Patent Publication Number: US-2022219702-A1

Title: Control device for vehicle, control method, non-transitory computer- readable storage medium, manager, and vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Japanese Patent Application No. 2021-004377 filed on Jan. 14, 2021, incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a control device for vehicle, a control method, and a non-transitory computer-readable storage medium, a manager and a vehicle. 
     2. Description of Related Art 
     Regarding a control device that is capable of executing coasting control in which a clutch is disengaged while a vehicle is traveling and coasting is performed, and fuel cut control in which supply of fuel to an engine is reduced, Japanese Unexamined Patent Application Publication No. 2013-096518 (JP 2013-096518 A) discloses technology for suppressing shock due to disengaging the clutch while the vehicle is traveling. This control device described in JP 2013-096518 A disengages the clutch after torque fluctuation on a drivetrain has converged at the time of starting coasting control, thereby suppressing shock such as vibrations due to torque fluctuation from occurring in the vehicle. 
     SUMMARY 
     When transitioning fuel cut from an implemented state to a non-implemented state in accordance with a request from a driving assistance system or the like, time is required for actual driving force that is driving force actually being generated in the vehicle to begin to follow a driving force lower limit that is the driving force that a powertrain actuator is capable of realizing at the current gear ratio. 
     When there is a request from the driving assistance system or the like for driving force exceeding the driving force lower limit of the powertrain actuator until the actual driving force of the vehicle begins to follow the driving force lower limit of the powertrain actuator, twisting of the driveshaft may cause vibrations and sound, particularly in vehicles with long driveshafts. 
     The present disclosure has been made in light of the above problem, and it is an object thereof to provide a control device and so forth that is capable of suppressing the driveshaft from twisting and causing vibrations and sound. 
     An aspect of the present disclosure relates to a control device installed in a vehicle, the control device comprising an electronic control unit configured to: accept a plurality of first requests from a driving assistance system; arbitrate the first requests; calculate a second request that is a physical amount that differs from the first requests based on a result of arbitration in which the first requests are arbitrated; and distribute the second request to at least one of a plurality of actuator systems, wherein the electronic control unit is configured to, when there is the first request requesting a driving force exceeding a first driving force necessary for recovery from a fuel cut state, perform arbitration such that an actual driving force generated by the vehicle is no greater than the first driving force, until reaching a driving force lower limit realizable by a powertrain actuator included in the actuator system at a current gear ratio. 
     According to the control device of the present disclosure, no requests for driving force exceeding the driving force lower limit occur until the actual driving force of the vehicle begins to follow the driving force lower limit of the powertrain actuator, and accordingly twisting of the driveshaft causing vibrations and sound can be suppressed. 
     Another aspect of the present disclosure relates to a manager installed in a vehicle, the manager including: an accepting unit that accepts a plurality of kinematic plans from a plurality of advanced driving-assistance system applications; an arbitrating unit that arbitrates the kinematic plans; a calculating unit that calculates a motion request based on arbitration results by the arbitrating unit; and a distributing unit that distributes the motion request to at least one of a plurality of actuator systems, wherein when there is the kinematic plan requesting a driving force exceeding a first driving force necessary for recovery from a fuel cut state, the arbitrating unit performs arbitration such that an actual driving force generated by the vehicle is no greater than the first driving force, until reaching a driving force lower limit realizable by a powertrain actuator included in the actuator system at a current gear ratio. 
     Another aspect of the present disclosure relates to a control method executed by a computer of a manager installed in a vehicle, the control method including: accepting a plurality of kinematic plans from a plurality of ADAS applications; arbitrating the kinematic plans; calculating a motion request based on arbitration results from the arbitrating; and distributing the motion request to at least one of a plurality of actuator systems, wherein when there is the kinematic plan requesting a driving force exceeding a first driving force necessary for recovery from a fuel cut state, in the arbitrating, arbitration is performed such that an actual driving force generated by the vehicle is no greater than the first driving force, until reaching a driving force lower limit realizable by a powertrain actuator included in the actuator system at a current gear ratio. 
     Another aspect of the present disclosure relates to a non-transitory computer-readable storage medium storing a program that is executable by a computer of a manager installed in a vehicle and that causes the computer to perform functions including: accepting a plurality of kinematic plans from a plurality of ADAS applications; arbitrating the kinematic plans; calculating a motion request based on arbitration results from the arbitrating; and distributing the motion request to at least one of a plurality of actuator systems, wherein when there is the kinematic plan requesting a driving force exceeding a first driving force necessary for recovery from a fuel cut state, in the arbitrating, arbitration is performed such that an actual driving force generated by the vehicle is no greater than the first driving force, until reaching a driving force lower limit realizable by a powertrain actuator included in the actuator system at a current gear ratio. 
     Another aspect of the present disclosure relates to a vehicle, wherein the control device of the present disclosure is installed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features, advantages, and technical and industrial significance of exemplary embodiments of the disclosure will be described below with reference to the accompanying drawings, in which like signs denote like elements, and wherein: 
         FIG. 1  is a configuration diagram of a control device according to an embodiment of the present disclosure and proximity portions thereof; 
         FIG. 2  is a flowchart showing processing procedures for arbitration control executed by an arbitrating unit of the control device; 
         FIG. 3  is a timing chart showing the arbitration control executed by the control device according to the embodiment; and 
         FIG. 4  is a timing chart showing arbitration control executed by a conventional control device. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     When there is a request for driving force exceeding a driving force necessary to recover from a fuel cut state in a vehicle that is implementing fuel cut and that is coasting, a control device according to the present disclosure performs arbitration based on a driving force lower limit that can be realized by a powertrain actuator with the accelerator fully open at the current gear ratio (availability lower limit). Twisting of the driveshaft causing vibrations and sound can be suppressed according to this arbitration control. Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. 
     Embodiment 
     Configuration 
       FIG. 1  is a diagram illustrating a configuration of a control device  10  installed in a vehicle according to an embodiment of the present disclosure, and proximity portions thereof. The control device  10  illustrated in  FIG. 1  is communicably connected to a driving assistance system  20 , a plurality of actuator systems  30  and  40 , an accelerator pedal sensor  50 , and a brake pedal sensor  60 , via an in-vehicle network  100 . Examples of the in-vehicle network  100  include a Controller Area Network (CAN), Ethernet (a registered trademark), and so forth. 
     The driving assistance system  20  is configured to realize various functions for assisting driving of the vehicle by executing predetermined applications, including at least drive control and braking control of the vehicle. Examples of applications implemented in the driving assistance system  20  include an automated driving application that realizes automated driving functions, an automated parking application that realizes automated parking functions, an advanced driving-assistance application, and so forth. The advanced driving-assistance application includes a plurality of advanced driving-assistance system (ADAS) applications, such as an application that realizes adaptive cruise control (ACC) functions in which a vehicle traveling ahead is followed, an application that realizes lane keeping assistance (LKA) functions in which lane maintaining is performed, an application that realizes collision mitigation braking (autonomous emergency braking (AEB)) functions to reduce damage in a collision, and so forth. The driving assistance system  20  outputs requested kinematic plans (forward/reverse acceleration/deceleration, etc.) guaranteeing functionality (merchantability) of the application alone, based on information of the vehicle acquired from various types of sensors and so forth that are omitted from illustration. 
     The driving assistance system  20  is realized by a computer, such as an electronic control unit (ECU) that has a processor such as a central processing unit (CPU), memory, and an input/output interface. Note that the number of applications implemented in the driving assistance system  20  is not limited in particular. Also, an individual ECU may be provided for each of the applications, as the driving assistance system  20 . Also, an automated driving ECU in which the automated driving application is implemented, an automated parking ECU in which the automated parking application is implemented, and an ADAS-ECU in which the advanced driving-assistance application is implemented, for example, may make up the driving assistance system  20 . Further, the ADAS applications may be implemented in a plurality of devices, such as an ECU in which an ADAS application that realizes ACC functions is implemented, an ECU in which an ADAS application that realizes LKA functions is implemented, an ECU in which an ADAS application that realizes AEB functions is implemented, and so forth. 
     The actuator systems  30  and  40  are one of realizing systems for realizing kinematic plan requests that the driving assistance system  20  outputs. The actuator system  30  includes a powertrain actuator  31  that is capable of generating driving force in the vehicle, and realizes kinematic plan requests by controlling actions of the powertrain actuator  31 . Examples of the powertrain actuator  31  include an engine, a transmission (T/M), and so forth. Note that examples of the actuator system  40  and other actuator systems include a brake actuator and a steering actuator (omitted from illustration). 
     The accelerator pedal sensor  50  is a configuration to detect an operation amount that is a depressing amount of an accelerator pedal operated by the driver of the vehicle. This accelerator pedal sensor  50  is attached to a vehicle accelerator mechanism or the like. 
     The brake pedal sensor  60  is a configuration to detect an operation amount that is a depressing amount of a brake pedal operated by the driver of the vehicle. This brake pedal sensor  60  is attached to a brake mechanism or the like of the vehicle. 
     The control device  10  decides control contents relating to braking/driving motions of the vehicle, based on kinematic plan requests accepted from the driving assistance system  20  and the operation amounts acquired from the accelerator pedal sensor  50  and the brake pedal sensor  60 , and performs control by giving instructions relating to necessary braking/driving to the actuator systems  30  and  40  based on the control contents that have been decided. This control device  10  functions as a so-called manager relating to motion of the vehicle (ADAS-Manager, Vehicle-Manager, etc.), or as part of a manager, and controls movement of the vehicle. The control device  10  includes an accepting unit  11 , an arbitrating unit  12 , a calculating unit  13 , and a distributing unit  14 , which are implemented by a processor or a computer such as an electronic control unit executing a program. 
     The accepting unit  11  accepts kinematic plan requests output from one or a plurality of the applications of the driving assistance system  20 . The kinematic plan requests according to the present embodiment are also a first request for calculating a motion request, requesting the vehicle for braking/driving force corresponding to speed change output from the ADAS application or the like that provides ACC functions in which a vehicle traveling ahead is followed, for example. Examples of kinematic plans include acceleration in the front-rear direction (longitudinal direction) of the vehicle, and so forth. 
     The arbitrating unit  12  arbitrates a plurality of first requests that the accepting unit  11  has accepted from the driving assistance system  20 . Examples of arbitration processing include selecting one braking request from a plurality of braking requests based on a predetermined selection reference, and setting a new braking request based on the braking requests. The arbitrating unit  12  also performs arbitration based on a driving force lower limit that can be realized by the powertrain actuator  31  in a state with the accelerator fully open at the current gear ratio (availability lower limit), when the vehicle is determined to be in a predetermined traveling state based on operation amounts and so forth acquired from the accelerator pedal sensor  50  and the brake pedal sensor  60 . The predetermined traveling state in the present embodiment is a state of traveling while transitioning fuel cut (F/C), which is control in which supply of fuel to an engine is reduced, from an implemented state to a non-implemented state (hereinafter referred to as “fuel-cut recovery”). 
     The calculating unit  13  calculates a second request for a physical amount that differs from the first request, based on the arbitration results of the first requests by the arbitrating unit  12 . This second request is a physical amount for controlling the actuator systems  30  and  40 . For example, when the first request is acceleration, driving force can be calculated as the second request. Thus, a request for acceleration is converted into a request for driving force. 
     The distributing unit  14  distributes the second request calculated by the calculating unit  13  to the actuator systems  30  and  40  as a motion request. Note that the driving force for the second request may be driving torque. Also, conversion from driving force to driving torque may be performed at the actuator systems  30  and  40 . 
     Note that the configuration of the equipment installed in the vehicle and the configuration of the control device  10  that are described above are exemplary, and additions, substitutions, modifications, omissions, and so forth can be made as appropriate. Also, the functions of each of the pieces of equipment can be implemented as appropriate by being integrated into one piece of equipment, or by being distributed among a plurality of pieces of equipment. 
     Control 
     Arbitration control executed by the control device  10  according to the present embodiment will be described with reference to  FIGS. 2 and 3  as well.  FIG. 2  is a flowchart showing processing procedures for arbitration control that is executed by the arbitrating unit  12  of the control device  10 .  FIG. 3  is a timing chart showing arbitration control executed by the arbitrating unit  12 . 
     The arbitration control shown in  FIG. 2  is started upon the accepting unit  11  of the control device  10  accepting a first request (acceleration request) from the driving assistance system  20 . 
     Step S 201   
     The arbitrating unit  12  determines whether the current state is immediately after starting ACC. That is to say, the arbitrating unit  12  determines whether the processing is regarding a first request accepted from the driving assistance system  20  for the first time after the ACC function is set to an on state (from off to on). When determining that the current state is immediately after starting ACC (YES in step S 201 ), the processing advances to step S 202 , and when determining that the current state is not immediately after starting ACC (NO in step S 201 ), the processing advances to step S 210 . 
     Step S 202   
     The arbitrating unit  12  determines whether the vehicle is in a state of implementing fuel cut (F/C) and also is coasting. Whether the vehicle is implementing F/C and also is coasting can be determined from signals indicating the speed of the vehicle, deceleration, operation amount of the accelerator pedal, operation amount of the brake pedal, the on/off state of F/C, and so forth. When determining that F/C is implemented and the vehicle is coasting (YES in step S 202 ), the processing advances to step S 203 , and when determining that the state is not a state in which both F/C is implemented and the vehicle is coasting are true (NO in step S 202 ), the processing advances to step S 210 . 
     Step S 203   
     The arbitrating unit  12  determines whether the originally-requested driving force obtained by arbitration of the first request accepted from the driving assistance system  20  (hereinafter referred to as “requested driving force”) exceeds the driving force lower limit (availability lower limit) of the powertrain actuator  31 . The driving force is obtained by converting acceleration. When determining that the requested driving force exceeds the driving force lower limit (YES in step S 203 ), the processing advances to step S 204 , and when determining that the requested driving force does not exceed the driving force lower limit (NO in step S 203 ), the processing advances to step S 210 . 
     In the arbitration control of the present embodiment, determination is made that there is a possibility of the driveshaft twisting and causing vibrations and sound when the determinations in steps S 201  through S 203  are all affirmative, and the processing of step S 204  and thereafter is executed. 
     Step S 204   
     The arbitrating unit  12  sets a first driving force that is a driving force obtained by adding a predetermined driving force α to the driving force lower limit (availability lower limit) of the powertrain actuator  31 , as the driving force to be output as arbitration results (hereinafter referred to as “arbitrated driving force”). That is to say, the first driving force (driving force lower limit+α) is set as the arbitrated driving force, instead of the original requested driving force. This driving force α is set to an optional magnitude at which fuel-cut recovery (from on to off) can be performed by requesting the powertrain actuator  31  for the first driving force (e.g., α=5 N), based on the capabilities of the powertrain actuator  31  and setting conditions for fuel cut, and so forth. When the first driving force is set to the arbitrated driving force, the processing advances to step S 205 . 
     Step S 205   
     The arbitrating unit  12  determines whether a first duration of time has elapsed from setting the first driving force (driving force lower limit+α) as the arbitrated driving force. This determination is made in order to determine that the powertrain actuator  31  has received the request for the first driving force and that control has actually been performed. Accordingly, the first duration of time is set to be a duration of time necessary for communication from the control device  10  to the actuator system  30  (first cycle of communication) or longer (e.g., 25 ms). After awaiting for the first duration of time to elapse (YES in step S 205 ), the processing advances to step S 206 . 
     Step S 206   
     The arbitrating unit  12  sets the driving force of the driving force lower limit (availability lower limit) of the powertrain actuator  31  as the arbitrated driving force. That is to say, the arbitrating unit  12  lowers the arbitrated driving force from the first driving force (driving force lower limit+α) to the driving force lower limit. In the present arbitration control, execution of fuel cut recovery (from on to off) is awaited in this state in which the arbitrated driving force is set to the driving force lower limit. Upon the driving force lower limit being set to the arbitrated driving force, the processing advances to step S 207 . 
     Step S 207   
     The arbitrating unit  12  determines whether a second duration of time has elapsed from setting the driving force lower limit to the arbitrated driving force. This determination is made in order to stand by until fuel cut recovery (from on to off) is executed. Accordingly, the second duration of time is set to be a duration of time necessary for fuel cut recovery to be executed with surety (e.g., 250 ms) or longer, based on output of the first driving force (driving force lower limit+α). After awaiting for the second duration of time to elapse (YES in step S 207 ), the processing advances to step S 208 . 
     Step S 208   
     The arbitrating unit  12  sets a driving force, in which the driving force lower limit is gradually increased by the greatest jerk that the powertrain actuator  31  is capable of generating, as the arbitrated driving force. Setting the arbitrated driving force with such a jerk restriction enables the arbitrated driving force, and hence the actual driving force of the vehicle, to be gradually made to approximate the original requested driving force. Once the arbitrated driving force with the jerk restriction is set, the processing advances to step S 209 . 
     Step S 209   
     The arbitrating unit  12  determines whether the arbitrated driving force has reached the original requested driving force. After awaiting for the arbitrated driving force to reach the original requested driving force (YES in step S 209 ), the processing advances to step S 210 . 
     Step S 210   
     The arbitrating unit  12  executes normal request arbitration processing in which the first requests are arbitrated. Thus, the present arbitration control ends. 
     Note that in the present arbitration control described above, when a predetermined cancel event occurs, such as cancelling ACC settings, the processing transitions to the normal request arbitration processing of step S 210 , regardless of which processing of steps S 201  to S 209  is being executed. 
     Also, in the present arbitration control described above, a point in time immediately after starting the ACC function is determined in step S 201  above, in order to determine a scene in which there is a possibility of the driveshaft twisting and causing vibrations and sound with a high level of precision, but this determination may be omitted. Further, when the vehicle is known in advance to be coasting when fuel cut (F/C) is in an on state, the determination of whether coasting in step S 202  above can be omitted. 
     An example of processing based on the arbitration control described above will be described with reference to  FIG. 3 . In  FIG. 3 , prior to time t 1 , the ACC function is off, fuel cut is on, the vehicle is in a coasting state, and arbitrated driving force and actual driving force corresponding to the requested driving force are generated. After the ACC function turns on at time t 1 , from time t 1  to time t 2  the first driving force (driving force lower limit+α) is output and fuel cut recovery is requested (first processing in steps S 204  and S 205 ). Thereafter, actual execution of fuel cut recovery is awaited, from time t 2  to time t 3  (second processing in steps S 206  and S 207 ). Subsequently thereafter, the driving force lower limit is gradually increased by the greatest jerk, and the arbitrated driving force and the actual driving force are made to follow the requested driving force (third processing in steps S 208  and S 209 ). By executing the first processing, the second processing, and the third processing, in sequence, twisting of the driveshaft causing vibrations and sound to occur can be suppressed, and deviation between acceleration requested by the driving assistance system  20  and estimated vehicle acceleration can be suppressed. 
       FIG. 4  shows an example of processing based on conventional arbitration control, for comparison. As shown in  FIG. 4 , in conventional arbitration control after fuel cut recovery, a request is made to the powertrain actuator for rapid generation of a large driving force, in which the driving force of the arbitration results and the driving force accompanying the fuel cut recovery are superimposed, causing the driveshaft to twist (great deviation between requested acceleration and estimated vehicle acceleration) and generate vibrations and sound. 
     Effects and Advantages 
     As described above, when there is the first request from the driving assistance system  20  requesting driving force exceeding the first driving force (driving force lower limit of the powertrain actuator  31 +α) necessary for fuel cut recovery, while implementing fuel cut and also coasting, the control device  10  according to an embodiment of the present disclosure arbitrates the request so as to be no greater than the first driving force until the actual driving force of the vehicle reaches the driving force lower limit. 
     According to this arbitration control, no request for driving force exceeding the driving force lower limit is generated until the actual driving force of the vehicle begins to follow the driving force lower limit of the powertrain actuator  31 , and accordingly twisting of the driveshaft causing vibrations and sound can be suppressed. 
     As one example, there are cases in which, in a state of strong engine braking, such as in a state in which a vehicle is coasting and decelerating, and also is implementing fuel cut, for example, the control device  10  accepts the first request, which requires fuel cut recovery, from the driving assistance system  20 . In the arbitration control according to the present embodiment, in such a case, the control device  10  does not output to the actuator system  30  the requested driving force that is the arbitration results of the request accepted from the driving assistance system  20  unchanged, and accordingly a great driving force in which the requested driving force and the driving force accompanying the fuel cut recovery are superimposed is not requested to the powertrain actuator  31 . Accordingly, a large driving force is not rapidly generated by the powertrain actuator  31 , and thus twisting of the driveshaft causing vibrations and sound can be suppressed. 
     Although an embodiment of the technology according to the present disclosure has been described above, the present disclosure is not limited to a control device, and can be understood as a control method executed by a control device provided with a processor and memory, a control program, a computer-readable non-transitory storage medium storing a control program, a manager, a vehicle provided with a control device, and so forth. For example, an aspect of the present disclosure relates to a manager installed in a vehicle, the manager comprising: an accepting unit that accepts a plurality of kinematic plans from a plurality of advanced driving-assistance system applications; an arbitrating unit that arbitrates the kinematic plans; a calculating unit that calculates a motion request based on arbitration results by the arbitrating unit; and a distributing unit that distributes the motion request to at least one of a plurality of actuator systems, wherein when there is the kinematic plan requesting a driving force exceeding a first driving force necessary for recovery from a fuel cut state, the arbitrating unit performs arbitration such that an actual driving force generated by the vehicle is no greater than the first driving force, until reaching a driving force lower limit realizable by a powertrain actuator included in the actuator system at a current gear ratio. 
     The present disclosure is useful in a control device installed in a vehicle or the like.