WO2020184300A1 - Wheel control system and wheel control method - Google Patents

Abstract

A wheel control system (100) comprises: a motor control device (10) that controls control circuits; and a brake control device (120) that controls a brake of each wheel. The motor control device includes: a target torque instruction unit (16) that instructs a target torque to the control circuits; a failure occurrence identification unit (21) that identifies a failure occurrence in any of the control circuits; a detection result acquisition unit that acquires a detection result of at least one of a yaw rate and a lateral acceleration; and a target value calculation unit (19, 19a) that calculates a target value using detection results of a vehicle speed sensor (44) and a steering angle sensor (42). If a failure occurrence has been identified, the target torque instruction unit instructs zero as the target torque to the control circuit in which the failure has been identified, and the brake control device applies the brake to a wheel different from a driving wheel so that the detection results approach the target value.

Description

Wheel control system and wheel control method Cross-reference of related applications

This application is based on Japanese Application No. 2019-43265 filed on March 11, 2019, and the contents of the description are incorporated herein by reference.

The present disclosure relates to the control of wheels driven by an electric motor.

It is equipped with a microcontroller as a control unit that controls actuators installed in the vehicle and a microcontroller monitoring unit as a monitoring unit that monitors the occurrence of abnormalities in the microcontroller, and executes file safe when an abnormality occurs inside the microcontroller. (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 the left and right wheels of a vehicle, and each electric motor drives the left and right wheels. Further, in such a technique, two control circuits may be used as control units for controlling the two left and right electric motors, respectively.

Japanese Unexamined Patent Publication No. 2016-147585

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 directs the torque to move forward to the motor to be controlled, and a failure control circuit directs the torque to move backward to the motor to be controlled, and as a result, the vehicle spins. The running stability may be impaired. However, in the past, the actual situation is that the measures (file-safe) to be taken when one of the control circuits fails has not been sufficiently studied. 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 fail-safe when one of the control circuits fails. ing.

This disclosure can be realized in the following forms.

As one embodiment of the present disclosure, an electric motor arranged on each wheel constituting at least one drive wheel of a pair of front wheels and a pair of rear wheels of the vehicle to drive the wheels, and the drive wheels are configured. Wheel control that is mounted on the vehicle and has a control circuit that is arranged corresponding to each wheel and controls the electric motor that drives the wheels, and controls the operation of the pair of front wheels and the pair of rear wheels. The system is provided. This wheel control system controls an electric motor control device that controls the control circuit arranged corresponding to each wheel constituting the drive wheel, and brakes of the pair of front wheels and the pair of rear wheels. It is provided with a brake control device capable of communicating with an electric motor control device. The electric motor control device includes a target torque indicating unit that instructs a target torque to the control circuit corresponding to each wheel constituting the drive wheel, and the control circuit corresponding to each wheel constituting the drive wheel. Of the failure occurrence identification unit that identifies the failure occurrence of any of the control circuits, the yaw rate sensor mounted on the vehicle to detect the yaw rate, and the acceleration sensor mounted on the vehicle to detect the lateral acceleration. The detection result acquisition unit that acquires at least one of the detection results, the vehicle speed sensor mounted on the vehicle to detect the vehicle speed, and the steering angle sensor mounted on the vehicle to detect the steering angle are used. It has a target value calculation unit that calculates a target value that is at least one of a target yaw rate and a target lateral acceleration of the vehicle. When the failure occurrence is specified, the target torque indicator unit instructs the failure identification control circuit, which is the control circuit in which the failure occurrence is specified, to have zero as the target torque. When the failure occurrence is specified, 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. The brake is applied so that the detection result acquired by the unit approaches the calculated target value.

According to the wheel control system of the above embodiment, when a failure is identified, zero is instructed as a target torque to the failure identification control circuit, and of the pair of front wheels and the pair of wheels constituting the rear wheels. Since the brake is applied to the wheels different from the drive wheels so that the detection result acquired by the detection result acquisition unit approaches the target value, the two electric motors that drive the two left and right wheels and each electric motor are controlled. In the configuration including the two control circuits, it is possible to suppress the deterioration of the running stability of the vehicle when a failure occurs in one of the control circuits, and it is possible to realize fail-safety.

This disclosure can also be realized in various forms other than the wheel control system. 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 for storing the computer program, and the like.

The above objectives and other objectives, features and advantages of the present disclosure will be clarified by the following detailed description with reference to the accompanying drawings. The drawing is
FIG. 1 is an explanatory view showing a schematic configuration of a vehicle equipped with a wheel control system as an embodiment of the present disclosure. FIG. 2 is a block diagram showing a functional configuration of the electric motor control device and the control circuit according to the first embodiment. FIG. 3 is an explanatory diagram showing an example of the setting contents of the torque map. FIG. 4 is an explanatory diagram showing a torque distribution rate determination map. FIG. 5 is an explanatory diagram showing a target yaw rate map. FIG. 6 is a flowchart showing the procedure of the lane deviation hazard detection process. FIG. 7 is a flowchart showing the procedure of the target torque determination process at the time of failure. FIG. 8 is a flowchart showing the procedure of the brake control process. FIG. 9 is a flowchart showing the procedure of the brake control process. FIG. 10 is an explanatory diagram showing an example of the operation of the vehicle when traveling straight when the control circuit on the right side fails. FIG. 11 is an explanatory diagram showing an example of the operation of the vehicle when turning right when the control circuit on the right side fails. FIG. 12 is a flowchart showing the procedure of the steering control process in the second embodiment. FIG. 13 is an explanatory diagram showing an example of the setting contents of the steering angle map. FIG. 14 is an explanatory view showing a schematic configuration of a vehicle equipped with the wheel control system according to the third embodiment. FIG. 15 is a block diagram showing a functional configuration of the electric motor control device and the control circuit according to the second embodiment. FIG. 16 is a flowchart showing the procedure of the brake control process in the third embodiment. FIG. 17 is a flowchart showing the procedure of the brake control process in the third embodiment.

A. First Embodiment:
A1. Device configuration:
As shown in FIG. 1, the wheel control system 100 of the present embodiment is mounted on a vehicle 200, which is a four-wheeled vehicle, and constitutes a pair of front wheels 201, 202, and a driven wheel that form a driving wheel of the vehicle 200. It controls the operation of the pair of rear wheels 203 and 204. The vehicle 200 uses two electric motors 30R and 30L driven by power supply from a battery (not shown) mounted on the vehicle 200 as a drive source. 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. 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 electric 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. The control circuit 31L is arranged corresponding to the front wheel 202 and controls the electric motor 30L. The detailed configuration of the electric motor control device 10 and the two control circuits 31R and 31L will be described later.

The brake control device 120 controls the brakes of the pair of front wheels 201 and 202 and the pair of rear wheels 203 and 204 by controlling the operations of the four brake devices 51, 52, 53 and 54. The braking device 51 realizes braking of the front wheels 201. Similarly, the brake device 52 brakes the front wheels 202, the brake device 53 brakes the rear wheels 203, and the brake device 54 brakes the rear wheels 204. 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. To 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 the in-vehicle network 220. As the in-vehicle network 220, 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-mounted 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 and an EPS actuator 111. The steering gear 211, the steering wheel 210, the accelerator opening sensor 41, the steering angle sensor 42, the range sensor 43, the vehicle speed sensor 44, and the yaw rate sensor 45 are provided.

The EPS (Electronic Power Steering) control device 110 controls the operation of the EPS actuator 111. In the present embodiment, the EPS control device 110 is composed of an ECU. The EPS control device 110 realizes so-called electric power steering. The EPS actuator 111 includes a 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 handle 210.

The steering gear 211 transmits the movement of the steering wheel 210 to the pair of front wheels 201 and 202. The accelerator opening sensor 41 detects the amount of depression of the accelerator pedal (not shown) included in the vehicle 200 as the accelerator opening, that is, the rotation angle of the motor for opening and closing the throttle valve. The steering angle sensor 42 is electrically connected to the EPS actuator 111 by a dedicated cable, and detects the steering angle of the vehicle 200 by the steering wheel 210 by using a signal output according to the operation of the EPS actuator 111. The steering angle sensor 42 is electrically connected to the EPS control device 110 by a dedicated cable, and notifies the EPS control device 110 of the detected steering angle. The range sensor 43 detects a shift range specified by a shift lever (not shown) included in the vehicle 200. The range sensor 43 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 shift range. The vehicle speed sensor 44 detects the rotational speed of each wheel 201 to 204. The vehicle speed sensor 44 is electrically connected to the electric motor control device 10 by a dedicated cable. The vehicle speed signal 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 notified to the electric motor control device 10 via a dedicated cable. The yaw rate sensor 45 detects the yaw rate when the vehicle 200 is traveling. 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 specifying unit 11, a vehicle speed specifying unit 12, a shift range specifying unit 13, a steering angle specifying unit 14, a yaw rate specifying unit 15, and a target torque instruction. A unit 16, a monitoring unit 17, a comparator 18, a target yaw rate calculation unit 19, a comparator 20, and a failure occurrence identification unit 21 are provided. In the present embodiment, the electric motor control device 10 is composed of an ECU.

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

The target torque indicating unit 16 determines the target torque and instructs the two control circuits 31R and 31L, respectively. A method for determining such a target torque will be described. First, the target torque indicator 16 calculates the target torque (hereinafter, referred to as "overall target torque") to be output by the two electric motors 30R and 30L as a whole. Specifically, the target torque indicating unit 16 includes an accelerator opening degree specified by the accelerator opening degree specifying unit 11, a vehicle speed specified by the vehicle speed specifying unit 12, and a shift range specified by the shift range specifying unit 13. Based on the above, the target torque is calculated with reference to the torque map shown in FIG. Such a torque map is a map in which the accelerator opening degree and the target torque are associated with each vehicle speed. As the magnitude (absolute value) of the target torque, a large value is set for increasing the accelerator opening. 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 backward (R) range. In FIG. 3, only three maps are shown when the vehicle speed V is v1, v2, and v3, but in the present embodiment, four or more maps are prepared in advance. Next, the target torque indicator 16 determines the distribution rate when distributing the calculated overall target torque to the left and right electric motors 30R and 30L, and sends a signal indicating the target torque according to the determined distribution rate. Notify the two control circuits 31R and 31L, respectively, and output to the comparator 18. The target torque distribution rate is determined using the torque distribution rate determination map shown in FIG. 4 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. This torque distribution rate determination map is a map in which the steering angle and the torque distribution rate 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 distribution ratio is such that the target torque of the electric motor 30L and the target torque of the electric motor 30R are 1: 0.5, that is, 2: 1. Is stipulated. This is because when turning to the right, it is necessary to output a larger torque to the electric motor 30L than to the electric motor 30R and to rotate the front wheel 202 at a higher speed than the front wheel 201. Note that FIG. 4 shows only three maps when the vehicle speed V is v1, v2, and v3, but in the present embodiment, four or more maps are prepared in advance.

The monitoring unit 17 shown in FIG. 2 monitors the failure of the target torque indicating unit 16. If the target torque indicator 16 fails, an erroneous value may be calculated as the overall target torque, or an erroneous distribution rate may be calculated. Therefore, in the electric motor control device 10, a monitoring unit 17 is provided to monitor whether or not the target torque indicating unit 16 has a failure. The monitoring unit 17 has the same configuration as the target torque indicating unit 16, determines the overall target torque and the distribution rate when distributing to the left and right electric motors 30R and 30L, and determines the distribution rate according to the determined distribution rate. Is output to the comparator 18.

The comparator 18 inputs signals indicating the target torque from the target torque indicating unit 16 and the monitoring unit 17, compares the target torques indicated by these two signals, and determines the comparison result, that is, the difference between the target torques, as a failure occurrence identification unit. Notify 21.

The target yaw rate calculation unit 19 calculates the target yaw rate with reference to the target yaw rate map shown in FIG. 5 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. The target yaw rate map is a map in which the steering angle and the target torque are associated with each vehicle speed. In FIG. 5, the horizontal axis represents the steering angle and the vertical axis represents the target yaw rate. When the vehicle speed V is v1, the target yaw rate is zero when the steering angle is zero, and the 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. Further, 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. In the target yaw rate map Lyn when the vehicle speed V is vn, the target yaw rate map Ly1 is represented by a broken line for easy comparison.

As can be understood by comparing the solid line target yaw rate map Lyn map and the broken line target yaw rate map Ly1 in FIG. 5, in the present embodiment, when the absolute values of the steering angles are the same, the larger the vehicle speed, the higher the target yaw rate. A small value is set as. The target yaw rate calculation unit 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 compares the comparison result, that is, the difference between these two yaw rates (hereinafter, "yaw rate"). "Difference") is notified to the failure occurrence specifying unit 21, the target torque indicating unit 16, and the monitoring unit 17. The yaw rate difference is used in the lane deviation hazard detection process and the brake control process, which will be described later.

The failure occurrence identification unit 21 identifies the failure of the target torque indicator 16 and the failure occurrence of the two control circuits 31R and 31L. Specifically, the failure occurrence specifying unit 21 identifies the occurrence of a failure of the target torque indicating unit 16 when the difference between the target torques received from the comparator 18 is equal to or greater than a predetermined threshold value. When the shift range is backward (R), the occurrence of a failure may be specified when the magnitude (absolute value) of the target torque output from the target torque indicator 16 is equal to or greater than a predetermined threshold value. Good. The failure occurrence identification unit 21 also receives at least one of the two control circuits 31R and 31L when a signal indicating the occurrence of a failure (hereinafter referred to as a “failure occurrence signal”) is received from the two control circuits 31R and 31L. Identify the occurrence of one of the failures. When the failure occurrence identification unit 21 identifies the failure occurrence as described above, the failure occurrence identification unit 21 notifies the target torque indicating unit 16 and the monitoring unit 17 of a signal indicating that the failure has occurred. As will be described later, the target torque indicating unit 16 and the monitoring unit 17 that have received the notification of the occurrence of a failure have a torque different from the normal target torque (normal target torque described later) when there is no failure, that is, the above-mentioned. A torque different from the target torque determined in this manner 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 calculation unit 33R, a comparator 34R, and an operation monitoring unit 35R. The driver IC 32R supplies the drive voltage to the electric motor 30R according to the target torque notified from the target torque indicating unit 16. 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 the rotation speed, the torque actually output by the electric motor 30R (hereinafter, "actual torque"). ) Is calculated. The value of the target torque notified from the target torque indicating unit 16 and the value of the actual torque calculated by the actual torque calculation unit 33R are input to the comparator 34R. The comparator 34R compares the values of these two input torques, and outputs the comparison result, that is, the difference in torque to the operation monitoring unit 35R. The operation monitoring unit 35R identifies the operation of the driver IC 32R. Specifically, the operation monitoring unit 35R identifies a failure of the driver IC 32R when the comparison result input from the comparator 34R is equal to or higher than a predetermined threshold value, 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 value, the driver IC 32R is operating normally, and the operation monitoring unit 35R does not output a failure occurrence signal.

The control circuit 31L has the same configuration as the control circuit 31R. That is, it includes a driver IC 32L, an actual torque calculation unit 33L, a comparator 34L, and an operation monitoring unit 35L. When the comparison result input from the comparator 34L is equal to or greater than a predetermined threshold value, the operation monitoring unit 35L identifies a failure of the driver IC 32L and notifies the electric motor control device 10 (failure occurrence specifying unit 21) of a failure occurrence signal.

In the wheel control system 100 having the above configuration, a lane deviation hazard detection process, a failure target torque determination process, and a brake control process, which will be described later, are executed, whereby one of the two control circuits 31R and 31L is executed. Even if a failure occurs, it is possible to prevent the vehicle 200 from deteriorating in running stability.

A2. Lane deviation hazard detection process:
The lane deviation hazard detection process shown in FIG. 6 is executed when the start button of the vehicle 200 is pressed and the power of the electric motor control device 10 is turned on. The lane deviation detection process is a process for detecting that a hazard that causes the vehicle 200 to deviate from the lane in which the vehicle is traveling may occur due to a failure of one of the two control circuits 31R and 31L. When the wheel control system 100 is first activated, the lane deviation hazard flag XF, the evacuation travel flag XR, and the normal side determination flag NF, which will be described later, are all set to "0". These flags can be set to different values after the first boot. Further, the set values of these flags XF, XR, and NF are written in a writable non-volatile memory of the motor control device 10, for example, EEPROM, and the value described in the non-volatile memory is used at the next start. Referenced. The details of these flags XF, XR, and NF will be described later.

The electric motor control device 10 determines whether or not the lane deviation hazard flag XF is on (step S105). The target yaw rate calculation unit 19 calculates the target yaw rate Yt from the vehicle speed specified by the vehicle speed specifying unit 12 and the steering angle specified by the steering angle specifying unit 14 (step S110). The comparator 20 acquires the detection result of the yaw rate sensor 45, that is, the actually measured value Y of the yaw rate via the yaw rate specifying unit 15 (step S115). The failure occurrence identification unit 21 is 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 acquired in step S115. Is larger than the predetermined threshold value α (step S120). The threshold value α is the absolute value of the yaw rate difference when the measured value Y of the yaw rate deviates from the target yaw rate Yt because one of the two control circuits 31R and 31L has failed, and the absolute value of the yaw rate difference is obtained from the obtained value. The failure of one of the two control circuits 31R and 31L is set as an estimated value.

When it is determined that the absolute value of the yaw rate difference is not larger than the threshold value α (step S120: NO), the failure occurrence identification unit 21 sets the time counter C to zero (step S125). The time-lapse counter C is a counter value corresponding to the elapsed time from the start of determination that the absolute value of the yaw rate difference is larger than the threshold value α. The initial value of the time-lapse counter C is zero. When it is determined that the absolute value of the yaw rate difference is larger than the threshold value α (step S120: YES), the failure occurrence specifying unit 21 increments the time counter C by 1 (step S130).

The failure occurrence identification unit 21 determines whether or not the value of the time-lapse counter C is larger than the threshold value Cth (step S135). The threshold value Cth is set in advance by experiments or the like as a counter value corresponding to a time at which one of the two control circuits 31R and 31L can be estimated to have a high possibility of failure. When it is determined that the value of the time-lapse counter C is not larger than the threshold value Cth (step S135: NO), the process returns to step S105 described above. On the other hand, when it is determined that the value of the time-lapse counter C is larger 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 the absolute value of the yaw rate difference began to be determined to be larger than the threshold value α. After the completion of step S140, the process returns to step S105 described above.

The yaw rate specifying unit 15 corresponds to a subordinate concept of the detection result acquisition unit of the present disclosure. Further, the target yaw rate calculation unit 19 corresponds to a subordinate concept of the target value calculation unit of the present disclosure.

A3. Target torque determination process at the time of failure:
The failure target torque determination process shown in FIG. 7 is executed when the start button of the vehicle 200 is pressed and the power of the electric motor control device 10 is turned on. The failure target torque determination process is a process for determining a 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 deviation hazard flag XF is turned on (step S205). If it is determined that the lane departure hazard flag XF is not turned on (step S205: NO), step S205 is executed again. That is, the failure occurrence identification unit 21 waits until the lane deviation hazard flag XF is turned on. On the other hand, when it is determined that the lane deviation hazard flag XF is ON (step S205: YES), the target torque indicating unit 16 specifies the accelerator opening degree and the vehicle speed specified by the accelerator opening degree specifying unit 11. The 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). The target torque indicating unit 16 determines the torque distribution rate to the left and right wheels 201 and 202 by referring to the torque distribution rate map shown in FIG. 4 using the vehicle speed and the steering angle specified by the steering angle specifying unit 14. (Step S215).

The failure occurrence identification unit 21 identifies the normality of the left and right control circuits 31R and 31L (step S220). Specifically, as described above, the normality of the control circuits 31R and 31L, that is, the presence or absence of the failure occurrence can be specified by whether or not the failure occurrence signal is received from the control circuit 31R and the control circuit 31L.

When the control circuit 31R is normal and the control circuit 31L is abnormal, the target torque indicator 16 obtains the target torque (hereinafter referred to as “right target torque”) TR instructed to the control circuit 31R in step S210. The target torque determined by applying the torque distribution rate determined in step S215 to the overall target torque (hereinafter referred to as "normal target torque") is set, and the target torque instructed to the control circuit 31L (hereinafter, "" The TL (referred to as "left side 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, "-1" is the right side (control circuit 31R), and "+1" is the left side (control). Circuit 31L) indicates that both "0 (zero)" are not normal.

When the control circuit 31R is abnormal and the control circuit 31L is normal, the target torque indicator 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". "(Step S230).

In other cases, that is, when both of the two control circuits 31R and 31L are abnormal, the target torque indicator 16 sets the right target torque to zero, sets the left target torque to zero, and determines the normal side. “0 (zero)” is set in the flag (step S235). The target torques determined in steps S225, S230, and S235 described above are instructed by the control circuits 31R and 31L, respectively. Therefore, for at least one of the pair of front wheels 201 and 202, which are the driving wheels, the target torque becomes zero, so that 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 travel flag XR is on (step S240). The evacuation running flag XR is a flag indicating whether or not the evacuation running should be performed, and when it is on, it indicates that the evacuation running should be performed. The evacuation running is a running different from the running in a situation where the control circuit 31R or the control circuit 31L is not abnormal (hereinafter, referred to as "normal running"), and is a running that suppresses the deterioration of the running stability of the vehicle 200. Means. When the evacuation running flag XR is not turned on (step S240: NO), the failure occurrence identification unit 21 determines whether or not the vehicle speed is zero (step S245). When it is determined that the vehicle speed is zero (step S245: YES), the failure occurrence identification unit 21 sets the evacuation travel flag XR to "1" and turns it on (step S250).

After executing the above-mentioned step S235, the process returns to the above-mentioned step S205. Further, when it is determined that the evacuation running 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 each case, the process returns to step S205 described above. Therefore, when at least one of the control circuits 31R and 31L becomes abnormal while the evacuation travel flag XR is off, the evacuation travel flag XR is turned on when the vehicle speed decreases and becomes zero. It becomes.

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

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

The brake control device 120 determines whether or not the 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 according to the normal brake operation amount by the driver for the brake devices 51 to 54. (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 or not the evacuation travel flag XR is ON (step S320). If it is determined that the evacuation running flag XR is not on (step S310: NO), the above-mentioned step S315 is executed. The case where it is determined that the evacuation running flag XR is not on means that the steps S225 to S230 of the above-mentioned failure target torque determination process are being executed and the vehicle 200 has not stopped yet. .. In this case, brake control is executed according to the amount of brake operation by the driver.

On the other hand, when it is determined that the evacuation travel flag XR is ON (step S320: YES), the brake control device 120 acquires the vehicle speed and steering angle from the electric motor control device 10 via the vehicle-mounted network 220, and obtains the vehicle speed and the steering angle. The target yaw rate Yt is calculated from the steering angle (step S325). The target yaw rate Yt, which is the result calculated in step S110 of the lane deviation hazard detection process, may be acquired from the electric motor control device 10 via the in-vehicle network 220.

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

The brake control device 120 determines whether or not the 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 identifies the normal side determination flag NF (step S345) as shown in FIG.

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 (| Y-Yt |) of the yaw rate difference calculated in step S335 by a predetermined coefficient k. That is, the braking device 54 is operated with a braking force having a magnitude proportional to the absolute value of the yaw rate difference. In the present embodiment, the coefficient k is a coefficient derived from a braking force obtained in advance by an experiment or the like so that the measured value Y of the yaw rate approaches the target yaw rate Yt when the braking device 53 is operated. is there.

As shown in FIG. 10, when the vehicle 200 goes straight when the control circuit 31R fails, the target torque of the front wheels 201 becomes zero, so that the front left side of the two front wheels 201 and 202, which are the driving wheels. Only the wheels 202 are driven, and the vehicle 200 attempts to make a right turn operation centered on its own center of gravity C1. However, in this case, since the above-mentioned step S355 is executed and the brake device 54 is activated, the right turning operation of the vehicle 200 can be suppressed. Therefore, even after the failure of the control circuit 31R occurs, it is possible to suppress the deterioration of the running stability of the vehicle 200, and the measured value Y of the yaw rate approaches the target yaw rate Yt. In FIG. 10, some components shown in FIG. 1, such as the electric 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 is set on the right rear wheel 203. The brake device 53 is operated (step S355). At this time, the braking force is a positive value obtained by multiplying the absolute value (| Y-Yt |) of the yaw rate difference calculated in step S335 by a predetermined coefficient k. That is, the braking device 53 is operated with a braking force having a magnitude 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 described above that the vehicle 200 is not traveling straight (step S340: NO), as shown in FIG. 9, the brake control device 120 is located on the inner wheel side of the pair of rear wheels 203 and 204. The wheel braking device is activated (step S360). At this time, the braking force is a positive value obtained by multiplying the absolute value (| Y-Yt |) of the yaw rate difference calculated in step S335 by a predetermined coefficient k. That is, the braking device for the wheels on the inner wheel side is operated with a braking force having a magnitude 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 to the right, the target torque of the front wheels 201 becomes zero, so that the left side of the two front wheels 201 and 202 that are the driving wheels Only the front wheels 202 of the vehicle are driven, and the vehicle 200 is suppressed from turning right around the center of gravity C1, which may cause so-called understeer. However, in this case, since the above-mentioned step S360 is executed and the brake device 53 of the right rear wheel 203, which is the brake device on the inner wheel side, is activated, the right turning operation of the vehicle 200 is promoted. Therefore, even after the control circuit 31R is generated, it is possible to suppress the 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 the completion of steps S350, S355 and S360, the process returns to step S305. When the value of the normal side determination flag NF specified in step S345 described above is other than "+1" and "-1", that is, when 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 for the control circuit in which the failure occurrence is specified, and one of the pair of rear wheels 203 and 204 that are the driven wheels. On the other hand, since the brake is applied so that the measured value Y of the yaw rate approaches the target yaw rate Yt, the two electric motors 30R and 30L for driving the two front wheels 201 and 202 on the left and right and the electric motors 30R and 30L are controlled. In the configuration including the two control circuits 31R and 31L, it is possible to suppress the deterioration of the running stability of the vehicle 200 when a failure occurs in one of the control circuits, and it is possible to realize fail-safety.

Further, when a failure is identified in a situation where it is determined that the vehicle 200 is traveling straight, a control circuit in which the failure is identified across the center of gravity C1 of the vehicle 200 among the pair of rear wheels 203 and 204. Since the brake is applied to the wheel arranged at a position symmetrical to the wheel corresponding to the above, the vehicle 200 is caused by driving only one of the pair of front wheels 201 and 202, which are the driving wheels. Can be suppressed from turning.

Further, when a failure is identified in a situation where it is determined that the vehicle 200 is performing a turning operation, the brake is applied to the inner wheel side of the pair of rear wheels 203 and 204, so that the vehicle is driven. Since only one of the pair of front wheels 201 and 202, which are wheels, is driven, the turning operation is hindered and so-called understeer can be suppressed.

B. Second embodiment:
Since 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, the same components are designated by the same reference numerals, and detailed description thereof will be omitted. Further, the wheel control system 100 of the second embodiment executes a lane deviation hazard detection process, a failure target torque determination process, and a brake control process by the same procedure as the wheel control system 100 of the first embodiment. The wheel control system 100 of the second embodiment is different from the wheel control system 100 of the first embodiment in that steering control processing is additionally executed.

The steering control process according to 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 for controlling the steering of the vehicle 200.

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

The control device 110 determines whether or not the 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 or not the evacuation travel flag XR is ON (step S420). If it is determined that the evacuation running flag XR is not on (step S410: NO), the above-mentioned step S415 is executed. The case where it is determined that the evacuation running flag XR is not on means that the steps S225 to S230 of the above-mentioned failure target torque determination process are being executed and the vehicle 200 has not stopped yet. .. In this case, steering control according to the steering amount by the driver is executed.

On the other hand, when it is determined that the evacuation travel 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 electric motor control device 10 via the in-vehicle network 220. (Step S425).

The EPS control device 110 controls the steering angle on the wheel side corresponding to the control circuit in which 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 the steering angle map described later based on the normal side determination flag NF identified in step S425 and controlling the steering 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 help understanding, the steering angle map Ls0 in the normal state, that is, the steering angle map referred to when the failure occurrence is not specified in any of the two control circuits 31R and 31L is represented by a thin solid line. .. In FIG. 13, the horizontal axis represents the amount of steering of the steering wheel 210 by the driver, and the vertical axis represents the steering angle. In the steering angle map Ls0, when the steering amount is zero, the steering angle is set to zero. Therefore, in the normal state, when the steering amount is zero, the vehicle 200 goes straight.

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

In the steering angle map Lsl1, the angle in the right direction is reduced by a predetermined offset amount and the angle in the left direction is increased 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 tries to perform a right-turning operation centered on its own center of gravity C1, so that the steering amount is higher than in the normal state. This is because the rightward angle is reduced and set in the same case so that the vehicle 200 can go straight when the steering amount, that is, the operation amount of the steering wheel 210 is zero.

In the steering angle map Lsr1, the angle in the left direction is reduced by a predetermined offset amount and the angle in the right direction is increased when the steering amount is the same as compared with the steering angle map Ls0. This is because when the control circuit 31R is normal and the control circuit 31L is abnormal, the vehicle 200 tries to perform a left-turning operation centered on its own center of gravity C1, so that the steering amount is larger than in the normal state. In the same case, the leftward angle is reduced and set 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 in the steering angle maps Lsln and Lsrn when the vehicle speed V is vn. However, in the present embodiment, the larger the vehicle speed, the larger the offset amount is set. The larger the vehicle speed V, the larger the vehicle 200 is likely to turn due to a slight change in the steering amount. However, as described above, the higher the vehicle speed, the more certain that the vehicle 200 will perform a turning operation, in other words, it will not go straight if a larger value is set as the offset amount described above. This is because it can be suppressed.

The wheel control system 100 of the second embodiment described above has the same effect 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 steering angle with respect to the steering amount (steering wheel steering amount) in the normal state, so that the steering amount is zero. In this case, since the steering of the vehicle is controlled so that the vehicle travels straight, it is possible to suppress the vehicle 200 from turning even though the steering amount is zero. Further, when the vehicle speed V is large, a larger value is set as the offset amount as compared with the case where the vehicle speed V is small. Therefore, since the vehicle speed V is large, the vehicle 200 becomes large due to a slight change in the steering amount. Even in a situation where it is easy to turn, it is possible to more reliably suppress 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 provided with the acceleration sensor 46 instead of the yaw rate sensor 45 and the wheel control system 100a instead of the wheel control system 100. It is different from the vehicle 200 of the form. Since the other configurations of the vehicle 200a are the same as those of the vehicle 200, the same components are designated by the same reference numerals, and detailed description thereof will be omitted. The acceleration sensor 46 detects the lateral acceleration of the vehicle 200 (hereinafter, referred to as “lateral acceleration”), in other words, the lateral acceleration. In the present embodiment, the acceleration sensor 46 is composed of a three-axis sensor. The wheel control system 100a is different from the wheel control system 100 of the first embodiment in that the electric motor control device 10a is provided in place of the electric motor control device 10. Since the other configurations in the wheel control system 100a are the same as those in the wheel control system 100, the same components are designated by the same reference numerals, and detailed description thereof will be omitted.

The electric motor control device 10a of the third embodiment shown in FIG. 15 is provided with an acceleration specifying unit 15a instead of the yaw rate specifying unit 15 and a target acceleration calculating unit 19a instead of the target yaw rate calculating unit 19. It is different from the electric motor control device 10 of the first embodiment. Since the other configurations of the electric motor control device 10a are the same as those of the electric motor control device 10, the same components are designated by the same reference numerals, and detailed description thereof will be omitted.

The acceleration specifying unit 15a identifies the lateral acceleration by receiving a signal indicating the lateral acceleration notified from the acceleration sensor 46. The target acceleration calculation unit 19a sets 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 with reference 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 that of the first embodiment. On the other hand, the procedure of the brake control process of the third embodiment is different from that of the brake control process of the first embodiment.

Specifically, as shown in FIGS. 16 and 17, the brake control process of the third embodiment replaces steps S325, S330, S335, S350, and S355 with steps S325a, S330a, S335a, S350a, and It differs from the brake control process of the first embodiment in that S355a is executed. Since the 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, the same procedures are designated 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 retracted travel flag XR is ON (step S320: YES), the brake control device 120 is subjected to vehicle speed and vehicle speed from the electric motor control device 10 via the vehicle-mounted network 220. The steering angle is acquired, and the target acceleration Gt in the lateral direction 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 from the electric motor control device 10 via the vehicle-mounted network 220, that is, the measured value G of the lateral acceleration (step S330a). The brake control device 120 calculates an absolute value (| G—Gt |) of the difference (acceleration difference) between the measured value G of the lateral acceleration acquired 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 is the brake device of the left rear wheel 204. 54 is operated (step S350a). At this time, the braking force is a positive value obtained by multiplying the absolute value (| G—Gt |) of the acceleration difference calculated in step S335a by a predetermined coefficient m. That is, the braking device 54 is operated with a braking force having a magnitude proportional to the absolute value of the acceleration difference. In the present embodiment, the coefficient m is derived from the braking force obtained in advance by experiments or the like so that the measured value G of the lateral acceleration approaches the target acceleration Gt when the braking device 54 is operated. It is a 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 rear wheel 203 on the right side ( Step S355a). At this time, the braking force is a positive value obtained by multiplying the absolute value (| G—Gt |) of the acceleration difference calculated in step S335a by a predetermined coefficient m. That is, the braking device 53 is operated with a braking force having a magnitude proportional to the absolute value of the acceleration difference. Since the coefficient m in step S355a is the same as the coefficient m in step S350a, detailed description thereof will be omitted.

When it is determined in step S340 described above that the vehicle 200 is not traveling straight (step S340: NO), as shown in FIG. 17, the brake control device 120 is located on the inner wheel side of the pair of rear wheels 203 and 204. The wheel braking device is activated (step S360a). At this time, the braking force is a positive value obtained by multiplying the absolute value (| G—Gt |) of the speed difference calculated in step S335a by a predetermined coefficient m. That is, the braking device for the wheels on the inner ring side is operated with a braking force having a magnitude proportional to the absolute value of the acceleration difference.

After the completion of steps S350a, S355a and S360a, the process returns to step S305. When the value of the normal side determination flag NF specified in step S345 described above is other than "+1" and "-1", that is, when 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 100a of the third embodiment described above, it has the same effect 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. It was premised that the evacuation running flag XR was turned on. That is, these processes were executed after the lane departure hazard flag XF was turned on and the vehicle speed became 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 the occurrence of the failure to the time when the vehicle speed becomes zero.

(D2) In the failure target torque determination process of each embodiment, the target torque determined in steps S225, S230, and S235 is immediately applied, but the present disclosure is not limited to this. For example, until the vehicle speed becomes zero, if at least one of the two control circuits 31R and 31L is identified as having a failure, the target torques of the two control circuits 31R and 31L are both zero. May be instructed. Further, in such a configuration, when the running of the vehicle 200 is restarted 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 try to do it.

(D3) In the brake control process of the first and second embodiments, steps S340 and S360 may be omitted. Similarly, in the brake control process of the third embodiment, steps S340 and S360a may be omitted. Even in these configurations, when at least one of the two control circuits 31R and 31L has a failure, the steering angle is zero and the driver intends to drive the vehicles 200 and 200a straight. , Vehicles 200, 200a can be suppressed from turning. Unlike the above, in the brake control process of the first and second embodiments, steps S340, S350, and S355 may be omitted. 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 will be executed after the completion of steps S335 and S335a. Even in these configurations, in a situation where at least one of the two control circuits 31R and 31L has a failure, the steering angle is not zero and the driver tries to turn the vehicles 200 and 200a. In addition, it is possible to prevent the vehicles 200 and 200a from becoming so-called understeer.

(D4) In the second embodiment, the steering angle map is set with a larger value as the offset amount when the vehicle speed V is large than when it is small, but the present disclosure is not limited to this. Regardless of the size of the vehicle speed V, only one map may be set as the steering angle map. Further, the steering angle maps Lsl1, Lsr1, Lsln, and Lsrn are set so that the steering angle changes continuously as the steering amount changes, but they may be set to change stepwise. ..

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

(D6) In the failure target torque determination process of each embodiment, in steps S225, S230, and S235, the target torque is set for the control circuit in which the failure occurrence (abnormality) is specified among the two control circuits 31R and 31L. By setting it to zero, the operation of the corresponding electric motor 30R or 30L was stopped, but 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 operation of the corresponding electric motor 30R or 30L can be performed. You may stop it.

(D7) The configurations of the wheel control systems 100 and 100a of each embodiment are merely examples and can be changed in various ways. For example, in each embodiment, at least one of the two motors 30R and 30L may be a motor generator. In such a configuration, the motor generator corresponds to the subordinate concept of the generator in the present disclosure. Further, in each embodiment, the vehicles 200 and 200a are configured to be equipped with both the yaw rate sensor 45 and the acceleration sensor 46, and the brake control process is executed using the detection results of the two sensors 45 and 46. May be good. For example, the braking force operated in steps S350, S355, S360, and S350a, S355a, S360a is multiplied by a predetermined coefficient by the value obtained by multiplying the absolute value of the yaw rate difference and the absolute value of the acceleration difference. You may ask for it.

(D8) In each embodiment, the failure of the two control circuits 31R and 31L means the 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 calculation units 33R and 33L, the comparators 34R and 34L, and the operation monitoring units 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 the normality, respectively, and when an abnormality is notified in such communication or when such notification does not arrive, 2 It may be configured to identify the failure of the two control circuits 31R and 31L. According to such a configuration, the electric motor control devices 10 and 10a can identify the occurrence of a failure of any component constituting the control circuits 31R and 31L, not limited to the failure of the driver ICs 32R and 32L.

(D9) The motor control devices 10, 10a, brake control device 120, and methods 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 be realized by a dedicated computer provided by configuring. Alternatively, the motor control devices 10, 10a, brake control device 120 and methods thereof described in the present disclosure may be realized by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Good. Alternatively, the motor control devices 10, 10a, brake control device 120 and methods thereof described in the present disclosure include a processor and memory programmed to perform one or more functions and one or more hardware logic circuits. It may be realized by one or more dedicated computers configured in combination with a processor configured by. Further, the computer program may be stored in a computer-readable non-transitional tangible recording medium as an instruction executed by the computer.

The present disclosure is not limited to the above-described embodiments, and can be realized with various configurations without departing from the spirit of the present disclosure. For example, the technical features in each embodiment corresponding to the technical features in the embodiments described in the column of the outline of the invention may be used to solve some or all of the above-mentioned problems, or one of the above-mentioned effects. It is possible to replace or combine as appropriate to achieve a part or all. Further, if the technical feature is not described as essential in the present specification, it can be appropriately deleted.

Claims (7)

1. It is arranged on each wheel constituting at least one of the pair of front wheels (201, 202) and the pair of rear wheels (203, 204) of the vehicle (200, 200a) to drive the wheels. It is mounted on the vehicle having an electric motor (30R, 30L) and a control circuit (31R, 31L) arranged corresponding to each wheel constituting the driving wheel and controlling the electric motor for driving the wheel. A wheel control system (100) that controls the operation of the pair of front wheels and the pair of rear wheels.
   An electric motor control device (10) that controls the control circuit arranged corresponding to each wheel constituting the drive wheel, and an electric motor control device (10).
   A brake control device (120) that controls the brakes of the pair of front wheels and the pair of rear wheels and can communicate with the electric motor control device.
   With
   The electric motor control device is
   A target torque indicator (16) for instructing a target torque to the control circuit corresponding to each wheel constituting the drive wheel,
   Among the control circuits corresponding to the wheels constituting the drive wheels, a failure occurrence specifying unit (21) for specifying the failure occurrence of any one of the control circuits, and
   A detection result acquisition unit (15) that acquires the detection result of at least one of the yaw rate sensor (46) mounted on the vehicle and detecting the yaw rate and the acceleration sensor (46) mounted on the vehicle and detecting the lateral acceleration. , 15a) and
   The target yaw rate and the target lateral direction of the vehicle are used by using the detection results of the vehicle speed sensor (44) mounted on the vehicle to detect the vehicle speed and the steering angle sensor (42) mounted on the vehicle to detect the steering angle. A target value calculation unit (19, 19a) that calculates a target value that is at least one of the accelerations,
   Have,
   When the failure occurrence is specified, the target torque indicator unit instructs the failure identification control circuit, which is the control circuit in which the failure occurrence is specified, to have zero as the target torque.
   When the failure occurrence is specified, 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. The brake is applied so that the detection result acquired by the unit approaches the calculated target value.
   Wheel control system.
2. In the wheel control system according to claim 1,
   The brake control device is one of two wheels different from the driving wheels 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 is applied to the wheels arranged at positions symmetrical with the wheels corresponding to the failure identification control circuit with the position of the center of gravity of the vehicle in between.
   Wheel control system.
3. In the wheel control system according to claim 1 or 2.
   In a situation where it is determined that the vehicle is turning based on the acquired detection result, the brake control device has two wheels different from the driving wheels when the failure occurs. Of these, apply the brakes to the wheels on the inner ring side.
   Wheel control system.
4. In the wheel control system according to any one of claims 1 to 3.
   The steering control device (110) that controls the steering of the vehicle, is configured to be communicable with the electric motor control device, and acquires the steering amount of the steering wheel, which is the operation amount of the steering wheel (210) mounted on the vehicle. Further, a steering control device for controlling the steering of the vehicle according to the acquired steering amount of the steering wheel and the vehicle speed is further provided.
   When the failure occurrence is specified, the steering control device determines the steering angle to the wheel side corresponding to the failure identification control circuit, which is the steering angle with respect to the steering amount of the steering wheel, when the failure occurrence is not specified. By setting the steering angle to an angle obtained by reducing the offset amount from the steering angle with respect to the steering amount of the steering wheel, the steering of the vehicle is controlled so that the vehicle goes straight when the steering amount of the steering wheel is zero.
   Wheel control system.
5. In the wheel control system according to claim 4,
   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.
6. In the wheel control system according to claim 4 or 5.
   When the failure occurrence is specified, the target torque indicator unit sets the target torque for all the control circuits corresponding to the wheels constituting the drive wheels in addition to the failure identification control circuit. Point to zero,
   The target torque indicating unit corresponds to each wheel constituting the driving wheel when the occurrence of the failure is identified and the vehicle is instructed to move forward or backward after the vehicle speed becomes zero. Among the control circuits, the detection of the accelerator opening sensor that indicates the failure identification control circuit to zero as the target torque and detects the vehicle speed and the accelerator opening of the vehicle to the other control circuits. The torque calculated by using the result and the detection result of the range sensor (43) that detects the position of the shift range of the vehicle is instructed as the target torque.
   The steering control device identifies the failure as a steering angle with respect to the steering amount of the steering wheel when the vehicle is instructed to move forward or backward after the occurrence of the failure is specified and the vehicle speed becomes zero. When the steering wheel steering amount is zero by setting the steering angle to the wheel side corresponding to the control circuit to an angle obtained by reducing the offset amount from the steering angle with respect to the steering wheel steering amount when the failure occurrence is not specified. Control the steering of the vehicle so that the vehicle travels straight.
   Wheel control system.
7. It is arranged on at least one drive wheel of the pair of front wheels (201, 202) and the pair of rear wheels (203, 204) of the vehicle (200, 200a) and each wheel constituting the drive wheel. The said motor having an electric motor (30R, 30L) for driving the wheel and a control circuit (31R, 31L) arranged corresponding to each wheel constituting the driving wheel and controlling the electric motor for driving the wheel. A wheel control method for controlling the operation of the pair of front wheels and the pair of rear wheels in a vehicle by using a wheel control system.
   In the wheel control system, a step of identifying a failure occurrence of any one of the control circuits corresponding to each wheel constituting the drive wheel, and
   In the wheel control system, a step of acquiring the detection result of at least one of a yaw rate sensor (46) mounted on the vehicle and an acceleration sensor (46) mounted on the vehicle to detect lateral acceleration. ,
   In the wheel control system, the target yaw rate and the target lateral acceleration of the vehicle are used by using the detection results of the vehicle speed sensor (44) mounted on the vehicle and the steering angle sensor (42) mounted on the vehicle. The process of calculating the target value, which is at least one of
   In the wheel control system, when the failure occurrence is specified, a step of instructing zero as a target torque to the failure identification control circuit, which is the control circuit in which the failure occurrence is specified,
   When the failure occurrence is specified in the wheel control system, the acquired wheel is obtained for a wheel different from the driving wheel among the wheels constituting the pair of front wheels and the pair of rear wheels. The process of braking so that the detection result approaches the calculated target value, and
   A wheel control method.

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