Steering control device

Abstract

To provide a steering control device that can appropriately take action when a control circuit normally operating is reset.SOLUTION: A steering control device includes: a dual reaction force control circuit configured to control a reaction force motor; and a dual turning control circuit configured to control a turning motor. For example, the reaction force control circuit is reset in a state where the reaction force motor and the turning motor are controlled only by the dual reaction force control circuit and the dual turning control circuit (YES in steps S101, S102). In such a case, when being restarted after reset is completed, the reaction force control circuit executes processing for stopping running of a vehicle (step S104). Also, when being restarted after reset is completed, the reaction force control circuit stops driving of the reaction force motor (step S103). The dual turning control circuit normally operating without being reset stops driving of the turning motor in synchronization with the reset reaction force control circuit (step S103).SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] Conventionally, there have been steering devices of the so-called steer-by-wire type, in which power transmission between the steering wheel and the steered wheels is separated. For example, the steer-by-wire system disclosed in Patent Document 1 has a reaction force actuator and a steering actuator. The reaction force actuator generates a steering reaction force applied to the steering shaft. The steering actuator generates a steering force that steers the steered wheels.

[0003] The reaction force actuator and the steering actuator each have two redundant control calculation units and two redundant motor drive units. The control calculation units perform calculations related to motor drive control. The motor drive units generate torque based on drive signals generated by their corresponding control calculation units.

[0004] When an abnormality occurs in the first or second system of either the reaction force actuator or the steering actuator, the control calculation unit of each actuator in the abnormal system stops drive control of the motor. Also, when an abnormality occurs in the inter-system communication between the first or second system, the control calculation unit of each actuator in the abnormal system stops drive control of the motor. The control calculation unit of the normal system in each actuator continues drive control of the motor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-70431 Summary of the Invention [Problem to be solved by the invention]

[0006] If the control and calculation unit of the normal system continues to control the drive of the motor, the following concerns arise. For example, the control and calculation unit of the normal system may be reset due to a drop in the power supply voltage. In this case, there is a risk that the appropriate control of the motor, which is the control target of the reset control and calculation unit, may be impaired. For this reason, it is necessary to take appropriate measures when the control and calculation unit is reset. [Means for solving the problem]

[0007] A steering control device that can solve the above problem has a plurality of control circuits configured to control, in cooperation with each other, a reaction motor that generates a steering reaction force applied to a steering wheel whose power transmission is separated from the steered wheels of a vehicle, and a steering motor that generates a steering force for turning the steered wheels. When at least one of the plurality of control circuits that are operating normally is reset, the reset control circuit is configured to execute a process for stopping the vehicle from traveling when it is restarted after the reset is completed.

[0008] When the reaction motor and the steering motor are controlled by multiple control circuits, the following concerns arise: At least one of the control circuits that is operating normally may be reset due to, for example, a drop in the power supply voltage, which may impede proper control of the reaction motor or the steering motor that is the control target of the reset control circuit.

[0009] In this regard, according to the steering control device described above, when at least one of the plurality of control circuits operating normally is reset, the reset control circuit executes processing to stop the vehicle from traveling when it restarts after the reset is complete. This makes it possible to prevent the vehicle from continuing to travel in a state where appropriate control of the reaction force motor or the steering motor is impaired. Therefore, it is possible to appropriately deal with the reset of the control circuit.

[0010] In the above steering control device, the reset control circuit may be configured to execute processing for stopping the drive of the reaction motor or the turning motor, which is its control target, when restarted after completion of resetting. The control circuit that is operating normally without being reset may be configured to execute processing for stopping the drive of the turning motor or the reaction motor, which is its control target, in synchronization with the reset control circuit.

[0011] According to the steering control device described above, if at least one of a plurality of control circuits operating normally is reset, the reset control circuit stops driving the reaction motor or the turning motor, which is its control target, when it restarts after the reset is complete. Furthermore, the control circuit that is operating normally without being reset stops driving the turning motor or the reaction motor, which is its control target. This makes it possible to suppress unintended behavior of the steering wheel and the steered wheels. Therefore, it is possible to appropriately deal with the reset of the control circuit.

[0012] In the above steering control device, the reaction motor and the turning motor may have two systems of winding groups, and the multiple control circuits may include a two-system reaction control circuit that controls power supply to the winding groups of the reaction motor, and a two-system steering control circuit that controls power supply to the winding groups of the turning motor. In this case, the multiple control circuits may have, as drive modes for the reaction motor and the turning motor, a single-system drive mode in which the reaction motor and the turning motor are controlled by only the reaction control circuit and the turning control circuit of one of the two systems. Furthermore, when the drive mode is the single-system drive mode, the multiple control circuits may be configured to execute the above process when at least one of the multiple control circuits that is operating normally is reset.

[0013] When at least one of the reaction force control circuit and the steering control circuit of the first or second system operating in the single-system drive mode is reset, the reset reaction force control circuit or the steering control circuit executes processing to stop the vehicle from traveling when it restarts after the reset is complete. This prevents the vehicle from continuing to travel in a state where proper control of the reaction force motor or the steering motor is impaired when operating in the single-system drive mode. Therefore, it is possible to appropriately deal with the reset of the control circuit.

[0014] Furthermore, if at least one of the reaction force control circuit and steering control circuit of the first or second system operating in single-system drive mode is reset, the reset reaction force control circuit or steering control circuit will stop driving the reaction force motor or steering motor that it controls when it restarts after the reset is complete. Furthermore, the reaction force control circuit and steering control circuit of the second or first system that is operating normally without being reset will stop driving the steering motor or reaction force motor that it controls. This makes it possible to suppress unintended behavior of the steering wheel and steered wheels. Therefore, it is possible to appropriately deal with the reset of the control circuit.

[0015] In the above steering control device, the control circuit that controls the steering motor may be configured to control the steering motor so that the steered wheels are steered in accordance with the amount of rotation of the steering wheel. The control circuit that controls the reaction motor may be configured to execute predetermined preparation processing at startup. The preparation processing may include a midpoint learning processing that learns a steering neutral position of the steering wheel by automatically rotating the steering wheel through driving of the reaction motor, and a steering angle synchronization processing that corrects the rotational position of the steering wheel so that the rotational position of the steering wheel corresponds to the steered position of the steered wheels.

[0016] It is conceivable that the control circuit that controls the reaction motor may be reset. In this case, when the control circuit that controls the reaction motor restarts after the reset is complete, it executes a predetermined preparatory process. The preparatory process includes a midpoint learning process and a steering angle synchronization process. While these processes are being executed, there is a risk that the steering wheel may automatically rotate. In this case, the control circuit that controls the turning motor controls the turning motor as usual. In other words, the control circuit that controls the turning motor controls the turning motor so that the steered wheels are steered in accordance with the amount of rotation of the steering wheel. Therefore, there is a risk that the steered wheels may automatically turn in conjunction with the automatic rotation of the steering wheel. Therefore, there is a concern that the driver of the vehicle may feel uncomfortable due to unintended behavior of the steering wheel and the steered wheels.

[0017] In this regard, as in the above-described steering control device, when the control circuit that controls the reaction motor is reset, the control circuit that controls the reset reaction motor executes processing to stop the vehicle from traveling when it is restarted after the reset is complete. Therefore, by executing the preparation processing associated with the restart, it is possible to prevent the vehicle from continuing to travel in a state in which the steering wheel and steered wheels are unintentionally operating. Therefore, it is possible to appropriately deal with the reset of the control circuit.

[0018] Furthermore, if a control circuit that controls a reaction motor is reset, the reset control circuit stops driving the reaction motor that it controls when it restarts after the reset is complete. Furthermore, a control circuit that controls a turning motor stops driving the turning motor that it controls in synchronization with the control circuit that controls the reaction motor. This makes it possible to suppress unintended behavior of the steering wheel and steered wheels that may result from the execution of preparatory processing associated with restart. Furthermore, the execution of preparatory processing associated with restart makes it possible to suppress the vehicle from continuing to travel in a state where the steering wheel and steered wheels are unintendedly moving. Therefore, it is possible to appropriately deal with the reset of a control circuit.

[0019] In the steering control device, the control circuit may be configured to store information indicating whether the control has been stopped as a result of the vehicle power being turned off. The control circuit may be configured, at startup, to determine that the control circuit has not been reset if information indicating that the control has been stopped as a result of the vehicle power being turned off is stored, and to determine that the control circuit has been reset if information indicating that the control has been stopped as a result of the vehicle power being turned off is not stored.

[0020] Since the control circuit is reset before the vehicle power supply is turned off, it cannot store information indicating that control has been stopped when the vehicle power supply is turned off. Therefore, as with the steering control device described above, the control circuit can determine whether it has been reset at startup based on whether information indicating that control has been stopped when the vehicle power supply is turned off is stored. [Effects of the Invention]

[0021] According to the steering control device of the present invention, when a control circuit that is operating normally is reset, it is possible to take appropriate measures. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a configuration diagram of a steer-by-wire type steering device in which an embodiment of a steering control device is mounted. [Figure 2] FIG. 2 is a block diagram of a reaction force control device and a steering control device according to an embodiment. [Figure 3] 4 is a time chart showing a start-up sequence of a reaction force control device and a vehicle control device according to an embodiment; [Figure 4] 10(a), (b), and (c) are configuration diagrams showing comparative examples of state transitions of a reaction force control device and a steering control device. [Figure 5] 3 is a flowchart showing a processing procedure of the reaction force control device according to the embodiment. [Figure 6]5A and 5B are configuration diagrams showing an example of state transitions of a reaction force control device and a steering control device according to an embodiment. [Figure 7] FIG. 10 is a configuration diagram showing another example of state transitions of the reaction force control device and the steering control device according to the embodiment. [Figure 8] FIG. 10 is a configuration diagram showing another example of state transitions of the reaction force control device and the steering control device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0023] An embodiment in which the steering control device is embodied in a steer-by-wire type steering device will be described below. As shown in FIG. 1, vehicle steering device 10 has steering shaft 12 connected to steering wheel 11. Steering device 10 also has steered shaft 13 extending in 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. The linear movement of steered shaft 13 changes the steering angle θw of steered wheels 15. Steering shaft 12 and steered shaft 13 constitute the steering mechanism of the vehicle. Note that FIG. 1 shows only steered wheels 15 on one side.

[0024] The steering device 10 has a reaction motor 21 and a reduction mechanism 22. The reaction motor 21 is a source of a steering reaction force. The steering reaction force is a force that acts in the opposite direction to the direction of operation of the steering wheel 11 by the driver. The rotation 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 response.

[0025] 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.

[0026] Steering device 10 has a steering motor 31 and a reduction mechanism 32. Steering motor 31 is a source of steering force. The steering force refers to the power for steering steered wheels 15. The 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 steering shaft 13. The torque of steering motor 31 is applied to steering shaft 13 via pinion shaft 33 as a steering force. In response to the rotation of steering motor 31, steering shaft 13 moves in the vehicle width direction.

[0027] 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.

[0028] The steering device 10 has a reaction force control device 40. The reaction force control device 40 controls the drive 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 matches the target steering reaction force. The reaction force control device 40 controls the power supply to each of the two systems of winding groups in the reaction force motor 21 independently.

[0029] 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 accordance with the steering torque Th detected by 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 accordance with the steering torque Th detected by the torque sensor 23.

[0030] The reaction force control device 40 and the on-board vehicle control device 60 are connected to each other via an on-board network 61. The on-board network 61 is, for example, a CAN (Controller Area Network). The reaction force control device 40 and the on-board vehicle control device 60 exchange information with each other via the on-board network 61. The vehicle control device 60 controls the running of the vehicle. Specifically, the vehicle control device 60 controls, for example, the vehicle's powertrain. The powertrain includes a driving source for running the vehicle and a power transmission mechanism. The driving source for running includes, for example, an engine or a motor. The power transmission mechanism is a mechanism for transmitting power generated by the driving source for running to the drive wheels. The reaction force control device 40 controls the driving of the reaction force motor 21 based on information exchanged with the vehicle control device 60.

[0031] Steering device 10 has steering control device 50. Steering control device 50 controls the drive of steering motor 31, which is the object to be controlled. Steering control device 50 executes steering control in which steering motor 31 generates a steering force for turning steered wheels 15 in accordance with the steering state. Steering control device 50 takes in steering angle θs detected via steering angle sensor 24 and stroke Xw of steered shaft 13 detected via stroke sensor 34. Steering angle θs is a state variable that indicates the amount of rotational operation of steering wheel 11. Stroke Xw is the amount of displacement of steered shaft 13 relative to the neutral position, and is a state variable that reflects steering angle θw. Steering angle sensor 24 is provided between torque sensor 23 of steering shaft 12 and reduction mechanism 22. Stroke sensor 34 is provided in the vicinity of steered shaft 13.

[0032] Steering control device 50 calculates a target steering angle of steered wheels 15 based on steering angle θs detected by steering angle sensor 24. The target steering angle can be obtained, for example, by multiplying the detected steering angle θs by a steering angle ratio. The steering angle ratio is the ratio of steering angle θw to steering angle θs. The steering angle ratio is a value that is set in advance according to product specifications, etc. Steering control device 50 calculates steering angle θw based on stroke Xw of steered shaft 13 detected by stroke sensor 34. Steering control device 50 controls the power supply to steering motor 31 so that steering angle θw calculated based on stroke Xw matches the target steering angle. Steering control device 50 controls the power supply to two systems of winding groups in steering motor 31 independently for each system.

[0033] Steering control device 50 has first circuit system 51 and second circuit system 52. First circuit system 51 controls the power supply to winding group N21 of the first system in steering motor 31, based on steering angle θs detected via steering angle sensor 24 and stroke Xw of steering shaft 13 detected via stroke sensor 34. Second circuit system 52 controls the power supply to winding group N22 of the second system in steering motor 31, based on steering angle θs detected via steering angle sensor 24 and stroke Xw of steering shaft 13 detected via stroke sensor 34.

[0034] Note that a so-called electromechanical integrated type reaction force actuator may be configured by integrally providing reaction force control device 40 and reaction force motor 21. Also, a so-called electromechanical integrated type steering actuator may be configured by integrally providing steering control device 50 and steering motor 31. Reaction force control device 40 and steering control device 50 configure a steering control device.

[0035] <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.

[0036] The first reaction force control circuit 41A is configured by processing circuits 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 perform at least some of the various processes; and (3) a combination thereof. The processor includes a central processing unit (CPU). The processor also includes memory, such as random-access memory (RAM) and read-only memory (ROM). The memory stores program code or instructions configured to cause the CPU to execute processes. Memory, i.e., non-transitory computer-readable medium, includes any available medium that can be accessed by a general-purpose or special-purpose computer.

[0037] 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 via 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 causes the value of the actual current supplied to the winding group N11 of the first system to follow the first current command value.

[0038] The motor drive circuit 41B is a PWM inverter in which three legs, each corresponding to one of the three phases (U, V, and W), are connected in parallel, with each leg consisting of two switching elements such as field-effect transistors (FETs) connected in series. The motor drive circuit 41B converts DC power supplied from the battery 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 a first winding group N11 of the reaction force motor 21 via a power supply path for each phase, which is formed by a bus bar or a cable. This causes the first winding group N11 to generate torque according to a first current command value.

[0039] The second reaction force control circuit 42A has basically 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 by 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 performing current feedback control that causes the value of the actual current supplied to the winding group N12 of the second system to follow the second current command value.

[0040] The motor drive circuit 42B has basically the same configuration as the motor drive circuit 41B. The motor drive circuit 42B converts DC power supplied from the battery 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 via power supply paths for each phase, which are made up of bus bars or cables, etc. This causes the second winding group N12 to generate 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.

[0041] Depending on the product specifications, there may be 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 may function as the master and the second circuit system 42 may function as the slave. Also, depending on the product specifications, the first circuit system 41 and the second circuit system 42 may have an equal relationship.

[0042] <Steering control device> Next, the configuration of the steering control device 50 will be described in detail. As shown in Fig. 2, the steering control device 50 has a first circuit system 51 and a second circuit system 52. The first circuit system 51 has a first steering control circuit 51A and a motor drive circuit 51B. The second circuit system 52 has a second steering control circuit 52A and a motor drive circuit 52B.

[0043] First steering control circuit 51A has basically the same configuration as 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 by steering angle sensor 24. Steering control device 50 calculates steering angle θw based on stroke Xw of steered shaft 13 detected by stroke sensor 34. First steering control circuit 51A calculates a target steering force to be generated in steering motor 31 by executing angle feedback control that causes steering angle θw calculated based on stroke Xw to follow the target steering angle, and calculates a third current command value for first system winding group N21 of steering motor 31 according to the value of this calculated target steering force. However, the third current command value is set to a value that is 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 performing current feedback control that causes the value of the actual current supplied to the first system winding group N21 to follow the third current command value.

[0044] Motor drive circuit 51B basically has the same configuration as motor drive circuit 41B. Motor drive circuit 51B converts DC power supplied from a battery 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 for each phase formed by bus bars, cables, or the like. This causes winding group N21 of the first system to generate torque according to the third current command value.

[0045] Second steering control circuit 52A has basically the same configuration as 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 by steering angle sensor 24. Steering control device 50 calculates steering angle θw based on stroke Xw of steered shaft 13 detected by stroke sensor 34. Second steering control circuit 52A calculates a target steering force to be generated in steering motor 31 by executing angle feedback control that causes steering angle θw calculated based on stroke Xw to follow the target steering angle, and calculates a fourth current command value for second system winding group N22 of steering motor 31 in accordance with the value of this calculated target steering force. However, fourth current command value is set to a value that is 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 performing 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.

[0046] Motor drive circuit 52B basically has the same configuration as motor drive circuit 41B. Motor drive circuit 51B converts DC power supplied from the battery 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 for each phase formed by bus bars, cables, or the like. 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 the torque generated by winding group N21 of the first system and the torque generated by winding group N22 of the second system.

[0047] Depending on the product specifications, there may be a master-slave relationship between the first circuit system 51 and the second circuit system 52 of the steering control device 50. In this case, for example, the first circuit system 51 may function as the master and the second circuit system 52 may function as the slave. Also, depending on the product specifications, the first circuit system 51 and the second circuit system 52 may have an equal relationship.

[0048] <Communication path> Next, the internal communication paths of the reaction force control device 40 and the steering control device 50, and the communication path between the reaction force control device 40 and the steering control device 50 will be described.

[0049] 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 about the first reaction force control circuit 41A, the second reaction force control circuit 42A, or the motor drive circuits 41B and 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.

[0050] The first steering control circuit 51A and the second steering control circuit 52A exchange information with each other via communication line L2. The information includes abnormality information of the first steering control circuit 51A, the second steering control circuit 52A, or the motor drive circuits 51B, 52B. The information also includes flag values ​​that indicate various states. The first steering control circuit 51A and the second steering control circuit 52A cooperate to control the drive of the steering motor 31 based on the information exchanged between them.

[0051] The first reaction force control circuit 41A and the first turning control circuit 51A exchange information with each other via communication line L3. The information includes abnormality information for 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 operate in cooperation with each other based on the information exchanged between them.

[0052] The second reaction force control circuit 42A and the second turning control circuit 52A exchange information with each other via 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.

[0053] <Motor drive mode> Next, a description will be given of 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.

[0054] The cooperative drive mode is a normal drive mode in which first system circuits 41, 51 and second system circuits 42, 52 are operating normally. First system circuit 41 and second system circuit 42 share information such as command values ​​and limit values ​​with each other, and generate equal torque in both the first system winding group N11 and the second system winding group N12 of reaction force motor 21. First system circuit 51 and second system circuit 52 share information such as command values ​​and limit values ​​with each other, and generate equal torque in both the first system winding group N21 and the second system winding group N22 of steering motor 31.

[0055] In the case where there is a master-slave relationship between first system circuit 41 and second system circuit 42 of 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 reaction force motor 21. Also, in the case where there is a master-slave relationship between first system circuit 51 and second system circuit 52 of 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 turning motor 31.

[0056] The independent drive mode is a drive mode used when one of the four control circuits (41A, 42A, 51A, 52A) momentarily stops operating but the abnormality has not been determined and there is a possibility that normal operation will be restored. In the independent drive mode, for example, when there is a possibility that one control circuit whose operation has stopped will return to normal operation, the remaining three control circuits generate torque in their corresponding winding groups based on their own calculation results without using information from inter-system communication.

[0057] 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.

[0058] The single-system drive mode is a drive mode used when an abnormality is confirmed in 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 first system circuits 41, 51, torque is generated in reaction force motor 21 and steering motor 31 only by second system circuits 42, 52. When an abnormality is confirmed in second system circuits 42, 52, torque is generated in reaction force motor 21 and steering motor 31 only by first system circuits 41, 51.

[0059] 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 single-system 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 single-system 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.

[0060] 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. When the cooperative drive mode is selected as the drive mode and an abnormality determination condition is satisfied, each control circuit switches the drive mode from the cooperative drive mode to the independent drive mode. Furthermore, when the independent drive mode is selected as the drive mode and a return determination condition is satisfied before an abnormality is confirmed, each control circuit returns the drive mode from the independent drive mode to the cooperative drive mode. Furthermore, when the independent drive mode is selected as the drive mode and an abnormality determination condition is satisfied, each control circuit switches the drive mode from the independent drive mode to the single-system drive mode.

[0061] The abnormality includes, for example, a communication abnormality between systems, a communication abnormality within the same system, a deviation in command values ​​between systems, and a temporary abnormality that can be recovered from, such as a decrease in the current limit value. <Startup sequence> Next, the startup sequence of the reaction force control device 40 and the vehicle control device 60 will be described. The startup sequence is a series of processes that are executed when the vehicle power supply is turned on. While the vehicle power supply is turned off, the reaction force control device 40 and the vehicle control device 60 remain in a stopped state. Turning the vehicle power supply on or off also corresponds to turning on or off a start switch provided in the driver's seat, for example. The start switch is operated to start or stop the drive source for running the vehicle, and is, for example, an ignition switch or a power switch.

[0062] First, the startup sequence of the vehicle control device 60 will be described. As shown in the time chart of FIG. 3, when the vehicle power supply is turned on (time T1), the vehicle control device 60 starts executing a predetermined startup preparation. The startup preparation includes an initial check of the vehicle control device 60 and processing required to start the vehicle's powertrain. After the startup preparation is complete, the vehicle control device 60 starts the powertrain (mainly the driving source for traveling). When the powertrain startup processing is completed, the vehicle control device 60 turns on the preparation completion signal S1 (time T2). The vehicle control device 60 turns on the preparation completion signal S1 regardless of the state of the reaction force control device 40.

[0063] The ready signal S1 is information indicating whether the vehicle is ready to run, including the completion of the powertrain start process, and whether the vehicle is ready to run. When the ready signal S1 is on, it indicates that the vehicle is ready to run. When the ready signal S1 is off, it indicates that the vehicle is not ready to run. The ready signal S1 is transmitted to the reaction force control device 40 as an electrical signal.

[0064] Next, the start-up sequence of the reaction force control device 40 will be described. 3, when the vehicle power supply is turned on (time T1), the reaction force control device 40 starts up and sequentially executes an initial check, a midpoint learning process, and a steering angle synchronization process, and then transitions to an assist start waiting state. The initial check, the midpoint learning process, and the steering angle synchronization process are a series of preparatory processes required to start executing reaction force control that causes the reaction force motor 21 to generate a steering reaction force.

[0065] The initial check is an initial inspection that is executed when the vehicle power is turned on, and includes, for example, a hardware check, initialization of the CPU (Central Processing Unit), and initialization of variables or flags.

[0066] The midpoint learning process is a process for learning the neutral steering position of the steering wheel 11. The steering device 10 has a stopper mechanism that restricts the rotation of the steering wheel 11 to set a limit on the steering angle of the steering wheel 11. The stopper mechanism, for example, restricts the steering range of the steering wheel 11 to less than 360°. The reaction force control device 40 controls the reaction force motor 21 to move the steering wheel 11 to a first operating end and then to a second operating end. After this, the reaction force control device 40 calculates the midpoint of the steering angle based on the rotation angle of the reaction force motor 21 at the start and end of the steering wheel 11's reversal movement. The midpoint of the steering angle corresponds to the motor midpoint, which is the rotational position of the reaction force motor 21 when the steering wheel 11 is located in the neutral steering position. The reaction force control device 40 stores the midpoint of the steering angle or the motor midpoint in memory as the neutral steering position of the steering wheel 11.

[0067] The reaction force control device 40 learns the neutral steering position of the steering wheel 11 when the information about the neutral steering position stored in the memory is lost. This applies, for example, when the vehicle power is turned on for the first time after a new battery is installed in the vehicle. This is because when the battery is removed from the vehicle for battery replacement, the information about the neutral steering position stored in the memory of the reaction force control device 40 is lost due to the loss of power supply to the reaction force control device 40.

[0068] Depending on the product specifications, the reaction force control device 40 may be configured to execute the midpoint learning process each time the vehicle power is turned on, or may be configured to execute the midpoint learning process when the reliability of the information regarding the steering neutral position stored in the memory has decreased.

[0069] The steering angle synchronization process is a process for correcting the rotational position of the steering wheel 11. When the rotational position of the steering wheel 11 is different from the rotational position corresponding to the steered position of the steered wheels 15, the reaction force control device 40 drives the reaction force motor 21 so that the rotational position of the steering wheel 11 becomes the rotational position corresponding to the steered position of the steered wheels 15.

[0070] For example, when the vehicle power supply is turned off, the reaction force control device 40 stores the steering angle θs detected immediately before as a reference steering angle. The reference steering angle is a reference for determining whether or not the steering wheel 11 is rotating while the vehicle power supply is turned off. When the steering angle θs immediately after the vehicle power supply is turned on does not match the reference steering angle, the reaction force control device 40 calculates the difference between the steering angle θs immediately after the vehicle power supply is turned on and the reference steering angle, and controls the power supply to the reaction force motor 21 to eliminate the difference.

[0071] In addition, the reaction force control device 40 may calculate the difference between the value of the steering angle θs immediately after the vehicle power supply is turned on and the value obtained by multiplying the steering angle θw immediately after the vehicle power supply is turned on by the reciprocal of the steering angle ratio, and control the power supply to the reaction force motor 21 so as to eliminate this difference.

[0072] The assist start waiting state is a state in which, after the preparation process has been completed, the reaction force control device 40 waits for confirmation that the vehicle control device 60 has completed the powertrain start process. The reaction force control device 40 determines whether or not to transition from the assist start waiting state to the normal control state, depending on the start state of the vehicle's powertrain. When the preparation complete signal S1 has not been turned on by the vehicle control device 60, the reaction force control device 40 determines that the vehicle's powertrain start process has not been completed, and maintains the assist start waiting state. When the preparation complete signal S1 has been turned on by the vehicle control device 60, the reaction force control device 40 determines that the vehicle's powertrain start process has been completed (time T3), and transitions from the assist start waiting state to the normal control state. The normal control state is a state in which reaction force control is performed to cause the reaction force motor 21 to generate a steering reaction force. When in the normal control state, the reaction force control device 40 controls the drive of the reaction force motor 21 depending on the steering state of the steering wheel 11.

[0073] In the time chart of FIG. 3, the vehicle control device 60 turns on the preparation completion signal S1 while the midpoint learning process is being executed, for example. <Supplementary explanation of the control circuit> Next, the configuration of each control circuit (41A, 42A, 51A, 52A) will be further explained.

[0074] The power supply voltage of each control circuit has a guaranteed operating range. The guaranteed operating range is the voltage range within which operation is guaranteed according to specifications. When the power supply voltage changes from a value outside the guaranteed operating range to a value within the guaranteed operating range, each control circuit begins operation and executes the startup sequence shown in the time chart of Figure 3.

[0075] Each control circuit has a reset function. When a predetermined reset cause occurs, each control circuit is reset. The reset is a process for initializing the internal state of each control circuit. The reset cause includes, for example, a drop in the power supply voltage of each control circuit. When the power supply voltage temporarily drops and the value of the power supply voltage falls outside the guaranteed operating range, each control circuit is reset. When the reset is complete, each control circuit again executes the startup sequence shown in the time chart of Figure 3.

[0076] However, the resetting of each control circuit raises the following concerns. 4(a), for example, when an abnormality is confirmed in first system circuits 41, 51, second system circuits 42, 52 operate in a single-system drive mode. That is, control of reaction force motor 21 and steering motor 31 continues only by second system circuits 42, 52. First system circuits 41, 51 are maintained in a stopped state.

[0077] As shown in FIG. 4(b), in a state in which control of reaction force motor 21 and steering motor 31 continues only by second system circuits 42, 52, for example, second reaction force control circuit 42A may be reset.

[0078] As shown in Figure 4(c), after the second reaction force control circuit 42A has completed the reset, it executes the startup sequence shown in the time chart of Figure 3. The startup sequence includes a midpoint learning process and a steering angle synchronization process. During the execution of these processes, the steering wheel 11 may automatically rotate in order to learn the steering neutral position of the steering wheel 11 or to correct the rotational position of the steering wheel 11.

[0079] At this time, second steering control circuit 52A continues to control steering motor 31 as usual. That is, second steering control circuit 52A controls steering angle θw of steered wheels 15 based on steering angle θs detected via steering angle sensor 24. For this reason, there is a risk that steered wheels 15 will be automatically steered as steering wheel 11 automatically rotates.

[0080] This phenomenon also occurs when the first system circuits 41, 51 are operating in the single-system drive mode after an abnormality is confirmed in the second system circuits 42, 52. When the first system circuits 41, 51 are operating in the single-system drive mode, there is a risk that the steered wheels 15 will automatically turn in conjunction with the automatic rotation of the steering wheel 11 when the first reaction force control circuit 41A is reset.

[0081] Therefore, there is a concern that the driver of the vehicle may feel uncomfortable with so-called self-steering, which is when the steering wheel 11 turns automatically or the steered wheels 15 turn automatically without the driver's intention.

[0082] Therefore, at the time of startup, each control circuit (41A, 42A, 51A, 52A) executes a process for dealing with the reset of each control circuit. <Control circuit processing procedure> Next, the processing steps executed by each control circuit (41A, 42A, 51A, 52A) at startup will be described with reference to the flowchart of FIG. 5. Each processing step in the flowchart is executed during the period from startup until the completion of the initial check after the vehicle power supply is turned on in the time chart of FIG. 3. Furthermore, each processing step in the flowchart is executed at a predetermined control cycle. However, startup does not only include startup when the vehicle power supply is turned on, but also restarts after each control circuit has been reset. Here, the first reaction force control circuit 41A will be used as an example for explanation.

[0083] As shown in the flowchart of FIG. 5, immediately after starting up, the first reaction force control circuit 41A determines whether a reset has occurred (step S101). When the vehicle power supply is turned on, the first reaction force control circuit 41A stores in memory that the control has started. When the vehicle power supply is turned off, the first reaction force control circuit 41A stores in memory that the control has stopped. The first reaction force control circuit 41A sets a flag to a specific value when the control has started or stopped, for example, depending on the state of the vehicle power supply. Specifically, when the control has started as a result of the vehicle power supply being turned on, the first reaction force control circuit 41A sets the value of the flag to "1." When the control has stopped as a result of the vehicle power supply being turned off, the first reaction force control circuit 41A sets the value of the flag to "0."

[0084] The first reaction force control circuit 41A determines that a reset has not occurred when the memory stores information that the control was stopped because the vehicle power supply was turned off, i.e., when the flag value is "0," at the next startup. The first reaction force control circuit 41A determines that a reset has occurred when the memory does not store information that the control was stopped because the vehicle power supply was turned off, i.e., when the flag value is "1." This is because the first reaction force control circuit 41A is reset before the vehicle power supply is turned off, so information indicating that the control was stopped cannot be stored in the memory, and the flag value remains "1."

[0085] When it is determined that a reset has occurred (YES in step S101), the first reaction force control circuit 41A determines whether the drive mode of the reaction force motor 21 is a single-system drive mode using its own system (here, the first system) (step S102).

[0086] The first reaction force control circuit 41A determines the drive mode of its own system based on the state of the control circuit of the other system, in this case the state of the second reaction force control circuit 42A, which is the second system. The first reaction force control circuit 41A recognizes the state of the second reaction force control circuit 42A through communication with the second reaction force control circuit 42A. When the second reaction force control circuit 42A is operating normally, the first reaction force control circuit 41A determines that the system is not in single-system drive mode. When the operation of the second reaction force control circuit 42A is stopped, the first reaction force control circuit 41A determines that the system is in single-system drive mode.

[0087] If the first reaction force control circuit 41A is unable to communicate with the second reaction force control circuit 42A, the first reaction force control circuit 41A may recognize the state of the second reaction force control circuit 42A based on the monitoring result of the intermediate voltage of the second reaction force control circuit 42A. The intermediate voltage is the voltage between the power relay and the reverse connection relay of the second reaction force control circuit 42A. The power relay and the reverse connection relay are provided in the power supply path to the second reaction force control circuit 42A. For example, when the intermediate voltage of the second reaction force control circuit 42A is less than a predetermined voltage threshold, the first reaction force control circuit 41A determines that the operation of the second reaction force control circuit 42A has stopped.

[0088] When it is determined that the mode is the single-system drive mode by its own system (YES in step S102), first reaction force control circuit 41A executes processing to stop driving of reaction force motor 21 and steering motor 31 by its own system (step S103).

[0089] The first reaction force control circuit 41A executes stop control to stop its own operation. Stopping the operation of the first reaction force control circuit 41A also stops the power supply to the first winding group N11 of the reaction force motor 21. When a predetermined period has elapsed since the start of execution of the stop control, the first reaction force control circuit 41A turns off its own power supply relay to cut off the power supply to itself. This causes the first reaction force control circuit 41A to stop operation.

[0090] First turning control circuit 51A, which is of the same system as first reaction force control circuit 41A, recognizes the state of first reaction force control circuit 41A through communication with first reaction force control circuit 41A. When first turning control circuit 51A recognizes that first reaction force control circuit 41A has started to execute stop control, it starts executing its own stop control in synchronization with first reaction force control circuit 41A. Stopping the operation of first turning control circuit 51A also stops the power supply to winding group N21 of the first system of steering motor 31. When a predetermined period has elapsed since the start of execution of stop control, first turning control circuit 51A turns off its own power supply relay to cut off the power supply to itself. This causes first turning control circuit 51A to stop operating.

[0091] Depending on the product specifications, first reaction force control circuit 41A may be configured to send a command signal to first turning control circuit 51A requesting that it begin executing stop control. In this case, first turning control circuit 51A begins executing stop control when it receives the command signal. Also, depending on the product specifications, first reaction force control circuit 41A may simply stop control of reaction force motor 21 rather than cutting off power supply to itself through the execution of stop control. In this case, first turning control circuit 51A stops control of turning motor 31 based on the state of first reaction force control circuit 41A.

[0092] Next, the first reaction force control circuit 41A executes a predetermined vehicle stop request process (step S104). The first reaction force control circuit 41A generates a vehicle stop request signal S2 for the vehicle control device 60 and transmits the generated vehicle stop request signal S2 to the vehicle control device 60 via the in-vehicle network 61. The stop request signal S2 is an electrical signal that requests the vehicle control device 60 to execute a process for safely stopping the vehicle.

[0093] The first reaction force control circuit 41A terminates the processing when it is not determined in the previous step S101 that a reset has occurred (NO in step S101) and when it is not determined in the previous step S102 that the single-system drive mode is being used by its own system (NO in step S102).

[0094] This completes the startup processing of the first reaction force control circuit 41A. Incidentally, second reaction force control circuit 42A, first turning control circuit 51A, and second turning control circuit 52A execute the processes of the flowchart in FIG. 5 at startup, similarly to first reaction force control circuit 41A.

[0095] <Operation of this embodiment> Next, the operation of this embodiment will be described. As shown in Figure 6(a), for example, when an abnormality is confirmed in first system circuits 41, 51, control of reaction force motor 21 and steering motor 31 continues only by second system circuits 42, 52. First system circuits 41, 51 are maintained in a stopped state. In this state, for example, it is conceivable that only second reaction force control circuit 42A is reset.

[0096] As shown in Fig. 6(b), the second reaction force control circuit 42A restarts after the reset is complete. However, the second reaction force control circuit 42A immediately starts executing stop control after restarting. The second reaction force control circuit 42A stops operation at the latest before the midpoint learning in the startup sequence starts, i.e., before the automatic rotation of the steering wheel 11 starts.

[0097] Second turning control circuit 52A, which is in the same system as second reaction force control circuit 42A, operates in cooperation with second reaction force control circuit 42A. Second turning control circuit 52A starts executing stop control so as to be synchronized with second reaction force control circuit 42A. Second turning control circuit 52A stops operation at the latest before midpoint learning in the startup sequence starts to be executed.

[0098] In this way, when the drive mode is the single-system mode using the second system, the midpoint learning process and the steering angle synchronization process in the startup sequence are not executed when the second reaction force control circuit 42A is reset, which prevents automatic rotation of the steering wheel 11. Also, unintended changes in the steering angle θw of the steered wheels 15 due to the influence of the automatic rotation of the steering wheel 11 are suppressed.

[0099] However, since the first circuit systems 41, 51 and the second circuit systems 42, 52 are all stopped, it becomes difficult to perform appropriate reaction force control and appropriate steering control. Therefore, when the second reaction force control circuit 42A is restarted after the reset is completed, it transmits a stop request signal S2 to the vehicle control device 60 before stopping operation. When the vehicle control device 60 receives the stop request signal S2, it executes a predetermined stopping process to safely stop the vehicle. The stopping process includes, for example, an automatic evacuation process that automatically stops the vehicle at a safe place such as the shoulder of the road, regardless of the driving state of the driver. Through the execution of the stopping process, the vehicle is safely stopped.

[0100] Incidentally, the following situation is also conceivable. As shown in FIG. 7, when control of reaction force motor 21 and steering motor 31 continues using only second system circuits 42, 52, it is possible that both second reaction force control circuit 42A and second steering control circuit 52A will be reset.

[0101] Even in this case, at least one of second reaction force control circuit 42A and second turning control circuit 52A executes the startup process shown in the flowchart of Fig. 5 when restarting after completion of reset. This stops the operation of second system circuits 42, 52. Furthermore, at least one of second reaction force control circuit 42A and second turning control circuit 52A sends a stop request signal S2 to vehicle control device 60, thereby allowing the vehicle to be stopped safely.

[0102] Note that if both second reaction force control circuit 42A and second turning control circuit 52A are reset, so-called self-steering does not occur. Therefore, it can be said that it is not necessarily necessary to stop the reset system. However, normal control cannot be restored unless the start-up sequences of both second reaction force control circuit 42A and second turning control circuit 52A are completed. In other words, there is a risk that a situation in which reaction force control and turning control are not being executed will continue for a long period of time. Therefore, it is desirable to stop the operation of the system in which the reset occurred.

[0103] The following situation is also anticipated. As shown in FIG. 8, when control of reaction force motor 21 and steering motor 31 continues only by second system circuits 42, 52, a situation may be considered in which only second steering control circuit 52A is reset.

[0104] Even in this case, when the second steering control circuit 52A is restarted after the reset is completed, it executes the startup process shown in the flowchart of Fig. 5. This stops the operation of the second system circuits 42, 52. Furthermore, the second steering control circuit 52A transmits a stop request signal S2 to the vehicle control device 60, thereby allowing the vehicle to be stopped safely.

[0105] Note that if only the second steering control circuit 52A is reset, it does not lead to so-called self-steering. Therefore, it can be said that it is not always necessary to stop the reset system. However, depending on the nature of the abnormality in the first system circuits 41, 51, the start-up sequence of the second steering control circuit 52A may not be completed normally, which may result in a situation in which reaction force control and steering control are not performed. Therefore, it is desirable to stop the system in which the reset occurred.

[0106] <Effects of this embodiment> This embodiment has the following advantages. (1) For example, when the drive mode of reaction force motor 21 and steering motor 31 is the single-system drive mode using the second system, if at least one of second reaction force control circuit 42A and second steering control circuit 52A is reset, the following processing is executed. That is, when at least one of reset second reaction force control circuit 42A and second steering control circuit 52A is restarted after the reset is complete, it executes processing to stop the vehicle from traveling.

[0107] Therefore, when operating in the single-system drive mode, it is possible to prevent the vehicle from continuing to travel in a state where appropriate control of reaction force motor 21 or steering motor 31 is impaired. In other words, it is possible to prevent the vehicle from continuing to travel in a state where steering wheel 11 and steered wheels 15 are unintentionally moved due to execution of the start-up sequence accompanying restart. Therefore, when operating in the single-system drive mode using the second system, it is possible to appropriately deal with the reset of at least one of second reaction force control circuit 42A and second steering control circuit 52A, which are operating normally.

[0108] When the drive mode of reaction force motor 21 and steering motor 31 is the single-system drive mode using the first system, even when at least one of first reaction force control circuit 41A and first steering control circuit 51A is reset, the same processing as in the single-system drive mode using the second system is executed. That is, when at least one of reset first reaction force control circuit 41A and first steering control circuit 51A is restarted after the reset is complete, it executes processing to stop the vehicle from traveling. Therefore, the same effect as in the single-system drive mode using the second system can be obtained.

[0109] (2) When the drive mode of reaction force motor 21 and steering motor 31 is the single-system drive mode using the second system, for example, when second reaction force control circuit 42A is reset, the following processing is executed. That is, when reset second reaction force control circuit 42A is restarted after the reset is complete, it stops driving reaction force motor 21, which is its own control target. Also, second steering control circuit 52A, which is operating normally without being reset, stops driving steering motor 31, which is its own control target, in synchronization with first reaction force control circuit 41A.

[0110] This makes it possible to suppress unintended behavior of the steering wheel 11 and the steered wheels 15 that would otherwise occur due to the execution of the startup sequence associated with restart. Furthermore, it is possible to suppress the vehicle from continuing to travel in a state in which the steering wheel 11 and the steered wheels 15 move unintendedly due to the execution of the startup sequence associated with restart. Therefore, when operating in the single-system drive mode using the second system, it is possible to appropriately deal with the reset of the second reaction force control circuit 42A that is operating normally.

[0111] In the following three cases A1 to A3, the same processing as when the second reaction force control circuit 42A is reset is executed, and therefore, the same effect as when the second reaction force control circuit 42A is reset can be obtained.

[0112] A1. When the drive mode of reaction force motor 21 and steering motor 31 is the single-system drive mode using the second system, and second steering control circuit 52A is reset. A2. When the drive mode of reaction force motor 21 and steering motor 31 is the single-system drive mode using the second system, and both second reaction force control circuit 42A and second steering control circuit 52A are reset.

[0113] A3. When the drive mode of reaction force motor 21 and steering motor 31 is the single-system drive mode using the first system, and at least one of second steering control circuit 52A and second steering control circuit 52A is reset.

[0114] (3) Each control circuit (41A, 42A, 51A, 52A) determines that it has not been reset if, at startup, information indicating that control has been stopped due to the vehicle power being turned off is stored. Also, each control circuit determines that it has been reset if, at startup, information indicating that control has been stopped due to the vehicle power being turned off is not stored.

[0115] If each control circuit is reset before the vehicle power is turned off, it cannot store in memory information indicating that control has been stopped when the vehicle power is turned off. Therefore, at startup, each control circuit can determine whether it has been reset based on whether information indicating that control has been stopped when the vehicle power is turned off is stored. The information indicating that control has been stopped when the vehicle power is turned off is, for example, a flag.

[0116] <Other embodiments> This embodiment may be modified as follows. The reaction force control device 40 may be configured to execute a start permission determination process when the vehicle power supply is turned on. The start permission determination process is a process for determining whether or not to permit the vehicle control device 60 to start the powertrain. When the start sequence, which is a preparation process for reaction force control, is completed, the reaction force control device 40 transitions to an assist start waiting state and turns on a start permission signal. When the start sequence is not completed, the reaction force control device 40 turns off the start permission signal. The start permission signal is information that indicates whether or not to permit the vehicle control device 60 to start the powertrain. When the start permission signal is on, it indicates that the vehicle control device 60 is permitted to start the powertrain. When the start permission signal is off, it indicates that the vehicle control device 60 is not permitted to start the powertrain. The start permission signal is transmitted to the vehicle control device 60 as an electrical signal.

[0117] When the vehicle power supply is turned on, the vehicle control device 60 starts executing a predetermined startup preparation. After the startup preparation is completed, the vehicle control device 60 transitions to a start permission waiting state. The start permission waiting state is a state in which the vehicle control device 60 waits for the reaction force control device 40 to permit the start of the powertrain, i.e., for the start permission signal to be turned on. When the vehicle control device 60 recognizes that the start permission signal has been turned on in the start permission waiting state, it starts the vehicle's powertrain. When the vehicle control device 60 completes the execution of the powertrain startup process, it turns on the preparation completion signal S1. When the reaction force control device 40 recognizes that the preparation completion signal S1 has been turned on in the assist start waiting state, it transitions to a normal control state. The reaction force control device 40 controls the drive of the reaction force motor 21 in accordance with the steering state of the steering wheel 11.

[0118] In this way, even if the vehicle control device 60 has completed its own startup preparation, if the reaction force control device 40 has not yet completed the preparation process for reaction force control, the vehicle control device 60 waits for the preparation process to be completed before starting the vehicle powertrain. As a result, the vehicle can only travel after the reaction force control device 40 has transitioned to an assist start waiting state in which it is able to execute reaction force control. This prevents the vehicle from entering a state in which it can travel even when the reaction force control device 40 is still in the middle of executing the preparation process. Furthermore, the vehicle can start traveling in a state that is safer for the driver, i.e., in a state in which it can turn the vehicle in the direction intended by the driver.

[0119] If the reaction force control device 40 has the function of executing the start permission determination process described above, in step S101 of the flowchart in FIG. 5, each control circuit (41A, 42A, 51A, 52A) may determine whether a reset has occurred as follows. That is, each control circuit determines that a reset has occurred when the preparation complete signal S1 is in the ON state immediately after startup. The reaction force control device 40 turns on the start permission signal to the vehicle control device 60 only when the startup sequence is completed normally. Therefore, the preparation complete signal S1 turns on immediately after startup of each control circuit only when each control circuit is reset.

[0120] The processing order of steps S103 and S104 in the flowchart of FIG. 5 may be reversed. Depending on the product specifications, in the single-system drive mode, when at least one of the two control circuits (41A, 51A) of the first system or the two control circuits (42A, 52A) of the second system is reset, each control circuit may not execute processing to stop the reaction force motor 21 and the steering motor 31.

[0121] In the present embodiment, reaction force motor 21 and steering motor 31 have two systems of winding groups, but they may also have one system of winding groups. In this case, reaction force control device 40 may have only one of first system circuit 41 and second system circuit 42. Also, steering control device 50 may have only one of first system circuit 51 and second system circuit 52. In this case, first reaction force control circuit 41A or second reaction force control circuit 42A corresponds to the reaction force control circuit. First steering control circuit 51A or second steering control circuit 52A corresponds to the steering control circuit.

[0122] When reaction force control device 40 has only first system circuit 41, and steering control device 50 has only first system circuit 51, the following processing is executed. For example, when first reaction force control circuit 41A that is operating normally is reset, the reset first reaction force control circuit 41A executes processing to stop the vehicle from traveling when it is restarted after the reset is completed.

[0123] Furthermore, if first reaction force control circuit 41A that is operating normally is reset, the reset first reaction force control circuit 41A will stop driving of its own control target, reaction force motor 21, when it restarts after the reset is complete. First turning control circuit 51A that is operating normally without being reset will stop driving of its own control target, turning motor 31, in synchronization with the reset first reaction force control circuit 41A.

[0124] Note that the same processing as above is executed even when first steering control circuit 51A, which is operating normally, is reset. Depending on the product specifications, the processing for stopping reaction force motor 21 and steering motor 31 may not be executed. [Explanation of symbols]

[0125] 11...Steering wheel 15...Steering wheel 21...Reaction motor 31...Steering motor 40...Reaction force control device constituting the steering control device 41A...First reaction force control circuit 42A...Second reaction force control circuit 50... Steering control device constituting the steering control device 51A...First steering control circuit 52A...Second steering control circuit N11: Winding group of the first reaction motor N12: Second winding group of reaction motor N21: First winding group of steering motor N22: Second winding group of steering motor

Claims

1. a plurality of control circuits configured to control, in cooperation with each other, a reaction motor that generates a steering reaction force applied to a steering wheel whose power transmission is separated from the steered wheels of a vehicle, and a turning motor that generates a turning force for turning the steered wheels; A steering control device configured such that when at least one of a plurality of control circuits operating normally is reset, the reset control circuit executes processing to stop the vehicle from traveling when it is restarted after the reset is completed.

2. the reset control circuit is configured to execute a process for stopping the drive of the reaction force motor or the steering motor, which is the control target of the reset control circuit, when the reset control circuit is restarted after completion of the reset; 2. The steering control device according to claim 1, wherein the control circuit that is operating normally without being reset is configured to execute processing to stop the driving of the steering motor or the reaction motor, which is its own control target, in synchronization with the reset control circuit.

3. the reaction motor and the steering motor each have two winding groups, The plurality of control circuits include: a two-system reaction force control circuit for controlling power supply to the winding group of the reaction force motor; a two-system steering control circuit that controls power supply to the winding group of the steering motor, a single-system drive mode in which the reaction motor and the steering motor are controlled by only the reaction force control circuit and the steering control circuit of one of two systems, as drive modes of the reaction motor and the steering motor; 3. A steering control device according to claim 1 or claim 2, configured to execute the processing when at least one of the plurality of control circuits operating normally is reset when the drive mode is the single-system drive mode.

4. the control circuit, which controls the steering motor, is configured to control the steering motor so that the steered wheels are turned in accordance with an amount of rotation of the steering wheel, the control circuit that controls the reaction motor is configured to execute a predetermined preparation process at startup, the preparation process includes a midpoint learning process for learning a steering neutral position of the steering wheel by automatically rotating the steering wheel through driving of the reaction motor; 3. The steering control device according to claim 1, further comprising a steering angle synchronization process for correcting the rotational position of the steering wheel so that the rotational position of the steering wheel corresponds to the steered position of the steered wheels.

5. the control circuit is configured to store information indicating whether the control has been stopped in response to the vehicle power being turned off; 3. The steering control device according to claim 1, wherein the control circuit is configured to determine that the control has not been reset when information indicating that control has been stopped due to the vehicle power being turned off is stored at the time of startup, and to determine that the control circuit has been reset when information indicating that control has been stopped due to the vehicle power being turned off is not stored.

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