Controller for vehicle

Abstract

To provide a controller for a vehicle capable of taking an appropriate action when an abnormality occurs.SOLUTION: A controller for a vehicle has control circuits (a set of 41A and 51A, and a set of 42A and 52A) of a plurality of systems. The control circuits control power feed independently for each system, to winding groups of a plurality of systems which a reaction force motor and a steering motor each have. Each of the control circuits drives the motor in a drive mode being switched depending on an operating status of a control circuit of the other system other than a self-system. The drive mode includes a self-system stop mode for stopping the power feed to a winding group of the self-system when an operating status of the control circuit of the other system other than the self-system is abnormal. The control circuit does not transition the drive mode into the self-system stop mode when an operating status of itself is in a specific operating status without a safety issue even when the operating status of the control circuit of the other system other than the self-system is abnormal.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a vehicle control device. [Background technology]

[0002] Conventionally, the following vehicle control device has been known. For example, the motor drive system of Patent Document 1 has a reaction force actuator that generates a reaction torque, and a steering actuator that generates a steering torque. The reaction force actuator and the steering actuator each function as a motor, and have two windings. Furthermore, the reaction force actuator and the steering actuator each have two motor drive units and two control calculation units. Each control calculation unit controls the supply of electricity to the winding of its own system via the motor drive unit of its own system.

[0003] The control and arithmetic units of each system can communicate with each other. The control and arithmetic units have a cooperative drive mode, a recoverable mode, and a fault confirmation mode. The cooperative drive mode is a drive mode in which the control and arithmetic unit of the home system and the control and arithmetic unit of the other system share information exchanged between them through communication. The recoverable mode is a drive mode in which, when an abnormality occurs in one of the control and arithmetic units of the two systems, if there is a possibility that the control and arithmetic unit of the abnormal system will return to normal, the control and arithmetic unit of the normal system does not use information acquired from the control and arithmetic unit of the abnormal system. The fault confirmation mode is a drive mode in which, when a fault is confirmed in one of the control and arithmetic units of the two systems, the control and arithmetic unit of the normal system generates torque in the corresponding motor drive unit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-075182 Summary of the Invention [Problem to be solved by the invention]

[0005] Vehicle control devices such as that described in Patent Document 1 have the following concerns. For example, depending on the operating state or control specifications of each control calculation unit, there is a concern that an abnormality may occur that makes it difficult to appropriately control the reaction force actuator and the steering actuator. Vehicle control devices are required to respond appropriately when an abnormality occurs. [Means for solving the problem]

[0006] A vehicle control device that can solve the above problem has a plurality of control circuits configured to calculate a current command value according to a torque to be generated in a motor having a plurality of winding groups, and to independently control the power supply to the winding groups of the plurality of winding groups for each system based on the calculated current command value. The control circuit is configured to drive the motor in a drive mode that is switched according to an operation state of the control circuit of another system other than the own system. The drive modes include an own system stop mode that stops the power supply to the winding group of the own system when the operation state of the control circuit of the other system other than the own system is abnormal. The control circuit is configured not to transition the drive mode to the own system stop mode when the operation state of the control circuit of the other system other than the own system is a specific operation state that is considered to be safe, even if the operation state of the control circuit of the other system other than the own system is abnormal.

[0007] According to this configuration, even if the operating state of the control circuit of the other system is abnormal, the control circuit does not transition the drive mode to the own system stop mode when its own operating state is a specific operating state that is considered to be safe. Therefore, the control circuit can appropriately respond to the abnormality of the control circuit of the other system according to its own operating state.

[0008] In the above vehicle control device, the control circuit may be configured to execute a start-up process and an initial check when a vehicle power source is turned on, and to monitor an operation state of the control circuit of another system other than the own system from the viewpoint of controlling the driving of the motor in synchronization with the control circuit of the other system. In this case, the specific operation state may be a state in which the start-up process or the initial check is being executed.

[0009] With this configuration, there is no safety problem during the start-up process and the initial check. Therefore, even if the operating state of the control circuit of the other system is abnormal, it is possible to prevent the drive mode from transitioning to the own system stop mode.

[0010] In the above vehicle control device, the plurality of control circuits may be configured to synchronize the drive modes with each other and communicate with a vehicle control device configured to control a vehicle. In this case, the control circuit may be configured to transition the drive mode to the own system stop mode when an operating state of the control circuit of another system other than the own system is abnormal while controlling the drive of the motor, and to transmit a notification signal indicating that all of the drive modes of the plurality of control circuits have transitioned to the own system stop mode through the synchronization to the vehicle control device.

[0011] According to this configuration, when the drive modes of the multiple control circuits are all transitioned to the local system stop mode while the drive of the motor is being controlled, a notification signal indicating this is transmitted to the vehicle control device, so that the vehicle control device can recognize that it is difficult to drive the motor based on the notification signal.

[0012] In the above vehicle control device, the motor may include a reaction motor having two winding groups configured to generate a steering reaction force applied to a steering wheel whose power transmission between the reaction motor and the steered wheels is separated, and a turning motor having two winding groups configured to generate a turning force for turning the steered wheels. In this case, the multiple control circuits may include a first reaction control circuit configured to control power supply to the reaction motor, a second reaction control circuit configured to control power supply to the reaction motor, a first turning control circuit configured to control power supply to the turning motor, and a second turning control circuit configured to control power supply to the turning motor. In this case, the first reaction control circuit and the first turning control circuit may be in a relationship of mutually monitoring operating states, while the second reaction control circuit and the second turning control circuit may be in a relationship of mutually monitoring operating states.

[0013] According to this configuration, even if the operation state of the first turning control circuit, which is a control circuit of another system other than the own system, is abnormal, when the operation state of the first reaction force control circuit is a specific operation state that is considered to be safe, the first reaction force control circuit does not transition the drive mode to the own system stop mode. Therefore, the first reaction force control circuit can appropriately respond to the abnormality of the first turning control circuit according to its own operation state. Also, even if the operation state of the first reaction force control circuit, which is a control circuit of another system other than the own system, is abnormal, when the operation state of the first reaction force control circuit is a specific operation state that is considered to be safe, the first turning control circuit does not transition the drive mode to the own system stop mode. Therefore, the first turning control circuit can appropriately respond to the abnormality of the first reaction force control circuit according to its own operation state. The same applies to the second reaction force control circuit and the second turning control circuit.

[0014] In the above vehicle control device, the motor may include a reaction motor having one winding group and configured to generate a steering reaction force applied to a steering wheel whose power transmission between the steering wheel and the steered wheels is separated, and a turning motor having one winding group and configured to generate a turning force for turning the steered wheels. In this case, the multiple control circuits may include a reaction control circuit configured to control power supply to the reaction motor, and a turning control circuit configured to control power supply to the turning motor.

[0015] According to this configuration, even if the operating state of the reaction force control circuit, which is a control circuit of another system other than the own system, is abnormal, when its own operating state is a specific operating state that is deemed safe. Therefore, the reaction force control circuit can appropriately respond to the abnormality of the turning control circuit according to its own operating state. Also, even if the operating state of the reaction force control circuit, which is a control circuit of another system other than the own system, is abnormal, when its own operating state is a specific operating state that is deemed safe, the turning control circuit does not transition the drive mode to the own system stop mode. Therefore, the turning control circuit can appropriately respond to the abnormality of the reaction force control circuit according to its own operating state.

[0016] In the above vehicle control device, the motor may be an assist motor configured to generate an assist force for assisting the operation of a steering wheel. In this case, the assist motor may have a first winding group and a second winding group. In this case, the multiple control circuits may include a first assist control circuit configured to control power supply to the first winding group and a second assist control circuit configured to control power supply to the second winding group.

[0017] According to this configuration, even if the operating state of the second assist control circuit, which is a control circuit of another system other than the own system, is abnormal, the first assist control circuit does not transition the drive mode to the own system stop mode when its own operating state is a specific operating state that is deemed safe. Therefore, the first assist control circuit can appropriately respond to the abnormality of the second assist control circuit according to its own operating state. Also, even if the operating state of the first assist control circuit, which is a control circuit of another system other than the own system, is abnormal, the second assist control circuit does not transition the drive mode to the own system stop mode when its own operating state is a specific operating state that is deemed safe. Therefore, the second assist control circuit can appropriately respond to the abnormality of the first assist control circuit according to its own operating state. Effect of the Invention

[0018] According to the vehicle control device of the present invention, it is possible to appropriately respond to an abnormality. [Brief description of the drawings]

[0019] [Figure 1] 1 is a configuration diagram of a steer-by-wire steering device in which a first embodiment of a vehicle control device is mounted. [Diagram 2] FIG. 2 is a block diagram of a reaction force control device and a steering control device according to the first embodiment. [Diagram 3] 4 is a time chart showing an example of state transition of each control circuit according to the first embodiment. [Figure 4] 4 is a time chart showing an example of an abnormality assumed in each control circuit according to the first embodiment. [Diagram 5] 4 is a time chart showing an example of state transition of each control circuit according to the first embodiment. [Figure 6] 4 is a time chart showing an example of state transition of each control circuit according to the first embodiment. [Figure 7] FIG. 4 is a configuration diagram of a second embodiment of a vehicle control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, a first embodiment in which a vehicle control device is embodied in a steer-by-wire type steering device will be described. As shown in FIG. 1, a vehicle steering device 10 has a steering shaft 12 connected to a steering wheel 11. Steering device 10 also has a steered shaft 13 extending along the vehicle width direction (left-right direction in FIG. 1). Steered wheels 15 are connected to both ends of steered shaft 13 via tie rods 14, respectively. The steered angle θw of steered wheels 15 is changed as steered shaft 13 moves linearly. However, power transmission between steered shaft 13 and steering shaft 12 is separated. Steering shaft 12 and steered shaft 13 constitute a steering mechanism of the vehicle. Note that FIG. 1 shows only steered wheels 15 on one side.

[0021] The steering device 10 has a reaction motor 21 and a reduction mechanism 22. The reaction motor 21 is a generating source of a steering reaction force. The steering reaction force is a force acting in a direction opposite to the direction of operation of the steering wheel 11 by the driver. The rotating shaft of the reaction motor 21 is connected to the steering shaft 12 via the reduction mechanism 22. The torque of the reaction motor 21 is applied to the steering shaft 12 as a steering reaction force. By applying the steering reaction force to the steering wheel 11, it is possible to give the driver an appropriate sense of responsiveness.

[0022] The reaction motor 21 is, for example, a three-phase brushless motor. The reaction motor 21 has a first winding group N11 and a second winding group N12. The first winding group N11 and the second winding group N12 are wound around a common stator (not shown). The first winding group N11 and the second winding group N12 have equivalent electrical characteristics.

[0023] Steering device 10 has a turning motor 31 and a reduction mechanism 32. Steering motor 31 is a source of turning force. The turning force refers to power for steering steered wheels 15. A rotating shaft of steering motor 31 is connected to pinion shaft 33 via reduction mechanism 32. Pinion teeth 33a of pinion shaft 33 mesh with rack teeth 13a of steered shaft 13. The torque of steering motor 31 is applied to steered shaft 13 via pinion shaft 33 as a turning force. In response to the rotation of steering motor 31, steered shaft 13 moves along the vehicle width direction.

[0024] The steering motor 31 is, for example, a three-phase brushless motor. The steering motor 31 has a first winding group N21 and a second winding group N22. The first winding group N21 and the second winding group N22 are wound around a common stator (not shown). The first winding group N21 and the second winding group N22 have equivalent electrical characteristics.

[0025] The steering device 10 has a reaction force control device 40. The reaction force control device 40 controls the driving of the reaction force motor 21, which is the object to be controlled. The reaction force control device 40 executes reaction force control in which the reaction force motor 21 generates a steering reaction force corresponding to the steering torque Th. The reaction force control device 40 calculates a target steering reaction force based on the steering torque Th detected through a torque sensor 23. The torque sensor 23 is provided on the steering shaft 12. The reaction force control device 40 controls the power supply to the reaction force motor 21 so that the actual steering reaction force applied to the steering shaft 12 coincides with the target steering reaction force. The reaction force control device 40 controls the power supply to the two systems of winding groups in the reaction force motor 21 independently for each system.

[0026] The reaction force control device 40 has a first circuit system 41 and a second circuit system 42. The first circuit system 41 controls the power supply to the winding group N11 of the first system in the reaction force motor 21 in response to the steering torque Th detected through the torque sensor 23. The second circuit system 42 controls the power supply to the winding group N12 of the second system in the reaction force motor 21 in response to the steering torque Th detected through the torque sensor 23.

[0027] The steering device 10 has a steering control device 50. The steering control device 50 controls the driving of the steering motor 31 which is the object of control. The steering control device 50 executes steering control in which the steering motor 31 generates a steering force for turning the steered wheels 15 according to the steering state. The steering control device 50 takes in the steering angle θs detected through the steering angle sensor 24 and the stroke Xw of the steered shaft 13 detected through the stroke sensor 34. The stroke Xw is a displacement amount based on the neutral position of the steered shaft 13, and is a state variable in which the steering angle θw is reflected. The steering angle sensor 24 is provided between the torque sensor 23 of the steering shaft 12 and the reduction mechanism 22. The stroke sensor 34 is provided in the vicinity of the steered shaft 13.

[0028] The steering control device 50 calculates a target steering angle of the steered wheels 15 based on the steering angle θs detected through the steering angle sensor 24. The steering control device 50 calculates the steering angle θw based on the stroke Xw of the steered shaft 13 detected through the stroke sensor 34. The steering control device 50 controls the supply of power to the steering motor 31 so as to match the steering angle θw calculated based on the stroke Xw with the target steering angle. The steering control device 50 controls the supply of power to the two systems of winding groups in the steering motor 31 independently for each system.

[0029] The steering control device 50 has a first circuit system 51 and a second circuit system 52. The first circuit system 51 controls the power supply to the winding group N21 of the first system in the steering motor 31, based on the steering angle θs detected through the steering angle sensor 24 and the stroke Xw of the steering shaft 13 detected through the stroke sensor 34. The second circuit system 52 controls the power supply to the winding group N22 of the second system in the steering motor 31, based on the steering angle θs detected through the steering angle sensor 24 and the stroke Xw of the steering shaft 13 detected through the stroke sensor 34.

[0030] Incidentally, a so-called mechanically and electrically integrated reaction force actuator may be configured by integrally providing reaction force control device 40 and reaction force motor 21. Also, a so-called mechanically and electrically integrated steering actuator may be configured by integrally providing steering control device 50 and steering motor 31.

[0031] <Power supply path> Next, the power supply paths to the reaction force control device 40 and the steering control device 50 will be described. The various on-vehicle control devices including the reaction force control device 40 and the steering control device 50 are each supplied with power from a DC power supply 60 mounted on the vehicle. The DC power supply 60 is, for example, a battery. The various sensors including the torque sensor 23, the steering angle sensor 24 and the stroke sensor 34 are also each supplied with power from the DC power supply 60.

[0032] The first and second circuit systems 41 and 42 of the reaction force control device 40 and the first and second circuit systems 51 and 52 of the turning control device 50 are each connected to a DC power source 60 via a start switch SW of the vehicle. The start switch SW is, for example, an ignition switch or a power switch. The start switch SW is operated when starting or stopping a driving source for running the vehicle, such as an engine. When the start switch SW is turned on, power from the DC power source 60 is supplied to the first and second circuit systems 41 and 42 of the reaction force control device 40 and the first and second circuit systems 51 and 52 of the turning control device 50 via the start switch SW. Turning on the start switch SW means that the vehicle power source is turned on. Turning off the start switch SW means that the vehicle power source is turned off.

[0033] The first circuit system 41 and the second circuit system 42 of the reaction force control device 40 and the first circuit system 51 and the second circuit system 52 of the turning control device 50 are connected to a DC power supply 60 via power supply relays 60A, 60B, 60C, and 60D. When the power supply relays 60A, 60B, 60C, and 60D are turned on, power from the DC power supply 60 is supplied to the first circuit system 41 and the second circuit system 42 of the reaction force control device 40 and the first circuit system 51 and the second circuit system 52 of the turning control device 50 via the power supply relays 60A, 60B, 60C, and 60D.

[0034] The first system circuit 41 of the reaction force control device 40 controls the on / off of the power relay 60A. When the start switch SW is switched from on to off, the first system circuit 41 executes power latch control to keep the power relay 60A in the on state for a specified period. Therefore, even after the start switch SW is turned off, the first system circuit 41 can operate. When the specified period has elapsed, the first system circuit 41 can cut off the power supply to itself by switching the power relay 60A from on to off.

[0035] The first system circuit 41 detects the on / off state of the start switch SW by, for example, monitoring the voltage across the start switch SW. The first system circuit 41 detects that the start switch SW is turned on when the voltage across the start switch SW falls below a set voltage threshold. The first system circuit 41 detects that the start switch SW is turned off when the voltage across the start switch SW is equal to or higher than a set voltage threshold.

[0036] The second system circuit 42 of the reaction force control device 40 controls the on / off of the power supply relay 60B. The second system circuit 42 executes power latch control in the same manner as the first system circuit 41. The second system circuit 42 maintains the power supply relay 60B in an on state for a determined period when the start switch SW is switched from on to off.

[0037] The first system circuit 51 of the steering control device 50 controls the on / off of the power supply relay 60C. The first system circuit 51 executes power latch control in the same manner as the first system circuit 41 of the reaction force control device 40. When the start switch SW is switched from on to off, the first system circuit 51 maintains the power supply relay 60C in an on state for a determined period of time.

[0038] The second circuit system 52 of the steering control device 50 controls the on / off of the power supply relay 60D. The second circuit system 52 executes power latch control in the same manner as the first circuit system 41 of the reaction force control device 40. When the start switch SW is switched from on to off, the second circuit system 52 maintains the power supply relay 60D in an on state for a determined period of time.

[0039] Among the components of the steering device 10, those that are required to operate even after the start switch SW is turned off, such as the torque sensor 23, the steering angle sensor 24, and the stroke sensor 34, are connected to the DC power supply 60 via at least one of the power supply relays 60A, 60B, 60C, and 60D. Therefore, even if the start switch SW is turned off, when at least one of the power supply relays 60A, 60B, 60C, and 60D is turned on, power continues to be supplied to the components, such as the torque sensor 23, the steering angle sensor 24, and the stroke sensor 34.

[0040] <Reaction force control device> Next, the configuration of the reaction force control device will be described in detail. 2, the reaction force control device 40 has a first circuit system 41 and a second circuit system 42. The first circuit system 41 has a first reaction force control circuit 41A and a motor drive circuit 41B. The second circuit system 42 has a second reaction force control circuit 42A and a motor drive circuit 42B.

[0041] The first reaction force control circuit 41A is configured by a processing circuit including: (1) one or more processors operating according to a computer program (software); (2) one or more dedicated hardware circuits such as an application specific integrated circuit (ASIC) that executes at least some of various processes; and (3) a combination thereof. The processor includes a central processing unit (CPU). The processor also includes memory such as a random-access memory (RAM) and a read-only memory (ROM). The memory stores program code or instructions configured to cause the CPU to execute processes. Memory, i.e., a non-transitory computer-readable medium, includes any available medium that can be accessed by a general-purpose or special-purpose computer.

[0042] The first reaction force control circuit 41A calculates a target steering reaction force to be generated in the reaction force motor 21 based on the steering torque Th detected through the torque sensor 23, and calculates a first current command value for the winding group N11 of the first system according to the value of the calculated target steering reaction force. However, the first current command value is set to a value that is half (50%) of the amount of current (100%) required for the reaction force motor 21 to generate the target steering reaction force. The first reaction force control circuit 41A generates a drive signal (PWM signal) for the motor drive circuit 41B by executing current feedback control that makes the value of the actual current supplied to the winding group N11 of the first system follow the first current command value.

[0043] The motor drive circuit 41B is a PWM inverter in which three legs corresponding to each of the three phases (U, V, W) are connected in parallel, with two switching elements such as field effect transistors (FETs) connected in series as a basic unit. The motor drive circuit 41B converts DC power supplied from the DC power source 60 into three-phase AC power by switching the switching elements of each phase based on a drive signal generated by the first reaction force control circuit 41A. The three-phase AC power generated by the motor drive circuit 41B is supplied to the first system winding group N11 of the reaction force motor 21 via a power supply path of each phase formed of a bus bar or a cable. As a result, the first system winding group N11 generates a torque according to the first current command value.

[0044] The second reaction force control circuit 42A basically has the same configuration as the first reaction force control circuit 41A. The second reaction force control circuit 42A calculates a target steering reaction force to be generated in the reaction force motor 21 based on the steering torque Th detected through the torque sensor 23, and calculates a second current command value for the winding group N12 of the second system according to the value of the calculated target steering reaction force. However, the second current command value is set to a value that is half (50%) of the amount of current required for the reaction force motor 21 to generate the target steering reaction force. The second reaction force control circuit 42A generates a drive signal for the motor drive circuit 42B by executing current feedback control that makes the value of the actual current supplied to the winding group N12 of the second system follow the second current command value.

[0045] The motor drive circuit 42B basically has the same configuration as the motor drive circuit 41B. The motor drive circuit 42B converts DC power supplied from the DC power source 60 into three-phase AC power based on a drive signal generated by the second reaction force control circuit 42A. The three-phase AC power generated by the motor drive circuit 42B is supplied to the second winding group N12 of the reaction force motor 21 through a power supply path of each phase formed of a bus bar or a cable. As a result, the second winding group N12 generates a torque according to the second current command value. The reaction force motor 21 generates a torque that is the sum of the torque generated by the first winding group N11 and the torque generated by the second winding group N12.

[0046] There is a master-slave relationship between the first circuit system 41 and the second circuit system 42 of the reaction force control device 40. In this case, for example, the first circuit system 41 functions as a master and the second circuit system 42 functions as a slave.

[0047] <Steering control device> Next, the configuration of the steering control device 50 will be described in detail. As shown in Fig. 2, the turning control device 50 has a first circuit system 51 and a second circuit system 52. The first circuit system 51 has a first turning control circuit 51A and a motor drive circuit 51B. The second circuit system 52 has a second turning control circuit 52A and a motor drive circuit 52B.

[0048] First steering control circuit 51A has a configuration basically similar to that of first reaction force control circuit 41A. First steering control circuit 51A calculates a target steering angle of steered wheels 15 based on steering angle θs detected through steering angle sensor 24. Steering control device 50 calculates steering angle θw based on stroke Xw of steered shaft 13 detected through stroke sensor 34. First steering control circuit 51A calculates a target steering force to be generated in steering motor 31 through execution of angle feedback control for making steering angle θw calculated based on stroke Xw follow the target steering angle, and calculates a third current command value for winding group N21 of the first system of steering motor 31 according to the value of the calculated target steering force. However, the third current command value is set to a value half (50%) of the amount of current required for steering motor 31 to generate the target steering force. The first steering control circuit 51A generates a drive signal for the motor drive circuit 51B by executing current feedback control that causes the value of the actual current supplied to the winding group N21 of the first system to follow the third current command value.

[0049] Motor drive circuit 51B basically has the same configuration as motor drive circuit 41B. Motor drive circuit 51B converts DC power supplied from DC power supply 60 into three-phase AC power based on a drive signal generated by first steering control circuit 51A. The three-phase AC power generated by motor drive circuit 42B is supplied to winding group N21 of the first system of steering motor 31 via power supply paths of each phase formed of a bus bar or a cable or the like. As a result, winding group N21 of the first system generates a torque according to the third current command value.

[0050] Second steering control circuit 52A has a configuration basically similar to that of first reaction force control circuit 41A. Second steering control circuit 52A calculates a target steering angle of steered wheels 15 based on steering angle θs detected through steering angle sensor 24. Steering control device 50 calculates steering angle θw based on stroke Xw of steered shaft 13 detected through stroke sensor 34. Second steering control circuit 52A calculates a target steering force to be generated in steering motor 31 through execution of angle feedback control for making steering angle θw calculated based on stroke Xw follow the target steering angle, and calculates a fourth current command value for winding group N22 of the second system of steering motor 31 according to the value of the calculated target steering force. However, the fourth current command value is set to a value half (50%) of the amount of current required for steering motor 31 to generate the target steering force. The second steering control circuit 52A generates a drive signal for the motor drive circuit 52B by executing current feedback control that causes the value of the actual current supplied to the second system winding group N22 to follow the fourth current command value.

[0051] Motor drive circuit 52B basically has the same configuration as motor drive circuit 41B. Motor drive circuit 51B converts DC power supplied from DC power supply 60 into three-phase AC power based on a drive signal generated by second steering control circuit 52A. The three-phase AC power generated by motor drive circuit 52B is supplied to winding group N22 of the second system of steering motor 31 via power supply paths of each phase formed of bus bars or cables. This causes winding group N22 of the second system to generate torque according to the fourth current command value. Steering motor 31 generates torque which is the sum of torque generated by winding group N21 of the first system and torque generated by winding group N22 of the second system.

[0052] There is a master-slave relationship between the first circuit system 51 and the second circuit system 52 of the turning control device 50. In this case, for example, the first circuit system 51 functions as a master and the second circuit system 52 functions as a slave.

[0053] <Communication Path> Next, the internal communication paths of the reaction force control device 40 and the steering control device 50, and the communication paths between the reaction force control device 40 and the steering control device 50 will be described.

[0054] As shown in Fig. 2, the first reaction force control circuit 41A and the second reaction force control circuit 42A exchange information with each other via a communication line L1. The information includes abnormality information of the first reaction force control circuit 41A, the second reaction force control circuit 42A, or the motor drive circuits 41B, 42B. The information also includes flag values ​​indicating various states. The first reaction force control circuit 41A and the second reaction force control circuit 42A cooperate to control the drive of the reaction force motor 21 based on the information exchanged between them.

[0055] The first turning control circuit 51A and the second turning control circuit 52A exchange information with each other via the communication line L2. The information includes abnormality information of the first turning control circuit 51A, the second turning control circuit 52A, or the motor drive circuits 51B, 52B. The information also includes flag values ​​indicating various states. The first turning control circuit 51A and the second turning control circuit 52A cooperate to control the drive of the turning motor 31 based on the information exchanged between them.

[0056] The first reaction force control circuit 41A and the first turning control circuit 51A exchange information with each other via the communication line L3. The information includes abnormality information of the first reaction force control circuit 41A, the first turning control circuit 51A, and the motor drive circuits 41B, 51B. The information also includes flag values ​​indicating various states. The first reaction force control circuit 41A and the first turning control circuit 51A work in cooperation with each other based on the information exchanged between them.

[0057] The second reaction force control circuit 42A and the second turning control circuit 52A exchange information with each other via the communication line L4. The information includes abnormality information of the second reaction force control circuit 42A, the second turning control circuit 52A, or the motor drive circuits 42B, 52B. The information also includes flag values ​​indicating various states. The second reaction force control circuit 42A and the second turning control circuit 52A operate in cooperation with each other based on the information exchanged between them.

[0058] <Motor drive mode> Next, there will be explained the drive modes of reaction force motor 21 and steering motor 31. The drive modes include a cooperative drive mode, an independent drive mode, and a single-system drive mode.

[0059] The cooperative drive mode is a normal drive mode in which the first system circuits 41, 51 and the second system circuits 42, 52 are operating normally. The first system circuit 41 and the second system circuit 42 share information such as command values ​​and limit values ​​with each other to generate equal torque in both the winding group N11 of the first system and the winding group N12 of the second system of the reaction force motor 21. The first system circuit 51 and the second system circuit 52 share information such as command values ​​and limit values ​​with each other to generate equal torque in both the winding group N21 of the first system and the winding group N22 of the second system of the steering motor 31.

[0060] In the case where there is a master-slave relationship between the first system circuit 41 and the second system circuit 42 of the reaction force control device 40, when the cooperative drive mode is selected as the drive mode, the slave uses the command value calculated by the master to control the drive of the reaction force motor 21. Also, in the case where there is a master-slave relationship between the first system circuit 51 and the second system circuit 52 of the turning control device 50, when the cooperative drive mode is selected as the drive mode, the slave uses the command value calculated by the master to control the drive of the turning motor 31.

[0061] The independent drive mode is a drive mode in which the operation of any one of the four control circuits (41A, 42A, 51A, 52A) stops momentarily, but the abnormality has not been confirmed, and there is a possibility that the operation will return to normal. In the independent drive mode, for example, when there is a possibility that the operation of one control circuit that has stopped will return to normal, the remaining three control circuits generate torque in the winding group corresponding to themselves based on their own calculation results without using information from inter-system communication.

[0062] In the case where there is a master-slave relationship between the first system circuit 41 and the second system circuit 42 of the reaction force control device 40, when the independent drive mode is selected as the drive mode, the master-slave relationship between the first system circuit 41 and the second system circuit 42 is temporarily canceled. Also, in the case where there is a master-slave relationship between the first system circuit 51 and the second system circuit 52 of the turning control device 50, when the independent drive mode is selected as the drive mode, the master-slave relationship between the first system circuit 51 and the second system circuit 52 is temporarily canceled.

[0063] The single-system drive mode is a drive mode when an abnormality is confirmed in any one of the four control circuits (41A, 42A, 51A, 52A) and there is no possibility of returning to normal operation. For example, when an abnormality is confirmed in the first system circuits 41, 51, torque is generated in the reaction motor 21 and the steering motor 31 only by the second system circuits 42, 52. When an abnormality is confirmed in the second system circuits 42, 52, torque is generated in the reaction motor 21 and the steering motor 31 only by the first system circuits 41, 51.

[0064] In the case where there is a master-slave relationship between the first circuit system 41 and the second circuit system 42 of the reaction force control device 40, when the single-system drive mode is selected as the drive mode, the master-slave relationship between the first circuit system 41 and the second circuit system 42 is temporarily canceled. Also, in the case where there is a master-slave relationship between the first circuit system 51 and the second circuit system 52 of the turning control device 50, when the single-system drive mode is selected as the drive mode, the master-slave relationship between the first circuit system 51 and the second circuit system 52 is temporarily canceled.

[0065] Each control circuit (41A, 42A, 51A, 52A) controls driving of each motor (21, 31) in the cooperative drive mode during normal operation when no abnormality occurs. Each control circuit switches the drive mode from the cooperative drive mode to the independent drive mode when an abnormality determination condition is satisfied in a state in which the cooperative drive mode is selected as the drive mode. Furthermore, each control circuit returns the drive mode from the independent drive mode to the cooperative drive mode when a return determination condition is satisfied before an abnormality is determined in a state in which the independent drive mode is selected as the drive mode. Furthermore, each control circuit switches the drive mode from the independent drive mode to the single-system drive mode when an abnormality determination condition is satisfied in a state in which the independent drive mode is selected as the drive mode.

[0066] The abnormality includes temporary abnormalities that can be recovered from, such as communication abnormalities between systems, communication abnormalities within the same system, deviations in command values ​​between systems, and a decrease in the current limit value. The abnormality determination condition corresponds to a transition condition for transitioning the drive mode from the cooperative drive mode to the independent drive mode. The return determination condition corresponds to a return condition for returning the drive mode from the independent drive mode or the single-system drive mode to the cooperative drive mode.

[0067] <Control circuit state transition> Next, the state transition of each of the control circuits (41A, 42A, 51A, 52A) will be described.

[0068] When the start switch SW is turned on, each control circuit executes a startup process and an initial check. The startup process and initial check are a series of processes required for the steering system to operate. The startup process and initial check include, for example, a hardware check, initialization of the CPU, and initialization of variables or flags. While the startup process and initial check are being executed, the control status of each control circuit is an unassisted state. The unassisted state is a state in which control of the reaction force motor 21 and the steering motor 31 has not yet begun. The control status is the operating state of each control circuit.

[0069] After the execution of the initial check is normally completed, the control status of each control circuit transitions from the unassisted state to the assist start waiting state, which is a state in which all control circuits are waiting for the execution of the initial check to be normally completed.

[0070] When the execution of the initial check is normally completed in all the control circuits, each control circuit becomes able to execute control of reaction force motor 21 or turning motor 31. The control status of each control circuit transitions from an assist start waiting state to a normal control state. Each control circuit starts executing normal control to generate a steering reaction force and a turning force according to the steering state of steering wheel 11. In the normal control state, the drive mode of reaction force motor 21 and turning motor 31 is a cooperative drive mode. That is, in the normal control state, each control circuit generates torque in both the first system winding group N11 and the second system winding group N12 of reaction force motor 21, and generates torque in both the first system winding group N21 and the second system winding group N22 of turning motor 31.

[0071] When the control status of each control circuit is in the assist start waiting state or the normal control state, the control status of each control circuit transitions from the assist start waiting state to the independent drive mode state or the single-system drive mode state when a specified abnormality determination condition is satisfied. When the control status of each control circuit is in the independent drive mode state, the control status of each control circuit transitions from the independent drive mode state to the single-system drive mode state when a specified return condition is satisfied. When the control status of each control circuit is in the independent drive mode state, the control status of each control circuit transitions from the independent drive mode state to the single-system drive mode state when a specified abnormality determination condition is satisfied.

[0072] <An example of state transition of each control circuit> Next, an example of state transition during a first abnormality in each control circuit (41A, 42A, 51A, 52A) will be described. Here, as an example of an abnormality in which the drive mode switches to the independent drive mode, a case where a communication abnormality occurs between the first reaction force control circuit 41A and the first turning control circuit 51A is taken as an example. However, the communication between the first reaction force control circuit 41A and the second reaction force control circuit 42A is normal. The communication between the first turning control circuit 51A and the second turning control circuit 52A is also normal.

[0073] As shown in the time chart of Fig. 3, when the control devices are controlling the driving of the motors (21, 31) in the cooperative drive mode, if a communication abnormality occurs between first reaction force control circuit 41A and first turning control circuit 51A (time T1), the control devices switch the drive mode as follows. That is, first reaction force control circuit 41A and first turning control circuit 51A switch their respective drive modes from the cooperative drive mode to the independent drive mode. Also, first reaction force control circuit 41A and first turning control circuit 51A switch the gain for the current command value calculated by each of them from "1x" during normal control to "0x".

[0074] The first current command value calculated by first reaction force control circuit 41A is multiplied by a gain "0 times", so that the final first current command value becomes "0". Also, the third current command value calculated by first steering control circuit 51A is multiplied by a gain "0 times", so that the final third current command value also becomes "0". That is, power supply to the first system winding group N11 of reaction force motor 21 and the first system winding group N21 of steering motor 31 is stopped. Therefore, the first system winding groups N11, N21 do not generate torque.

[0075] The second reaction force control circuit 42A recognizes that a communication abnormality has occurred in the first system via the first reaction force control circuit 41 A. The second turning control circuit 52A recognizes that a communication abnormality has occurred in the first system via the first turning control circuit 51A.

[0076] When it is recognized that a communication abnormality has occurred in the first system, the second reaction force control circuit 42A and the second turning control circuit 52A switch their respective drive modes from the cooperative drive mode to the independent drive mode. Also, the second reaction force control circuit 42A and the second turning control circuit 52A switch the gain for the current command value that they each calculate from "1x" during normal control to "2x".

[0077] The second current command value calculated by the second reaction force control circuit 42A is multiplied by the gain "2x", so that the final second current command value is twice as large as the normal value. Also, the fourth current command value calculated by the second turning control circuit 52A is multiplied by the gain "2x", so that the final fourth current command value is also twice as large as the normal value. That is, it is possible to supply twice as much power as the normal value to the second system winding group N12 of the reaction force motor 21 and the second system winding group N22 of the turning motor 31. Therefore, the second system winding groups N12, N22 can generate twice as much torque as the normal value. Therefore, it is possible to compensate for the decrease in torque generated by the first system winding groups N11, N21 with the torque generated by the second system winding groups N12, N22. However, depending on the product specifications, when the second current command value and the fourth current command value exceed a defined tolerance range, the second current command value and the fourth current command value may be limited to a limit value that is set based on the limit value of the tolerance range.

[0078] Here, when the drive of the motors (21, 31) is controlled in the independent drive mode by the second system, it is possible that the communication abnormality in the first system is resolved before the communication abnormality in the first system is confirmed (time T2).

[0079] When a set return determination condition is satisfied, the first reaction force control circuit 41A and the first turning control circuit 51A of the abnormal system return the drive mode from the independent drive mode to the cooperative drive mode (time T3). The return determination condition includes that the communication abnormality between the first reaction force control circuit 41A and the first turning control circuit 51A has been resolved. When returning the drive mode from the independent drive mode to the cooperative drive mode, the first reaction force control circuit 41A and the first turning control circuit 51A of the abnormal system switch the gain for the current command value calculated by each of them from "0 times" during the abnormal state to "1 times" during normal control.

[0080] Accordingly, the second reaction force control circuit 42A and the second turning control circuit 52A of the normal system return the drive mode from the independent drive mode to the cooperative drive mode. Also, the second reaction force control circuit 42A and the second turning control circuit 52A switch the gain for the current command value calculated by each of them from "2 times" during abnormality to "1 times" during normal control. The drive modes are synchronized between the first reaction force control circuit 41A and the second reaction force control circuit 42A. The drive modes are synchronized between the first turning control circuit 51A and the second turning control circuit 52A.

[0081] The return determination condition may include that the stopped state continues for a first determination time and that the state in which the steering wheel 11 is not steered continues for a second determination time. Whether the vehicle is stopped is determined, for example, based on the vehicle speed detected by a vehicle speed sensor. The state in which the steering wheel 11 is not steered includes, for example, a steering state when the vehicle is moving straight and a steering state when the vehicle is making a steady turn. Whether the steering wheel 11 is steered is determined, for example, based on the steering torque Th.

[0082] <Examples of possible abnormalities in each control circuit> Next, an example of a possible abnormality in each of the control circuits (41A, 42A, 51A, 52A) will be described.

[0083] There is concern that the following types of abnormality may occur in each control device. Here, for example, a case where an abnormality occurs in communication between first turning control circuit 51A and second turning control circuit 52A from the time when each control circuit (41A, 42A, 51A, 52A) is started with the vehicle power turned on will be described as an example. However, the abnormality also includes a case where first reaction force control circuit 41A and second reaction force control circuit 42A, which are started earlier, each detect a communication abnormality due to a delay in starting first turning control circuit 51A and second turning control circuit 52A.

[0084] As shown in the time chart of Fig. 4, when the vehicle power supply is turned on (time T11), for example, if an abnormality occurs in the communication between the first steering control circuit 51A and the second steering control circuit 52A, the control status of the first steering control circuit 51A becomes a state of waiting for the start of the other system. The other system is the second steering control circuit 52A. The control status of the second steering control circuit 52A also becomes a state of waiting for the start of the other system, like the first steering control circuit 51A. The other system is the first steering control circuit 51A.

[0085] The first reaction force control circuit 41A executes a start-up process and an initial check when the vehicle power supply is turned on (time T11). During the start-up process and the initial check, the control status of the first reaction force control circuit 41A is in the unassisted state.

[0086] Also, the first reaction force control circuit 41A monitors the operating state of the first turning control circuit 51A during the execution of the start-up process or the initial check. This is based on the viewpoint of controlling the drive of the reaction force motor 21 in synchronization with the control of the turning motor 31 by the first turning control circuit 51A. In the example of FIG. 4, since the first turning control circuit 51A is not started, the first reaction force control circuit 41A transitions the drive mode of the reaction force motor 21 from the cooperative drive mode to the own system stop mode (time T12). That is, the first reaction force control circuit 41A switches the gain for the first current command value calculated by itself from "1x" during normal control to "0x". When the execution of the initial check is normally completed, the first reaction force control circuit 41A transitions the control status to a state waiting for the start of assist of the other system (time T13).

[0087] When the start-up waiting state of the other system has elapsed for a specified period, the first turning control circuit 51A executes the start-up process and the initial check (time T14). During the start-up process and the initial check, the control status of the first turning control circuit 51A is the unassisted state. However, the first turning control circuit 51A acquires the drive mode of the reaction force motor 21 from the first reaction force control circuit 41A, and synchronizes the drive mode of the turning motor 31 with the acquired drive mode (time T15). That is, the first turning control circuit 51A transitions the drive mode of the turning motor 31 from the cooperative drive mode to the own system stop mode. The first turning control circuit 51A switches the gain for the third current command value calculated by itself from "1x" during normal control to "0x".

[0088] When the first steering control circuit 51A completes the initial check normally (time T16), it transitions the control status to a state waiting for the start of assist of the other system. However, communication between the first steering control circuit 51A and the second steering control circuit 52A is abnormal, and the first steering control circuit 51A is not communicating with the second steering control circuit 52A. Therefore, the first steering control circuit 51A transitions the control status from the state waiting for the start of assist of the other system to the independent drive mode (time T17).

[0089] When the execution of the initial check by the first turning control circuit 51A is completed (time T16), the first reaction force control circuit 41A determines that the first turning control circuit 51A has been started and transitions the control status from a state waiting for the start of assist of the other system to a normal control state. Also, the first reaction force control circuit 41A transitions the drive mode of the reaction force motor 21 from the self-system stop mode to the cooperative drive mode.

[0090] However, first reaction force control circuit 41A acquires the control status and the drive mode of steering motor 31 from first steering control circuit 51A (time T18). The first reaction force control circuit 41A synchronizes the control status of the first reaction force control circuit 41A with the control status of the first turning control circuit 51A that is acquired. That is, the first reaction force control circuit 41A transitions the control status from a normal control state to an independent drive state. The first reaction force control circuit 41A also synchronizes the drive mode of the reaction force motor 21 with the drive mode that is acquired. That is, the first reaction force control circuit 41A transitions the drive mode of the reaction force motor 21 from a cooperative drive mode to a self-system stop mode. The first reaction force control circuit 41A switches the gain for the first current command value that it calculates from "1x" during normal control to "0x".

[0091] At this point in time, the gain of first reaction force control circuit 41A and the gain of first turning control circuit 51A are both “0 times.” For example, if communication returns to a normal state (time T19) before a communication abnormality between first turning control circuit 51A and second turning control circuit 52A is confirmed, the gain is maintained at “0 times.”

[0092] The second reaction force control circuit 42A executes the same process as the first reaction force control circuit 41A. The second turning control circuit 52A executes the same process as the first turning control circuit 51A. The information exchanged between the first reaction force control circuit 41A and the first turning control circuit 51A is the same as the information exchanged between the second reaction force control circuit 42A and the second turning control circuit 52A. For this reason, a situation may occur in which the gain of the second reaction force control circuit 42A and the gain of the second turning control circuit 52A are both "0 times". That is, a situation may occur in which the gains of all the four control circuits (41A, 42A, 51A, 52A) are all "0 times". When the communication between the first turning control circuit 51A and the second turning control circuit 52A returns to a normal state before the communication abnormality is confirmed, the state in which all the gains are "0 times" is maintained.

[0093] If the gains of all of the four control circuits (41A, 42A, 51A, 52A) become "0x," it becomes difficult to apply a steering reaction force to the steering wheel 11 and a steering force to the steered wheels 15. In other words, it becomes difficult to execute appropriate reaction force control and appropriate steering control. Therefore, in this embodiment, in order to respond appropriately to such abnormalities, the following two configurations are adopted for each control circuit (41A, 42A, 51A, 52A).

[0094] <First Configuration> First, the first configuration will be described. Before the control status transitions to the normal control state, each control circuit (41A, 42A, 51A, 52A) does not execute a process for determining whether to transition the drive mode of each motor (21, 31) to the own system stop mode. This is because there is no safety problem even if a communication abnormality occurs before the drive mode transitions to the normal control state. For this reason, even if, for example, a communication abnormality occurs between the systems before the drive mode transitions to the normal control state, the control status does not transition to the own system stop mode, i.e., the gain does not switch to "0 times". A specific example is as follows.

[0095] As shown in the time chart of FIG. 5, when the vehicle power supply is turned on (time T21), for example, if an abnormality occurs in communication between the first steering control circuit 51A and the second steering control circuit 52A, the control status of the first steering control circuit 51A becomes a waiting state for activation of the other system.

[0096] When the start-up waiting state of the other system has elapsed for a predetermined period (time T22), the first turning control circuit 51A executes the start-up process and the initial check. During the start-up process and the initial check, the control status of the first turning control circuit 51A is the unassisted state. The drive mode of the turning motor 31 is the cooperative drive mode.

[0097] When the execution of the initial check is normally completed (time T23), the first turning control circuit 51A executes SBW (Steer-By-Wire) control (time T35). The SBW control here is turning control. The first turning control circuit 51A also transitions the control status to a state waiting for the start of assist of the other system. However, communication between the first turning control circuit 51A and the second turning control circuit 52A is abnormal, and the first turning control circuit 51A is not communicating with the second turning control circuit 52A. Therefore, the first turning control circuit 51A transitions the control status from the state waiting for the start of assist of the other system to an independent drive mode (time T24). The drive mode of the turning motor 31 is maintained in the cooperative drive mode.

[0098] Thereafter, communication may return to a normal state before the communication abnormality between the first turning control circuit 51A and the second turning control circuit 52A is confirmed (time T25). The second steering control circuit 52A executes the same processing as the first steering control circuit 51A. After the execution of the initial check is completed, the control status of the second steering control circuit 52A transitions to the independent drive mode via the assist start waiting state. The drive mode of the steering motor 31 is maintained in the cooperative drive mode.

[0099] When the vehicle power supply is turned on (time T21), the first reaction force control circuit 41A executes a start-up process and an initial check. During the start-up process and the initial check, the control status of the first reaction force control circuit 41A is in the unassisted state. Although the first turning control circuit 51A is not started, the first reaction force control circuit 41A does not execute a process of determining whether or not to transition the drive mode to the own system stop mode because the control status has not yet transitioned to the normal control state. Therefore, even if the first turning control circuit 51A is not started, the drive mode is maintained in the cooperative drive mode without transitioning to the own system stop mode. That is, the gain for the first current command value calculated by the first reaction force control circuit 41A is not switched from "1x" during normal control to "0x".

[0100] When the first reaction force control circuit 41A has completed the execution of the initial check (time T26), it transitions the control status from the unassisted state to a state waiting for the start of assistance from the other system. When the execution of the initial check by the first turning control circuit 51A is completed (time T23), the first reaction force control circuit 41A executes SBW control assuming that the first turning control circuit 51A has been started. The SBW control here is reaction force control. Also, the first reaction force control circuit 41A transitions the control status from a state waiting for the start of assist of the other system to a normal control state. The drive mode of the reaction force motor 21 is the cooperative drive mode.

[0101] The second reaction force control circuit 42A executes the same process as the first reaction force control circuit 41A. After the initial check is completed, the control status of the second reaction force control circuit 42A transitions to a normal control state via a waiting state for the start of assist of the other system. The drive mode of the reaction force motor 21 is maintained in the cooperative drive mode.

[0102] In this way, even if an abnormality occurs in the communication between the first turning control circuit 51A and the second turning control circuit 52A from the start of each control circuit (41A, 42A, 51A, 52A) due to the vehicle power being turned on, the drive mode of the reaction force motor 21 and the turning motor will not transition to the self-system stop mode. That is, the gains of each control circuit will not all become "0 times." Furthermore, even if the communication returns to a normal state before the communication abnormality between the first turning control circuit 51A and the second turning control circuit 52A is confirmed, the drive mode of the reaction force motor 21 and the turning motor 31 will be maintained in the cooperative drive mode.

[0103] The same applies to the case where an abnormality occurs in communication between the first reaction force control circuit 41A and the second reaction force control circuit 42A from the start-up of each control circuit (41A, 42A, 51A, 52A) when the vehicle power supply is turned on.

[0104] Furthermore, the abnormality is not limited to a communication abnormality between the systems. The abnormality includes a case where the first reaction force control circuit 41A and the second reaction force control circuit 42A execute reset processing simultaneously at the time of startup, causing a delay in startup. In this case, the first turning control circuit 51A and the second turning control circuit 52A, which start first, each detect a communication abnormality. The abnormality also includes a case where the first turning control circuit 51A and the second turning control circuit 52A execute reset processing simultaneously at the time of startup, causing a delay in startup. In this case, the first reaction force control circuit 41A and the second reaction force control circuit 42A, which start first, each detect a communication abnormality.

[0105] <Second Configuration> Next, the second configuration will be described. When an unintended gain combination occurs during execution of normal control, each control circuit (41A, 42A, 51A, 52A) transmits a notification signal S1 indicating the occurrence of the unintended gain combination to the vehicle control device 90. A specific example is as follows.

[0106] As shown in the time chart of FIG. 6, when each control circuit (41A, 42A, 51A, 52A) is performing normal control, for example, the first turning control circuit 51A and the second turning control circuit 52A are reset simultaneously (time T31).

[0107] In this case, since the first turning control circuit 51A is not activated, the first reaction force control circuit 41A transitions the control status from the normal control state to the independent drive state. The first reaction force control circuit 41A also transitions the drive mode of the reaction force motor 21 from the cooperative drive mode to the own system stop mode (time T32). That is, the first reaction force control circuit 41A switches the gain for the first current command value that it calculates from "1x" during normal control to "0x".

[0108] The second reaction force control circuit 42A executes the same processing as the first reaction force control circuit 41A. Since the second turning control circuit 52A is not activated, the second reaction force control circuit 42A transitions the control status from the normal control state to the independent drive state. In addition, the second reaction force control circuit 42A transitions the drive mode of the reaction force motor 21 from the cooperative drive mode to the self-system stop mode. That is, the first reaction force control circuit 41A switches the gain for the second current command value that it calculates from "1x" during normal control to "0x".

[0109] After the first turning control circuit 51A has been reset, it executes a start-up process and an initial check (time T33). When the first turning control circuit 51A has normally completed the execution of the initial check (time T34), it executes SBW control after an assist start waiting period (time T35). The SBW control here is turning control.

[0110] However, the first turning control circuit 51A acquires the control status and the drive mode of the reaction force motor 21 from the first reaction force control circuit 41A. The first turning control circuit 51A synchronizes the control status of the first turning control circuit 51A with the acquired control status of the first reaction force control circuit 41A. That is, the first turning control circuit 51A transitions the control status from the normal control state to the independent drive state. Also, the first turning control circuit 51A synchronizes the drive mode of the turning motor 31 with the acquired drive mode of the reaction force motor 21. That is, the first turning control circuit 51A transitions the drive mode of the turning motor 31 from the cooperative drive mode to the self-system stop mode. The first turning control circuit 51A switches the gain for the third current command value calculated by itself from "1x" during normal control to "0x".

[0111] The second turning control circuit 52A executes the same process as the first turning control circuit 51A. After completing the reset, the second turning control circuit 52A executes the start process and the initial check. When the execution of the initial check is normally completed, the second turning control circuit 52A executes the SBW control after an assist start waiting period. However, the second turning control circuit 52A synchronizes the control status of the second turning control circuit 52A with the control status of the second reaction force control circuit 42A acquired. That is, the second turning control circuit 52A transitions the control status from the normal control state to the independent drive state. In addition, the second turning control circuit 52A synchronizes the drive mode of the turning motor 31 with the drive mode of the reaction force motor 21 acquired. That is, the second turning control circuit 52A transitions the drive mode of the turning motor 31 from the cooperative drive mode to the self-system stop mode. The second turning control circuit 52A switches the gain for the fourth current command value that it itself calculates from "1x" during normal control to "0x."

[0112] Therefore, the gains of the four control circuits (41A, 42A, 51A, 52A) are all "0 times." When all the gains are "0 times," an unintended gain combination occurs. In this case, at least one of the four control circuits generates a notification signal S1 and transmits the generated notification signal S1 to the vehicle control device 90.

[0113] The vehicle control device 90 controls, for example, the running of the vehicle. Specifically, the vehicle control device 90 controls, for example, the powertrain of the vehicle. The powertrain includes a drive source for running the vehicle and a power transmission mechanism. The drive source for running includes, for example, an engine or a motor. The power transmission mechanism is a mechanism for transmitting power generated by the drive source for running to drive wheels.

[0114] The vehicle control device 90 executes a predetermined process when the notification signal S1 is received. The process includes, for example, a stop process for safely stopping the vehicle. The stop process includes a process for automatically stopping the vehicle within the lane. The stop process also includes an automatic evacuation process for automatically stopping the vehicle at a safe place such as a road shoulder, regardless of the driving state of the driver. The vehicle control device 90 can recognize the surrounding environment of the vehicle through the camera and sensor mounted on the vehicle. The vehicle is safely stopped through the execution of the stop process.

[0115] The processing may include a notification process for notifying the driver of the occurrence of an abnormality. The notification process may include a process for notifying the driver of the occurrence of an abnormality by appealing to the driver's visual sense via an in-vehicle display device. The notification process may also include a process for notifying the driver of the occurrence of an abnormality by appealing to the driver's auditory sense via an in-vehicle speaker. The driver can recognize the occurrence of an abnormality through his or her visual or auditory sense. It is also possible to prompt the driver to take action when an abnormality occurs.

[0116] <Advantages of the First Embodiment> The first embodiment provides the following advantages. (1-1) Even if the operating state of the control circuit of the other system other than the own system is abnormal, each control circuit (41A, 42A, 51A, 52A) does not transition the drive mode to the own system stop mode when its own operating state is a specific operating state that is deemed safe. The abnormality includes, for example, a communication abnormality caused by a start-up delay when the vehicle power supply is turned on, or a communication abnormality caused by a reset of the control circuit. According to this configuration, even if the operating state of the control circuit of the other system other than the own system is abnormal, each control circuit does not transition the drive mode to the own system stop mode when its own operating state is a specific operating state that is deemed safe. Therefore, each control circuit can appropriately respond to an abnormality in the control circuit of the other system other than the own system according to its own operating state.

[0117] (1-2) When the vehicle power supply is turned on, each control circuit (41A, 42A, 51A, 52A) executes a start-up process and an initial check. In addition, each control circuit monitors the operating state of the control circuits of the other systems from the viewpoint of controlling the drive of the reaction force motor 21 and the steering motor 31 in synchronization with the control circuits of the other systems. A specific operating state that does not transition the drive mode to the own system stop mode is a state in which the start-up process or the initial check is being executed. With this configuration, there is no safety problem while the start-up process and the initial check are being executed. Therefore, even if the operating state of the control circuit of the other system is abnormal, it is possible to prevent the drive mode from transitioning to the own system stop mode.

[0118] (1-3) Each control circuit (41A, 42A, 51A, 52A) synchronizes the drive modes with each other. In addition, each control circuit is capable of communicating with vehicle control device 90 that controls the vehicle. When each control circuit is controlling the drive of reaction motor 21 or steering motor 31, and the operating state of the control circuit of the other system is abnormal, each control circuit transitions the drive mode to its own system stop mode. When the drive modes of all the control circuits have transitioned to their own system stop mode through the above-mentioned synchronization, each control circuit transmits a notification signal S1 indicating this to vehicle control device 90. Therefore, vehicle control device 90 can recognize that it is difficult to drive reaction motor 21 and steering motor 31 based on the notification signal S1.

[0119] An example of a case in which the drive modes of all the control circuits transition to the own system stop mode is when the first turning control circuit 51A and the second turning control circuit 52A are simultaneously reset while the first reaction force control circuit 41A and the second reaction force control circuit 42A are each controlling the drive of the reaction force motor 21. Another example of a case in which the drive modes of all the control circuits transition to the own system stop mode is when the first reaction force control circuit 41A and the second reaction force control circuit 52A are simultaneously reset while the first turning control circuit 51A and the second turning control circuit 52A are each controlling the drive of the turning motor 31.

[0120] (1-4) The first reaction force control circuit 41A and the first turning control circuit 51A are in a relationship of mutually monitoring their operating states. Also, the second reaction force control circuit 42A and the second turning control circuit 52A are in a relationship of mutually monitoring their operating states. According to this configuration, even if the operating state of the first reaction force control circuit 51A, which is a control circuit of another system other than the own system, is abnormal, when the operating state of the first reaction force control circuit 41A is a specific operating state that is deemed safe. Therefore, the first reaction force control circuit 41A can appropriately respond to the abnormality of the first turning control circuit 51A according to its own operating state. Also, even if the operating state of the first reaction force control circuit 41A, which is a control circuit of another system other than the own system, is abnormal, when the operating state of the first reaction force control circuit 41A is a specific operating state that is deemed safe, the first turning control circuit 51A does not transition the driving mode to the own system stop mode. Therefore, the first turning control circuit 51A can appropriately respond to an abnormality in the first reaction force control circuit 41A according to its own operating state. The same applies to the second reaction force control circuit 42A and the second turning control circuit 52A.

[0121] <Second embodiment> Next, a second embodiment in which the vehicle control device is embodied in an electric power steering device will be described. Note that the same members as those in the first embodiment are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0122] The electric power steering device is configured by mechanically connecting the steering wheel 11 and the steered wheels 15 shown in Fig. 1 above. That is, the steering shaft 12, the pinion shaft 33 and the steered shaft 13 function as a power transmission path between the steering wheel 11 and the steered wheels 15. When the steering wheel 11 is steered, the steered shaft 13 moves linearly, so that the steered angle θw of the steered wheels 15 is changed.

[0123] The electric power steering device has an assist motor and an assist control device. The assist motor is provided in the same position as reaction motor 21 or steering motor 31 shown in FIG. 1 above. The assist motor generates an assist force for assisting the operation of steering wheel 11. The assist force is a torque in the same direction as the steering direction of steering wheel 11. The assist control device controls the drive of the assist motor, which is the object of control.

[0124] As shown in FIG. 7, the assist motor 70 has a first winding group N31 and a second winding group N32. The assist control device 80 has a first system circuit 81. The first system circuit 81 has a first assist control circuit 81A and a motor drive circuit 81B. The first assist control circuit 81A controls the power supply to the winding group N31 of the first system. The first assist control circuit 81A generates a drive signal for the motor drive circuit 81B based on the steering torque Th detected via the torque sensor 23.

[0125] The motor drive circuit 81B converts the DC power supplied from the DC power supply 60 into three-phase AC power based on a drive signal generated by the first assist control circuit 81A. The three-phase AC power generated by the motor drive circuit 81B is supplied to the first system winding group N31 of the assist motor 70 via power supply paths for each phase, which are formed of bus bars or cables.

[0126] The assist control device 80 has a second system circuit 82. The second system circuit 82 has a second assist control circuit 82A and a motor drive circuit 82B. The second assist control circuit 82A controls the power supply to the winding group N32 of the second system. The second assist control circuit 82A generates a drive signal for the motor drive circuit 82B based on the steering torque Th detected via the torque sensor 23.

[0127] The motor drive circuit 82B converts the DC power supplied from the DC power supply 60 into three-phase AC power based on a drive signal generated by the second assist control circuit 82A. The three-phase AC power generated by the motor drive circuit 82B is supplied to the second system winding group N32 of the assist motor 70 via power supply paths for each phase, which are formed of bus bars or cables or the like.

[0128] The first assist control circuit 81A and the second assist control circuit 82A exchange information with each other via a communication line. The information includes abnormality information of the first assist control circuit 81A, the second assist control circuit 82A, or the motor drive circuits 81B, 82B. The information also includes the values ​​of various flags. The first assist control circuit 81A and the second assist control circuit 82A cooperate to control the drive of the assist motor 70 based on the information exchanged between them.

[0129] First assist control circuit 81A basically has a configuration similar to that of first reaction force control circuit 41A or second reaction force control circuit 42A shown in Fig. 2. Second assist control circuit 82A basically has a configuration similar to that of first turning control circuit 51A or second turning control circuit 52A shown in Fig. 2. First assist control circuit 81A and second assist control circuit 82A control the drive of assist motor 70 in one of a cooperative drive mode, an independent drive mode, and a single-system drive mode, like the control circuits (41A, 42A, 51A, 52A) in the first embodiment.

[0130] If a communication abnormality occurs between the first assist control circuit 81A and the second assist control circuit 82A when the vehicle power supply is on, the first assist control circuit 81A and the second assist control circuit 82A execute the following processing. That is, the first assist control circuit 81A executes processing similar to that of the first reaction force control circuit 41A or the second reaction force control circuit 42A in the first embodiment shown in Fig. 5. The second assist control circuit 82A executes processing similar to that of the first turning control circuit 51A or the second turning control circuit 52A in the first embodiment shown in Fig. 5.

[0131] Also, when first assist control circuit 81A and second assist control circuit 82A are executing normal control, for example when second assist control circuit 82A is reset, first assist control circuit 81A and second assist control circuit 82A execute the following processing. That is, first assist control circuit 81A executes processing similar to that of first reaction force control circuit 41A or second reaction force control circuit 42A in the first embodiment shown in FIG 6. Second assist control circuit 82A executes processing similar to that of first turning control circuit 51A or second turning control circuit 52A in the first embodiment shown in FIG 6.

[0132] Therefore, the second embodiment has the following advantages. (2-1) Even if the operation state of the second assist control circuit 82A, which is a control circuit of another system other than the own system, is abnormal, the first assist control circuit 81A does not transition the drive mode to the own system stop mode when its own operation state is a specific operation state that is deemed safe. Therefore, the first assist control circuit 81A can appropriately respond to the abnormality of the second assist control circuit 82A according to its own operation state. Also, even if the operation state of the first assist control circuit 81A, which is a control circuit of another system other than the own system, is abnormal, the second assist control circuit 82A does not transition the drive mode to the own system stop mode when its own operation state is a specific operation state that is deemed safe. Therefore, the second assist control circuit 82A can appropriately respond to the abnormality of the first assist control circuit 81A according to its own operation state.

[0133] (2-2) Each control circuit (81A, 82A) executes a startup process and an initial check when the vehicle power supply is turned on. In addition, each control circuit monitors the operating state of the control circuit of the other system from the viewpoint of controlling the drive of the assist motor 70 in synchronization with the control circuit of the other system. A specific operating state that does not transition the drive mode to the own system stop mode is a state in which the startup process or the initial check is being executed. With this configuration, there is no safety problem while the startup process and the initial check are being executed. Therefore, even if the operating state of the control circuit of the other system is abnormal, it is possible to prevent the drive mode from transitioning to the own system stop mode.

[0134] (2-3) The control circuits (81A, 82A) synchronize the drive modes with each other. Furthermore, each control circuit is configured to be able to communicate with a vehicle control device 90 that controls the vehicle. When each control circuit is controlling the drive of the assist motor 70 and the operating state of the control circuit of the other system is abnormal, the control circuit transitions the drive mode to the own system stop mode. When the drive modes of all the control circuits have transitioned to the own system stop mode through the above-mentioned synchronization, each control circuit transmits a notification signal S1 indicating this to the vehicle control device 90. Therefore, the vehicle control device 90 can recognize that it is difficult to drive the assist motor 70 based on the notification signal S1.

[0135] An example of a case in which the drive modes of all the control circuits transition to the own system stop mode is when the second assist control circuit 82A is reset while the first assist control circuit 81A is controlling the drive of the assist motor 70. Another example of a case in which the drive modes of all the control circuits transition to the own system stop mode is when the first assist control circuit 81A is reset while the second assist control circuit 82A is controlling the drive of the assist motor 70.

[0136] <Other embodiments> This embodiment may be modified as follows. In the first embodiment, the first reaction force control circuit 41A and the second reaction force control circuit 42A may determine whether the steering wheel 11 is being steered. Whether the steering wheel 11 is being steered is determined, for example, based on the steering torque Th. When the first current command value and the second current command value are both "0" even though the steering wheel 11 is being steered, the first reaction force control circuit 41A and the second reaction force control circuit 42A determine that an abnormal state in which a steering reaction force is not being applied to the steering wheel 11 is occurring, and transmit a notification signal S1 indicating this to the vehicle control device 90. In this way, the vehicle control device 90 can recognize that an abnormal state in which a steering reaction force is not being applied to the steering wheel 11 is occurring, based on the notification signal S1. When the abnormal state is recognized, the vehicle control device 90 may execute, for example, a stopping process for safely stopping the vehicle, or a notification process for notifying the driver of the occurrence of an abnormality.

[0137] In the first embodiment, the reaction force motor 21 and the turning motor 31 have two winding groups, but may have one winding group. In this case, the reaction force control device 40 may have only one of the first circuit system 41 and the second circuit system 42. Also, in this case, the turning control device 50 may have only one of the first circuit system 51 and the second circuit system 52. The first reaction force control circuit 41A or the second reaction force control circuit 42A corresponds to a reaction force control circuit. The first turning control circuit 51A or the second turning control circuit 52A corresponds to a turning control circuit. According to this configuration, the same effects as those of (2-1) to (2-3) of the second embodiment can be obtained. The first assist control circuit 81A may be read as a reaction force control circuit, and the second assist control circuit 82A may be read as a turning control circuit.

[0138] In the first embodiment, the vehicle control device is embodied in a steer-by-wire steering device, and in the second embodiment, the vehicle control device is embodied in an electric power steering device. However, for example, the vehicle control device may be embodied in an electric door mirror device that opens and closes in conjunction with a door lock after the vehicle power supply is turned off. It is possible to embody the present invention in all vehicle control devices having redundant control circuits and motor drive circuits. The redundant control circuits may require, for example, state transitions that are synchronized with each other. [Explanation of symbols]

[0139] 11…Steering wheel 15…Steering wheel 21…Reaction motor 31...Steering motor 41A...First reaction force control circuit 42A...Second reaction force control circuit 51A...First steering control circuit 52A...Second steering control circuit 70...Assist motor 81A...First assist control circuit 82A...Second assist control circuit 90...Vehicle control device N11: Winding group of reaction motor 1 N12: Second winding group of reaction motor N21: First winding group of steering motor N22: Second winding group of steering motor N31: Assist motor first system winding group N32: Second winding group of the assist motor

Claims

1. a control circuit for a plurality of systems configured to calculate a current command value according to a torque to be generated in a motor having a plurality of winding groups, and to independently control power supply to the plurality of winding groups for each system based on the calculated current command value; the control circuit is configured to drive the motor in a drive mode that is switched depending on an operation state of the control circuit of another system other than the control circuit of the own system; the drive modes include an own system stop mode in which, when an operating state of the control circuit of another system other than the own system is abnormal, power supply to the winding group of the own system is stopped, The control circuit is configured not to transition the drive mode to the own system stop mode when its own operating state is a specific operating state that is deemed not to pose a safety problem, even if the operating state of the control circuit of another system other than the own system is abnormal.

2. the control circuit is configured to execute a start-up process and an initial check when a vehicle power source is turned on, and to monitor an operation state of the control circuit of another system other than the own system from the viewpoint of controlling the drive of the motor in synchronization with the control circuit of the other system; The vehicle control device according to claim 1 , wherein the specific operating state is a state in which the startup process or the initial check is being performed.

3. The control circuits are configured to synchronize the drive modes with each other and to communicate with a vehicle controller configured to control the vehicle; 3. The vehicle control device according to claim 1, wherein the control circuit, when controlling the drive of the motor, is configured to transition the drive mode to the own system stop mode when an operating state of the control circuit of another system other than the own system is abnormal, and when the drive modes of all of the multiple control circuits have transitioned to the own system stop mode through the synchronization, to transmit an alarm signal indicating this to the vehicle control device.

4. The motor is a reaction motor having two winding groups and configured to generate a steering reaction force to be applied to a steering wheel whose power transmission between the reaction motor and the steered wheels is separated; a steering motor having two winding groups and configured to generate a steering force for steering the steered wheels; The plurality of control circuits include a first reaction force control circuit configured to control power supply to the reaction force motor; a second reaction force control circuit configured to control power supply to the reaction force motor; A first steering control circuit configured to control power supply to the steering motor; A second steering control circuit configured to control power supply to the steering motor, The first reaction force control circuit and the first steering control circuit are in a relationship of monitoring each other's operating states, 3. The vehicle control device according to claim 1, wherein the second reaction force control circuit and the second steering control circuit are in a relationship in which they monitor each other's operating states.

5. The motor is a reaction motor having one system of windings configured to generate a steering reaction force to be applied to a steering wheel whose power transmission between the reaction motor and the steered wheels is separated; a steering motor having one system of winding groups, the steering motor being configured to generate a steering force for steering the steered wheels; The plurality of control circuits include a reaction force control circuit configured to control power supply to the reaction force motor; 3. The vehicle control device according to claim 1, further comprising: a steering control circuit configured to control power supply to the steering motor.

6. The motor is an assist motor configured to generate an assist force for assisting an operation of a steering wheel, the assist motor has a first winding group and a second winding group, The plurality of control circuits include a first assist control circuit configured to control power supply to the first system of windings; 3. The vehicle control device according to claim 1, further comprising: a second assist control circuit configured to control power supply to the second system of windings.

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