controller 100 is operable to monitor the operation of the
auxiliary device to ensure that the device and its subsystems are
operating consistently within predetermined operating
specifications or parameters. To prevent user injury and lift
damage due to undesirable stress on lift components, the controller
100 is operable to monitor lift velocity (i.e., speed) and
acceleration during requested operations (e.g., stow, deploy,
raise, lower). For example, throughout the range of passenger
operation (i.e., occupied operation of the auxiliary device) it is
important that both the vertical and horizontal velocity of the
platform be less than or equal to a predetermined safe speed such
as six inches per second. In a further example, during stow and
deploy operations of the auxiliary device (i.e., when the auxiliary
device is unoccupied), both the vertical and horizontal velocity of
any portion of the lift should be less than or equal to a second
safe speed that may be greater than or equal to the first safe
speed, for example, twelve inches per second. Further, it is
desirable that the acceleration of the auxiliary device be less
than or equal to 0.3 G. To monitor the velocity and acceleration of
the lift 10, various sensors may be employed, including lift motor
current and voltage sensors, accelerometers, and motor shaft speed
or torque sensors that may communicate with a motor speed control
240, such as a pulse width modulation (PWM) type module to effect
feedback motor control. Sensors 230-234 in connection with A/D
converter 233 enable microprocessor 20 to monitor and control
operation of the lift 10 within such foregoing predetermined
operating specifications. For example, if the lift speed or
acceleration are determined to be outside of an acceptable range,
microprocessor 20 may output a signal via control output module 24
to vary the output of motor control 240 or hydraulic components,
such as a hydraulic valve 241. Additionally, microprocessor 20 may
be operable to limit the operating noise of the lift by use of the
motor control 240. Moreover, motor control 240 may effect soft
starts and stops of a motor such as one used in a hydraulic power
unit thereby allowing for smooth, consistent, and quiet operation
of the lift 10.
[0031] In monitoring system operations, the controller 100 may
advantageously assist the operator or technician if and when system
malfunctions occur. User interface module 25 includes one or more
status indicators 250 that displays the state of the lift 10 (e.g.,
on, off). The status indicator 250 may include incandescent or LED
indicator lights which illuminate relative to a master on-off
switch, button or the like. Further, the microprocessor 20 may
illuminate the one or more status indicators 250 with varying
intensities during sensed low ambient light conditions to
distinguish between important and unimportant indicators. To this
end, the microprocessor 20 is operable through the multiplex
interface module 21 to sense when the vehicle's headlights are
illuminated and in response to a user or operator illuminating the
vehicle's headlights, or the vehicle light sensor 260 (e.g.,
photodetector) detecting a low light condition, the microprocessor
20 may illuminate one or more of indicators 250 through 255 as
desired or appropriate.
[0032] User interface module 25 also includes a status indicator
for the above mentioned interlocks. The interlock status indicator
251 may include one or more indicators (e.g., visual and/or audible
indicators) that are actuated in response to an interlock
condition. In addition, user interface module 25 includes an
operations counter or cycle count indicator 254. Cycle count
indicator 254 records each complete raise/lower operation of the
lift 10 to provide a general indication of lift usage and remaining
useful life. Relative to the cycle counter 254, the user interface
module 25 may include one or more service interval indicators 225.
Service interval indicator 225 may be operable to indicate one or
more recommended service or maintenance items to an operator or
user based on the cycle count of the lift. For example,
microprocessor 20 may actuate the service interval indicator 225
via user interface module 25 when a predetermined lift count is
reached or exceeded. The service interval indicator 225 may display
a static message (e.g., lift service recommended), or may indicate
one or more specific subsystems for which preventative maintenance
is recommended (e.g., check hydraulic power unit). In addition to
the foregoing, user interface module 25 may include a diagnostic
display interface 253 and an error message display 252. Error
message display 252 may enable an operator or user to perform basic
maintenance to the lift 10, or may indicate specific faults or
failures within the system that require repair or replacement by a
technician. As mentioned above, the diagnostic display interface
253 may help or enable a technician to perform troubleshooting with
the assistance of a menu-driven interface display or the like.
[0033] Referring now to FIGS. 3A-C, an electrical circuit schematic
illustrating one exemplary embodiment of the controller of FIGS.
1A-B is shown. It will be readily understood by a person
knowledgeable in the art that the illustrated components and
electrical connections of FIGS. 3A-C are provided for exemplary
purposes only and that other suitable components and
interconnections may be provided. As can be appreciated, the
controller 100 may be embodied by a "black box" that includes a
number of connectors for interfacing with various OEM and auxiliary
device subsystems such that the controller 100 is a "plug and play"
type module. As shown in FIGS. 3A-1 through A-4, one exemplary
microprocessor 20 is a Motorola MC9S12DG128B 16-bit microcontroller
unit (MCU) composed of standard on-chip peripherals, but other
suitable integrated circuit (IC) modules may be substituted.
Software running on the microprocessor 20 effects control outputs
relative to a plurality of received inputs. The microprocessor 20
communicates with an OEM interface module 21 comprising a Motorola
MC33388 (FIG. 3B-1), but other suitable communication interface
modules known in the art may be substituted. The MC33388 is a CAN
physical interface device, dedicated to automotive body electronic
multiplexing applications. As shown in FIGS. 3B-1 and 3B-1, the
MC33388 is connected to the vehicle OEM communications bus 30 with
a suitable connector. As shown in FIG. 3B-4, a switch detection
module 22 comprising a Motorola 33993DW is linked to a plurality of
sensors as shown. As known in the art, the Motorola 33993 is
designed to detect the closing and opening of up to twenty-two
switch contacts, however other suitable ICs or circuit modules may
be provided for controlling fewer or additional switch contacts or
other elements. As shown in FIG. 3B-5, the control output module 24
comprising a Motorola MC33298DW is operatively linked to control
various status indicators and the like. The MC33298 is an octal
series switch comprising interfaces directly with a MCU to control
various inductive (e.g., relays, solenoids, switches) or
incandescent loads.
[0034] The user interface module 25 of FIGS. 1A-B may comprise a
4.times.20 character LCD panel as shown in FIG. 3B-2 for displaying
various status messages and indications. However, the user
interface module 25 may comprise other types of displays known in
the art such as TFT or the like. Additionally as shown in FIG.
3B-3, a diagnostic interface 31 embodied by an RS232 interface is
illustrated to be operatively linked with the microprocessor 20 to
allow an individual to troubleshoot the controller 100 and one or
more OEM and auxiliary subsystems. The RS232 interface 31 comprises
a Dallas Semiconductor DS14C232 module and 9-pin subminiature "D"
interface for connecting a personal computer, dumb terminal,
display terminal, laptop or the like with the controller. As shown
in FIG. 3A4, the controller 100 may include a multipurpose data
storage/clock/calendar module 19. As shown, this module 19
comprises a Ramtron FM30C256 which is a 256 Kb data collection
subsystem including nonvolatile RAM, and timekeeping and time-stamp
functionality.
[0035] Referring now to FIG. 3C-1 through 3C-4, one or more voltage
regulators may be linked to the microprocessor 20 to regulate
voltage to the controller 100 and the auxiliary device and/or its
subsystems. As shown, one exemplary voltage regulator comprises a
LT1761ES5-5 low noise, low dropout regulators that provide reverse
battery protection, current limiting, thermal limiting and reverse
current protection available from the Linear Technology company.
Further as shown, a current transducer, embodied by a HY12
available from the LEM company, operates to monitor the current of
the lift motor for reporting to the microprocessor 20. Moreover,
temperature sensor 236 comprising a Maxim MAX 6635MSA may be
operatively linked to the microprocessor 20 to sense
over-temperature conditions and output a shutdown signal relative
to, for example, the auxiliary device motor (not shown). A
hydraulic valve controller 241 is operatively linked to the
microprocessor 20 to control operation of one or more hydraulic
valves. As shown in FIG. 3C-1, one exemplary valve controller 241
comprises a Burr-Brown DRV102 high-side, bipolar power switch
employing a PWM output for driving electromechanical and thermal
devices (e.g., solenoids, positioners, contactors, etc.).
Additionally, one or more driver circuits may be operatively linked
to the microprocessor 20 to control the operation of motors such as
a rollstop motor, lift motor, and the like. As shown in FIGS. 3C-2
and 3C-3, the motor control 240 may include exemplary integrated
circuits (ICs) such as the Motorola MC33883 full bridge pre-driver
and the Motorola MC33486 dual high side switch for H-bridge
automotive applications.
[0036] The use of any and all examples, or exemplary language
(e.g., "such as") provided herein, is intended merely to better
illuminate the invention and does not pose a limitation on the
scope of the invention unless otherwise claimed. Exemplary
embodiments of this invention are described herein. Variations of
those exemplary embodiments may become apparent to those of
ordinary skill in the art upon reading the foregoing description.
The inventors expect skilled artisans to employ such variations as
appropriate, and the inventors intend for the invention to be
practiced otherwise than as specifically described herein.
Accordingly, this invention includes all modifications and
equivalents of the subject matter recited in the claims appended
hereto as permitted by applicable law. Moreover, any combination of
the above-described elements in all possible variations thereof is
encompassed by the invention unless otherwise indicated herein or
otherwise clearly contradicted by context.
* * * * *