WO2024053309A1 - Vehicle control device, vehicle control method, and steering system - Google Patents

Vehicle control device, vehicle control method, and steering system Download PDF

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Publication number
WO2024053309A1
WO2024053309A1 PCT/JP2023/028710 JP2023028710W WO2024053309A1 WO 2024053309 A1 WO2024053309 A1 WO 2024053309A1 JP 2023028710 W JP2023028710 W JP 2023028710W WO 2024053309 A1 WO2024053309 A1 WO 2024053309A1
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WIPO (PCT)
Prior art keywords
vehicle
steering
braking
force
behavior
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PCT/JP2023/028710
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French (fr)
Japanese (ja)
Inventor
遊 佐藤
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日立Astemo株式会社
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Publication of WO2024053309A1 publication Critical patent/WO2024053309A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/74—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with electrical assistance or drive
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T17/00—Component parts, details, or accessories of power brake systems not covered by groups B60T8/00, B60T13/00 or B60T15/00, or presenting other characteristic features
    • B60T17/18—Safety devices; Monitoring
    • B60T17/22—Devices for monitoring or checking brake systems; Signal devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits

Definitions

  • the present invention relates to a vehicle control device, a vehicle control method, and a steering system.
  • the vehicle steering control device disclosed in Patent Document 1 includes an assist means for assisting steering based on the steering torque, detects the actual braking force actually generated by the braking device of the vehicle, and calculates the left and right actual braking forces. By calculating the braking force difference, which is the difference between maintain.
  • the present invention has been made in view of the conventional situation, and its purpose is to prevent a vehicle from moving when an abnormality occurs that causes a yaw moment when a braking device generates a braking force.
  • An object of the present invention is to provide a vehicle control device, a vehicle control method, and a steering system that can improve stability.
  • the braking device when an abnormality occurs in the vehicle that causes abnormal behavior of the vehicle when the braking device generates a braking force, the braking device is not activated.
  • a predicted behavior that is a vehicle behavior that is predicted to occur in the vehicle according to the above, and suppresses the predicted behavior so that the vehicle behavior is based on the operation amount of the steering operation input member when the braking device is activated. Generates steering force in the direction.
  • the stability of the vehicle can be improved when an abnormality occurs that causes a yaw moment when the braking device generates a braking force.
  • FIG. 1 is a configuration diagram showing a braking device and a steering system of a vehicle. It is a flowchart which shows the control operation of a braking device. 5 is a flowchart showing a control operation of the steering system.
  • FIG. 3 is a state diagram illustrating the occurrence of yaw moment due to an abnormality in the braking device.
  • FIG. 2 is a control block diagram of a braking device and a steering system. It is a time chart showing changes in steering angle, reaction torque, etc. in a braking state. 3 is a flowchart showing a control operation of the steering system in consideration of the coefficient of friction of the road surface.
  • 5 is a flowchart showing a control operation of the braking device including a process of changing braking force distribution. It is a time chart showing changes in braking force, steering angle, reaction torque, etc. of each wheel in a braking state.
  • FIG. 1 is a schematic diagram showing one aspect of a vehicle 100.
  • the vehicle 100 is a four-wheeled vehicle having a pair of left and right front wheels 101, 102 and a pair of left and right rear wheels 103, 104.
  • the vehicle 100 includes a braking device 200 and a steer-by-wire steering system 300.
  • Braking device 200 includes a brake pedal 210 operated by the driver of vehicle 100, and brake actuators 221-224 arranged at each wheel 101-104.
  • the braking device 200 is an electric braking device that has no physical connection between the brake pedal 210 and each brake actuator 221-224 and can independently control the braking force of each of the four wheels 101-104. be.
  • the brake actuators 221-224 are mechanisms that generate braking force by operating a motor, and are, for example, electric calipers that generate frictional force by driving a motor.
  • the braking device 200 can be a regenerative braking device that generates braking force on each wheel 101-104 by regenerative operation of an in-wheel motor disposed on each wheel 101-104.
  • the braking device 200 includes, in addition to a brake pedal 210 and brake actuators 221-224, brake thrust sensors 231-234 provided in each of the brake actuators 221-224, and a brake control unit 240 that outputs control signals to each of the brake actuators 221-224. It has a brake pedal sensor 250 that detects the amount of operation of the brake pedal 210.
  • the brake control unit 240 is a vehicle control device mainly composed of a microcomputer 241.
  • the microcomputer 241 includes an MPU (Microprocessor Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and controls the braking force generated by each of the brake actuators 221 to 224 according to the amount of operation of the brake pedal 210. It has the function of a control unit.
  • the microcomputer 241 acquires a signal output from the brake pedal sensor 250 that indicates the operation amount (in other words, the stroke amount) of the brake pedal 210.
  • the microcomputer 241 also acquires signals output from the brake thrust sensors 231-234, which indicate the thrust generated by each of the brake actuators 221-224.
  • the microcomputer 241 controls the motors of each brake actuator 221-224 based on a signal indicating the amount of operation of the brake pedal 210, a signal indicating the thrust generated by each brake actuator 221-224, etc. , independently controls the braking force applied to each wheel 101-104.
  • Steering system 300 is a system that changes the steering angle of front wheels 101 and 102, which are steered wheels, based on the amount of operation of steering wheel 311, which is a steering operation input member operated by the driver of vehicle 100. Further, the steering system 300 is a steer-by-wire type in which there is no physical connection between the steering wheel 311 and the front wheels 101, 102, and the steering angle of the front wheels 101, 102 can be independently controlled with respect to the amount of operation of the steering wheel 311. steering system.
  • the steering system 300 includes a steering operation input device 310 that includes a steering wheel 311, a steering device 320 that includes a steering actuator 321 that applies steering force to the front wheels 101 and 102, and a steering control unit 330.
  • the steering operation input device 310 includes an operation amount sensor 312 that detects the amount of operation of the steering wheel 311 , and a reaction force actuator 313 that applies an operation reaction force to the steering wheel 311 .
  • the steering control unit 330 is a vehicle control device mainly composed of a microcomputer 331.
  • the microcomputer 331 includes an MPU, a ROM, a RAM, and the like, and has a function as a control unit that outputs a control signal to the steering actuator 321 based on a signal indicating the amount of operation of the steering wheel 311.
  • the microcomputer 331 of the steering control unit 330 and the microcomputer 241 of the brake control unit 240 can communicate with each other via a CAN (Controller Area Network) bus or the like.
  • CAN Controller Area Network
  • the microcomputer 331 acquires a signal indicating the operation amount of the steering wheel 311 outputted by the operation amount sensor 312, and adjusts the target steering angle of the front wheels 101, 102 and the steering wheel 311 according to the conditions at the time of operation of the steering wheel 311. Find the target reaction force to be applied to.
  • the microcomputer 331 then outputs a steering control signal determined based on the target steering angle to the steering actuator 321 to control the steering angles of the front wheels 101 and 102 to the target steering angle. Further, the microcomputer 331 outputs a reaction force control signal determined based on the target reaction force to the reaction force actuator 313, and controls the reaction force applied to the steering wheel 311 to the target reaction force.
  • FIG. 2 is a flowchart showing a control operation of the braking device 200 by the microcomputer 241 of the brake control unit 240, in other words, a method of controlling the braking device 200 executed by the microcomputer 241.
  • the microcomputer 241 starts system operation, first, in step S401, the microcomputer 241 executes a process of detecting the presence or absence of an abnormality in the braking device 200.
  • the abnormality in the braking device 200 detected by the microcomputer 241 in step S401 is an abnormality in which a difference in braking force occurs between the left and right sides of the vehicle 100 when the braking device 200 generates a braking force, and a yaw moment is generated in the vehicle 100. It is.
  • the detection target in step S401 is that one of the brake actuators 221 to 224 is in a failure state in which it is unable to generate braking force or the braking force that can be generated is lower than normal. It's abnormal.
  • any one of the brake actuators 221 to 224 fails, a yaw moment is generated due to a difference in braking force between the left and right wheels when the braking device 200 is activated, and a yaw moment is generated based on the amount of operation of the steering wheel 311.
  • Abnormal behavior different from vehicle behavior in other words, behavior in which vehicle 100 deviates from the target trajectory occurs.
  • the microcomputer 241 can detect failures of the brake actuators 221-224 as occurrences such as motor disconnection or motor inverter failure, and can also detect failures of the brake actuators 221-224 based on thrust detection results when controlling the motor drive. 224 failures can be detected.
  • a state where one tire among the four wheels 101 to 104 is punctured or whose air pressure is lower than the normal range can be set as an abnormality to be detected in step S401.
  • the microcomputer 241 can detect an abnormality in tire air pressure as well as an abnormality in the braking device 200.
  • the microcomputer 241 identifies a tire that is flat or has low air pressure based on the signal from the air pressure sensor, and applies braking to the tire. This is detected as an abnormality that causes a yaw moment.
  • the microcomputer 241 When the microcomputer 241 detects the presence or absence of an abnormality in the braking device 200 in step S401, the microcomputer 241 obtains a braking force command from the signal of the operation amount of the brake pedal 210, etc. in the next step S402.
  • the vehicle 100 includes a warning device 242 (see FIG. 1) that warns the driver of the vehicle 100 of the occurrence of an abnormality in the braking device 200
  • the microcomputer 241 when detecting the occurrence of an abnormality in step S401, an activation signal that activates the warning device 242 can be output.
  • the warning device 242 is, for example, a voice guidance device, a warning light, a buzzer, a liquid crystal display device, or the like.
  • step S403 the microcomputer 241 determines whether one wheel failure in the braking device 200 has been detected. If the microcomputer 241 detects failure of one wheel in the braking device 200, the microcomputer 241 proceeds to step S404. In other words, if the microcomputer 241 has acquired an abnormality detection signal indicating the occurrence of an abnormality that causes a yaw moment in the vehicle 100 when the braking device 200 generates a braking force, the microcomputer 241 proceeds to step S404. move on.
  • step S404 the microcomputer 241 determines whether there is a braking request based on the signal of the operation amount of the brake pedal 210, etc. If the microcomputer 241 has detected failure of one wheel in the braking device 200 and a braking request has occurred, the microcomputer 241 proceeds to step S405.
  • step S405 the microcomputer 241 calculates a predicted yaw moment that is a yaw moment that is predicted to occur in the vehicle 100 due to the difference in braking force between the left and right wheels caused by failure of one wheel in the braking device 200. Note that even when one tire is punctured, the microcomputer 241 proceeds to step S405 in the same manner as when one wheel failure occurs in the braking device 200, and calculates the yaw moment that is predicted to occur with braking. seek.
  • the microcomputer 241 then transmits the predicted yaw moment signal obtained in step S405 to the microcomputer 331 of the steering control unit 330. That is, when the microcomputer 241 detects the occurrence of an abnormality in the braking device 200, the microcomputer 241 obtains a predicted behavior, which is a vehicle behavior predicted to occur in the vehicle 100 in response to the operation of the braking device 200, as a predicted yaw moment.
  • step S405 After the microcomputer 241 calculates and transmits the predicted yaw moment (in other words, predicted behavior) in step S405, the process proceeds to step S406. Further, when the microcomputer 241 determines that one wheel failure has not been detected in step S403, the microcomputer 241 bypasses steps S404 and S405 and proceeds to step S406.
  • step S404 determines in step S404 that no braking request has occurred, that is, when one wheel of the braking device 200 is in a failed state but there is no braking request
  • the microcomputer 241 bypasses step S405 and The process advances to step S406.
  • step S406 the microcomputer 241 drives and controls the brake actuators 221-224 based on the braking force command obtained in step S402.
  • FIG. 3 is a flowchart showing a control operation of the steering system 300 by the microcomputer 331 of the steering control unit 330, in other words, a method of controlling the steering system 300 executed by the microcomputer 331.
  • the microcomputer 331 starts the system operation, first, in step S411, it determines whether a predicted yaw moment signal has been acquired from the microcomputer 241 of the brake control unit 240.
  • the state in which the microcomputer 331 is acquiring a predicted yaw moment signal means that one wheel failure has occurred in the braking device 200, there is a request for operation of the braking device 200, and the braking force between the left and right wheels is being increased. This is a situation in which the occurrence of yaw moment (in other words, abnormal behavior of vehicle 100) due to the difference can be predicted.
  • the microcomputer 331 bypasses steps S412 and S413 and proceeds to step S414.
  • step S412 the microcomputer 331 calculates a corrected steering angle for suppressing the predicted yaw moment (in other words, abnormal behavior), and further determines the position of the steering wheel 311 at a position corresponding to the vehicle behavior due to the predicted yaw moment. Find the corrected reaction torque so that
  • FIG. 4 is a diagram illustrating that a yaw moment is generated in the vehicle 100 due to failure of one wheel of the braking device 200.
  • FIG. 4 illustrates a case where the brake actuators 222-224 of the front right wheel 102 and the left and right rear wheels 103, 104 are normal, but the brake actuator 221 of the front left wheel 101 is in a failure state where it cannot generate braking force. do.
  • normal braking force acts on the right front wheel 102 and the left and right rear wheels 103, 104.
  • the braking force acting on the left front wheel 101 is smaller than the braking force acting on the right front wheel 102 (in other words, normal braking force).
  • a difference in braking force is generated between the left front wheel 101 and the right front wheel 102, and a yaw moment in the right turning direction is generated in the vehicle 100.
  • the microcomputer 241 can predict that a yaw moment will occur in the direction of turning the vehicle 100 to the right when the brake system 200 is activated.
  • the microcomputer 331 acquires a predicted yaw moment signal in the direction of turning the vehicle 100 to the right, the microcomputer 331 adjusts the steering angles of the front wheels 101 and 102 so as to prevent the vehicle 100 from turning to the right due to the braking operation. , performs feedforward control to correct the steering angle to the left according to the amount of operation of the steering wheel 311.
  • the microcomputer 331 controls the steering wheel 311 in the direction in which the yaw moment occurs due to failure of one wheel of the braking device 200, that is, the braking of the left front wheel 101. If the actuator 221 is in a failed state, a corrected reaction torque in the direction of rotating it in the right direction is determined. Then, in the next step S413, the microcomputer 331 adds a value corresponding to the amount of operation of the steering wheel 311 by the driver to the corrected steering angle and corrected reaction force torque obtained in step S412.
  • step S414 the microcomputer 331 determines a steering angle command value and a reaction torque command value based on the calculation result in step S413, and in step S415, controls the steering actuator 321 based on the steering angle command value,
  • the reaction actuator 313 is controlled based on the reaction torque command value.
  • the microcomputer 331 bypasses steps S412 and S413 and proceeds to step S414, thereby normally responding to the amount of operation of the steering wheel 311 by the driver.
  • the steering actuator 321 and the reaction force actuator 313 are controlled based on the steering angle command value and reaction torque command value.
  • FIG. 5 is a block diagram showing basic components in controlling the braking device 200 and the steering system 300.
  • the microcomputer 241 of the brake control unit 240 acquires brake thrust detection signals output by the brake thrust sensors 231-234, pedal operation amount detection signals output by the brake pedal sensor 250, and the like.
  • the microcomputer 241 calculates the predicted yaw moment that will occur when the braking device 200 brakes when one wheel fails, and also calculates command values for the brake actuators 221-224, based on the acquired various signals.
  • the microcomputer 241 transmits the calculated predicted yaw moment signal to the microcomputer 331 of the steering control unit 330.
  • the microcomputer 241 drives and controls the brake actuators 221-224 based on the calculated command values for the brake actuators 221-224.
  • the microcomputer 331 of the steering control unit 330 acquires the operation amount detection signal of the steering wheel 311 outputted by the operation amount sensor 312, and also acquires the predicted yaw moment signal from the brake control unit 240. Then, the microcomputer 331 suppresses the predicted yaw moment under the conditions in which the predicted yaw moment occurs (that is, when braking with one wheel lost), so that the vehicle behavior is based on the operation amount of the steering wheel 311. Find the steering angle command and reaction torque command.
  • the microcomputer 331 Under conditions where there is no abnormality in the braking device 200 and no predicted yaw moment occurs, the microcomputer 331 normally obtains a steering angle command and a reaction torque command according to the operation amount of the steering wheel 311 and the like.
  • the microcomputer 331 drives and controls the steering actuator 321 based on the steering angle command, and drives and controls the reaction force actuator 313 based on the reaction torque command.
  • FIG. 6 is a time chart showing one aspect of the control operation of the steering system 300 based on the predicted yaw moment.
  • FIG. 6 shows a control operation in a situation where one wheel of the braking device 200 has failed and the driver operates the brake while the vehicle 100 is traveling straight.
  • the driver starts deceleration operation, that is, depressing the brake pedal 210 at time t1 when the vehicle 100 is traveling straight at a constant speed, and continues to press the brake pedal 210 further (in other words, from time t1 to time t2).
  • the amount of operation of the brake pedal 210 continues to increase), and after time t3, the amount of depression of the brake pedal 210 (the amount of operation) is kept constant.
  • dotted lines indicate steering operations using a steering mechanism in which the steering wheel 311 and the front wheels 101, 102 are physically connected. If one wheel in the braking device 200 is malfunctioning, a yaw moment is generated due to a difference in braking force between the left and right sides in the braking state, resulting in lateral displacement of the vehicle 100. In the case of a steering mechanism in which the steering wheel 311 and the front wheels 101 and 102 are physically connected, the driver can recognize the occurrence of lateral displacement from the movement of the steering wheel 311 accompanying the lateral displacement.
  • the steering wheel 311 and the front wheels 101, 102 are not physically connected, so even if lateral displacement of the vehicle 100 occurs, the rotational force due to the lateral displacement is transferred to the steering wheel. It does not join the wheel 311. Therefore, at time t3 when the amount of lateral displacement of the vehicle 100 becomes large to a certain extent, the driver recognizes the occurrence of unintended lateral displacement due to brake failure (occurrence of left-right difference in braking force), and then The steering wheel 311 is operated in a direction to suppress the yaw behavior of the vehicle 100, and the motion of the vehicle 100 is stabilized at time t4.
  • the steering control unit 330 controls the front wheels in a direction that suppresses the predicted yaw moment from time t1 when the driver starts brake operation. Feedforward control for correcting the steering angles 101 and 102 is started. Thereby, even if a braking force difference occurs between the left and right wheels due to failure of the braking device 200, an increase in lateral displacement can be suppressed and the vehicle 100 can be stabilized in a short time.
  • the steering control unit 330 sets the correction of the steering angle of the front wheels 101 and 102 (in other words, the correction of the steering force generated by the steering actuator 321) to be smaller than the value required to cancel the predicted yaw moment.
  • the need for corrective operation of the steering wheel 311 by the driver remains. With such a configuration, the driver becomes aware of the failure of the braking device 200 (specifically, failure of one wheel) due to the necessity of steering operation to correct the lateral displacement of the vehicle 100 during braking. can be recognized.
  • the steering control unit 330 can also provide the driver with a corrective reaction force torque in the direction of rotating the steering wheel 311 in the direction in which a yaw moment is generated due to failure of one wheel of the braking device 200. (Specifically, one wheel failure) can be sensually notified. That is, in a steering mechanism in which the steering wheel 311 and the front wheels 101, 102 are physically connected, when lateral displacement occurs due to the difference in braking force between the left and right sides, the steering wheel 311 begins to rotate.
  • the steering control unit 330 uses the reaction force actuator 313 to apply a force to rotate the steering wheel 311 in the direction in which the predicted yaw moment is generated. generate.
  • FIG. 7 is a flowchart showing another aspect of the control operation of the steering system 300 by the microcomputer 331 of the steering control unit 330.
  • the microcomputer 331 acquires a friction coefficient signal, which is a signal related to the friction coefficient ⁇ of the road surface on which the vehicle 100 travels, and adjusts the correction steering angle (in other words, It has a function to change the steering force.
  • step S421 it acquires from the steering device 320 information on reaction force, specifically, information on self-aligning torque that the front wheels 101 and 102 receive from the road surface.
  • step S422 the microcomputer 331 estimates the friction coefficient ⁇ of the road surface on which the vehicle 100 travels from the self-aligning torque information.
  • the microcomputer 331 has a function as a friction coefficient estimator that estimates the friction coefficient ⁇ of the road surface from the self-aligning torque information.
  • the method for estimating the friction coefficient ⁇ from the information on the self-aligning torque for example, the method disclosed in Japanese Patent Application Laid-open No. 2003-341502 can be adopted. Furthermore, the method of acquiring the signal regarding the friction coefficient ⁇ is not limited to the method of estimating it from the information on the self-aligning torque.
  • the microcomputer 331 can acquire information regarding the friction coefficient ⁇ from outside the vehicle 100 through road-to-vehicle communication or the like. Further, the information regarding the friction coefficient ⁇ includes information on the weather when the vehicle 100 is traveling, such as information on the amount of rainfall and snowfall.
  • step S423 the microcomputer 331 determines whether a predicted yaw moment signal has been acquired from the microcomputer 241 of the brake control unit 240.
  • the microcomputer 331 bypasses steps S424 and S425 and proceeds to step S426 if the predicted yaw moment signal has not been acquired, and proceeds to step S424 if the predicted yaw moment signal has been acquired. .
  • step S424 the microcomputer 331 determines a corrected steering angle for suppressing the predicted yaw moment, and further adjusts the corrected reaction torque so that the position of the steering wheel 311 is in accordance with the vehicle behavior due to the predicted yaw moment. seek.
  • the microcomputer 331 decreases the maximum value (in other words, the upper limit value) of the corrected steering angle as the estimated friction coefficient ⁇ is smaller and the road surface on which the vehicle 100 runs is more slippery.
  • the microcomputer 331 can prevent the corrected steering angle (in other words, the corrected steering force) from becoming excessive when the friction coefficient ⁇ is smaller than the standard, and can control the corrected steering angle even if the friction coefficient ⁇ changes. Corners can be set appropriately.
  • the microcomputer 331 can correct the predicted yaw moment used for setting the corrected steering angle to be smaller as the friction coefficient ⁇ is smaller. That is, the microcomputer 331 can reduce the control gain of the corrected steering angle for the predicted yaw moment calculated by the microcomputer 241 of the brake control unit 240 as the friction coefficient ⁇ becomes smaller than the standard value.
  • step S425 the microcomputer 331 adds a value corresponding to the amount of operation of the steering wheel 311 by the driver to the corrected steering angle and corrected reaction force torque obtained in step S424.
  • step S426 the microcomputer 331 determines a steering angle command value and a reaction torque command value based on the calculation result in step S425.
  • step S427 the microcomputer 331 controls the steering actuator 321 based on the steering angle command value, and controls the reaction force actuator 313 based on the reaction torque command value.
  • the microcomputer 331 determines in step S423 that the predicted yaw moment signal has not been acquired, the microcomputer 331 bypasses steps S424 and S425 and proceeds to step S426, thereby allowing the driver to control the steering wheel 311 normally.
  • the steering actuator 321 and the reaction force actuator 313 are controlled based on a steering angle command value and a reaction torque command value corresponding to the operation amount.
  • FIG. 8 is a flowchart showing another aspect of the control operation of the braking device 200 by the microcomputer 241 of the brake control unit 240.
  • the microcomputer 241 distributes the braking force to the remaining three wheels so that the yaw moment generated by the one wheel failure is reduced, that is, Changes are made so that the difference in braking force between the left and right sides of the vehicle 100 is reduced.
  • the microcomputer 241 obtains the yaw moment that is predicted to occur with the braking force distribution changed as the predicted yaw moment.
  • the processing contents in steps S431 to S434 in the flowchart in FIG. 8 are the same as the processing contents in steps S401 to S404 in the flowchart in FIG. 2, so a detailed explanation will be omitted.
  • the microcomputer 241 proceeds to step S435 in a situation where one wheel of the braking device 200 has failed and there is a braking request. Then, in step S435, the microcomputer 241 determines, based on the braking force command obtained in step S432 and the information on the wheels that have failed in the braking device 200, that the occurrence of a A braking force distribution in which the yaw moment caused by the brake force is smaller than that in the standard braking force distribution is calculated, and a braking force command for each of the three wheels is determined based on the calculated braking force distribution.
  • the microcomputer 241 changes the braking force distribution so that the yaw moment generated due to braking is minimized while maintaining the deceleration of the vehicle 100 when one wheel of the braking device 200 is in a failed state. be able to.
  • the microcomputer 241 controls the brake actuator of the left rear wheel 103 by the amount of braking force that the brake actuator 221 should generate. 221 increases the braking force generated. That is, when the brake actuator 221 of the left front wheel 101 fails, the microcomputer 241 adds the required braking force of the left front wheel 101 to the required braking force of the left rear wheel 103 and sets it as a braking force command for the left rear wheel 103. .
  • the braking force distribution to the right front wheel 102 and the right rear wheel 104 is left unchanged at the standard value.
  • the braking force applied to the left side of the vehicle 100 becomes equal to the braking force applied to the right side, so that the yaw moment generated in the vehicle 100 by the operation of the braking device 200 is reduced.
  • step S436 the microcomputer 241 proceeds to step S436, and calculates the predicted yaw moment that is predicted to occur in the braking state based on the braking force distribution (in other words, the braking force command) obtained in step S435, and calculates the predicted yaw moment that is predicted to occur in the braking state based on the braking force distribution (in other words, the braking force command) obtained in step S435.
  • the information is sent to the microcomputer 331 of the steering control unit 330.
  • the microcomputer 241 drives and controls the brake actuators 221-224 based on the braking force command in step S437.
  • the microcomputer 241 operates the brake actuators 221-224 based on the braking force command obtained in step S435, that is, the braking force command after changing the braking force distribution. Drive control.
  • the microcomputer 241 drives the brake actuators 221-224 based on the braking force command obtained in step S432, that is, the braking force command with the standard braking force distribution. Control.
  • the braking force distribution is changed to reduce the yaw moment that occurs due to the difference in braking force between the left and right sides, and then the yaw moment that occurs due to the difference in braking force is changed. If the steering angle is corrected to suppress the yaw moment, the generation of yaw moment due to the braking force difference can be stably suppressed to a small value from the start of the braking operation, and the stability of the vehicle 100 can be maintained.
  • FIG. 9 is a time chart showing one aspect of the control operation involving the above-described braking force distribution changing process. Specifically, FIG. 9 shows that when the vehicle 100 is traveling straight with the brake actuator 221 of the left front wheel 101 of the braking device 200 having failed, the driver performs a braking operation, that is, an operation of the brake pedal 210. It shows changes in braking force, steering angle, etc. when Here, the microcomputer 241 of the brake control unit 240 adds the required braking force of the left front wheel 101 to the required braking force of the left rear wheel 103 as a braking force distribution process to reduce the yaw moment generated with braking. It is assumed that the following processing is executed.
  • the driver starts operating the brake pedal 210 at time t1 while the vehicle 100 is traveling straight.
  • the microcomputer 241 of the brake control unit 240 reduces the yaw moment generated by the difference in braking force by changing the braking force distribution to the normal three wheels according to the required braking force according to the operation amount of the brake pedal 210.
  • the required deceleration is generated while being suppressed to a small value.
  • the microcomputer 241 adds the braking force command for the left front wheel 101 to the braking force command for the left rear wheel 103 after time t1, which is the braking start time, thereby adding the braking force to the left side of the vehicle 100.
  • the braking force of the left rear wheel 103 is equal to the braking force applied to the right side (specifically, the braking force of the right front wheel 102 + the braking force of the right rear wheel 104), and the occurrence of yaw rate due to braking. deter.
  • the microcomputer 331 of the steering control unit 330 applies a reaction torque to the steering wheel 311 to bring it into a position that matches the vehicle behavior due to the predicted yaw moment. 311 reaction force) changes, and the driver is sensually informed of the failure of the braking device 200.
  • the braking force of the left rear wheel 103 is saturated at time t2 while the driver is depressing the brake pedal 210, and thereafter the braking force of the right front wheel 102 and the right rear wheel 104 is increased to generate deceleration.
  • the brake actuator 223 of the left rear wheel 103 reaches the maximum braking force that can be generated at time t2, and the required braking force after time t2 is reached. Unable to follow the increase in power, the braking force of the left rear wheel 103 remains at the maximum braking force.
  • the steering control unit 330 changes the steering angle (steering force) of the front wheels 101, 102 in a direction in which the predicted yaw moment calculated by the brake control unit 240 becomes smaller, and after time t2 when the difference in left and right braking force becomes large. The yaw moment generated in the vehicle 100 is suppressed.
  • the driver maintains the amount of operation of brake pedal 210 constant and requests constant deceleration.
  • a difference in braking force occurs between the left and right sides of the vehicle 100, but by controlling the steering angle by the steering control unit 330, the driver can move the steering wheel 311 near the neutral position.
  • the vehicle 100 can be decelerated without generating a yaw moment.
  • the microcomputer 241 of the brake control unit 240 performs the calculation process of the predicted yaw moment, but the microcomputer 331 of the steering control unit 330 collects information on failures in the braking device 200, information on braking requests, etc. It is possible to obtain the predicted yaw moment and execute the calculation process of the predicted yaw moment. Further, a system may be provided in which one control unit outputs control signals to both the braking device 200 and the steering system 300.
  • the steering system 300 can separately include a control unit that outputs a control signal to the steering actuator 321 and a control unit that outputs a control signal to the reaction force actuator 313. Further, the steering system 300 can include a backup mechanism that mechanically couples the steering wheel 311 and the front wheels 101 and 102 using a clutch or the like.
  • SYMBOLS 100... Vehicle, 101-104... Wheel, 200... Braking device, 240... Brake control unit (vehicle control device), 241... Microcomputer (control part), 300... Steer-by-wire type steering system, 311... Steering wheel (steering operation input member), 320... steering device, 321... steering actuator, 330... steering control unit (vehicle control device), 331... microcomputer (control unit)

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  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Steering Control In Accordance With Driving Conditions (AREA)
  • Regulating Braking Force (AREA)

Abstract

The present invention relates to a vehicle control device, a vehicle control method, and a steering system that, if there is an anomaly in a vehicle that would cause an anomalous behavior of the vehicle when a braking device generates a braking force, determines a predicted behavior, which is a vehicle behavior predicted to occur in the vehicle in accordance with activation of the braking device, and causes a steering force to be generated in a direction in which the predicted behavior is suppressed, so that a vehicle behavior based on the amount of operation of a steering operation input member is achieved when the braking device is activated. In this way, the stability of the vehicle can be increased.

Description

車両制御装置、車両制御方法、及びステアリングシステムVehicle control device, vehicle control method, and steering system
　本発明は、車両制御装置、車両制御方法、及びステアリングシステムに関する。 The present invention relates to a vehicle control device, a vehicle control method, and a steering system.
　特許文献１の車両の操舵制御装置は、操舵トルクに基づいて転舵のアシストを行うアシスト手段を備え、車両の制動装置により実際に発生している実制動力を検出し、左右の実制動力の差である制動力差を演算し、前記制動力差に基づく操舵補正量を、アシスト手段が演算する転舵アシスト量に反映させることにより、制動装置に異常が発生した場合でも車両安定性を維持する。 The vehicle steering control device disclosed in Patent Document 1 includes an assist means for assisting steering based on the steering torque, detects the actual braking force actually generated by the braking device of the vehicle, and calculates the left and right actual braking forces. By calculating the braking force difference, which is the difference between maintain.
特開２００６－２１３１７３号公報Japanese Patent Application Publication No. 2006-213173
　ところで、ステアリングシステムの制御装置が、制動装置が実際に発生している左右の制動力の差に応じて操舵力を制御する場合、左右の制動力の差によるヨーモーメントが実際に生じてからの対処となるため、車両の安定を維持することに課題があった。 By the way, when the control device of the steering system controls the steering force according to the difference between the left and right braking forces actually generated by the braking device, the yaw moment due to the difference between the left and right braking forces is actually generated. As a countermeasure, there was an issue in maintaining the stability of the vehicle.
　本発明は、従来の実情に鑑みてなされたものであり、その目的は、制動装置が制動力を発生させたときにヨーモーメントを生じさせることになる異常が発生しているときに、車両の安定性を向上させることができる、車両制御装置、車両制御方法、及びステアリングシステムを提供することにある。 The present invention has been made in view of the conventional situation, and its purpose is to prevent a vehicle from moving when an abnormality occurs that causes a yaw moment when a braking device generates a braking force. An object of the present invention is to provide a vehicle control device, a vehicle control method, and a steering system that can improve stability.
　本発明に係る発明は、その一態様において、制動装置が制動力を発生させたときに車両の異常挙動を生じさせることになる前記車両の異常が発生している場合、前記制動装置の作動に応じて前記車両に発生すると予測される車両挙動である予測挙動を求め、前記制動装置が作動した際に、操舵操作入力部材の操作量に基づく車両挙動となるように、前記予測挙動を抑制する方向へ操舵力を発生させる。 In one aspect of the present invention, when an abnormality occurs in the vehicle that causes abnormal behavior of the vehicle when the braking device generates a braking force, the braking device is not activated. a predicted behavior that is a vehicle behavior that is predicted to occur in the vehicle according to the above, and suppresses the predicted behavior so that the vehicle behavior is based on the operation amount of the steering operation input member when the braking device is activated. Generates steering force in the direction.
　本発明によれば、制動装置が制動力を発生させたときにヨーモーメントを生じさせることになる異常が発生しているときに、車両の安定性を向上させることができる。 According to the present invention, the stability of the vehicle can be improved when an abnormality occurs that causes a yaw moment when the braking device generates a braking force.
車両の制動装置及びステアリングシステムを示す構成図である。FIG. 1 is a configuration diagram showing a braking device and a steering system of a vehicle. 制動装置の制御動作を示すフローチャートである。It is a flowchart which shows the control operation of a braking device. ステアリングシステムの制御動作を示すフローチャートである。5 is a flowchart showing a control operation of the steering system. 制動装置の異常によるヨーモーメントの発生を説明する状態図である。FIG. 3 is a state diagram illustrating the occurrence of yaw moment due to an abnormality in the braking device. 制動装置及びステアリングシステムの制御ブロック図である。FIG. 2 is a control block diagram of a braking device and a steering system. 制動状態における操舵角、反力トルクなどの変化を示すタイムチャートである。It is a time chart showing changes in steering angle, reaction torque, etc. in a braking state. 路面の摩擦係数を考慮したステアリングシステムの制御動作を示すフローチャートである。3 is a flowchart showing a control operation of the steering system in consideration of the coefficient of friction of the road surface. 制動力配分の変更処理を含む制動装置の制御動作を示すフローチャートである。5 is a flowchart showing a control operation of the braking device including a process of changing braking force distribution. 制動状態における各車輪の制動力、操舵角、反力トルクなどの変化を示すタイムチャートである。It is a time chart showing changes in braking force, steering angle, reaction torque, etc. of each wheel in a braking state.
　以下、本発明に係る車両制御装置、車両制御方法、及びステアリングシステムの実施形態を、図面に基づいて説明する。
　図１は、車両１００の一態様を示す概略図である。
　車両１００は、左右一対の前輪１０１，１０２及び左右一対の後輪１０３，１０４を有する４輪自動車である。
　そして、車両１００は、制動装置２００と、ステアバイワイヤ式のステアリングシステム３００とを備える。 DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a vehicle control device, a vehicle control method, and a steering system according to the present invention will be described based on the drawings.
FIG. 1 is a schematic diagram showing one aspect of a vehicle 100.
The vehicle 100 is a four-wheeled vehicle having a pair of left and right front wheels 101, 102 and a pair of left and right rear wheels 103, 104.
The vehicle 100 includes a braking device 200 and a steer-by-wire steering system 300.
　制動装置２００は、車両１００の運転者が操作するブレーキペダル２１０と、各車輪１０１－１０４に配置したブレーキアクチュエータ２２１－２２４とを有する。
　ここで、制動装置２００は、ブレーキペダル２１０と各ブレーキアクチュエータ２２１－２２４との間に物理的接続がなく、４輪１０１－１０４それぞれの制動力を独立に制御することが可能な電動ブレーキ装置である。 Braking device 200 includes a brake pedal 210 operated by the driver of vehicle 100, and brake actuators 221-224 arranged at each wheel 101-104.
Here, the braking device 200 is an electric braking device that has no physical connection between the brake pedal 210 and each brake actuator 221-224 and can independently control the braking force of each of the four wheels 101-104. be.
　ブレーキアクチュエータ２２１－２２４は、モータの作動によって制動力を発生する機構であって、たとえば、モータの駆動により摩擦力を発生する電動キャリパである。
　なお、制動装置２００は、各車輪１０１－１０４に配置したインホイールモータの回生作動によって、各車輪１０１－１０４に制動力を発生させる、回生ブレーキ装置とすることができる。 The brake actuators 221-224 are mechanisms that generate braking force by operating a motor, and are, for example, electric calipers that generate frictional force by driving a motor.
Note that the braking device 200 can be a regenerative braking device that generates braking force on each wheel 101-104 by regenerative operation of an in-wheel motor disposed on each wheel 101-104.
　制動装置２００は、ブレーキペダル２１０、ブレーキアクチュエータ２２１－２２４に加え、ブレーキアクチュエータ２２１－２２４それぞれに設けたブレーキ推力センサ２３１－２３４、ブレーキアクチュエータ２２１－２２４それぞれに制御信号を出力するブレーキコントロールユニット２４０、ブレーキペダル２１０の操作量を検出するブレーキペダルセンサ２５０を有する。 The braking device 200 includes, in addition to a brake pedal 210 and brake actuators 221-224, brake thrust sensors 231-234 provided in each of the brake actuators 221-224, and a brake control unit 240 that outputs control signals to each of the brake actuators 221-224. It has a brake pedal sensor 250 that detects the amount of operation of the brake pedal 210.
　ブレーキコントロールユニット２４０は、マイクロコンピュータ２４１を主体とする車両制御装置である。
　マイクロコンピュータ２４１は、ＭＰＵ（Microprocessor Unit）、ＲＯＭ（Read Only Memory）、ＲＡＭ（Random Access Memory）などを備え、ブレーキペダル２１０の操作量などに応じてブレーキアクチュエータ２２１－２２４それぞれが発生する制動力を制御する、コントロール部としての機能を有する。 The brake control unit 240 is a vehicle control device mainly composed of a microcomputer 241.
The microcomputer 241 includes an MPU (Microprocessor Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and controls the braking force generated by each of the brake actuators 221 to 224 according to the amount of operation of the brake pedal 210. It has the function of a control unit.
　マイクロコンピュータ２４１は、ブレーキペダルセンサ２５０が出力する、ブレーキペダル２１０の操作量（換言すれば、ストローク量）を示す信号を取得する。
　また、マイクロコンピュータ２４１は、ブレーキ推力センサ２３１－２３４それぞれが出力する、各ブレーキアクチュエータ２２１－２２４が発生する推力を示す信号を取得する。
　そして、マイクロコンピュータ２４１は、ブレーキペダル２１０の操作量を示す信号、各ブレーキアクチュエータ２２１－２２４それぞれが発生する推力を示す信号などに基づき、各ブレーキアクチュエータ２２１－２２４のモータをそれぞれに制御することで、各車輪１０１－１０４に与える制動力を独立に制御する。 The microcomputer 241 acquires a signal output from the brake pedal sensor 250 that indicates the operation amount (in other words, the stroke amount) of the brake pedal 210.
The microcomputer 241 also acquires signals output from the brake thrust sensors 231-234, which indicate the thrust generated by each of the brake actuators 221-224.
The microcomputer 241 controls the motors of each brake actuator 221-224 based on a signal indicating the amount of operation of the brake pedal 210, a signal indicating the thrust generated by each brake actuator 221-224, etc. , independently controls the braking force applied to each wheel 101-104.
　ステアリングシステム３００は、車両１００の運転者が操作する操舵操作入力部材としてのステアリングホイール３１１の操作量に基づき、操舵輪である前輪１０１，１０２の操舵角を変化させるシステムである。
　また、ステアリングシステム３００は、ステアリングホイール３１１と前輪１０１，１０２との間に物理的接続がなく、ステアリングホイール３１１の操作量に対して前輪１０１，１０２の操舵角を独立に制御可能なステアバイワイヤ式のステアリングシステムである。 Steering system 300 is a system that changes the steering angle of front wheels 101 and 102, which are steered wheels, based on the amount of operation of steering wheel 311, which is a steering operation input member operated by the driver of vehicle 100.
Further, the steering system 300 is a steer-by-wire type in which there is no physical connection between the steering wheel 311 and the front wheels 101, 102, and the steering angle of the front wheels 101, 102 can be independently controlled with respect to the amount of operation of the steering wheel 311. steering system.
　ステアリングシステム３００は、ステアリングホイール３１１を含む操舵操作入力装置３１０と、前輪１０１，１０２に操舵力を付与する操舵アクチュエータ３２１を備える操舵装置３２０と、ステアリングコントロールユニット３３０とを有する。
　操舵操作入力装置３１０は、ステアリングホイール３１１に加え、ステアリングホイール３１１の操作量を検出する操作量センサ３１２、ステアリングホイール３１１に操作反力を付与する反力アクチュエータ３１３を有する。 The steering system 300 includes a steering operation input device 310 that includes a steering wheel 311, a steering device 320 that includes a steering actuator 321 that applies steering force to the front wheels 101 and 102, and a steering control unit 330.
In addition to the steering wheel 311 , the steering operation input device 310 includes an operation amount sensor 312 that detects the amount of operation of the steering wheel 311 , and a reaction force actuator 313 that applies an operation reaction force to the steering wheel 311 .
　ステアリングコントロールユニット３３０は、マイクロコンピュータ３３１を主体とする車両制御装置である。
　マイクロコンピュータ３３１は、ＭＰＵ、ＲＯＭ、ＲＡＭなどを備え、ステアリングホイール３１１の操作量を示す信号などに基づいて操舵アクチュエータ３２１へ制御信号を出力する、コントロール部としての機能を有する。
　また、ステアリングコントロールユニット３３０のマイクロコンピュータ３３１と、ブレーキコントロールユニット２４０のマイクロコンピュータ２４１とは、ＣＡＮ（Controller Area Network）バスなどを介して相互に通信できる。 The steering control unit 330 is a vehicle control device mainly composed of a microcomputer 331.
The microcomputer 331 includes an MPU, a ROM, a RAM, and the like, and has a function as a control unit that outputs a control signal to the steering actuator 321 based on a signal indicating the amount of operation of the steering wheel 311.
Furthermore, the microcomputer 331 of the steering control unit 330 and the microcomputer 241 of the brake control unit 240 can communicate with each other via a CAN (Controller Area Network) bus or the like.
　マイクロコンピュータ３３１は、操作量センサ３１２が出力するステアリングホイール３１１の操作量を示す信号などを取得し、ステアリングホイール３１１の操作時の条件に応じて、前輪１０１，１０２の目標操舵角及びステアリングホイール３１１に与える目標反力を求める。
　そして、マイクロコンピュータ３３１は、目標操舵角に基づき求めた操舵制御信号を操舵アクチュエータ３２１に出力して、前輪１０１，１０２の操舵角を目標操舵角に制御する。
　また、マイクロコンピュータ３３１は、目標反力に基づき求めた反力制御信号を反力アクチュエータ３１３に出力して、ステアリングホイール３１１に与える反力を目標反力に制御する。 The microcomputer 331 acquires a signal indicating the operation amount of the steering wheel 311 outputted by the operation amount sensor 312, and adjusts the target steering angle of the front wheels 101, 102 and the steering wheel 311 according to the conditions at the time of operation of the steering wheel 311. Find the target reaction force to be applied to.
The microcomputer 331 then outputs a steering control signal determined based on the target steering angle to the steering actuator 321 to control the steering angles of the front wheels 101 and 102 to the target steering angle.
Further, the microcomputer 331 outputs a reaction force control signal determined based on the target reaction force to the reaction force actuator 313, and controls the reaction force applied to the steering wheel 311 to the target reaction force.
　図２は、ブレーキコントロールユニット２４０のマイクロコンピュータ２４１による制動装置２００の制御動作、換言すれば、マイクロコンピュータ２４１が実行する制動装置２００の制御方法を示すフローチャートである。
　マイクロコンピュータ２４１は、システム動作を開始すると、まず、ステップＳ４０１で、制動装置２００における異常の有無を検出する処理を実行する。 FIG. 2 is a flowchart showing a control operation of the braking device 200 by the microcomputer 241 of the brake control unit 240, in other words, a method of controlling the braking device 200 executed by the microcomputer 241.
When the microcomputer 241 starts system operation, first, in step S401, the microcomputer 241 executes a process of detecting the presence or absence of an abnormality in the braking device 200.
　ステップＳ４０１でマイクロコンピュータ２４１が検出する制動装置２００の異常とは、制動装置２００が制動力を発生させたときに車両１００の左右で制動力差が生じて、車両１００にヨーモーメントを発生させる異常である。
　たとえば、ブレーキアクチュエータ２２１－２２４のうちのいずれかが、制動力を発生できなくなるか若しくは発生できる制動力が正常時よりも低下する失陥状態となっていることが、ステップＳ４０１で検出対象とする異常である。 The abnormality in the braking device 200 detected by the microcomputer 241 in step S401 is an abnormality in which a difference in braking force occurs between the left and right sides of the vehicle 100 when the braking device 200 generates a braking force, and a yaw moment is generated in the vehicle 100. It is.
For example, the detection target in step S401 is that one of the brake actuators 221 to 224 is in a failure state in which it is unable to generate braking force or the braking force that can be generated is lower than normal. It's abnormal.
　そして、ブレーキアクチュエータ２２１－２２４のうちのいずれか１つが失陥すると、制動装置２００が作動したときに左右輪で制動力差が生じることでヨーモーメントが発生し、ステアリングホイール３１１の操作量に基づく車両挙動と異なる異常挙動、換言すれば、目標軌道から車両１００が逸脱する挙動が生じる。
　マイクロコンピュータ２４１は、ブレーキアクチュエータ２２１－２２４の失陥を、モータの断線やモータインバータの故障などの発生として検出でき、また、モータの駆動制御を実施したときの推力の検出結果からブレーキアクチュエータ２２１－２２４の失陥を検出することができる。 If any one of the brake actuators 221 to 224 fails, a yaw moment is generated due to a difference in braking force between the left and right wheels when the braking device 200 is activated, and a yaw moment is generated based on the amount of operation of the steering wheel 311. Abnormal behavior different from vehicle behavior, in other words, behavior in which vehicle 100 deviates from the target trajectory occurs.
The microcomputer 241 can detect failures of the brake actuators 221-224 as occurrences such as motor disconnection or motor inverter failure, and can also detect failures of the brake actuators 221-224 based on thrust detection results when controlling the motor drive. 224 failures can be detected.
　なお、４輪１０１―１０４のうち１輪のタイヤが、パンク若しくは空気圧が正常範囲よりも低下した状態を、ステップＳ４０１で検出対象とする異常とすることができる。
　換言すれば、マイクロコンピュータ２４１は、タイヤの空気圧異常を、制動装置２００の異常に含めて検知することができる。 Note that a state where one tire among the four wheels 101 to 104 is punctured or whose air pressure is lower than the normal range can be set as an abnormality to be detected in step S401.
In other words, the microcomputer 241 can detect an abnormality in tire air pressure as well as an abnormality in the braking device 200.
　４輪１０１―１０４のうち１輪のタイヤが、パンク若しくは空気圧が低下していると、制動装置２００が作動したときにヨーモーメントが発生させることになる。
　そこで、車両１００が４輪１０１―１０４のタイヤそれぞれの空気圧を検出する空気圧センサを備える場合、マイクロコンピュータ２４１は、空気圧センサの信号に基づきパンク若しくは空気圧が低下しているタイヤを特定し、制動に伴ってヨーモーメントを発生させる異常として検知する。 If one tire among the four wheels 101-104 is punctured or has low air pressure, a yaw moment will be generated when the braking device 200 is activated.
Therefore, when the vehicle 100 is equipped with an air pressure sensor that detects the air pressure of each of the four tires 101 to 104, the microcomputer 241 identifies a tire that is flat or has low air pressure based on the signal from the air pressure sensor, and applies braking to the tire. This is detected as an abnormality that causes a yaw moment.
　マイクロコンピュータ２４１は、ステップＳ４０１で、制動装置２００における異常の有無を検出すると、次のステップＳ４０２で、ブレーキペダル２１０の操作量の信号などから制動力指令を求める。
　なお、車両１００が、制動装置２００における異常の発生を車両１００の運転者に警告する警告装置２４２（図１参照）を備える場合、マイクロコンピュータ２４１は、ステップＳ４０１で異常の発生を検知したときに、警告装置２４２を作動させる作動信号を出力することができる。
　警告装置２４２は、たとえば、音声案内装置、警告灯、ブザー、液晶表示装置などである。 When the microcomputer 241 detects the presence or absence of an abnormality in the braking device 200 in step S401, the microcomputer 241 obtains a braking force command from the signal of the operation amount of the brake pedal 210, etc. in the next step S402.
Note that when the vehicle 100 includes a warning device 242 (see FIG. 1) that warns the driver of the vehicle 100 of the occurrence of an abnormality in the braking device 200, the microcomputer 241, when detecting the occurrence of an abnormality in step S401, , an activation signal that activates the warning device 242 can be output.
The warning device 242 is, for example, a voice guidance device, a warning light, a buzzer, a liquid crystal display device, or the like.
　次いで、マイクロコンピュータ２４１は、ステップＳ４０３で、制動装置２００における１輪失陥を検出しているか否かを判別する。
　そして、マイクロコンピュータ２４１は、制動装置２００における１輪失陥を検出している場合、ステップＳ４０４に進む。
　換言すれば、マイクロコンピュータ２４１は、制動装置２００が制動力を発生させたときに車両１００にヨーモーメントを生じさせることになる異常の発生を示す異常検出信号を取得している場合、ステップＳ４０４に進む。 Next, in step S403, the microcomputer 241 determines whether one wheel failure in the braking device 200 has been detected.
If the microcomputer 241 detects failure of one wheel in the braking device 200, the microcomputer 241 proceeds to step S404.
In other words, if the microcomputer 241 has acquired an abnormality detection signal indicating the occurrence of an abnormality that causes a yaw moment in the vehicle 100 when the braking device 200 generates a braking force, the microcomputer 241 proceeds to step S404. move on.
　マイクロコンピュータ２４１は、ステップＳ４０４で、制動要求の有無を、ブレーキペダル２１０の操作量の信号などから判別する。
　マイクロコンピュータ２４１は、制動装置２００における１輪失陥を検出していて、かつ、制動要求が発生している場合、ステップＳ４０５に進む。 In step S404, the microcomputer 241 determines whether there is a braking request based on the signal of the operation amount of the brake pedal 210, etc.
If the microcomputer 241 has detected failure of one wheel in the braking device 200 and a braking request has occurred, the microcomputer 241 proceeds to step S405.
　マイクロコンピュータ２４１は、ステップＳ４０５で、制動装置２００における１輪失陥によって発生する左右輪間での制動力差によって、車両１００に発生すると予測するヨーモーメントである予測ヨーモーメントを求める。
　なお、マイクロコンピュータ２４１は、１輪のタイヤがパンクしている場合も、制動装置２００における１輪失陥が生じている場合と同様にステップＳ４０５に進み、制動に伴って発生すると予測するヨーモーメントを求める。 In step S405, the microcomputer 241 calculates a predicted yaw moment that is a yaw moment that is predicted to occur in the vehicle 100 due to the difference in braking force between the left and right wheels caused by failure of one wheel in the braking device 200.
Note that even when one tire is punctured, the microcomputer 241 proceeds to step S405 in the same manner as when one wheel failure occurs in the braking device 200, and calculates the yaw moment that is predicted to occur with braking. seek.
　そして、マイクロコンピュータ２４１は、ステップＳ４０５で求めた予測ヨーモーメントの信号を、ステアリングコントロールユニット３３０のマイクロコンピュータ３３１に送信する。
　つまり、マイクロコンピュータ２４１は、制動装置２００における異常の発生を検知したときに、制動装置２００の作動に応じて車両１００に発生すると予測される車両挙動である予測挙動を、予測ヨーモーメントとして求める。 The microcomputer 241 then transmits the predicted yaw moment signal obtained in step S405 to the microcomputer 331 of the steering control unit 330.
That is, when the microcomputer 241 detects the occurrence of an abnormality in the braking device 200, the microcomputer 241 obtains a predicted behavior, which is a vehicle behavior predicted to occur in the vehicle 100 in response to the operation of the braking device 200, as a predicted yaw moment.
　マイクロコンピュータ２４１は、ステップＳ４０５で予測ヨーモーメント（換言すれば、予測挙動）の演算・送信を行った後、ステップＳ４０６に進む。
　また、マイクロコンピュータ２４１は、ステップＳ４０３で１輪失陥を検出していないと判断したときは、ステップＳ４０４及びステップＳ４０５を迂回して、ステップＳ４０６に進む。 After the microcomputer 241 calculates and transmits the predicted yaw moment (in other words, predicted behavior) in step S405, the process proceeds to step S406.
Further, when the microcomputer 241 determines that one wheel failure has not been detected in step S403, the microcomputer 241 bypasses steps S404 and S405 and proceeds to step S406.
　また、マイクロコンピュータ２４１は、ステップＳ４０４で制動要求が発生していないと判断したとき、つまり、制動装置２００の１輪失陥状態であるものの制動要求がない場合は、ステップＳ４０５を迂回して、ステップＳ４０６に進む。
　マイクロコンピュータ２４１は、ステップＳ４０６で、ステップＳ４０２で求めた制動力指令に基づき、ブレーキアクチュエータ２２１－２２４を駆動制御する。 Further, when the microcomputer 241 determines in step S404 that no braking request has occurred, that is, when one wheel of the braking device 200 is in a failed state but there is no braking request, the microcomputer 241 bypasses step S405 and The process advances to step S406.
In step S406, the microcomputer 241 drives and controls the brake actuators 221-224 based on the braking force command obtained in step S402.
　図３は、ステアリングコントロールユニット３３０のマイクロコンピュータ３３１によるステアリングシステム３００の制御動作、換言すれば、マイクロコンピュータ３３１が実行するステアリングシステム３００の制御方法を示すフローチャートである。
　マイクロコンピュータ３３１は、システム動作を開始すると、まず、ステップＳ４１１で、ブレーキコントロールユニット２４０のマイクロコンピュータ２４１から、予測ヨーモーメントの信号を取得したか否かを判別する。 FIG. 3 is a flowchart showing a control operation of the steering system 300 by the microcomputer 331 of the steering control unit 330, in other words, a method of controlling the steering system 300 executed by the microcomputer 331.
When the microcomputer 331 starts the system operation, first, in step S411, it determines whether a predicted yaw moment signal has been acquired from the microcomputer 241 of the brake control unit 240.
　マイクロコンピュータ３３１が予測ヨーモーメントの信号を取得している状態は、制動装置２００で１輪失陥が発生していて、かつ、制動装置２００の作動要求があって、左右輪間での制動力差によるヨーモーメント（換言すれば、車両１００の異常挙動）の発生が予測できる状況である。
　ここで、マイクロコンピュータ３３１は、予測ヨーモーメントの信号を取得していない場合は、ステップＳ４１２及びステップＳ４１３を迂回してステップＳ４１４に進む。 The state in which the microcomputer 331 is acquiring a predicted yaw moment signal means that one wheel failure has occurred in the braking device 200, there is a request for operation of the braking device 200, and the braking force between the left and right wheels is being increased. This is a situation in which the occurrence of yaw moment (in other words, abnormal behavior of vehicle 100) due to the difference can be predicted.
Here, if the microcomputer 331 has not acquired the predicted yaw moment signal, the microcomputer 331 bypasses steps S412 and S413 and proceeds to step S414.
　一方、マイクロコンピュータ３３１は、予測ヨーモーメントの信号を取得している場合は、ステップＳ４１２に進む。
　マイクロコンピュータ３３１は、ステップＳ４１２で、予測ヨーモーメント（換言すれば、異常挙動）を抑制するための補正操舵角を求め、更に、ステアリングホイール３１１の位置が、予測ヨーモーメントによる車両挙動にあった位置になるように補正反力トルクを求める。 On the other hand, if the microcomputer 331 has acquired the predicted yaw moment signal, the process proceeds to step S412.
In step S412, the microcomputer 331 calculates a corrected steering angle for suppressing the predicted yaw moment (in other words, abnormal behavior), and further determines the position of the steering wheel 311 at a position corresponding to the vehicle behavior due to the predicted yaw moment. Find the corrected reaction torque so that
　図４は、制動装置２００の１輪失陥によって、車両１００にヨーモーメントが発生することを説明する図である。
　図４は、右前輪１０２及び左右の後輪１０３，１０４のブレーキアクチュエータ２２２－２２４が正常であるのに対し、左前輪１０１のブレーキアクチュエータ２２１が制動力を発生できない失陥状態である場合を例示する。 FIG. 4 is a diagram illustrating that a yaw moment is generated in the vehicle 100 due to failure of one wheel of the braking device 200.
FIG. 4 illustrates a case where the brake actuators 222-224 of the front right wheel 102 and the left and right rear wheels 103, 104 are normal, but the brake actuator 221 of the front left wheel 101 is in a failure state where it cannot generate braking force. do.
　係る制動装置２００の異常状態（詳細には、左前輪１０１の失陥状態）で制動装置２００が作動すると、右前輪１０２及び左右の後輪１０３，１０４には通常の制動力が作用するのに対し、左前輪１０１に作用する制動力は、右前輪１０２に作用する制動力（換言すれば、通常の制動力）よりも小さくなる。
　これにより、左前輪１０１と右前輪１０２との間で制動力差が生じ、車両１００には、右旋回方向のヨーモーメントが発生する。 When the braking device 200 operates in an abnormal state of the braking device 200 (specifically, a failure state of the left front wheel 101), normal braking force acts on the right front wheel 102 and the left and right rear wheels 103, 104. On the other hand, the braking force acting on the left front wheel 101 is smaller than the braking force acting on the right front wheel 102 (in other words, normal braking force).
As a result, a difference in braking force is generated between the left front wheel 101 and the right front wheel 102, and a yaw moment in the right turning direction is generated in the vehicle 100.
　つまり、マイクロコンピュータ２４１は、左前輪１０１のブレーキアクチュエータ２２１が失陥している場合、制動装置２００が作動したときに車両１００を右旋回させる方向のヨーモーメントが発生すると予測できる。
　そして、マイクロコンピュータ３３１は、車両１００を右旋回させる方向の予測ヨーモーメントの信号を取得した場合、制動動作に伴う車両１００の右旋回を抑止するように、前輪１０１，１０２の操舵角を、ステアリングホイール３１１の操作量に応じた操舵角よりも左方向に補正するフィードフォワード制御を実施する。 In other words, if the brake actuator 221 of the left front wheel 101 has failed, the microcomputer 241 can predict that a yaw moment will occur in the direction of turning the vehicle 100 to the right when the brake system 200 is activated.
When the microcomputer 331 acquires a predicted yaw moment signal in the direction of turning the vehicle 100 to the right, the microcomputer 331 adjusts the steering angles of the front wheels 101 and 102 so as to prevent the vehicle 100 from turning to the right due to the braking operation. , performs feedforward control to correct the steering angle to the left according to the amount of operation of the steering wheel 311.
　また、マイクロコンピュータ３３１は、前輪１０１，１０２の操舵角のフィードフォワード制御に並行して、ステアリングホイール３１１を、制動装置２００の１輪失陥によるヨーモーメントの発生方向、つまり、左前輪１０１のブレーキアクチュエータ２２１が失陥している状態であれば右方向に回転させる方向の補正反力トルクを求める。
　そして、マイクロコンピュータ３３１は、次のステップＳ４１３で、ステップＳ４１２で求めた補正操舵角及び補正反力トルクに、運転者によるステアリングホイール３１１の操作量などに応じた値を加算する。 In addition, in parallel with the feedforward control of the steering angles of the front wheels 101 and 102, the microcomputer 331 controls the steering wheel 311 in the direction in which the yaw moment occurs due to failure of one wheel of the braking device 200, that is, the braking of the left front wheel 101. If the actuator 221 is in a failed state, a corrected reaction torque in the direction of rotating it in the right direction is determined.
Then, in the next step S413, the microcomputer 331 adds a value corresponding to the amount of operation of the steering wheel 311 by the driver to the corrected steering angle and corrected reaction force torque obtained in step S412.
　次いで、マイクロコンピュータ３３１は、ステップＳ４１４で、ステップＳ４１３での算出結果に基づき、操舵角指令値及び反力トルク指令値を求め、ステップＳ４１５で、操舵アクチュエータ３２１を操舵角指令値に基づき制御し、反力アクチュエータ３１３を反力トルク指令値に基づき制御する。
　一方、マイクロコンピュータ３３１は、予測ヨーモーメントの信号を取得していない場合、ステップＳ４１２及びステップＳ４１３を迂回してステップＳ４１４に進むことで、通常に、運転者によるステアリングホイール３１１の操作量などに応じた操舵角指令値、反力トルク指令値に基づき、操舵アクチュエータ３２１、反力アクチュエータ３１３を制御する。 Next, in step S414, the microcomputer 331 determines a steering angle command value and a reaction torque command value based on the calculation result in step S413, and in step S415, controls the steering actuator 321 based on the steering angle command value, The reaction actuator 313 is controlled based on the reaction torque command value.
On the other hand, if the microcomputer 331 has not acquired the predicted yaw moment signal, the microcomputer 331 bypasses steps S412 and S413 and proceeds to step S414, thereby normally responding to the amount of operation of the steering wheel 311 by the driver. The steering actuator 321 and the reaction force actuator 313 are controlled based on the steering angle command value and reaction torque command value.
　図５は、制動装置２００の制御及びステアリングシステム３００の制御における基本の構成要素を示すブロック図である。
　ブレーキコントロールユニット２４０のマイクロコンピュータ２４１は、ブレーキ推力センサ２３１－２３４が出力するブレーキ推力検出信号や、ブレーキペダルセンサ２５０が出力するペダル操作量検出信号などを取得する。 FIG. 5 is a block diagram showing basic components in controlling the braking device 200 and the steering system 300.
The microcomputer 241 of the brake control unit 240 acquires brake thrust detection signals output by the brake thrust sensors 231-234, pedal operation amount detection signals output by the brake pedal sensor 250, and the like.
　そして、マイクロコンピュータ２４１は、取得した各種信号に基づき、制動装置２００の１輪失陥状態での制動で発生する予測ヨーモーメントを算出し、また、ブレーキアクチュエータ２２１－２２４の指令値を算出する。
　ここで、マイクロコンピュータ２４１は、算出した予測ヨーモーメントの信号を、ステアリングコントロールユニット３３０のマイクロコンピュータ３３１に送信する。
　また、マイクロコンピュータ２４１は、算出したブレーキアクチュエータ２２１－２２４の指令値に基づき、ブレーキアクチュエータ２２１－２２４を駆動制御する。 Then, the microcomputer 241 calculates the predicted yaw moment that will occur when the braking device 200 brakes when one wheel fails, and also calculates command values for the brake actuators 221-224, based on the acquired various signals.
Here, the microcomputer 241 transmits the calculated predicted yaw moment signal to the microcomputer 331 of the steering control unit 330.
Furthermore, the microcomputer 241 drives and controls the brake actuators 221-224 based on the calculated command values for the brake actuators 221-224.
　一方、ステアリングコントロールユニット３３０のマイクロコンピュータ３３１は、操作量センサ３１２が出力する、ステアリングホイール３１１の操作量検出信号などを取得し、また、ブレーキコントロールユニット２４０から予測ヨーモーメントの信号を取得する。
　そして、マイクロコンピュータ３３１は、予測ヨーモーメントの発生条件、つまり、１輪失陥状態での制動時）では、予測ヨーモーメントを抑制し、ステアリングホイール３１１の操作量に基づく車両挙動となるように、操舵角指令、反力トルク指令を求める。 On the other hand, the microcomputer 331 of the steering control unit 330 acquires the operation amount detection signal of the steering wheel 311 outputted by the operation amount sensor 312, and also acquires the predicted yaw moment signal from the brake control unit 240.
Then, the microcomputer 331 suppresses the predicted yaw moment under the conditions in which the predicted yaw moment occurs (that is, when braking with one wheel lost), so that the vehicle behavior is based on the operation amount of the steering wheel 311. Find the steering angle command and reaction torque command.
　また、マイクロコンピュータ３３１は、制動装置２００に異常がなく予測ヨーモーメントが発生しない条件では、通常に、ステアリングホイール３１１の操作量などに応じた操舵角指令、反力トルク指令を求める。
　ここで、マイクロコンピュータ３３１は、操舵角指令に基づき操舵アクチュエータ３２１を駆動制御し、反力トルク指令に基づき反力アクチュエータ３１３を駆動制御する。 Further, under conditions where there is no abnormality in the braking device 200 and no predicted yaw moment occurs, the microcomputer 331 normally obtains a steering angle command and a reaction torque command according to the operation amount of the steering wheel 311 and the like.
Here, the microcomputer 331 drives and controls the steering actuator 321 based on the steering angle command, and drives and controls the reaction force actuator 313 based on the reaction torque command.
　図６は、予測ヨーモーメントに基づくステアリングシステム３００の制御動作の一態様を示すタイムチャートである。
　図６は、制動装置２００の１輪が失陥している状態であって、車両１００の直進走行中であるときに、運転者がブレーキ操作を行う状況での制御動作を示す。
　運転者は、車両１００が一定の速度で直進走行している時刻ｔ１で、減速操作、つまり、ブレーキペダル２１０の踏み込み操作を開始し、時刻ｔ１から時刻ｔ２までブレーキペダル２１０の踏み増し（換言すれば、ブレーキペダル２１０の操作量の増大）を続け、時刻ｔ３以降は、ブレーキペダル２１０の踏み込み量（操作量）を一定に保つ。 FIG. 6 is a time chart showing one aspect of the control operation of the steering system 300 based on the predicted yaw moment.
FIG. 6 shows a control operation in a situation where one wheel of the braking device 200 has failed and the driver operates the brake while the vehicle 100 is traveling straight.
The driver starts deceleration operation, that is, depressing the brake pedal 210 at time t1 when the vehicle 100 is traveling straight at a constant speed, and continues to press the brake pedal 210 further (in other words, from time t1 to time t2). For example, the amount of operation of the brake pedal 210 continues to increase), and after time t3, the amount of depression of the brake pedal 210 (the amount of operation) is kept constant.
　図６において点線は、ステアリングホイール３１１と前輪１０１，１０２とを物理的に接続した操舵機構でのステアリング動作を示す。
　制動装置２００において１輪が失陥している場合、制動状態で左右に制動力差が生じることでヨーモーメントが発生するため、車両１００に横変位が発生する。
　ステアリングホイール３１１と前輪１０１，１０２とを物理的に接続した操舵機構の場合、運転者は、横変位に伴うステアリングホイール３１１の動きから横変位の発生を認識できる。 In FIG. 6, dotted lines indicate steering operations using a steering mechanism in which the steering wheel 311 and the front wheels 101, 102 are physically connected.
If one wheel in the braking device 200 is malfunctioning, a yaw moment is generated due to a difference in braking force between the left and right sides in the braking state, resulting in lateral displacement of the vehicle 100.
In the case of a steering mechanism in which the steering wheel 311 and the front wheels 101 and 102 are physically connected, the driver can recognize the occurrence of lateral displacement from the movement of the steering wheel 311 accompanying the lateral displacement.
　これに対し、ステアバイワイヤ式のステアリングシステム３００の場合、ステアリングホイール３１１と前輪１０１，１０２とが物理的に接続されないため、車両１００の横変位が発生しても、係る横変位による回転力はステアリングホイール３１１に加わらない。
　そのため、運転者は、車両１００の横変位量がある程度大きくなった時刻ｔ３の時点で、ブレーキ失陥（制動力の左右差の発生）による意図しない横変位の発生を認識し、その後、車両１００のヨー挙動を抑える方向にステアリングホイール３１１を操作し、時刻ｔ４で車両１００の運動を安定させる。 In contrast, in the case of the steer-by-wire steering system 300, the steering wheel 311 and the front wheels 101, 102 are not physically connected, so even if lateral displacement of the vehicle 100 occurs, the rotational force due to the lateral displacement is transferred to the steering wheel. It does not join the wheel 311.
Therefore, at time t3 when the amount of lateral displacement of the vehicle 100 becomes large to a certain extent, the driver recognizes the occurrence of unintended lateral displacement due to brake failure (occurrence of left-right difference in braking force), and then The steering wheel 311 is operated in a direction to suppress the yaw behavior of the vehicle 100, and the motion of the vehicle 100 is stabilized at time t4.
　一方、ステアリングコントロールユニット３３０が、予測ヨーモーメントに基づきステアリングシステム３００をフィードフォワード制御する場合、ステアリングコントロールユニット３３０は、運転者がブレーキ操作を開始する時刻ｔ１から、予測ヨーモーメントを抑止する方向に前輪１０１，１０２の操舵角を補正するフィードフォワード制御を開始する。
　これにより、制動装置２００の失陥によって左右輪間で制動力差が生じても、横変位の増加を抑え、車両１００を短時間に安定化させることができる。 On the other hand, when the steering control unit 330 performs feedforward control of the steering system 300 based on the predicted yaw moment, the steering control unit 330 controls the front wheels in a direction that suppresses the predicted yaw moment from time t1 when the driver starts brake operation. Feedforward control for correcting the steering angles 101 and 102 is started.
Thereby, even if a braking force difference occurs between the left and right wheels due to failure of the braking device 200, an increase in lateral displacement can be suppressed and the vehicle 100 can be stabilized in a short time.
　ここで、ステアリングコントロールユニット３３０は、前輪１０１，１０２の操舵角の補正（換言すれば、操舵アクチュエータ３２１が発生する操舵力の補正）を、予測ヨーモーメントを打ち消すために必要な値よりも小さく設定し、運転者によるステアリングホイール３１１の修正操作の必要性を残すようにすることができる。
　係る構成とすれば、運転者は、制動時に車両１００の横変位を修正する操舵操作が必要になったことで、制動装置２００の失陥（詳細には、１輪失陥）を感覚的に認識することができる。 Here, the steering control unit 330 sets the correction of the steering angle of the front wheels 101 and 102 (in other words, the correction of the steering force generated by the steering actuator 321) to be smaller than the value required to cancel the predicted yaw moment. However, the need for corrective operation of the steering wheel 311 by the driver remains.
With such a configuration, the driver becomes aware of the failure of the braking device 200 (specifically, failure of one wheel) due to the necessity of steering operation to correct the lateral displacement of the vehicle 100 during braking. can be recognized.
　また、ステアリングコントロールユニット３３０が、ステアリングホイール３１１を、制動装置２００の１輪失陥によるヨーモーメントの発生方向に回転させる方向の補正反力トルクを与えることでも、運転者に制動装置２００の失陥（詳細には、１輪失陥）を感覚的に知らせることができる。
　つまり、ステアリングホイール３１１と前輪１０１，１０２とを物理的に接続した操舵機構において、左右の制動力差によって横変位が発生すると、ステアリングホイール３１１が回転するようになる。
　このようなステアリングホイール３１１の回転動作を、ステアバイワイヤ式のステアリングシステム３００で模擬するように、ステアリングコントロールユニット３３０は、予測ヨーモーメントの発生方向にステアリングホイール３１１を回転させる力を反力アクチュエータ３１３によって発生させる。 Furthermore, the steering control unit 330 can also provide the driver with a corrective reaction force torque in the direction of rotating the steering wheel 311 in the direction in which a yaw moment is generated due to failure of one wheel of the braking device 200. (Specifically, one wheel failure) can be sensually notified.
That is, in a steering mechanism in which the steering wheel 311 and the front wheels 101, 102 are physically connected, when lateral displacement occurs due to the difference in braking force between the left and right sides, the steering wheel 311 begins to rotate.
In order to simulate such rotational movement of the steering wheel 311 using the steer-by-wire steering system 300, the steering control unit 330 uses the reaction force actuator 313 to apply a force to rotate the steering wheel 311 in the direction in which the predicted yaw moment is generated. generate.
　また、前輪１０１，１０２の操舵角の補正を、予測ヨーモーメントを打ち消すために必要な値よりも小さく設定し、さらに、ステアリングホイール３１１に予測ヨーモーメントの発生方向の回転力を与えれば、左右の制動力差によってヨー挙動が発生する状況で、ヨー挙動の発生を抑止しつつ、ステアリングホイール３１１と前輪１０１，１０２とが物理的に接続される操舵機構に近い操舵感覚を運転者に与えることができるため、運転者は左右の制動力差によってヨーモーメントが発生する状況を容易に認識できる。 Furthermore, by setting the correction of the steering angles of the front wheels 101 and 102 to be smaller than the value required to cancel out the predicted yaw moment, and further applying a rotational force in the direction of generation of the predicted yaw moment to the steering wheel 311, it is possible to In a situation where yaw behavior occurs due to a difference in braking force, it is possible to suppress the occurrence of yaw behavior and give the driver a steering sensation similar to that of a steering mechanism in which the steering wheel 311 and the front wheels 101 and 102 are physically connected. Therefore, the driver can easily recognize the situation where a yaw moment is generated due to the difference in braking force between the left and right sides.
　図７は、ステアリングコントロールユニット３３０のマイクロコンピュータ３３１によるステアリングシステム３００の制御動作の別の態様を示すフローチャートである。
　ここで、マイクロコンピュータ３３１は、車両１００が走行する路面の摩擦係数μに関する信号である摩擦係数信号を取得し、路面の摩擦係数μに応じて予測ヨーモーメントを抑制するための補正操舵角（換言すれば、操舵力）を変化させる機能を備える。 FIG. 7 is a flowchart showing another aspect of the control operation of the steering system 300 by the microcomputer 331 of the steering control unit 330.
Here, the microcomputer 331 acquires a friction coefficient signal, which is a signal related to the friction coefficient μ of the road surface on which the vehicle 100 travels, and adjusts the correction steering angle (in other words, It has a function to change the steering force.
　マイクロコンピュータ３３１は、システム動作を開始すると、まず、ステップＳ４２１で、操舵装置３２０から、反力の情報、詳細には、前輪１０１，１０２が路面から受けるセルフアライニングトルクの情報を取得する。
　次いで、マイクロコンピュータ３３１は、ステップＳ４２２で、セルフアライニングトルクの情報から、車両１００が走行する路面の摩擦係数μを推定する。
　つまり、マイクロコンピュータ３３１は、セルフアライニングトルクの情報から路面の摩擦係数μを推定する、摩擦係数推定部としての機能を有する。 When the microcomputer 331 starts the system operation, first, in step S421, it acquires from the steering device 320 information on reaction force, specifically, information on self-aligning torque that the front wheels 101 and 102 receive from the road surface.
Next, in step S422, the microcomputer 331 estimates the friction coefficient μ of the road surface on which the vehicle 100 travels from the self-aligning torque information.
In other words, the microcomputer 331 has a function as a friction coefficient estimator that estimates the friction coefficient μ of the road surface from the self-aligning torque information.
　なお、セルフアライニングトルクの情報から摩擦係数μを推定する方法としては、たとえば、特開２００３－３４１５０２号公報が開示する方法を採用できる。
　また、摩擦係数μに関する信号の取得方法を、セルフアライニングトルクの情報から推定する方法に限定するものではない。 Note that as a method for estimating the friction coefficient μ from the information on the self-aligning torque, for example, the method disclosed in Japanese Patent Application Laid-open No. 2003-341502 can be adopted.
Furthermore, the method of acquiring the signal regarding the friction coefficient μ is not limited to the method of estimating it from the information on the self-aligning torque.
　たとえば、マイクロコンピュータ３３１は、路車間通信などによって車両１００の外部から摩擦係数μに関する情報を取得することができる。
　また、摩擦係数μに関する情報は、車両１００が走行しているときの天候の情報、たとえば、降雨量や積雪の情報などを含む。 For example, the microcomputer 331 can acquire information regarding the friction coefficient μ from outside the vehicle 100 through road-to-vehicle communication or the like.
Further, the information regarding the friction coefficient μ includes information on the weather when the vehicle 100 is traveling, such as information on the amount of rainfall and snowfall.
　次いで、マイクロコンピュータ３３１は、ステップＳ４２３で、ブレーキコントロールユニット２４０のマイクロコンピュータ２４１から、予測ヨーモーメントの信号を取得したか否かを判別する。
　ここで、マイクロコンピュータ３３１は、予測ヨーモーメントの信号を取得していない場合はステップＳ４２４及びステップＳ４２５を迂回してステップＳ４２６に進み、予測ヨーモーメントの信号を取得している場合はステップＳ４２４に進む。 Next, in step S423, the microcomputer 331 determines whether a predicted yaw moment signal has been acquired from the microcomputer 241 of the brake control unit 240.
Here, the microcomputer 331 bypasses steps S424 and S425 and proceeds to step S426 if the predicted yaw moment signal has not been acquired, and proceeds to step S424 if the predicted yaw moment signal has been acquired. .
　マイクロコンピュータ３３１は、ステップＳ４２４で、予測ヨーモーメントを抑制するための補正操舵角を求め、更に、ステアリングホイール３１１の位置が、予測ヨーモーメントによる車両挙動にあった位置になるように補正反力トルクを求める。
　ここで、マイクロコンピュータ３３１は、推定した摩擦係数μが小さく車両１００が走行する路面が滑り易いほど、補正操舵角の最大値（換言すれば、上限値）を小さくする。
　これによって、マイクロコンピュータ３３１は、摩擦係数μが標準よりも小さいときに、補正操舵角（換言すれば、補正操舵力）が過大になることを抑止でき、摩擦係数μが変化しても補正操舵角を適切に設定することができる。 In step S424, the microcomputer 331 determines a corrected steering angle for suppressing the predicted yaw moment, and further adjusts the corrected reaction torque so that the position of the steering wheel 311 is in accordance with the vehicle behavior due to the predicted yaw moment. seek.
Here, the microcomputer 331 decreases the maximum value (in other words, the upper limit value) of the corrected steering angle as the estimated friction coefficient μ is smaller and the road surface on which the vehicle 100 runs is more slippery.
Thereby, the microcomputer 331 can prevent the corrected steering angle (in other words, the corrected steering force) from becoming excessive when the friction coefficient μ is smaller than the standard, and can control the corrected steering angle even if the friction coefficient μ changes. Corners can be set appropriately.
　なお、マイクロコンピュータ３３１は、予測ヨーモーメントに基づき補正操舵角を設定するときに、補正操舵角の設定に用いる予測ヨーモーメントを、摩擦係数μが小さいときほど小さく補正することができる。
　つまり、マイクロコンピュータ３３１は、ブレーキコントロールユニット２４０のマイクロコンピュータ２４１が算出した予測ヨーモーメントに対する補正操舵角の制御ゲインを、摩擦係数μが標準よりも小さくなるほど小さくすることができる。 Note that when setting the corrected steering angle based on the predicted yaw moment, the microcomputer 331 can correct the predicted yaw moment used for setting the corrected steering angle to be smaller as the friction coefficient μ is smaller.
That is, the microcomputer 331 can reduce the control gain of the corrected steering angle for the predicted yaw moment calculated by the microcomputer 241 of the brake control unit 240 as the friction coefficient μ becomes smaller than the standard value.
　マイクロコンピュータ３３１は、ステップＳ４２５で、ステップＳ４２４で求めた補正操舵角及び補正反力トルクに、運転者によるステアリングホイール３１１の操作量に応じた値を加算する。
　次いで、マイクロコンピュータ３３１は、ステップＳ４２６で、ステップＳ４２５での算出結果に基づいて操舵角指令値及び反力トルク指令値を求める。 In step S425, the microcomputer 331 adds a value corresponding to the amount of operation of the steering wheel 311 by the driver to the corrected steering angle and corrected reaction force torque obtained in step S424.
Next, in step S426, the microcomputer 331 determines a steering angle command value and a reaction torque command value based on the calculation result in step S425.
　そして、マイクロコンピュータ３３１は、ステップＳ４２７で、操舵アクチュエータ３２１を操舵角指令値に基づき制御し、反力アクチュエータ３１３を反力トルク指令値に基づき制御する。
　一方、マイクロコンピュータ３３１は、ステップＳ４２３で予測ヨーモーメントの信号を取得していないと判断した場合、ステップＳ４２４及びステップＳ４２５を迂回してステップＳ４２６に進むことで、通常に、運転者によるステアリングホイール３１１の操作量に応じた操舵角指令値、反力トルク指令値に基づき、操舵アクチュエータ３２１、反力アクチュエータ３１３を制御する。 Then, in step S427, the microcomputer 331 controls the steering actuator 321 based on the steering angle command value, and controls the reaction force actuator 313 based on the reaction torque command value.
On the other hand, if the microcomputer 331 determines in step S423 that the predicted yaw moment signal has not been acquired, the microcomputer 331 bypasses steps S424 and S425 and proceeds to step S426, thereby allowing the driver to control the steering wheel 311 normally. The steering actuator 321 and the reaction force actuator 313 are controlled based on a steering angle command value and a reaction torque command value corresponding to the operation amount.
　図８は、ブレーキコントロールユニット２４０のマイクロコンピュータ２４１による制動装置２００の制御動作の別の態様を示すフローチャートである。
　ここで、マイクロコンピュータ２４１は、制動装置２００において１輪失陥が生じたときに、残る３輪への制動力の配分を、１輪失陥によって発生するヨーモーメントが小さくなるように、つまり、車両１００の左右での制動力差が小さくなるように変更する。 FIG. 8 is a flowchart showing another aspect of the control operation of the braking device 200 by the microcomputer 241 of the brake control unit 240.
Here, when one wheel failure occurs in the braking device 200, the microcomputer 241 distributes the braking force to the remaining three wheels so that the yaw moment generated by the one wheel failure is reduced, that is, Changes are made so that the difference in braking force between the left and right sides of the vehicle 100 is reduced.
　そして、マイクロコンピュータ２４１は、制動力配分を変更した状態で発生すると予測するヨーモーメントを予測ヨーモーメントとして求める。
　なお、図８のフローチャートのステップＳ４３１－ステップＳ４３４での処理内容は、図２のフローチャートのステップＳ４０１－４０４での処理内容と同じであるため、詳細な説明は省略する。 Then, the microcomputer 241 obtains the yaw moment that is predicted to occur with the braking force distribution changed as the predicted yaw moment.
Note that the processing contents in steps S431 to S434 in the flowchart in FIG. 8 are the same as the processing contents in steps S401 to S404 in the flowchart in FIG. 2, so a detailed explanation will be omitted.
　マイクロコンピュータ２４１は、制動装置２００の１輪失陥状態であって、かつ、制動要求がある状況で、ステップＳ４３５に進む。
　そして、マイクロコンピュータ２４１は、ステップＳ４３５で、ステップＳ４３２で求めた制動力指令と、制動装置２００において失陥している車輪の情報とから、失陥していない３輪について、制動に伴って発生するヨーモーメントが標準の制動力配分のときよりも小さくなる制動力配分を算出し、算出した制動力配分に基づき３輪それぞれの制動力指令を求める。
　ここで、マイクロコンピュータ２４１は、制動装置２００の１輪失陥状態において、車両１００の減速度を維持しつつ、制動に伴って発生するヨーモーメントが最小となるように、制動力配分を変更することができる。 The microcomputer 241 proceeds to step S435 in a situation where one wheel of the braking device 200 has failed and there is a braking request.
Then, in step S435, the microcomputer 241 determines, based on the braking force command obtained in step S432 and the information on the wheels that have failed in the braking device 200, that the occurrence of a A braking force distribution in which the yaw moment caused by the brake force is smaller than that in the standard braking force distribution is calculated, and a braking force command for each of the three wheels is determined based on the calculated braking force distribution.
Here, the microcomputer 241 changes the braking force distribution so that the yaw moment generated due to braking is minimized while maintaining the deceleration of the vehicle 100 when one wheel of the braking device 200 is in a failed state. be able to.
　たとえば、制動装置２００において左前輪１０１のブレーキアクチュエータ２２１が、制動力を発生できない失陥状態であるとき、マイクロコンピュータ２４１は、ブレーキアクチュエータ２２１が発生すべき制動力分だけ左後輪１０３のブレーキアクチュエータ２２１が発生する制動力を増加させる。
　つまり、左前輪１０１のブレーキアクチュエータ２２１が失陥すると、マイクロコンピュータ２４１は、左後輪１０３の要求制動力に左前輪１０１の要求制動力を付加して、左後輪１０３の制動力指令とする。 For example, when the brake actuator 221 of the left front wheel 101 in the braking device 200 is in a failure state where it cannot generate braking force, the microcomputer 241 controls the brake actuator of the left rear wheel 103 by the amount of braking force that the brake actuator 221 should generate. 221 increases the braking force generated.
That is, when the brake actuator 221 of the left front wheel 101 fails, the microcomputer 241 adds the required braking force of the left front wheel 101 to the required braking force of the left rear wheel 103 and sets it as a braking force command for the left rear wheel 103. .
　一方、右前輪１０２及び右後輪１０４に対する制動力配分は、変更せずに標準値のままとする。
　係る制動力配分の変更によって、車両１００の左側に加わる制動力が、右側に加わる制動力と同等になるため、制動装置２００の作動によって車両１００に発生するヨーモーメントが小さくなる。 On the other hand, the braking force distribution to the right front wheel 102 and the right rear wheel 104 is left unchanged at the standard value.
By changing the braking force distribution, the braking force applied to the left side of the vehicle 100 becomes equal to the braking force applied to the right side, so that the yaw moment generated in the vehicle 100 by the operation of the braking device 200 is reduced.
　次いで、マイクロコンピュータ２４１は、ステップＳ４３６に進んで、ステップＳ４３５で求めた制動力配分（換言すれば、制動力指令）での制動状態で発生すると予測する予測ヨーモーメントを求め、求めた予測ヨーモーメントの情報をステアリングコントロールユニット３３０のマイクロコンピュータ３３１に送信する。
　マイクロコンピュータ２４１は、ステップＳ４３７で、制動力指令に基づきブレーキアクチュエータ２２１－２２４を駆動制御する。
　ここで、制動装置２００の１輪失陥状態である場合、マイクロコンピュータ２４１は、ステップＳ４３５で求めた制動力指令、つまり、制動力配分変更後の制動力指令に基づき、ブレーキアクチュエータ２２１－２２４を駆動制御する。 Next, the microcomputer 241 proceeds to step S436, and calculates the predicted yaw moment that is predicted to occur in the braking state based on the braking force distribution (in other words, the braking force command) obtained in step S435, and calculates the predicted yaw moment that is predicted to occur in the braking state based on the braking force distribution (in other words, the braking force command) obtained in step S435. The information is sent to the microcomputer 331 of the steering control unit 330.
The microcomputer 241 drives and controls the brake actuators 221-224 based on the braking force command in step S437.
Here, if one wheel of the braking device 200 is in a failure state, the microcomputer 241 operates the brake actuators 221-224 based on the braking force command obtained in step S435, that is, the braking force command after changing the braking force distribution. Drive control.
　一方、制動装置２００の１輪失陥状態でない場合、マイクロコンピュータ２４１は、ステップＳ４３２で求めた制動力指令、つまり、標準の制動力配分での制動力指令に基づき、ブレーキアクチュエータ２２１－２２４を駆動制御する。
　上記のように、制動装置２００において１輪が失陥しているときに、左右の制動力差で発生するヨーモーメントを小さくするように制動力配分を変更した上で、制動力差で発生するヨーモーメントを抑制するように操舵角を補正すれば、制動力差によるヨーモーメントの発生を制動動作の開始時から安定して小さく抑制することができ、車両１００の安定を維持できる。 On the other hand, if one wheel of the braking device 200 is not in a failure state, the microcomputer 241 drives the brake actuators 221-224 based on the braking force command obtained in step S432, that is, the braking force command with the standard braking force distribution. Control.
As described above, when one wheel fails in the braking device 200, the braking force distribution is changed to reduce the yaw moment that occurs due to the difference in braking force between the left and right sides, and then the yaw moment that occurs due to the difference in braking force is changed. If the steering angle is corrected to suppress the yaw moment, the generation of yaw moment due to the braking force difference can be stably suppressed to a small value from the start of the braking operation, and the stability of the vehicle 100 can be maintained.
　図９は、前述した制動力配分の変更処理を伴う制御動作の一態様を示すタイムチャートである。
　詳細には、図９は、制動装置２００の左前輪１０１のブレーキアクチュエータ２２１が失陥した状態で車両１００が直進走行しているときに、運転者が制動操作、つまり、ブレーキペダル２１０の操作を行った場合での制動力、操舵角などの変化を示す。
　ここで、ブレーキコントロールユニット２４０のマイクロコンピュータ２４１は、制動に伴って発生するヨーモーメントを小さくするための制動力配分処理として、左後輪１０３の要求制動力に左前輪１０１の要求制動力を付加する処理を実行するものとする。 FIG. 9 is a time chart showing one aspect of the control operation involving the above-described braking force distribution changing process.
Specifically, FIG. 9 shows that when the vehicle 100 is traveling straight with the brake actuator 221 of the left front wheel 101 of the braking device 200 having failed, the driver performs a braking operation, that is, an operation of the brake pedal 210. It shows changes in braking force, steering angle, etc. when
Here, the microcomputer 241 of the brake control unit 240 adds the required braking force of the left front wheel 101 to the required braking force of the left rear wheel 103 as a braking force distribution process to reduce the yaw moment generated with braking. It is assumed that the following processing is executed.
　図９において、車両１００の直進走行中である時刻ｔ１で、運転者はブレーキペダル２１０の操作を開始する。
　ブレーキコントロールユニット２４０のマイクロコンピュータ２４１は、ブレーキペダル２１０の操作量に応じた要求制動力に応じて、正常な３輪への制動力配分を変更することで、制動力差によって発生するヨーモーメントを小さく抑制しつつ、要求の減速度を発生させるようにする。 In FIG. 9, the driver starts operating the brake pedal 210 at time t1 while the vehicle 100 is traveling straight.
The microcomputer 241 of the brake control unit 240 reduces the yaw moment generated by the difference in braking force by changing the braking force distribution to the normal three wheels according to the required braking force according to the operation amount of the brake pedal 210. The required deceleration is generated while being suppressed to a small value.
　つまり、マイクロコンピュータ２４１は、制動の開始時刻である時刻ｔ１以降において、左後輪１０３の制動力指令に、左前輪１０１の制動力指令分を付加することで、車両１００の左側に加わる制動力（詳細には、左後輪１０３の制動力）を、右側に加わる制動力（詳細には、右前輪１０２の制動力＋右後輪１０４の制動力）と同等とし、制動に伴うヨーレイトの発生を抑止する。
　この時、ステアリングコントロールユニット３３０のマイクロコンピュータ３３１は、ステアリングホイール３１１に、予測ヨーモーメントによる車両挙動にあった位置になるような反力トルクを与えることで、ステアリングホイール３１１の操作角（またはステアリングホイール３１１の反力）が変化し、制動装置２００の失陥を運転者に感覚的に知らせる。 In other words, the microcomputer 241 adds the braking force command for the left front wheel 101 to the braking force command for the left rear wheel 103 after time t1, which is the braking start time, thereby adding the braking force to the left side of the vehicle 100. (Specifically, the braking force of the left rear wheel 103) is equal to the braking force applied to the right side (specifically, the braking force of the right front wheel 102 + the braking force of the right rear wheel 104), and the occurrence of yaw rate due to braking. deter.
At this time, the microcomputer 331 of the steering control unit 330 applies a reaction torque to the steering wheel 311 to bring it into a position that matches the vehicle behavior due to the predicted yaw moment. 311 reaction force) changes, and the driver is sensually informed of the failure of the braking device 200.
　運転者によるブレーキペダル２１０の踏み込み操作中の時刻ｔ２で左後輪１０３の制動力が飽和し、その後は、右前輪１０２及び右後輪１０４の制動力を増加させて減速度を発生させる。
　つまり、左後輪１０３において、左前輪１０１の要求制動力も発生させるため、時刻ｔ２で、左後輪１０３のブレーキアクチュエータ２２３が発生し得る最大制動力に達してしまい、時刻ｔ２以降の要求制動力の増大に追従できず、左後輪１０３の制動力は最大制動力を維持することになる。 The braking force of the left rear wheel 103 is saturated at time t2 while the driver is depressing the brake pedal 210, and thereafter the braking force of the right front wheel 102 and the right rear wheel 104 is increased to generate deceleration.
In other words, since the left rear wheel 103 also generates the required braking force of the left front wheel 101, the brake actuator 223 of the left rear wheel 103 reaches the maximum braking force that can be generated at time t2, and the required braking force after time t2 is reached. Unable to follow the increase in power, the braking force of the left rear wheel 103 remains at the maximum braking force.
　一方、時刻ｔ２の時点で、右前輪１０２及び右後輪１０４それぞれの制動力は最大制動力に達していないため、時刻ｔ２以降における要求制動力の増大要求に対し、右前輪１０２及び右後輪１０４の制動力を増加させる。
　このように、時刻ｔ２以降は、右前輪１０２の制動力と右後輪１０４の制動力との合計が増えるのに対し、左後輪１０３の制動力は最大値に飽和した状態となるため、車両１００の左右で制動力差が生じるようになる。
　そこで、ステアリングコントロールユニット３３０は、ブレーキコントロールユニット２４０が求めた予測ヨーモーメントが小さくなる方向に前輪１０１，１０２の操舵角（操舵力）を変化させ、左右の制動力差が大きくなる時刻ｔ２以降において車両１００に発生するヨーモーメントを抑制する。 On the other hand, as of time t2, the braking force of each of the front right wheel 102 and the rear right wheel 104 has not reached the maximum braking force. 104 braking force is increased.
In this way, after time t2, the sum of the braking force of the right front wheel 102 and the braking force of the right rear wheel 104 increases, while the braking force of the left rear wheel 103 is saturated to the maximum value. A difference in braking force occurs between the left and right sides of the vehicle 100.
Therefore, the steering control unit 330 changes the steering angle (steering force) of the front wheels 101, 102 in a direction in which the predicted yaw moment calculated by the brake control unit 240 becomes smaller, and after time t2 when the difference in left and right braking force becomes large. The yaw moment generated in the vehicle 100 is suppressed.
　時刻ｔ３で、運転者は、ブレーキペダル２１０の操作量を一定にし、一定の減速度を要求する。
　このとき、運転者の要求減速度を達成するために、車両１００の左右で制動力差が発生するが、ステアリングコントロールユニット３３０による操舵角の制御によって、運転者は、ステアリングホイール３１１を中立位置付近に維持した状態で、ヨーモーメントを発生させることなく車両１００を減速させることができる。 At time t3, the driver maintains the amount of operation of brake pedal 210 constant and requests constant deceleration.
At this time, in order to achieve the deceleration requested by the driver, a difference in braking force occurs between the left and right sides of the vehicle 100, but by controlling the steering angle by the steering control unit 330, the driver can move the steering wheel 311 near the neutral position. The vehicle 100 can be decelerated without generating a yaw moment.
　上記実施形態で説明した各技術的思想は、矛盾が生じない限りにおいて、適宜組み合わせて使用することができる。
　また、好ましい実施形態を参照して本発明の内容を具体的に説明したが、本発明の基本的技術思想及び教示に基づいて、当業者であれば、種々の変形態様を採り得ることは自明である。 The technical ideas described in the above embodiments can be used in combination as appropriate, as long as there is no contradiction.
Further, although the content of the present invention has been specifically explained with reference to preferred embodiments, it is obvious that those skilled in the art can make various modifications based on the basic technical idea and teachings of the present invention. It is.
　上記実施形態では、ブレーキコントロールユニット２４０のマイクロコンピュータ２４１が予測ヨーモーメントの算出処理を実施するが、ステアリングコントロールユニット３３０のマイクロコンピュータ３３１が、制動装置２００における失陥の情報、制動要求の情報などを取得して、予測ヨーモーメントの算出処理を実行することができる。
　また、１つのコントロールユニットが、制動装置２００と、ステアリングシステム３００との双方に制御信号を出力するシステムとすることができる。 In the above embodiment, the microcomputer 241 of the brake control unit 240 performs the calculation process of the predicted yaw moment, but the microcomputer 331 of the steering control unit 330 collects information on failures in the braking device 200, information on braking requests, etc. It is possible to obtain the predicted yaw moment and execute the calculation process of the predicted yaw moment.
Further, a system may be provided in which one control unit outputs control signals to both the braking device 200 and the steering system 300.
　また、ステアリングシステム３００は、操舵アクチュエータ３２１に制御信号を出力するコントロールユニットと、反力アクチュエータ３１３に制御信号を出力するコントロールユニットとを個別に備えることができる。
　また、ステアリングシステム３００は、ステアリングホイール３１１と前輪１０１，１０２とをクラッチなどで機械的に結合するバックアップ機構を備えることができる。 Further, the steering system 300 can separately include a control unit that outputs a control signal to the steering actuator 321 and a control unit that outputs a control signal to the reaction force actuator 313.
Further, the steering system 300 can include a backup mechanism that mechanically couples the steering wheel 311 and the front wheels 101 and 102 using a clutch or the like.
　１００…車両、１０１－１０４…車輪、２００…制動装置、２４０…ブレーキコントロールユニット（車両制御装置）、２４１…マイクロコンピュータ（コントロール部）、３００…ステアバイワイヤ式のステアリングシステム、３１１…ステアリングホイール（操舵操作入力部材）、３２０…操舵装置、３２１…操舵アクチュエータ、３３０…ステアリングコントロールユニット（車両制御装置）、３３１…マイクロコンピュータ（コントロール部） DESCRIPTION OF SYMBOLS 100... Vehicle, 101-104... Wheel, 200... Braking device, 240... Brake control unit (vehicle control device), 241... Microcomputer (control part), 300... Steer-by-wire type steering system, 311... Steering wheel (steering operation input member), 320... steering device, 321... steering actuator, 330... steering control unit (vehicle control device), 331... microcomputer (control unit)

Claims (14)

  1. 　車両の各車輪に制動力を発生させる制動装置と、
    　ステアバイワイヤ式のステアリングシステムであって、
    　操舵操作入力部材と、
    　前記車両の車輪に操舵力を付与する操舵アクチュエータを有する操舵装置と、
    　を有し、
    　前記操舵操作入力部材の操作量に対して前記車輪の操舵角を独立に制御可能に構成された、前記ステアリングシステムと、
    　を有する前記車両に備えられ、
    　前記操舵操作入力部材の操作量に基づいて前記操舵アクチュエータへ制御信号を出力するコントロール部を備える車両制御装置であって、
    　前記コントロール部は、
    　前記制動装置が制動力を発生させたときに前記車両の異常挙動を生じさせることになる前記車両の異常の有無を示す異常検出信号を取得し、
    　前記異常検出信号に基づいて前記異常の発生を検知したときに、前記制動装置の作動に応じて前記車両に発生すると予測される車両挙動である予測挙動を求め、
    　前記制動装置が作動した際に、前記操舵操作入力部材の操作量に基づく車両挙動となるように、前記予測挙動を抑制する方向へ操舵力を発生させる前記制御信号を前記操舵アクチュエータへ出力する、
    　車両制御装置。     a braking device that generates braking force on each wheel of the vehicle;
    A steer-by-wire steering system,
    a steering operation input member;
    a steering device including a steering actuator that applies steering force to the wheels of the vehicle;
    has
    the steering system configured to be able to independently control the steering angle of the wheels with respect to the operation amount of the steering operation input member;
    The vehicle is equipped with:
    A vehicle control device comprising a control unit that outputs a control signal to the steering actuator based on an operation amount of the steering operation input member,
    The control section includes:
    obtaining an abnormality detection signal indicating the presence or absence of an abnormality in the vehicle that causes abnormal behavior of the vehicle when the braking device generates a braking force;
    determining a predicted behavior that is a vehicle behavior that is predicted to occur in the vehicle in response to the operation of the braking device when the occurrence of the abnormality is detected based on the abnormality detection signal;
    outputting the control signal to the steering actuator to generate a steering force in a direction that suppresses the predicted behavior so that the vehicle behavior is based on the operation amount of the steering operation input member when the braking device is activated;
    Vehicle control device.
  2. 　請求項１に記載の車両制御装置であって、
    　前記コントロール部は、
    　前記予測挙動を抑制する方向へ操舵力を発生させる前記制御信号を、前記予測挙動を打ち消すために必要な操舵力よりも小さい操舵力となる前記制御信号とする、
    　車両制御装置。     The vehicle control device according to claim 1,
    The control section includes:
    The control signal that generates a steering force in a direction that suppresses the predicted behavior is the control signal that results in a steering force smaller than the steering force required to cancel the predicted behavior.
    Vehicle control device.
  3. 　請求項２に記載の車両制御装置であって、
    　前記コントロール部は、
    　前記予測挙動を、前記制動装置の作動に応じて前記車両に発生すると予測されるヨーモーメントとして設定する、
    　車両制御装置。     The vehicle control device according to claim 2,
    The control section includes:
    setting the predicted behavior as a yaw moment that is predicted to occur in the vehicle in response to the operation of the braking device;
    Vehicle control device.
  4. 　請求項２に記載の車両制御装置であって、
    　前記ステアリングシステムは、
    　前記操舵操作入力部材に操作反力を付与する反力アクチュエータを更に備え、
    　前記コントロール部は、
    　前記予測挙動を打ち消すために必要な操舵力よりも小さい操舵力となる前記制御信号を出力する際に、前記操舵操作入力部材の位置が前記車両の挙動に合った位置となるように、前記反力アクチュエータへ反力制御信号を出力する、
    　車両制御装置。     The vehicle control device according to claim 2,
    The steering system includes:
    further comprising a reaction force actuator that applies an operation reaction force to the steering operation input member,
    The control section includes:
    When outputting the control signal that results in a steering force smaller than the steering force required to cancel the predicted behavior, the reaction is performed so that the position of the steering operation input member matches the behavior of the vehicle. Outputs a reaction force control signal to the force actuator,
    Vehicle control device.
  5. 　請求項１に記載の車両制御装置であって、
    　前記コントロール部は、
    　前記車両が走行する路面の摩擦係数に関する摩擦係数信号を取得し、
    　前記摩擦係数信号に基づいて、前記予測挙動を抑制する方向に発生させる操舵力を変化させる、
    　車両制御装置。     The vehicle control device according to claim 1,
    The control section includes:
    obtaining a friction coefficient signal regarding a friction coefficient of a road surface on which the vehicle runs;
    changing a steering force generated in a direction to suppress the predicted behavior based on the friction coefficient signal;
    Vehicle control device.
  6. 　請求項５に記載の車両制御装置であって、
    　前記コントロール部は、
    　前記操舵装置に付与されるセルフアライニングトルクに基づいて、前記摩擦係数信号を求める摩擦係数推定部を有する、
    　車両制御装置。     The vehicle control device according to claim 5,
    The control section includes:
    a friction coefficient estimator that calculates the friction coefficient signal based on the self-aligning torque applied to the steering device;
    Vehicle control device.
  7. 　請求項１に記載の車両制御装置であって、
    　前記車両は、前記異常の発生を警告する警告装置を有し、
    　前記コントロール部は、
    　前記異常の発生を検知したときに、前記警告装置を作動させる作動信号を出力する、
    　車両制御装置。     The vehicle control device according to claim 1,
    The vehicle has a warning device that warns of the occurrence of the abnormality,
    The control section includes:
    outputting an activation signal to activate the warning device when the occurrence of the abnormality is detected;
    Vehicle control device.
  8. 　請求項１に記載の車両制御装置であって、
    　前記制動装置は、モータの作動により制動力を発生する電動ブレーキ装置である、
    　車両制御装置。     The vehicle control device according to claim 1,
    The braking device is an electric braking device that generates braking force by operating a motor.
    Vehicle control device.
  9. 　請求項８に記載の車両制御装置であって、
    　前記電動ブレーキ装置は、前記車両の各車輪に配置され、前記モータの駆動により摩擦力を発生する電動キャリパである、
    　車両制御装置。     The vehicle control device according to claim 8,
    The electric brake device is an electric caliper that is disposed on each wheel of the vehicle and generates a friction force by driving the motor.
    Vehicle control device.
  10. 　請求項８に記載の車両制御装置であって、
    　前記電動ブレーキ装置は、前記車両の車輪に配置されるインホイールモータの回生作動によって前記車輪に制動力を発生させる回生ブレーキ装置である、
    　車両制御装置。     The vehicle control device according to claim 8,
    The electric brake device is a regenerative brake device that generates braking force on the wheels by regenerative operation of an in-wheel motor disposed in the wheels of the vehicle.
    Vehicle control device.
  11. 　請求項１に記載の車両制御装置であって、
    　前記異常検出信号は、前記制動装置の異常の有無を示す、
    　車両制御装置。     The vehicle control device according to claim 1,
    The abnormality detection signal indicates whether or not there is an abnormality in the braking device.
    Vehicle control device.
  12. 　請求項１１に記載の車両制御装置であって、
    　前記コントロール部は、
    　前記制動装置の異常発生を検知したときに、前記制動装置の異常によって前記車両に発生するヨーモーメントを小さくするように、前記車両の各車輪に対する制動力の配分を変更し、
    　前記制動力の配分を変更した状態での前記予測挙動を求める、
    　車両制御装置。     The vehicle control device according to claim 11,
    The control section includes:
    When detecting an abnormality in the braking device, changing the distribution of braking force to each wheel of the vehicle so as to reduce a yaw moment generated in the vehicle due to the abnormality in the braking device;
    determining the predicted behavior with the braking force distribution changed;
    Vehicle control device.
  13. 　車両の各車輪に制動力を発生させる制動装置と、
    　ステアバイワイヤ式のステアリングシステムであって、
    　操舵操作入力部材と、
    　前記車両の車輪に操舵力を付与する操舵アクチュエータを有する操舵装置と、
    　を有し、
    　前記操舵操作入力部材の操作量に対して前記車輪の操舵角を独立に制御可能に構成された、前記ステアリングシステムと、
    　を有する前記車両に備えられたコントロール部であって、
    　前記操舵操作入力部材の操作量に基づいて前記操舵アクチュエータへ制御信号を出力する前記コントロール部が実行する車両制御方法であって、
    　前記コントロール部は、
    　前記制動装置が制動力を発生させたときに前記車両の異常挙動を生じさせることになる前記車両の異常の有無を示す異常検出信号を取得し、
    　前記異常検出信号に基づいて前記異常の発生を検知したときに、前記制動装置の作動に応じて前記車両に発生すると予測される車両挙動である予測挙動を求め、
    　前記制動装置が作動した際に、前記操舵操作入力部材の操作量に基づく車両挙動となるように、前記予測挙動を抑制する方向へ操舵力を発生させる前記制御信号を前記操舵アクチュエータへ出力する、
    　車両制御方法。     a braking device that generates braking force on each wheel of the vehicle;
    A steer-by-wire steering system,
    a steering operation input member;
    a steering device including a steering actuator that applies steering force to the wheels of the vehicle;
    has
    the steering system configured to be able to independently control the steering angle of the wheels with respect to the operation amount of the steering operation input member;
    A control unit provided in the vehicle having:
    A vehicle control method executed by the control unit that outputs a control signal to the steering actuator based on the operation amount of the steering operation input member,
    The control section includes:
    obtaining an abnormality detection signal indicating the presence or absence of an abnormality in the vehicle that causes abnormal behavior of the vehicle when the braking device generates a braking force;
    determining a predicted behavior that is a vehicle behavior that is predicted to occur in the vehicle in response to the operation of the braking device when the occurrence of the abnormality is detected based on the abnormality detection signal;
    outputting to the steering actuator the control signal that generates a steering force in a direction that suppresses the predicted behavior so that the vehicle behavior is based on the operation amount of the steering operation input member when the braking device is activated;
    Vehicle control method.
  14. 　車両に取り付けられる操舵操作入力部材と、
    　前記車両の車輪に操舵力を付与する操舵アクチュエータを有する操舵装置と、
    　を有し、
    　前記操舵操作入力部材の操作量に対して前記車輪の操舵角を独立に制御可能に構成された、ステアバイワイヤ式のステアリングシステムであって、
    　前記操舵操作入力部材の操作量に基づいて前記操舵アクチュエータへ制御信号を出力するコントロール部を備え、
    　前記コントロール部は、
    　前記車両が備える制動装置が前記車両の各車輪に制動力を発生させたときに前記車両の異常挙動を生じさせることになる前記車両の異常の有無を示す異常検出信号を取得し、
    　前記異常検出信号に基づいて前記異常の発生を検知したときに、前記制動装置の作動に応じて前記車両に発生すると予測される車両挙動である予測挙動を求め、
    　前記制動装置が作動した際に、前記操舵操作入力部材の操作量に基づく車両挙動となるように、前記予測挙動を抑制する方向へ操舵力を発生させる前記制御信号を前記操舵アクチュエータへ出力する、
    　ステアリングシステム。     a steering operation input member attached to a vehicle;
    a steering device including a steering actuator that applies steering force to the wheels of the vehicle;
    has
    A steer-by-wire steering system configured to be able to independently control the steering angle of the wheels with respect to the operation amount of the steering operation input member,
    comprising a control section that outputs a control signal to the steering actuator based on the operation amount of the steering operation input member,
    The control section includes:
    Obtaining an abnormality detection signal indicating the presence or absence of an abnormality in the vehicle that causes abnormal behavior of the vehicle when a braking device included in the vehicle generates a braking force on each wheel of the vehicle;
    determining a predicted behavior that is a vehicle behavior that is predicted to occur in the vehicle in response to the operation of the braking device when the occurrence of the abnormality is detected based on the abnormality detection signal;
    outputting the control signal to the steering actuator to generate a steering force in a direction that suppresses the predicted behavior so that the vehicle behavior is based on the operation amount of the steering operation input member when the braking device is activated;
    steering system.
PCT/JP2023/028710 2022-09-05 2023-08-07 Vehicle control device, vehicle control method, and steering system WO2024053309A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004352030A (en) * 2003-05-28 2004-12-16 Toyota Motor Corp Running controller for vehicle
JP2005112285A (en) * 2003-10-10 2005-04-28 Toyoda Mach Works Ltd Steering control device for vehicle
JP2005247054A (en) * 2004-03-02 2005-09-15 Advics:Kk Steering control device for vehicle
JP2012035708A (en) * 2010-08-05 2012-02-23 Nissan Motor Co Ltd Steering control device
JP2020189547A (en) * 2019-05-21 2020-11-26 アイシン精機株式会社 Vehicle control device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004352030A (en) * 2003-05-28 2004-12-16 Toyota Motor Corp Running controller for vehicle
JP2005112285A (en) * 2003-10-10 2005-04-28 Toyoda Mach Works Ltd Steering control device for vehicle
JP2005247054A (en) * 2004-03-02 2005-09-15 Advics:Kk Steering control device for vehicle
JP2012035708A (en) * 2010-08-05 2012-02-23 Nissan Motor Co Ltd Steering control device
JP2020189547A (en) * 2019-05-21 2020-11-26 アイシン精機株式会社 Vehicle control device

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