Abstract:
A system of verifying the integrity of a data bus for a motor vehicle. The system includes a first module for acknowledging a manual input signal initiated by the motor vehicle occupant. The first module has active and inactive mode. The first module is in inactive mode during its normal condition, and it is activated upon receiving the input signal. The first module transmits a triggering signal to a second module over the data bus. The second module also has active and inactive modes, and it is in inactive mode during the normal condition. The second module is activated upon receiving the triggering signal from the first module, and subsequently transmits a signal back to the first module. The integrity of data bus is verified by the data transfer between first and second modules over the data bus within a predetermined time period.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Serial No. 60/239,591, filed on Oct. 11, 2000. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates generally to a system for pedal adjustment for motor vehicles, and more particularly, to apparatuses and methods for verifying the integrity of the data bus prior to pedal adjustment for motor vehicles.  
           [0004]    2. Description of the Related Art  
           [0005]    With increasing sophistication of motor vehicles, several electronic control units (ECU) are used to control different systems of the vehicle. Such ECUs monitor various control inputs and operational conditions of various systems. For example, a engine control unit may monitor engine speed, torque, pedal depression and other operating parameters of the engine to optimize the performance of the engine.  
           [0006]    The various ECUs are interconnected by a data bus so that information may be interchanged between them. The data bus enables the ECUs to function in an integrated manner. As the number of systems that are controlled by the ECUs increases, it has become critical that the data bus does not malfunction since it may affect the correct operation of the vehicle ECUs to which it provides information.  
           [0007]    Verification of the integrity of the data bus has heretofore been necessary to confirm that communication between various vehicle systems and their control modules is provided to optimize the performance of the vehicle. Conventionally, the integrity of the data bus is verified upon receiving all of the identifying messages. This traditional method requires more time since the control module has to wait for all of the identifying messages from various vehicle systems to which it is interconnected. In addition, this method could be performed only when the vehicle engine is running. Thus, it is difficult to check the performance of vehicle systems that are active in a vehicle key-off condition.  
           [0008]    Therefore, it would be desirable to provide an apparatus or method to verify the integrity of the data bus when the vehicle is in a key-off condition. Accordingly, the performance of vehicle systems, which are activated in the key-off condition, can also be optimized. It would also be highly desirable to provide an apparatus or method to verify the integrity of data bus that does not require waiting for the identifying messages from all of systems connected to the data bus, thus minimizing the data transfer time and the current draw from the vehicle&#39;s battery.  
         SUMMARY OF THE INVENTION  
         [0009]    This invention is directed to a system and method of verifying the integrity of a data bus for a motor vehicle. More particularly, this invention is directed to a system and method of verifying the integrity of a data bus for a motor vehicle using at least two vehicle modules that have active and inactive modes when the vehicle is in key-off condition.  
           [0010]    The system includes a first module to acknowledge a manual input signal initiated by the motor vehicle occupant. The first module has an active and an inactive mode. The first module is in an inactive mode during its normal key-off condition. The first module is activated upon receipt of an input signal. The first module transmits a triggering signal to a second module over the data bus. The second module communicates bi-directionally with the first module. The second module also has an active and an inactive mode. The second module is in an inactive mode during the normal condition. The second module is activated upon receipt of a triggering signal from the first module. The second module subsequently transmits a signal back to the first module. The data bus provides a bi-directional communication between the first and second modules. The integrity of data bus is verified by the data transfer between the first and second modules over the data bus within a predetermined time period.  
           [0011]    The present invention is applicable for motor vehicles that includes at least two modules with an active and an inactive mode when the vehicle is in key-off condition. The present invention, thus enables the vehicle to check the integrity of the data bus even when the vehicle is in a key-off condition. In addition, since these two modules are active only when the manual interrupt signal is received, the current draw from the battery of the motor vehicle is kept to a minimum.  
           [0012]    Further areas of applicability of the present invention will become apparent from the detailed description. It should be understood however that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0014]    [0014]FIG. 1 is a perspective view depicting the adjustable pedal assembly system of the presently preferred embodiment of the invention;  
         [0015]    [0015]FIG. 2 is a block diagram depicting the adjustable pedal assembly system of the presently preferred embodiment of the invention;  
         [0016]    [0016]FIG. 3 is a flow chart depicting the acquisition of a required adjustment of the pedal assembly of the presently preferred embodiment of the invention;  
         [0017]    [0017]FIG. 4 is a flow chart depicting the method of verifying the integrity of data bus of the presently preferred embodiment of the invention;  
         [0018]    [0018]FIG. 5 is a table describing the data bus message communication during different ignition states; and  
         [0019]    [0019]FIG. 6 is a table describing fault condition lockouts according to the presently preferred embodiment of the invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0020]    Referring to FIG. 1, an adjustable pedal module system (APMS)  10  for a motor vehicle is illustrated in accordance with the teachings of the present invention. The APMS  10  includes a brake pedal assembly  12 , an accelerator pedal assembly  14 , an adjustable pedal module (APM)  16 , and supporting electrical circuits (not shown). The APM  16  controls the pedal assemblies  12  and  14  and communicates with other vehicle electronic control units (ECUs)  30 . The APM  16  may receive a manual interrupt input from either a manual switch  28  or from memory  26 . The APM  16  is connected to the ECUs via a data bus  32 . Movements of the accelerator pedal assembly  14  are monitored by a movement sensor  22 . The movement sensor  22  is connected to a motor module  18  through a cable  24 .  
         [0021]    [0021]FIG. 2 of the drawings illustrates the preferred embodiment of the APM  16  in greater detail. The APM  16  further contains a pedal movement module  19 , an operating condition sensor  34 , and a lockout module  36 . The pedal movement module  19  receives manual interrupt inputs from the manual switch  28  and memory  26 . The pedal movement module  19  communicates with the ECUs  30  through the data bus  32 . The operating condition sensor  34  receives identifying messages from the various modules of the motor vehicle. The operating conditional messages are collected in the operating condition sensor  34  and sent to the lockout module  36 . The lockout module  36  determines the existence of any lockout conditions based upon the identifying messages received by the operating condition sensor  34 . If any of lockout conditions are detected, the pedal movement module  19  of the APM  16  disables the adjustment of the pedal assemblies  12  and  14 . If no lockout conditions are detected, the pedal movement module  19  adjusts the pedal assemblies  12  and  14  to a desired position.  
         [0022]    With further reference to FIG. 3 of the drawings, a process for adjusting the pedal assemblies  12  and  14  in accordance with the teachings of the present invention is illustrated. The APMS  10  receives an input at step  40 . The input signal may be from either the manual switch  28 , which is pressed by a vehicle occupant, or memory  26 . The memory  26  retains at least two different pedal positions. Upon a request for adjustment of the pedal assembly  12  and  14  by the vehicle occupant, the input signal is sent to the pedal movement module  19  of the APM  16 .  
         [0023]    The pedal movement module  19  of the APM  16  controls the movement of both the brake assembly  12  and the accelerator assembly  14 . When the pedal movement module  19  acknowledges an input signal, the APM  16  determines whether the data bus  32  is in an active mode, step  41 . If the data bus  32  is in an active mode, the APM  16  proceeds on to checking lockout conditions, step  44 . On the other hand, if the data bus  32  is in an inactive mode, the integrity of data bus  32  is verified, step  42 . More particularly, at step  42 , the APMS  10  determines if the data bus  32  is capable of providing bi-directional communication between the ECUs  30  and the APM  16 . The step of verifying the integrity of data bus  32  will be described below in greater detail with reference to FIG. 4.  
         [0024]    In the preferred embodiment, a SAE J 1850  bus is used as the data bus  32  for providing bi-directional communication between the APM  16  and the ECUs  30 . However, it should be understood that any data bus, such as a Controller Area Network (CAN) data bus, can also be used so long as bi-directional communication is supported between vehicle ECUs.  
         [0025]    Once the integrity of the data bus  32  has been established, other ECUs place lockout information on the bus. After the integrity of data bus  32  is verified, the APM  16  determines whether lockout conditions exist, step  44 . The pedal movement module  19  interfaces with the vehicle ECUs  30  via data bus  32  in order to monitor operating conditions of the vehicle.  
         [0026]    The signals from the ECUs  30  are transmitted to the lockout module  36 . The lockout module  36  monitors the signals to determine whether any lockout conditions exist. What constitutes a lockout condition will be more fully described below with reference to FIGS. 5 and 6.  
         [0027]    The presence of lockout conditions determines whether to adjust the pedal assemblies  12  and  14  to a desired position. If any of the lockout conditions are detected, the APMS  10  does not adjust the pedal assemblies  12  and  14 , but instead terminates the process, step  52 . If no lockout conditions are found, the pedal assemblies  12  and  14  are adjusted to the desired position, step  50 . If the input signal is received from the memory  26  and no lockout conditions are identified, the APMS  10  retrieves the desired pedal position from memory  26 . Subsequently, the APMS  10  moves the pedal assemblies  12  and  14  to the stored position, step  48 . At step  52 , the APMS  10  waits for the next input from the vehicle occupant, and enters a sleeping mode, step  54 .  
         [0028]    With reference to FIG. 4, a more detailed flowchart of the APMS  10  is illustrated. At step  60 , the data bus is in an inactive mode and the APM  16  is in a sleeping mode. As mentioned above, the APMS  10  receives a manual interrupt input signal from a manual switch  28  to adjust the pedal assemblies  12  and  14 , step  62 . Upon receiving the manual interrupt input signal, the APM  16  debounces and decodes the input signal. The maximum rate at which the APMS  10  receives the input signal and adjusts the pedal assemblies  12  and  14  is forty msec.  
         [0029]    At step  64 , the APMS  10  monitors the SAE J 1850  data bus  32  for an active mode. If the SAE J 1850  is active, the APM  16  of APMS  10  checks for lockout conditions, step  74 . The following table  1  shows the lockout conditions for the APMS  10 .  
                   TABLE I                       Vehicle conditions   Lockout                   Transmission in Reverse Gear   The switches and memory recall shall           lockout       Cruise Control engaged (speed set)   The switches and memory recall shall           lockout       Transmission in Neutral, Drive, or   Only memory recall shall lockout       Low gear or speed &gt;0                  
 
         [0030]    The APMS  10  disables the adjustable pedal feature under certain conditions. In the preferred embodiment of present invention, the APMS  10  has different lockout conditions depending on the source of the manual interrupt input signal. If the input signal is from the memory  26 , the APMS  10  will only adjust the pedal assemblies  12  and  14  when the transmission of vehicle is in Park. If the input signal is from the manual switch  28 , the pedal assemblies  12  and  14  are locked out only when the transmission is in Reverse or when cruise control is engaged.  
         [0031]    In order to determine if the vehicle is under any of the lockout conditions, the pedal movement module  18  of the APM  16  monitors signals from various ECUs  30  via the SAE J1850 data bus  32 . The ECUs  30  periodically transmit signals indicative of operating conditions of the vehicle. Tables 2 and 3 shows bus messages used to determine lockout conditions and a description of each bus message.  
                           TABLE 2                       Frame                   ID #   Description   Source   Rate                   $5B   Ignition Switch   Body controller module   1 Sec. And on           Status   (BCM)   change       $10   Engine RPM,   Engine Controller   86 msec.           Speed, and MAP   Module (SBEC/DEC)       $35   Misc. Engine   Engine Controller   344 msec. and           Status   Module (SBEC/DEC)   on change       $37   PRNDL Display   Transmission   896 msec. and               Controller Module   on change               (EATX)       $54   Warning Data   Front Control Module   2 sec. And on               (FCM)   change                  
 
         [0032]    [0032]                   TABLE 3                       Frame ID #   Description                   $5B   The ARM 16 shall receive the $5B bus message to detect           the ignition switch bus status for logging communication           faults       $10   Also, the APM 16 shall use the $10 bus message to monitor           the speed during memory recall and determine if the feature           needs to be locked out.       $35   The APM 16 shall receive the $35 bus message to detect if           the cruise control is engaged or detected if the vehicle is in           Park/Neutral and determine if the feature needs to be locked           out.       $37   The ARM 16 shall receive $37 bus message to detect if the           vehicle is in Park, Reverse, Neutral, Drive, or Low Gear.       $54   The APM 16 shall receive the $54 bus message to detect if           the vehicle is in Reverse gear and determine if the feature           needs to be locked out.                    
         [0033]    As briefly mentioned above, the APM  16  determines if lockout conditions exist before the APM  16  adjusts the pedal assemblies  12  and  14 . Frame $35 shows when cruise control is engaged or if the transmission is in Park or Neutral. The APMS  10  locks out the pedal assemblies  12  and  14  when $35 message indicates that either cruise control is engaged and the vehicle transmission is in neither Park nor Neutral.  
         [0034]    The bus message $37 indicates whether the vehicle transmission is in Park, Neutral, Drive, or Low. In bus message $37, the least three significant bits of a data byte may show if the transmission is in Reverse. The status of the vehicle transmission determines whether to lock out the pedal assemblies  12  and  14 . For example, the vehicle transmission must be in Park for the pedal assemblies  12  and  14  to be adjusted when the input signal is transmitted from memory recall  26 .  
         [0035]    Bus message $37 is available only for vehicles with automatic transmissions. For vehicles with manual transmissions, bus message $37 is not available. This is because the manual transmission is not controlled by ECUs, but is controlled strictly mechanically. For vehicles with automatic transmissions, the APM  16  uses bus messages $35 and $54 to determine which gear the transmission of the vehicle is in. The bus message $35 is indicative of whether the transmission is in PARK or NEUTRAL, and the bus message $54 is used to check if the transmission is in REVERSE. Thus, the APM  16  determines whether the transmission of the vehicle is in DRIVE depending on bus messages $35 and $54 for automatic transmission vehicles only.  
         [0036]    Referring back to FIG. 4, the APM  16  checks for lockout conditions in step  74  from operating conditions transmitted from the aforementioned bus messages. If conditional step  76  of the APMS  10  detecting any of the lockout conditions is satisfied, in other words if the data bus  32  is inactive, the APMS  10  does not adjust the pedal assemblies  12  and  14 , and returns to stand-by mode, step  80 . If the lockout conditions are not determined, likewise if the data bus  32  is inactive, the APMS  10  adjusts the pedal assemblies  12  and  14  to a desired position and returns to the stand-by mode, steps  78  and  80 .  
         [0037]    The APMS  10  will lockout manual or memory controls due to a diagnostic issues. Still with reference to FIG. 4 of the drawings, if it is determined that the J1850 data bus  32  is inactive at step  64 , the APMS  10  verifies the integrity of the data bus  32 . When the integrity of the data bus  32  is verified, the APMS  10  checks for an open circuit condition. Open circuit provides miscommunications, which, in turn, cause the APMS  10  to malfunction. For example, if an open circuit exists and the integrity of the bus  32  is not verified, the APM  16  is likely to determine that the bus is inactive, and the other modules are asleep. Operation of the APM  16  is then excluded because the data bus  32  does not respond to the lockout conditions due to an open circuit.  
         [0038]    Therefore, in this present invention, the APMS  10  verifies the integrity of the data bus using a handshake method between two vehicle modules which are still active when the vehicle is in a key-off condition. Two vehicle modules that are used, are still in an active mode to minimize the current draw from the battery. Thus, the battery size can be kept to a minimum.  
         [0039]    If the SAE J1850 is inactive, the APM  16  wakes up in 8 msec, step  66 . As the APM  16  wakes up, it transmits the $5C-2A-02-00-CRC message to the Body Control Module (BCM), step  68 . The $5C-2A-02-00-CRC is a motion status message used by the memory system, that is indicative of whether or not the APM  16  is manually performing an adjustment. In the presently preferred embodiment, BCM is used for the handshake method. However, it would be understood that any vehicle module that is still active in key-off condition could also be used.  
         [0040]    The BCM has been in an inactive mode until it receives $5C-2A-02-00-CRC bus message from the APM  16 . As shown in step  70 , when the BCM receives a signal, the BCM is activated sending $5B bus message back to the APM  16  in 60 msec. Within 25 msec., the APM  16  must receive the $5B bus message in order to verify the integrity of the SAE J1850  32  bus.  
         [0041]    As indicated in Tables 2 and 3, the $5B bus message is indicative of the ignition status. If APM  16  receives $5B from the BCM within 60 msec., APM  16  confirms that the SAE J1850 data bus  32  is capable of receiving and transmitting data signals. If the APM  16  does not receive the $5B bus message within 90 msec. after transmitting $5C bus message, then the APM  16  returns to sleep mode and tries again with the next activation of a manual switch.  
         [0042]    $5B bus message indicates whether the ignition state is in RUN mode. In RUN mode, the APM  16  retrieves the SAE J1850 bus  32 . The APM  16  logs a fault when the APM  16  does not receive a needed bus message within a maximum period of 5 seconds. Therefore, by monitoring the ignition status, the APM  16  determines which lockout conditions are relevant before adjusting the pedal assemblies  12  and  14 .  
         [0043]    [0043]FIG. 5 is a table  90  depicting the bus messages and transmission rates  92  for different ignition states. The different ignition states are accessory-mode  94 , lock-mode  96 , unlock-mode  98 , run-mode  100  and start-mode  102 . All of the bus messages are available when the ignition state is in run-mode  100 . The PRNDL bus message is available when the ignition state is in unlock-mode  98 . The APMS  10  can adjust the pedal assemblies  12  and  14  if the input signal comes from the memory  26  during unlock mode  98 . Also, $37 message is not available when the ignition state is in start-mode  102 . This is because $37 message is generated by the transmission module such as EATX that is asleep in the ignition start mode. Bus message $37 is, thus, generated only when the associated transmission module is awake.  
         [0044]    [0044]FIG. 6 shows fault lockout conditions  110  to disable the APM  16  when at least one of the bus messages $5B  112 , $10  114 , $35 116 , $37  118  and $54  120  is missing. Comments  126  show where the log fault is located when one or more bus messages are missing. Whether to disable the APM  16  when at least one of the bus messages is missing also depends on whether the input signal comes from the manual switch  28  or the memory  26 . Manual pedal adjustment  122  and memory recall adjustment  124  columns show if the pedal assemblies  12  and  14  are adjusted when various faults are present.  
         [0045]    The APMS  10  controls the movement of the brake  12  and accelerator  14  pedal assemblies through a full range of adjustment as selected by the vehicle occupant. The pedal assemblies  12  and  14  can be adjusted in the range of 80 mm from the nominal position (fully forward position) by the use of a manual switch. The pedal assembly  12  and  14  adjust at a speed of 11.5 mm/sec under nominal conditions of 13.5 volts and 25° C. The APMS  10  has at least two positions stored in memory  26  for the purpose of the vehicle occupant&#39;s personalization.  
         [0046]    Those skilled in the art can now appreciate from the foregoing description that the broad teachings of the present invention can be implemented in a variety of ways. Therefore, while this invention has been described in connection with particular examples thereof, the true scope of the invention should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, specifications and following claims.