JP7287011B2 - Wheel control system and wheel control method - Google Patents

Description

The present disclosure relates to controlling wheels driven by electric motors.

Equipped with a microcontroller as a control unit that controls the actuator installed in the vehicle and a microcontroller monitoring unit as a monitoring unit that monitors the occurrence of an abnormality in the microcontroller, and executes file safe when an abnormality occurs inside the microcontroller. A technique for doing so is known (for example, Patent Document 1). In recent years, a technique (so-called in-wheel motor) has been proposed in which electric motors as actuators are arranged on left and right wheels of a vehicle, and the electric motors drive the left and right wheels. Moreover, in such a technique, two control circuits may be used as control units for controlling the two left and right electric motors, respectively.

JP 2016-147585 A

In the above technology, if one of the two control circuits fails, the running stability of the vehicle may be impaired. For example, a normal control circuit instructs the controlled motor to drive forward torque, and a faulty control circuit instructs the controlled motor to reverse torque, causing the vehicle to spin. Running stability may be impaired. However, in the past, the actual situation is that sufficient consideration has not been given to how to deal with a failure in one of the control circuits (file safe). Therefore, in a configuration including two electric motors for driving two left and right wheels and two control circuits for controlling each electric motor, it is desired to realize a fail-safe when one of the control circuits fails. ing.

The present disclosure can be implemented as the following forms.

As one form of the present disclosure, it is arranged in each wheel constituting at least one drive wheel of a pair of front wheels (201, 202) and a pair of rear wheels (203, 204) of a vehicle (200, 200a). electric motors (30R, 30L) for driving the wheels, and control circuits (31R, 31L) for controlling the electric motors for driving the wheels, arranged corresponding to the wheels constituting the driving wheels. A wheel control system (100) is provided for controlling the operation of the pair of front wheels and the pair of rear wheels. This wheel control system includes an electric motor control device (10) that controls the control circuit arranged corresponding to each wheel constituting the drive wheels, and controls the brakes of the pair of front wheels and the pair of rear wheels. and a brake control device (120) capable of communicating with the electric motor control device. The electric motor control device includes a target torque instructing section (16) for instructing a target torque to the control circuit corresponding to each wheel constituting the drive wheels, and the control circuit corresponding to each wheel constituting the drive wheels. A failure occurrence identification unit (21) for identifying failure occurrence in any of the control circuits among the control circuits, a yaw rate sensor (46) mounted on the vehicle for detecting a yaw rate, and a lateral acceleration mounted on the vehicle. a detection result acquisition unit (15, 15a) for acquiring the detection result of at least one of an acceleration sensor (46) for detecting a vehicle speed sensor (44) mounted on the vehicle for detecting the vehicle speed; a steering angle sensor (42) mounted to detect the steering angle; and a target value calculation unit ( 19, 19a). The target torque instruction unit, when the occurrence of the failure is identified, instructs the failure identification control circuit, which is the control circuit in which the occurrence of the failure has been identified, to set the target torque to zero. When the occurrence of the failure is identified, the brake control device acquires the detection result for a wheel different from the driving wheel among the wheels constituting the pair of front wheels and the pair of rear wheels. a steering control device (110) for controlling steering of the vehicle by applying a brake so that the detection result obtained by the unit approaches the calculated target value, the steering control device being configured to communicate with the electric motor control device; and obtains a steering amount, which is an operation amount of a steering wheel (210) mounted on the vehicle, and controls the steering of the vehicle according to the obtained steering amount and the vehicle speed. and, when the occurrence of the failure is identified, the steering control device adjusts the steering angle to the wheel side corresponding to the steering angle of the steering wheel and corresponding to the failure identification control circuit to the failure occurrence By reducing the offset amount from the steering angle for the steering wheel steering amount when is not specified, the steering of the vehicle is controlled so that the vehicle moves straight when the steering wheel steering amount is zero, and the The target torque instructing unit sets the target torque to zero for all the control circuits corresponding to the wheels constituting the drive wheels in addition to the failure identification control circuit when the occurrence of the failure is specified. and the target torque instructing unit instructs the vehicle to move forward or backward after the occurrence of the failure is identified and the vehicle speed becomes zero, each wheel constituting the driving wheel of the control circuits corresponding to the failure identification control circuit, instructing zero as the target torque to the other control circuits, and detecting the vehicle speed and the accelerator opening of the vehicle for the other control circuits A torque calculated using a detection result of a speed sensor and a detection result of a range sensor (43) for detecting a position of a shift range of the vehicle is indicated as the target torque, and the steering control device is configured to: When the vehicle is instructed to move forward or backward after the occurrence of the failure is identified and the vehicle speed becomes zero, the steering angle corresponding to the steering wheel steering amount and the wheel corresponding to the failure identification control circuit By setting the steering angle to the side to an angle obtained by reducing the offset amount from the steering angle corresponding to the steering amount of the steering wheel when the occurrence of the failure is not specified, the vehicle travels straight when the steering amount of the steering wheel is zero. to control the steering of the vehicle .

According to the wheel control system of the above aspect, when the occurrence of a failure is identified, zero is instructed as the target torque to the failure identification control circuit, and the wheels constituting the pair of front wheels and the pair of rear wheels , the wheels other than the drive wheels are braked so that the detection result obtained by the detection result obtaining unit approaches the target value. In the configuration provided with two control circuits, it is possible to suppress deterioration in running stability of the vehicle when a failure occurs in one of the control circuits, and to realize fail-safe.

The present disclosure can also be implemented in various forms other than wheel control systems. For example, it can be realized in the form of a vehicle equipped with a wheel control system, a wheel control method, a computer program for realizing these devices and methods, a storage medium storing such a computer program, or the like.

1 is an explanatory diagram showing a schematic configuration of a vehicle equipped with a wheel control system according to an embodiment of the present disclosure; FIG. 2 is a block diagram showing functional configurations of a motor control device and a control circuit in the first embodiment; FIG. FIG. 4 is an explanatory diagram showing an example of setting contents of a torque map; FIG. 4 is an explanatory diagram showing a torque distribution ratio determination map; FIG. 4 is an explanatory diagram showing a target yaw rate map; 4 is a flowchart showing the procedure of lane departure hazard detection processing; 4 is a flow chart showing a procedure of failure target torque determination processing; 4 is a flowchart showing a procedure of brake control processing; 4 is a flowchart showing a procedure of brake control processing; FIG. 5 is an explanatory diagram showing an example of the operation of the vehicle when traveling straight when the right control circuit fails. FIG. 5 is an explanatory diagram showing an example of the operation of the vehicle during right turning when the right control circuit fails. 9 is a flowchart showing the procedure of steering control processing in the second embodiment; FIG. 4 is an explanatory diagram showing an example of setting contents of a steering angle map; FIG. 11 is an explanatory diagram showing a schematic configuration of a vehicle equipped with a wheel control system according to a third embodiment; FIG. 5 is a block diagram showing functional configurations of a motor control device and a control circuit in a second embodiment; It is a flow chart which shows a procedure of brake control processing in a 3rd embodiment. It is a flow chart which shows a procedure of brake control processing in a 3rd embodiment.

A. First embodiment:
A1. Device configuration:
As shown in FIG. 1, a wheel control system 100 of the present embodiment is mounted on a vehicle 200, which is a four-wheeled vehicle, and includes a pair of front wheels 201 and 202 that constitute driving wheels of the vehicle 200, and driven wheels. It controls the operation of a pair of rear wheels 203,204. Vehicle 200 uses two electric motors 30R and 30L, which are driven by power supply from a battery (not shown), as drive sources. The electric motor 30R is attached to the front wheel 201, and the electric motor 30L is a so-called in-wheel motor attached to the front wheel 202. FIG. The wheel control system 100 includes an electric motor control device 10 and a brake control device 120 that can communicate with each other.

The motor control device 10 controls two control circuits 31R and 31L. The control circuit 31R is arranged corresponding to the front wheel 201 and controls the electric motor 30R. 31 L of control circuits are arrange|positioned corresponding to the front wheel 202, and control 30 L of electric motors. Detailed configurations of the motor control device 10 and the two control circuits 31R and 31L will be described later.

The brake control device 120 controls the braking of the pair of front wheels 201 , 202 and the pair of rear wheels 203 , 204 by controlling the operation of the four braking devices 51 , 52 , 53 , 54 . The braking device 51 implements braking of the front wheels 201 . Similarly, the braking device 52 provides braking of the front wheels 202, the braking device 53 provides braking of the rear wheels 203, and the braking device 54 provides braking of the rear wheels 204, respectively. Each of the four brake devices 51 to 54 has a brake rotor, a brake pad, a hydraulic actuator for operating the brake pad, and the like, and brakes each wheel 201 to 204 according to a command from the brake control device 120. Realize

Both the electric motor control device 10 and the brake control device 120 are configured to be able to communicate with each other via an in-vehicle network 220 . As the in-vehicle network 220, for example, any type of network such as CAN (Controller Area Network), LIN (Local Interconnect Network), and Ethernet (registered trademark) may be used.

In addition to the wheel control system 100, the vehicle network 220, the four braking devices 51 to 54, and the two control circuits 31R and 31L, the vehicle 200 includes an EPS (Electronic Power Steering) control device 110, an EPS actuator 111, and , a steering gear 211 , a steering wheel 210 , an accelerator opening sensor 41 , a steering angle sensor 42 , a range sensor 43 , a vehicle speed sensor 44 and a yaw rate sensor 45 .

An EPS (Electronic Power Steering) controller 110 controls the operation of an EPS actuator 111 . In this embodiment, the EPS control device 110 is configured by an ECU. EPS control device 110 implements so-called electric power steering. The EPS actuator 111 has fluid (oil), an oil pump for flowing the fluid, and the like, and generates hydraulic pressure according to a command from the EPS control device 110 to assist the operation of the steering wheel 210 .

A steering gear 211 transmits movement of the steering wheel 210 to a pair of front wheels 201,202. The accelerator opening sensor 41 detects the amount of depression of an accelerator pedal (not shown) of the vehicle 200 as the accelerator opening, that is, the rotation angle of the motor for opening and closing the throttle valve. Steering angle sensor 42 is electrically connected to EPS actuator 111 by a dedicated cable, and detects the steering angle of vehicle 200 by steering wheel 210 using a signal output according to the operation of EPS actuator 111 . The steering angle sensor 42 is electrically connected to the EPS control device 110 by a dedicated cable, and notifies the detected steering angle to the EPS control device 110 . Range sensor 43 detects a shift range specified by a shift lever (not shown) of vehicle 200 . Range sensor 43 is electrically connected to motor control device 10 by a dedicated cable, and notifies motor control device 10 of the detected shift range. A vehicle speed sensor 44 detects the rotation speed of each wheel 201-204. The vehicle speed sensor 44 is electrically connected to the electric motor control device 10 by a dedicated cable. A signal indicating the vehicle speed output from the vehicle speed sensor 44 is a voltage value proportional to the wheel speed or a pulse wave indicating an interval corresponding to the wheel speed, and is sent to the electric motor control device 10 via a dedicated cable. The yaw rate sensor 45 detects the yaw rate during running of the vehicle 200 . The yaw rate sensor 45 is electrically connected to the electric motor control device 10 by a dedicated cable, and notifies the electric motor control device 10 of the detected yaw rate.

As shown in FIG. 2, the electric motor control device 10 includes an accelerator opening degree identifying portion 11, a vehicle speed identifying portion 12, a shift range identifying portion 13, a steering angle identifying portion 14, a yaw rate identifying portion 15, a target torque instruction A unit 16 , a monitoring unit 17 , a comparator 18 , a target yaw rate calculator 19 , a comparator 20 , and a fault occurrence identification unit 21 . In this embodiment, the motor control device 10 is configured by an ECU.

The accelerator opening specifying unit 11 specifies the accelerator opening by receiving a signal indicating the accelerator opening notified from the accelerator opening sensor 41 . Vehicle speed identifying unit 12 identifies the vehicle speed of vehicle 200 by receiving a signal indicating the vehicle speed notified from vehicle speed sensor 44 . Shift range specifying unit 13 specifies the shift range by receiving a signal indicating the shift range notified from range sensor 43 . The steering angle identification unit 14 identifies the steering angle by receiving a signal indicating the steering angle notified from the steering angle sensor 42 . The yaw rate identifying unit 15 identifies the yaw rate by receiving a signal indicating the yaw rate notified from the yaw rate sensor 45 .

The target torque instruction unit 16 determines the target torque and instructs the two control circuits 31R and 31L. A method for determining such target torque will be described. First, the target torque instruction unit 16 calculates a target torque that the two electric motors 30R and 30L should output as a whole (hereinafter referred to as "overall target torque"). Specifically, the target torque instruction unit 16 determines the accelerator opening specified by the accelerator opening specifying unit 11, the vehicle speed specified by the vehicle speed specifying unit 12, and the shift range specified by the shift range specifying unit 13. , the target torque is calculated with reference to the torque map shown in FIG. This torque map is a map in which accelerator opening and target torque are associated with each vehicle speed. As the magnitude (absolute value) of the target torque, a larger value is set as the accelerator opening increases. A positive target torque means that the shift range is the drive (D) range, and a negative target torque means that the shift range is the reverse (R) range. Although FIG. 3 shows only three maps when the vehicle speed V is v1, v2, and v3, four or more maps are prepared in advance in this embodiment. Next, the target torque instruction unit 16 determines a distribution ratio for distributing the calculated overall target torque to the left and right electric motors 30R and 30L, and outputs a signal indicating the target torque according to the determined distribution ratio. It notifies the two control circuits 31R and 31L, respectively, and also outputs to the comparator 18. FIG. The target torque distribution ratio is determined based on the vehicle speed specified by the vehicle speed specifying unit 12 and the steering angle specified by the steering angle specifying unit 14 using a torque distribution ratio determination map shown in FIG. This torque distribution ratio determination map is a map in which the steering angle and the torque distribution ratio are associated with each vehicle speed. In FIG. 4, the target torque of the electric motor 30L is indicated by a thick solid line L1, and the target torque of the electric motor 30R is indicated by a thin solid line L2. For example, when the steering angle is 0°, that is, when the vehicle 200 is traveling straight, the distribution ratio is set so that the target torque of the electric motor 30L and the target torque of the electric motor 30R are 1:1. Further, for example, when the steering angle is a certain angle when turning to the right, the target torque of the electric motor 30L and the target torque of the electric motor 30R are 1:0.5, that is, the distribution ratio is 2:1. is defined. This is because, when turning to the right, it is necessary to output a larger torque from the electric motor 30L than from the electric motor 30R and rotate the front wheels 202 at a higher speed than the front wheels 201 . Although FIG. 4 shows only three maps when the vehicle speed V is v1, v2, and v3, four or more maps are prepared in advance in this embodiment.

A monitoring unit 17 shown in FIG. 2 monitors failure of the target torque instruction unit 16 . If the target torque indicator 16 fails, there is a risk that an erroneous value will be calculated as the overall target torque or an erroneous distribution ratio will be calculated. Therefore, in the electric motor control device 10, a monitoring section 17 is provided to monitor whether or not the target torque instruction section 16 has failed. The monitoring unit 17 has the same configuration as the target torque instructing unit 16, determines the total target torque and the distribution ratio for distribution to the left and right electric motors 30R and 30L, and determines the target torque according to the determined distribution ratio. is output to the comparator 18.

The comparator 18 receives signals indicating the target torque from the target torque indicating section 16 and the monitoring section 17, compares the target torques indicated by these two signals, and outputs the comparison result, that is, the difference between the target torques, to the failure occurrence identifying section. 21.

The target yaw rate calculator 19 calculates the target yaw rate by referring to the target yaw rate map shown in FIG. The target yaw rate map is a map in which the steering angle and target torque are associated with each vehicle speed. In FIG. 5, the horizontal axis indicates the steering angle, and the vertical axis indicates the target yaw rate. When the vehicle speed V is v1, the target yaw rate is zero when the steering angle is zero, and a curve Ly1 in which the target yaw rate gradually increases as the steering angle increases to the left or right is set as the target yaw rate map. . In the target yaw rate map Lyn when the vehicle speed V is vn larger than v1, the target yaw rate when the steering angle is zero is the same as the target yaw rate map Ly1 and is set to zero. In the target yaw rate map Lyn, similarly to the target yaw rate map Ly1, the target yaw rate is set to gradually increase as the absolute value of the steering angle increases. Note that the target yaw rate map Ly1 for the target yaw rate map Lyn when the vehicle speed V is vn is indicated by a dashed line for easy comparison.

As can be understood by comparing the solid-line target yaw rate map Lyn and the dashed-line target yaw rate map Ly1 in FIG. A small value is set as The target yaw rate calculator 19 notifies the comparator 20 of the target yaw rate calculated using the target yaw rate map.

The comparator 20 inputs and compares the yaw rate specified by the yaw rate specifying unit 15 and the yaw rate calculated by the target yaw rate calculating unit 19, and obtains the comparison result, that is, the difference between these two yaw rates (hereinafter referred to as "yaw rate "difference") is notified to the failure occurrence identifying unit 21, the target torque instructing unit 16, and the monitoring unit 17. The yaw rate difference is used in lane departure hazard detection processing and brake control processing, which will be described later.

The failure occurrence identification unit 21 identifies failure of the target torque instruction unit 16 and occurrence of failures of the two control circuits 31R and 31L. Specifically, the failure occurrence identification unit 21 identifies occurrence of a failure in the target torque instruction unit 16 when the target torque difference received from the comparator 18 is equal to or greater than a predetermined threshold. Note that when the shift range is reverse (R), the occurrence of failure may be specified when the magnitude (absolute value) of the target torque output from the target torque instruction unit 16 is equal to or greater than a predetermined threshold value. good. Further, when receiving a signal indicating the occurrence of a failure (hereinafter referred to as a "failure occurrence signal") from the two control circuits 31R and 31L, the failure occurrence identification unit 21 detects at least one of the two control circuits 31R and 31L. Identify the occurrence of one failure. When failure occurrence identification unit 21 identifies failure occurrence as described above, failure occurrence identification unit 21 notifies target torque instruction unit 16 and monitoring unit 17 of a signal indicating that a failure has occurred. As will be described later, the target torque instructing unit 16 and the monitoring unit 17 that have received the notification of the occurrence of a failure indicate a torque different from the target torque (normal target torque described later) when there is no failure. A torque different from the target torque thus determined is notified to the two control circuits 31R and 31L as the target torque.

The control circuit 31R shown in FIG. 2 includes a driver IC 32R, an actual torque calculator 33R, a comparator 34R, and an operation monitor 35R. The driver IC 32R supplies drive voltage to the electric motor 30R according to the target torque notified from the target torque instruction section 16. FIG. The actual torque calculation unit 33R detects the current value of the current flowing through the electric motor 30R and the rotation speed of the electric motor 30R, and based on these current values and rotation speed, the torque actually output by the electric motor 30R (hereinafter referred to as "actual torque") is calculated. ) is calculated. The target torque value notified from the target torque instruction unit 16 and the actual torque value calculated by the actual torque calculation unit 33R are input to the comparator 34R. The comparator 34R compares these two input torque values and outputs the comparison result, that is, the torque difference, to the operation monitoring section 35R. The operation monitoring unit 35R identifies the operation of the driver IC 32R. Specifically, when the comparison result input from the comparator 34R is equal to or greater than a predetermined threshold value, the operation monitoring unit 35R identifies a failure in the driver IC 32R and outputs a failure occurrence signal to the motor control device 10 (failure occurrence identification unit 21). ). If the comparison result is less than the threshold, the driver IC 32R is operating normally, and the operation monitoring section 35R does not output the failure occurrence signal.

The control circuit 31L has a configuration similar to that of the control circuit 31R. That is, it includes a driver IC 32L, an actual torque calculator 33L, a comparator 34L, and an operation monitor 35L. The operation monitoring unit 35L identifies a failure in the driver IC 32L and notifies the motor control device 10 (failure occurrence identification unit 21) of a failure occurrence signal when the comparison result input from the comparator 34L is equal to or greater than a predetermined threshold.

In the wheel control system 100 having the above configuration, a lane departure hazard detection process, a failure target torque determination process, and a brake control process, which will be described later, are executed. Even in the event of a failure, deterioration in running stability of vehicle 200 is suppressed.

A2. Lane departure hazard detection processing:
The lane departure hazard detection process shown in FIG. 6 is executed when the start button of vehicle 200 is pressed and the electric motor control device 10 is powered on. The lane deviation detection process is a process for detecting the possibility that vehicle 200 may deviate from the lane in which vehicle 200 is traveling due to a failure in one of two control circuits 31R and 31L. Note that, when the wheel control system 100 is first activated, a lane departure hazard flag XF, an evacuation running flag XR, and a normal side determination flag NF, which will be described later, are all set to "0". These flags may be set to different values after initial startup. The set values of these flags XF, XR, and NF are written in a writable non-volatile memory, such as an EEPROM, of the motor control device 10, and the values written in the non-volatile memory are restored at the next start-up. Referenced. Details of these flags XF, XR, and NF will be described later.

The electric motor control device 10 determines whether or not the lane departure hazard flag XF is on (step S105). The target yaw rate calculator 19 calculates a target yaw rate Yt from the vehicle speed identified by the vehicle speed identifier 12 and the steering angle identified by the steering angle identifier 14 (step S110). The comparator 20 acquires the detection result of the yaw rate sensor 45, that is, the actual measurement value Y of the yaw rate, via the yaw rate specifying unit 15 (step S115). The failure occurrence identifying unit 21 determines the absolute value of the yaw rate difference notified from the comparator 20, that is, the absolute value of the difference between the target yaw rate Yt calculated in step S110 and the measured yaw rate Y obtained in step S115. is greater than a predetermined threshold α (step S120). The threshold value α is determined by experiments and simulations to determine the absolute value of the yaw rate difference when the measured value Y of the yaw rate deviates from the target yaw rate Yt due to failure of one of the two control circuits 31R and 31L. , is set as a value at which failure of one of the two control circuits 31R and 31L is estimated.

When it is determined that the absolute value of the yaw rate difference is not greater than the threshold value α (step S120: NO), the fault occurrence identification unit 21 sets the elapsed counter C to zero (step S125). The elapsed time counter C is a counter value corresponding to the elapsed time after it is determined that the absolute value of the yaw rate difference is greater than the threshold value α. The initial value of the elapsed counter C is zero. If it is determined that the absolute value of the yaw rate difference is greater than the threshold value α (step S120: YES), the fault occurrence identification unit 21 increases the elapsed counter C by 1 (step S130).

The failure occurrence identifying unit 21 determines whether or not the value of the elapsed counter C is greater than the threshold value Cth (step S135). The threshold value Cth is determined and set in advance by experiments or the like as a counter value corresponding to the time during which it can be estimated that one of the two control circuits 31R and 31L has a high probability of failure. If it is determined that the value of the elapsed counter C is not greater than the threshold value Cth (step S135: NO), the process returns to step S105. On the other hand, if it is determined that the value of the elapsed counter C is greater than the threshold value Cth (step S135: YES), the failure occurrence identification unit 21 sets the lane deviation hazard flag XF to "1" and turns it on. (Step S140). That is, according to steps S135 and S140 described above, the lane departure hazard flag XF is turned on when a predetermined time has elapsed since it was determined that the absolute value of the yaw rate difference was greater than the threshold value α. After completion of step S140, the process returns to step S105 described above.

Note that the yaw rate specifying unit 15 corresponds to a subordinate concept of the detection result acquiring unit of the present disclosure. Also, the target yaw rate calculator 19 corresponds to a subordinate concept of the target value calculator of the present disclosure.

A3. Failure target torque determination process:
The failure target torque determination process shown in FIG. 7 is executed when the start button of vehicle 200 is pressed to turn on the electric motor control device 10 . The failure target torque determination process is a process for determining the target torque to be instructed to each of the control circuits 31R and 31L when one of the two control circuits 31R and 31L has a failure.

The failure occurrence identification unit 21 determines whether or not the lane departure hazard flag XF is on (step S205). If it is determined that the lane departure hazard flag XF is not ON (step S205: NO), step S205 is executed again. In other words, the failure occurrence identification unit 21 waits until the lane departure hazard flag XF is turned on. On the other hand, when it is determined that the lane departure hazard flag XF is ON (step S205: YES), the target torque instruction unit 16 determines the accelerator opening and the vehicle speed specified by the accelerator opening specifying unit 11. An overall target torque To is calculated from the vehicle speed specified by the unit 12 and the shift range specified by the shift range specifying unit 13 (step S210). Using the vehicle speed and the steering angle specified by the steering angle specifying unit 14, the target torque instruction unit 16 refers to the torque distribution ratio map shown in FIG. (step S215).

The fault occurrence identification unit 21 identifies normality of the left and right control circuits 31R and 31L (step S220). Specifically, as described above, it is possible to identify the normality of the control circuits 31R and 31L, that is, the presence or absence of a failure, depending on whether or not the failure occurrence signal has been received from the control circuits 31R and 31L.

When the control circuit 31R is normal and the control circuit 31L is abnormal, the target torque instruction unit 16 obtains the target torque (hereinafter referred to as "right target torque") TR to be instructed to the control circuit 31R in step S210. A target torque determined by applying the torque distribution ratio determined in step S215 to the overall target torque (hereinafter referred to as "normal target torque") is set, and a target torque (hereinafter referred to as " TL (referred to as "left target torque") is set to zero, and the normal side determination flag NF is set to "-1" (step S225). The normal side determination flag is a flag indicating which of the control circuit 31R and the control circuit 31L is normal. circuit 31L), respectively, a "0 (zero)" indicates that both are not normal.

When the control circuit 31R is abnormal and the control circuit 31L is normal, the target torque instruction unit 16 sets the right target torque to zero, sets the left target torque to the normal target torque, and sets the normal side determination flag to "+1 ” is set (step S230).

Otherwise, that is, when both of the two control circuits 31R and 31L are abnormal, the target torque instruction unit 16 sets the right target torque to zero, sets the left target torque to zero, and determines the normal side. The flag is set to "0 (zero)" (step S235). Note that the target torques determined in steps S225, S230, and S235 described above are instructed to the control circuits 31R, 31L, respectively. As a result, the target torque of at least one of the pair of front wheels 201 and 202, which are the driving wheels, becomes zero, so the vehicle speed gradually decreases.

After the completion of steps S225 and S230 described above, the failure occurrence identification unit 21 determines whether or not the evacuation flag XR is ON (step S240). The emergency travel flag XR is a flag indicating whether or not the emergency travel should be performed. When it is ON, it indicates that the emergency travel should be performed. Evacuation running is running that is different from running in a state where control circuit 31R or control circuit 31L is not abnormal (hereinafter referred to as "normal running"), and is running that suppresses deterioration in running stability of vehicle 200. means If the evacuation flag XR is not ON (step S240: NO), the failure occurrence identification unit 21 determines whether or not the vehicle speed is zero (step S245). If it is determined that the vehicle speed is zero (step S245: YES), the fault occurrence identification unit 21 sets the evacuation flag XR to "1" and turns it on (step S250).

After executing step S235 described above, the process returns to step S205 described above. Further, when it is determined that the evacuation flag XR is ON in step S240 described above (step S240: YES), and when it is determined that the vehicle speed is not zero in step S245 described above (step S245: NO), In both cases, the process returns to step S205 described above. Therefore, if at least one of the control circuits 31R and 31L becomes abnormal while the emergency travel flag XR is off, the emergency travel flag XR will be turned ON when the vehicle speed decreases to zero. becomes.

A4. Brake control processing:
The brake control process shown in FIGS. 8 and 9 is executed when the start button of vehicle 200 is pressed and the power of brake control device 120 is turned on. The brake control process is a process for controlling the operation of the brake devices 51-54.

The brake control device 120 acquires set values of three types of flags, the lane departure hazard flag XF, the evacuation flag XR, and the normal side determination flag NF, from the electric motor control device 10 via the in-vehicle network 220 (step S305). .

Brake control device 120 determines whether or not lane departure hazard flag XF is on (step S310). When it is determined that the lane departure hazard flag XF is not ON (step S310: NO), the brake control device 120 executes brake control for the brake devices 51 to 54 according to the normal amount of brake operation by the driver. (step S315).

When it is determined that the lane departure hazard flag XF is ON (step S310: YES), the brake control device 120 determines whether the evacuation flag XR is ON (step S320). If it is determined that the emergency travel flag XR is not ON (step S310: NO), the above-described step S315 is executed. When it is determined that the emergency travel flag XR is not ON, that is, when steps S225 to S230 of the failure target torque determination process are being executed and the vehicle 200 has not yet stopped. . In this case, brake control is executed according to the amount of brake operation by the driver.

On the other hand, if it is determined that the evacuation flag XR is on (step S320: YES), the brake control device 120 acquires the vehicle speed and the steering angle from the electric motor control device 10 via the in-vehicle network 220, and determines the vehicle speed and steering angle. A target yaw rate Yt is calculated from the steering angle (step S325). Note that the target yaw rate Yt, which is the result calculated in step S110 of the lane departure hazard detection process, may be acquired from the motor control device 10 via the in-vehicle network 220. FIG.

The brake control device 120 acquires the detection result of the yaw rate sensor 45, that is, the measured value Y of the yaw rate, from the electric motor control device 10 via the in-vehicle network 220 (step S330). The brake control device 120 calculates the absolute value (|Y−Yt|) of the difference (yaw rate difference) between the measured yaw rate Y obtained in step S330 and the target yaw rate Yt calculated in step S325 (step S335).

Brake control device 120 determines whether or not vehicle 200 is traveling straight from the vehicle speed and steering angle acquired in step S325 (step S340). When it is determined that the vehicle 200 is traveling straight (step S340: YES), the brake control device 120 specifies the normal side determination flag NF as shown in FIG. 9 (step S345).

When the normal side determination flag NF is "+1", that is, when the control circuit 31R is abnormal and the control circuit 31L is normal, the brake control device 120 operates the brake device 54 of the left rear wheel 204 (step S350). ). At this time, the braking force is a positive value obtained by multiplying the absolute value of the yaw rate difference (|Y−Yt|) calculated in step S335 by a predetermined coefficient k. That is, the braking device 54 is operated with a braking force proportional to the absolute value of the yaw rate difference. In the present embodiment, the coefficient k is a coefficient derived from the braking force obtained through experiments or the like in advance so that the measured value Y of the yaw rate approaches the target yaw rate Yt when the braking device 53 is operated. be.

As shown in FIG. 10, if the vehicle 200 runs straight when the control circuit 31R fails, the target torque of the front wheels 201 becomes zero. Only the wheels 202 are driven, and the vehicle 200 attempts to turn right around its own center of gravity C1. However, in this case, the above-described step S355 is executed and the brake device 54 is operated, so that the right turning operation of the vehicle 200 can be suppressed. Therefore, even after the control circuit 31R fails, it is possible to prevent the running stability of the vehicle 200 from deteriorating, and the measured value Y of the yaw rate approaches the target yaw rate Yt. 10, such as the motor control device 10, the in-vehicle network 220, and the EPS control device 110, are omitted for convenience of explanation.

As shown in FIG. 9, when the normal side determination flag NF is "-1", that is, when the control circuit 31R is normal and the control circuit 31L is abnormal, the brake control device 120 The brake device 53 is operated (step S355). At this time, the braking force is a positive value obtained by multiplying the absolute value of the yaw rate difference (|Y−Yt|) calculated in step S335 by a predetermined coefficient k. That is, the braking device 53 is operated with a braking force proportional to the absolute value of the yaw rate difference. Since the coefficient k in step S355 is the same as the coefficient k in step S350, detailed description thereof will be omitted.

When it is determined in step S340 that the vehicle 200 is not traveling straight (step S340: NO), as shown in FIG. The wheel braking device is activated (step S360). At this time, the braking force is a positive value obtained by multiplying the absolute value of the yaw rate difference (|Y−Yt|) calculated in step S335 by a predetermined coefficient k. In other words, the braking device for the inner wheel is actuated with a braking force proportional to the absolute value of the yaw rate difference.

As shown in FIG. 11, for example, if the control circuit 31R fails when the vehicle 200 turns right, the target torque of the front wheels 201 becomes zero. Only the front wheels 202 are driven, and the vehicle 200 is restrained from turning to the right about the center of gravity C1, which may cause so-called understeer. However, in this case, step S360 described above is executed, and the braking device 53 for the right rear wheel 203, which is the braking device for the inner wheels, is actuated, so that the right turning operation of the vehicle 200 is promoted. Therefore, even after the control circuit 31R is generated, it is possible to suppress deterioration of the running stability of the vehicle 200, and the measured value Y of the yaw rate approaches the target yaw rate Yt.

As shown in FIGS. 8 and 9, after completion of steps S350, S355 and S360, return to step S305. If the value of the normal side determination flag NF specified in step S345 described above is other than "+1" and "-1", that is, if it is "0 (zero)", step S315 described above is executed, Brake control is executed according to the normal amount of brake operation.

According to the wheel control system 100 of the first embodiment described above, zero is instructed as the target torque to the control circuit in which the occurrence of a failure has been identified, and one of the pair of rear wheels 203 and 204, which are driven wheels, , the brake is applied so that the measured value Y of the yaw rate approaches the target yaw rate Yt. In the configuration including the two control circuits 31R and 31L, it is possible to suppress deterioration in running stability of the vehicle 200 when a failure occurs in one of the control circuits, thereby realizing fail-safe.

Further, when the occurrence of a failure is identified in a situation in which it is determined that the vehicle 200 is traveling straight ahead, the control circuit identifies the occurrence of a failure between the pair of rear wheels 203 and 204 with the center of gravity C1 of the vehicle 200 therebetween. Since the brakes are applied to the wheels located symmetrically to the wheels corresponding to the vehicle 200 can be suppressed from rotating.

Further, when it is determined that the vehicle 200 is turning, and the occurrence of a failure is identified, the inner wheel of the pair of rear wheels 203 and 204 is braked. It is possible to suppress so-called understeer, which is caused by hindering the turning motion due to driving only one of the pair of front wheels 201 and 202, which are wheels.

B. Second embodiment:
The device configuration of the wheel control system 100 of the second embodiment is the same as that of the wheel control system 100 of the first embodiment. Further, the wheel control system 100 of the second embodiment executes lane departure hazard detection processing, failure target torque determination processing, and brake control processing in the same procedure as the wheel control system 100 of the first embodiment. The wheel control system 100 of the second embodiment differs from the wheel control system 100 of the first embodiment in that steering control processing is additionally executed.

The steering control process in the second embodiment shown in FIG. 12 is executed when the start button of the vehicle 200 is pressed and the power of the EPS control device 110 is turned on. The operation control process is a process of controlling steering of the vehicle 200 .

The EPS control device 110 acquires the set values of the three types of flags, the lane departure hazard flag XF, the evacuation flag XR, and the normal side determination flag NF, from the electric motor control device 10 via the in-vehicle network 220 (step S405). .

Control device 110 determines whether lane departure hazard flag XF is on (step S410). When it is determined that the lane departure hazard flag XF is not ON (step S410: NO), the EPS control device 110 executes operation control according to the normal steering amount by the driver (step S415).

When it is determined that the lane departure hazard flag XF is on (step S410: YES), the EPS control device 110 determines whether the evacuation flag XR is on (step S420). If it is determined that the evacuation flag XR is not ON (step S410: NO), step S415 is executed. When it is determined that the emergency travel flag XR is not ON, that is, when steps S225 to S230 of the failure target torque determination process are being executed and the vehicle 200 has not yet stopped. . In this case, steering control is executed according to the amount of steering by the driver.

On the other hand, if it is determined that the evacuation running flag XR is ON (step S420: YES), the EPS control device 110 acquires the set value of the normal side determination flag NF from the motor control device 10 via the in-vehicle network 220. (step S425).

The EPS control device 110 controls the steering angle of the wheel corresponding to the control circuit in which the occurrence of the failure has been identified to an angle obtained by reducing the offset amount from the normal steering angle (hereinafter referred to as "normal steering angle"). (step S430). Such control is realized by determining the steering angle with reference to a steering angle map, which will be described later, based on the normal side determination flag NF specified in step S425, and controlling the steering angle to that angle. Such control will be described with reference to FIG.

FIG. 13 shows two steering angle maps Lsr1 and Lsl1 as steering angle maps when the vehicle speed V is v1, and two steering angle maps Lsrn and Lsln as steering angle maps when the vehicle speed V is vn. is represented. In order to facilitate understanding, the normal steering angle map Ls0, that is, the steering angle map referred to when no failure is identified in either of the two control circuits 31R and 31L, is represented by a thin solid line. . In FIG. 13, the horizontal axis indicates the steering amount of the steering wheel 210 by the driver, and the vertical axis indicates the steering angle. In the steering angle map Ls0, the steering angle is set to zero when the steering amount is zero. Therefore, during normal operation, when the steering amount is zero, the vehicle 200 travels straight.

The steering angle map Lsl1 represented by a thick solid line when the vehicle speed V is v1 is the steering angle map referred to when the control circuit 31R is abnormal and the control circuit 31L is normal. On the other hand, the steering angle map Lsr1 when the vehicle speed V is v1, represented by a thick dashed line, is the steering angle map referred to when the control circuit 31R is normal and the control circuit 31L is abnormal.

The steering angle map Lsl1 is set to a value obtained by decreasing the rightward angle by a predetermined offset amount and increasing the leftward angle when the steering amount is the same as compared with the steering angle map Ls0. This is because when the control circuit 31R is abnormal and the control circuit 31L is normal, the vehicle 200 attempts to turn right about its own center of gravity C1. This is because the vehicle 200 is allowed to go straight when the steering amount, that is, the amount of operation of the steering wheel 210 is zero, by setting the rightward angle to be reduced when the V is the same.

In the steering angle map Lsr1, when the steering amount is the same as in the steering angle map Ls0, the leftward angle is decreased by a predetermined offset amount and the rightward angle is increased. This is because when the control circuit 31R is normal and the control circuit 31L is abnormal, the vehicle 200 attempts to turn left around its own center of gravity C1, so the steering amount is lower than in the normal state. This is because, in the same case, the leftward angle is set to be reduced so that the vehicle 200 can go straight when the steering amount, that is, the operation amount of the steering wheel 210 is zero.

Such a tendency is the same for the steering angle maps Lsln and Lsrn when the vehicle speed V is vn. However, in the present embodiment, the higher the vehicle speed, the larger the offset amount is set. The greater the vehicle speed V, the easier it is for the vehicle 200 to make a large turn due to a slight change in the steering amount. However, as described above, the higher the vehicle speed, the more certainty that the vehicle 200 will turn, in other words, the vehicle 200 will not travel straight if a larger value is set as the offset amount. This is because it can be suppressed to

The wheel control system 100 of the second embodiment described above has the same effects as the wheel control system 100 of the first embodiment. In addition, when the occurrence of a failure is identified, the target steering angle is set to an angle obtained by reducing the offset amount from the normal steering amount (steering wheel steering amount), thereby reducing the steering wheel steering amount to zero. In this case, the steering of the vehicle is controlled so that the vehicle travels straight. Therefore, it is possible to prevent the vehicle 200 from turning even though the steering amount is zero. When the vehicle speed V is high, a larger value is set as the offset amount than when the vehicle speed V is low. Even in a situation where it is easy to turn, it is possible to more reliably prevent the vehicle 200 from turning when the steering amount is zero.

C. Third embodiment:
As shown in FIG. 14, the vehicle 200a of the third embodiment is different from the first embodiment in that it includes an acceleration sensor 46 instead of the yaw rate sensor 45 and a wheel control system 100a instead of the wheel control system 100. It differs from the vehicle 200 in form. Other configurations of vehicle 200a are the same as those of vehicle 200, so the same components are denoted by the same reference numerals, and detailed description thereof will be omitted. Acceleration sensor 46 detects lateral acceleration of vehicle 200 (hereinafter referred to as "lateral acceleration"), in other words, lateral acceleration. In this embodiment, the acceleration sensor 46 is composed of a triaxial sensor. The wheel control system 100a differs from the wheel control system 100 of the first embodiment in that it includes an electric motor control device 10a instead of the electric motor control device 10 . Since other configurations of the wheel control system 100a are the same as those of the wheel control system 100, the same components are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the electric motor control device 10a of the third embodiment shown in FIG. It differs from the motor control device 10 of the first embodiment. Since other configurations of the motor control device 10a are the same as those of the motor control device 10, the same components are denoted by the same reference numerals, and detailed description thereof will be omitted.

The acceleration identifying unit 15a identifies the lateral acceleration by receiving a signal indicating the lateral acceleration notified from the acceleration sensor 46. FIG. The target acceleration calculation unit 19a calculates a target value of lateral acceleration (hereinafter referred to as "target acceleration") based on the vehicle speed specified by the vehicle speed specifying unit 12 and the steering angle specified by the steering angle specifying unit 14. calculate. For example, a map similar to the target yaw rate map shown in FIG. 5 may be set in advance, and the lateral acceleration may be specified based on the vehicle speed and the steering angle by referring to the map.

In the wheel control system 100a of the third embodiment, the lane deviation hazard detection process and the failure target torque determination process are executed by the same procedure as in the first embodiment. On the other hand, the brake control process procedure of the third embodiment differs from the brake control process of the first embodiment.

Specifically, as shown in FIGS. 16 and 17, the brake control process of the third embodiment includes steps S325a, S330a, S335a, S350a and This differs from the brake control process of the first embodiment in that S355a is executed. Other procedures of the brake control process of the third embodiment are the same as those of the brake control process of the first embodiment, so the same steps are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 16, when it is determined in step S320 that the emergency travel flag XR is ON (step S320: YES), the brake control device 120 receives the vehicle speed and A steering angle is obtained, and a lateral target acceleration Gt is calculated from the vehicle speed and the steering angle (step S325a).

The brake control device 120 acquires the detection result of the acceleration sensor 46, that is, the measured value G of the lateral acceleration from the electric motor control device 10 via the in-vehicle network 220 (step S330a). The brake control device 120 calculates the absolute value (|G−Gt|) of the difference (acceleration difference) between the measured lateral acceleration G obtained in step S330 and the target acceleration Gt calculated in step S325. (Step S335a).

As shown in FIG. 17, when the normal side determination flag NF is "+1", that is, when the control circuit 31R is abnormal and the control circuit 31L is normal, the brake control device 120 controls the brake device for the left rear wheel 204. 54 is activated (step S350a). At this time, the braking force is a positive value obtained by multiplying the absolute value of the acceleration difference (|G−Gt|) calculated in step S335a by a predetermined coefficient m. That is, the braking device 54 is operated with a braking force proportional to the absolute value of the acceleration difference. In the present embodiment, the coefficient m is derived from the braking force obtained through experiments or the like in advance so that the actual measured value G of lateral acceleration approaches the target acceleration Gt when the braking device 54 is actuated. is the coefficient.

When the normal side determination flag NF is "-1", that is, when the control circuit 31R is normal and the control circuit 31L is abnormal, the brake control device 120 operates the brake device 53 of the right rear wheel 203 ( Step S355a). At this time, the braking force is a positive value obtained by multiplying the absolute value of the acceleration difference (|G−Gt|) calculated in step S335a by a predetermined coefficient m. That is, the braking device 53 is operated with a braking force proportional to the absolute value of the acceleration difference. The coefficient m in step S355a is the same as the coefficient m in step S350a, so detailed description is omitted.

When it is determined in step S340 that the vehicle 200 is not traveling straight (step S340: NO), as shown in FIG. The wheel braking device is activated (step S360a). At this time, the braking force is a positive value obtained by multiplying the absolute value of the speed difference (|G−Gt|) calculated in step S335a by a predetermined coefficient m. That is, the braking device for the inner wheel is actuated with a braking force proportional to the absolute value of the acceleration difference.

After completion of steps S350a, S355a and S360a, return to step S305. If the value of the normal side determination flag NF specified in step S345 described above is other than "+1" and "-1", that is, if it is "0 (zero)", step S315 described above is executed, Brake control is executed according to the normal amount of brake operation.

The wheel control system 100a of the third embodiment described above has the same effects as the wheel control system 100 of the first embodiment.

D. Other embodiments:
(D1) In the brake control process of each embodiment, processes other than the brake control (step S315) according to the normal brake operation amount, specifically, steps S350, S355, S360, and S350a, S355a, S360a are executed. This was done on the premise that the evacuation flag XR was turned on. That is, these processes are executed after the lane departure hazard flag XF is turned on and the vehicle speed becomes zero, but the present disclosure is not limited to this. For example, these processes may be executed only on the condition that the lane departure hazard flag XF is turned on. In this case, these processes are executed even during the period from when the failure occurs until the vehicle speed becomes zero.

(D2) In the failure target torque determination process of each embodiment, the target torques determined in steps S225, S230, and S235 are applied immediately, but the present disclosure is not limited to this. For example, until the vehicle speed becomes zero, if it is determined that at least one of the two control circuits 31R and 31L has failed, the two control circuits 31R and 31L are set to zero target torque. may be instructed. In this configuration, when the vehicle 200 resumes running after the vehicle speed becomes zero, the target torques determined in steps S225, S230, and S235 are instructed to the two control circuits 31R and 31L. You may make it

(D3) Steps S340 and S360 may be omitted in the brake control process of the first and second embodiments. Similarly, steps S340 and S360a may be omitted in the brake control process of the third embodiment. In these configurations as well, when at least one of the two control circuits 31R and 31L has failed, the steering angle is zero, and the driver intends to drive the vehicles 200 and 200a straight. , the vehicles 200 and 200a are prevented from turning. Unlike the above, steps S340, S350, and S355 may be omitted in the brake control process of the first and second embodiments. Similarly, in the brake control process of the third embodiment, steps S340, S350a, and S355a may be omitted. In these configurations, steps S360 and S360a are executed after steps S335 and S335a are completed. Even in these configurations, when at least one of the two control circuits 31R and 31L has a failure and the steering angle is not zero, the driver attempts to turn the vehicle 200 or 200a. In addition, the vehicle 200, 200a can be prevented from so-called understeer.

(D4) In the second embodiment, in the steering angle map, a larger value is set as the offset amount when the vehicle speed V is high than when the vehicle speed V is low, but the present disclosure is not limited to this. Regardless of the magnitude of the vehicle speed V, only one map may be set as the steering angle map. Further, each of the steering angle maps Lsl1, Lsr1, Lsln, and Lsrn is set such that the steering angle changes continuously as the steering amount changes, but may be set so as to change stepwise. .

(D5) In each embodiment, the driving wheels of the vehicles 200 and 200a were the pair of front wheels 201 and 202, but instead of the pair of front wheels 201 and 202, Additionally, the pair of rear wheels 203, 204 may be drive wheels. In this configuration, motors are attached to the pair of rear wheels 203 and 204, respectively, and a control circuit is installed corresponding to each motor.

(D6) In the failure target torque determination process of each embodiment, in steps S225, S230, and S235, the target torque is determined for the control circuit for which failure (abnormality) has been identified among the two control circuits 31R and 31L. Although setting to zero stops the operation of the corresponding electric motor 30R or 30L, the present disclosure is not limited to this. For example, by disconnecting the relay provided in the power supply circuit connecting the failure identification control circuit and the battery to cut off the power supply from the battery to the failure identification control circuit, the corresponding electric motor 30R or 30L can be operated. You can stop it.

(D7) The configuration of the wheel control systems 100 and 100a of each embodiment is merely an example, and various modifications are possible. For example, in each embodiment, at least one of the two electric motors 30R, 30L may be a motor generator. In such a configuration, the motor generator corresponds to a subordinate concept of the generator in the present disclosure. Further, in each embodiment, the vehicle 200, 200a is configured to include both the yaw rate sensor 45 and the acceleration sensor 46, and the detection results of these two sensors 45, 46 are both used to execute the brake control process. good too. For example, the brake force applied in steps S350, S355, S360, S350a, S355a, and S360a is obtained by multiplying the absolute value of the yaw rate difference and the absolute value of the acceleration difference by a predetermined coefficient. You can also ask for

(D8) In each embodiment, failure of the two control circuits 31R and 31L means failure of the driver ICs 32R and 32L, but the present disclosure is not limited to this. For example, it may be a failure of any component constituting the control circuits 31R and 31L, such as the actual torque calculators 33R and 33L, the comparators 34R and 34L, and the operation monitor sections 35R and 35L. For example, the two control circuits 31R and 31L are configured to periodically notify the motor control devices 10 and 10a of normality, respectively. It may be configured to identify the failure of one control circuit 31R, 31L. According to such a configuration, the motor control devices 10, 10a can identify the occurrence of a failure not only in the driver ICs 32R, 32L but also in any component of the control circuits 31R, 31L.

(D9) The motor controllers 10, 10a, brake controller 120, and techniques thereof described in the present disclosure include a processor and memory programmed to perform one or more functions embodied by a computer program. It may also be implemented by a dedicated computer provided by the configurator. Alternatively, the motor controllers 10, 10a, brake controller 120 and techniques described in this disclosure may be implemented by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. good. Alternatively, the motor controllers 10, 10a, brake controllers 120, and techniques described in this disclosure can be implemented using a processor and memory and one or more hardware logic circuits programmed to perform one or more functions. may be implemented by one or more dedicated computers configured in combination with a processor configured by The computer program may also be stored as computer-executable instructions on a computer-readable non-transitional tangible recording medium.

The present disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from the scope of the present disclosure. For example, the technical features in each embodiment corresponding to the technical features in the form described in the outline of the invention are used to solve some or all of the above problems, or Substitutions and combinations may be made as appropriate to achieve some or all. Moreover, if the technical feature is not described as essential in this specification, it can be deleted as appropriate.

Reference Signs List 10 electric motor control device 16 target torque instruction unit 19, 19a target value calculation unit 21 failure occurrence identification unit 30R, 30L electric motors 31R, 31L control circuit 42 steering angle sensor 44 vehicle speed sensor 45 yaw rate sensor 46 Acceleration sensor 100 wheel control system 120 brake control device 200, 200a vehicle 201, 202 front wheels 203, 204 rear wheels

Claims (5)

A pair of front wheels (201, 202) and a pair of rear wheels (203, 204) of a vehicle (200, 200a) are arranged in each wheel constituting at least one drive wheel to drive the wheel. Mounted on the vehicle having electric motors (30R, 30L) and control circuits (31R, 31L) arranged corresponding to the respective wheels constituting the driving wheels and controlling the electric motors for driving the wheels, A wheel control system (100) for controlling the operation of the pair of front wheels and the pair of rear wheels, comprising:
an electric motor control device (10) for controlling the control circuit arranged corresponding to each wheel constituting the driving wheel;
a brake control device (120) that controls the brakes of the pair of front wheels and the pair of rear wheels and is communicable with the electric motor control device;
with
The motor control device includes:
a target torque instruction unit (16) for instructing a target torque to the control circuit corresponding to each wheel constituting the driving wheels;
a failure occurrence identification unit (21) that identifies occurrence of a failure in one of the control circuits corresponding to the wheels constituting the drive wheels;
A detection result acquisition unit (15) for acquiring a detection result of at least one of a yaw rate sensor ( 45 ) mounted on the vehicle and detecting a yaw rate and an acceleration sensor (46) mounted on the vehicle and detecting lateral acceleration. , 15a) and
A target yaw rate and a target lateral direction of the vehicle are detected by using detection results of a vehicle speed sensor (44) mounted on the vehicle and detecting a vehicle speed and a steering angle sensor (42) mounted on the vehicle and detecting a steering angle. a target value calculation unit (19, 19a) that calculates a target value that is at least one of acceleration;
has
When the occurrence of the failure is identified, the target torque instruction unit instructs the failure identification control circuit, which is the control circuit in which the occurrence of the failure has been identified, to set the target torque to zero,
When the occurrence of the failure is identified, the brake control device acquires the detection result for a wheel different from the driving wheel among the wheels constituting the pair of front wheels and the pair of rear wheels. apply a brake so that the detection result obtained by the unit approaches the calculated target value ;
A steering control device (110) for controlling steering of the vehicle, which is configured to be able to communicate with the electric motor control device, acquires a steering wheel steering amount that is an operation amount of a steering wheel (210) mounted on the vehicle, further comprising a steering control device that controls steering of the vehicle according to the acquired steering wheel steering amount and vehicle speed,
When the failure occurrence is identified, the steering control device adjusts the steering angle to the wheel side corresponding to the failure identification control circuit, which is the steering angle with respect to the steering wheel steering amount, in the case where the failure occurrence is not identified. controlling the steering of the vehicle so that the vehicle runs straight when the steering amount of the steering wheel is zero by setting the steering angle to the steering amount of the steering wheel by reducing the offset amount;
When the occurrence of a failure is specified, the target torque instructing unit outputs, as the target torque, to all the control circuits corresponding to the wheels constituting the drive wheels in addition to the failure identification control circuit. indicate zero,
The target torque instructing unit, when the occurrence of the failure is identified and the vehicle is instructed to move forward or backward after the vehicle speed becomes zero, the Of the control circuits, instructing the failure identification control circuit to set the target torque to zero, and detecting the vehicle speed and an accelerator opening sensor for detecting the accelerator opening of the vehicle for the other control circuits. instructing, as the target torque, a torque calculated using the result and a detection result of a range sensor (43) that detects the position of the shift range of the vehicle;
When the vehicle is instructed to move forward or backward after the occurrence of the failure is identified and the vehicle speed becomes zero, the steering control device controls the steering angle relative to the steering amount to determine the failure. When the steering wheel steering amount is zero, the steering angle to the wheel side corresponding to the control circuit is set to an angle obtained by reducing the offset amount from the steering angle corresponding to the steering wheel steering amount when the occurrence of the failure is not specified. controlling the steering of the vehicle so that the vehicle goes straight to
wheel control system. The wheel control system of claim 1,
When the occurrence of the failure is identified in a situation where it is determined that the vehicle is traveling straight based on the acquired detection result, the brake control device selects two wheels different from the drive wheels, applying a brake to a wheel arranged at a position symmetrical to the wheel corresponding to the fault identification control circuit across the center of gravity of the vehicle;
wheel control system. In the wheel control system according to claim 1 or claim 2,
When the occurrence of the failure is identified in a situation in which it is determined that the vehicle is turning based on the acquired detection result, the brake control device controls the operation of two wheels other than the drive wheels. Of these, apply the brake to the inner wheel side,
wheel control system. The wheel control system of claim 1 ,
When the vehicle speed detected by the vehicle speed sensor is high, the steering control device sets a larger value as the offset amount than when the vehicle speed is low.
wheel control system. At least one driving wheel of a pair of front wheels (201, 202) and a pair of rear wheels (203, 204) of a vehicle (200, 200a), and each wheel constituting the driving wheels. Electric motors (30R, 30L) for driving the wheels, and control circuits (31R, 31L) arranged corresponding to the respective wheels constituting the driving wheels for controlling the electric motors for driving the wheels. A wheel control method for controlling the operation of the pair of front wheels and the pair of rear wheels in a vehicle using a wheel control system,
(a) in the wheel control system, a step of identifying failure occurrence in any one of the control circuits corresponding to the wheels constituting the drive wheels;
(b) obtaining the detection result of at least one of a yaw rate sensor (46) mounted on the vehicle and an acceleration sensor ( 45 ) mounted on the vehicle and detecting lateral acceleration in the wheel control system; and
(c) In the wheel control system, a vehicle speed sensor (44) mounted on the vehicle and a steering angle sensor (42) mounted on the vehicle utilize the detection results of the target yaw rate and the target yaw rate of the vehicle. calculating a target value that is at least one of lateral acceleration;
(d) in the wheel control system, when the occurrence of the failure is identified, a step of instructing the failure identification control circuit, which is the control circuit in which the occurrence of the failure has been identified, to set zero as the target torque;
(e) in the wheel control system, when the occurrence of the failure is specified, among the wheels constituting the pair of front wheels and the pair of rear wheels, for wheels different from the drive wheels, applying a brake so that the detected result approaches the calculated target value;
(f) In the wheel control system, a steering wheel steering amount, which is an operation amount of a steering wheel (210) mounted on the vehicle, is acquired, and the steering wheel of the vehicle is controlled according to the acquired steering wheel steering amount and the vehicle speed. controlling steering;
with
In the step (f), when the occurrence of the failure is identified, the steering angle to the wheel side corresponding to the steering angle corresponding to the steering amount of the steering wheel, which corresponds to the failure identification control circuit, is changed when the occurrence of the failure is not identified. controlling the steering of the vehicle so that the vehicle travels straight when the steering amount of the steering wheel is zero by setting the steering angle to the steering amount of the steering wheel in the step of reducing the offset amount from the steering angle,
In the step (d), when the occurrence of the failure is specified, in addition to the failure identification control circuit, all the control circuits corresponding to the wheels constituting the driving wheels are set to the target torque. including the step of indicating zero;
The wheel control method further comprises:
(g) In the wheel control system, when the vehicle is instructed to move forward or backward after the occurrence of the failure is identified and the vehicle speed becomes zero, the wheels constituting the drive wheels are supported. an accelerator opening sensor for detecting the vehicle speed and the accelerator opening of the vehicle for the other control circuits. and a step of indicating, as the target torque, a torque calculated using the detection result of and the detection result of a range sensor (43) that detects the position of the shift range of the vehicle;
(h) in the wheel control system, when the vehicle is instructed to move forward or backward after the occurrence of the failure is identified and the vehicle speed becomes zero, the steering angle with respect to the steering amount; By setting the steering angle to the wheel side corresponding to the fault identification control circuit to an angle obtained by reducing the offset amount from the steering angle corresponding to the steering wheel steering amount when the occurrence of the fault is not identified, the steering wheel steering amount is reduced. controlling the steering of the vehicle so that the vehicle steers straight when zero;
A wheel control method comprising:

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