Vehicle control device

Abstract

To provide a vehicle control device that can start up more appropriately when powered on.SOLUTION: A vehicle control device includes: two turning control circuits configured to control power feeding to two winding groups of a turning motor; and two rotation detection circuits configured to detect the number of rotations of the turning motor. The turning control circuit calculates an absolute rotation angle of the turning motor by using the number of rotations of the turning motor. At power off, the turning control circuit stores the absolute rotation angle of the turning motor at that time. At power on, the turning control circuit confirms that the two rotation detection circuits are normal and then starts up. For example, if an error is detected in either one of the two rotation detection circuits at power on, the turning control circuit starts up, provided that an absolute value of the difference between the absolute rotation angle of the turning motor stored at the previous power off and the absolute rotation angle of the motor calculated at the current power on is a predetermined threshold value or lower (YES in step S203).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 devices have been known. For example, an ECU (electronic control unit) disclosed in Patent Document 1 controls a motor of an electric power steering device mounted on a vehicle. The ECU has two systems of magnetic detection elements. The ECU generates motor rotation angle information from a first rotation angle signal generated by the magnetic detection elements of the first system and a second rotation angle signal generated by the magnetic detection elements of the second system. The ECU calculates the position of the steering wheel from the motor rotation angle information.

[0003] The ECU compares first motor rotation angle information obtained from the first rotation angle signal with second motor rotation angle information obtained from the second rotation angle signal. When the first motor rotation angle information and the second motor rotation angle information match, the ECU executes assist control to assist steering of the steering wheel using steering wheel position information obtained from the motor rotation angle information. When the first motor rotation angle information and the second motor rotation angle information do not match, the ECU detects an abnormality in the magnetic detection element of the first system or the magnetic detection element of the second system. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-116964 Summary of the Invention [Problem to be solved by the invention]

[0005] The ECU in Patent Document 1 can detect that one of the two magnetic detection elements is abnormal. However, the ECU in Patent Document 1 cannot identify which of the two magnetic detection elements is abnormal. Therefore, even if one of the two magnetic detection elements is normal, the motor may not start driving. [Means for solving the problem]

[0006] A vehicle control device that can solve the above problem includes two control circuits that independently control the power supply to two winding groups of a motor, and two rotation detection circuits that detect the number of rotations of the motor. The control circuit has a function of calculating an absolute rotation angle of the motor using the number of rotations of the motor, and is configured to store the absolute rotation angle of the motor at that time when the power is off, and to start up when the power is on after confirming that both of the two rotation detection circuits are normal. When the power is on, the control circuit detects that an abnormality has occurred in one of the two rotation detection circuits, or cannot determine that an abnormality exists in either of the two rotation detection circuits, if the absolute value of the difference between the absolute rotation angle of the motor stored when the power was last turned off and the absolute rotation angle of the motor calculated when the power is on this time is equal to or less than a predetermined threshold value. , and it is determined that the rotation detection circuit of the own system is normal. It is configured to start.

[0007] With this configuration, when the absolute value of the difference between the absolute rotation angle of the motor stored when the power was turned off and the absolute rotation angle of the motor calculated the next time the power is turned on is equal to or less than a predetermined threshold value, it can be said that the rotation detection circuit of the own system is normal. Therefore, by appropriately starting up the control circuit of the first system or the second system, it is possible to start controlling the motor.

[0008] In the above vehicle control device, the two control circuits may be configured to exchange the number of rotations of the motor detected by the rotation detection circuit of their own system with each other and to determine whether there is an abnormality in the rotation detection circuits of the two systems by comparing the number of rotations of the motor detected by the rotation detection circuits of the two systems. The control circuits of the two systems may have a master-slave relationship, with the control circuit of the first system functioning as a master and the control circuit of the second system functioning as a slave. If there is no abnormality in the rotation detection circuits of the two systems, it may be possible to determine whether there is an abnormality in the control circuit of the first system when the power is turned on. The control circuit of the second system is configured to determine that the rotation detection circuit of its own system is normal and to start up, even if the control circuit of the first system does not start up when the power is turned on, if the absolute value of the difference between the absolute rotation angle of the motor stored when the power was previously turned off and the absolute rotation angle of the motor calculated when the power is turned on this time is equal to or less than a predetermined threshold value.

[0009] With this configuration, even if the master control circuit of the first system does not start up when the power is turned on, if the absolute value of the difference between the absolute rotation angle of the motor stored the previous time the power was turned off and the absolute rotation angle of the motor calculated the current time the power is turned on is equal to or less than a predetermined threshold value, the rotation detection circuit of the second system can be said to be normal. Therefore, the slave control circuit of the second system can start up independently.

[0010] In the above-described vehicle control device, the motor may be a drive source for a mechanical device, and the mechanical device may have a sensor that detects the absolute position of a component linked to the motor. Only the control circuit of a first system may be connected to the sensor. The control circuit of the first system may be configured to, when powered on, perform a process of calculating an absolute rotation angle of the motor using the absolute positions of the components detected through the sensor if an abnormality is detected in one of the rotation detection circuits of the two systems or if an abnormality in the rotation detection circuits of the two systems cannot be determined. and a process of transmitting the absolute positions of the components detected through the sensor to the control circuit of the second system.

[0011] According to this configuration, when the power is turned on, if an abnormality is detected in one of the two rotation detection circuits, or if an abnormality in one of the two rotation detection circuits cannot be determined, the control circuit of the first system and the control circuit of the second system can calculate the absolute rotation angle of the motor using the absolute positions of the components of the mechanical device.

[0012] In the vehicle control device, the mechanical device may be a steering device of the vehicle, the component may be a steering shaft for steering steered wheels of the vehicle, and the sensor may be a stroke sensor for detecting an absolute axial position of the steering shaft.

[0013] According to this configuration, when the power is turned on, if an abnormality is detected in one of the two rotation detection circuits, or if an abnormality in one of the two rotation detection circuits cannot be determined, the control circuit of the first system and the control circuit of the second system can calculate the absolute rotation angle of the motor using the absolute position of the steered shaft, which is a component of the steering device.

[0014] In the above vehicle control device, the motor may be a steering motor that generates a steering force for steering steered wheels of the vehicle. The two control circuits may include a first steering control circuit that controls power supply to the winding group of the first system of the steering motor, and a second steering control circuit that controls power supply to the winding group of the second system of the steering motor.

[0015] With this configuration, it is sometimes required that the steering motor be started as quickly as possible, even if only one system is used. This requirement can be met. In the above vehicle control device, the motor may be an assist motor that generates an assist force to assist steering wheel operation. The two control circuits may include a first assist control circuit that controls power supply to the winding group of the first system of the assist motor, and a second assist control circuit that controls power supply to the winding group of the second system of the assist motor.

[0016] With this configuration, it is sometimes required that the assist motor be started as quickly as possible, even if only one system is used. This requirement can be met. [Effects of the Invention]

[0017] According to the vehicle control device of the present invention, it is possible to more appropriately start up when the power is turned on. [Brief explanation of the drawings]

[0018] [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. [Figure 2] FIG. 2 is a block diagram of a reaction force control device and a steering control device according to the first embodiment. [Figure 3] FIG. 4 is a list showing an example of the state of each control circuit. [Figure 4] 10 is a flowchart showing the processing procedure of the second steering control circuit when the vehicle power supply is turned off. [Figure 5] 10 is a flowchart showing the processing procedure of the second steering control circuit when the vehicle power supply is turned on. [Figure 6] 10(a), (b), and (c) are diagrams for verifying the accumulation of detection errors of the rotation angle sensor. [Figure 7] FIG. 2 is a configuration diagram of a second embodiment of a vehicle control device. DETAILED DESCRIPTION OF THE INVENTION

[0019] First Embodiment A first embodiment in which the vehicle control device is embodied in a steer-by-wire steering device will be described below. The steering device is a mechanical device.

[0020] 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.

[0021] 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.

[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 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.

[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 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.

[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 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.

[0027] 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. 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.

[0028] Steering control device 50 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. Steering control device 50 controls the supply of power 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 supply of power to two systems of winding groups in steering motor 31 independently for each system.

[0029] 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.

[0030] 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.

[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-board 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 supply 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 to start or stop a drive source for running the vehicle, such as an engine. When the start switch SW is turned on, power from the DC power supply 60 is supplied via the start switch SW 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. Turning the start switch SW on means that the vehicle power supply is on. Turning the start switch SW off means that the vehicle power supply is 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 supply relay 60A. When the start switch SW is switched from on to off, the first system circuit 41 executes power latch control to maintain the power supply relay 60A in the on state for a predetermined period of time. Therefore, the first system circuit 41 can operate even after the start switch SW is turned off. The first system circuit 41 can cut off the power supply to itself by switching the power supply relay 60A from on to off after the predetermined period has elapsed.

[0035] The first system circuit 41 detects whether the start switch SW is on or off by, for example, monitoring the voltage across the start switch SW. The first system circuit 41 detects that the start switch SW is on when the voltage across the start switch SW falls below a predetermined voltage threshold. The first system circuit 41 detects that the start switch SW is off when the voltage across the start switch SW is equal to or greater than the predetermined 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. When the start switch SW is switched from on to off, the second system circuit 42 maintains the power supply relay 60B in an on state for a predetermined period of time.

[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 keeps the power supply relay 60C in an on state for a predetermined period of time.

[0038] The second system circuit 52 of the turning control device 50 controls the on / off of the power supply relay 60D. The second system circuit 52 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 second system circuit 52 maintains the power supply relay 60D in an on state for a predetermined period of time.

[0039] Among the components of the steering device 10, those that are required to continue operating 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, power continues to be supplied to the components, such as the torque sensor 23, the steering angle sensor 24, and the stroke sensor 34, as long as at least one of the power supply relays 60A, 60B, 60C, and 60D is turned on.

[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 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.

[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 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.

[0043] 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 DC power supply 60 into three-phase AC power by switching the switching elements of each phase based on drive signals 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 winding group N11 of the reaction force motor 21 via power supply paths for each phase, such as bus bars or cables. This causes the first winding group N11 to generate torque according to a first current command value.

[0044] 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.

[0045] 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 a DC power supply 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 via power supply paths for each phase, which are formed by 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.

[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 the master, and the second circuit system 42 functions as the 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 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.

[0048] 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. First steering control circuit 51A 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.

[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 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.

[0050] 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. Second steering control circuit 52A 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 according to 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.

[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 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.

[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 the master, and the second circuit system 52 functions as the 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 path 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 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] <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.

[0059] 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.

[0060] 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.

[0061] 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.

[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 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.

[0064] 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.

[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. 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.

[0066] 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. <Supplementary explanation of the steering control device 50> Next, a supplementary explanation will be given of the configuration of the steering control device 50. The steering control device 50 further has the following configurations (A1) to (A6).

[0067] (A1) First system circuit 51 and second system circuit 52 start up when the vehicle power supply is turned on. At start-up, first system circuit 51 and second system circuit 52 calculate the rotation angle of steering motor 31 as an absolute angle. Steering angle θw is an absolute angle. First system circuit 51 and second system circuit 52 start up after confirming that the rotation angle of steering motor 31 has been calculated correctly.

[0068] (A2) First system circuit 51 has rotation detection circuit 51C (TC: Turn Counter). Second system circuit 52 has rotation detection circuit 52C. Rotation detection circuits 51C, 52C take in electrical signals generated by a rotation angle sensor of steering motor 31 at a set sampling period. The electrical signals correspond to the rotation angle of steering motor 31. The electrical signals include a sine signal (sin signal) that varies sinusoidally with respect to the rotation angle of steering motor 31, and a cosine signal (cos signal) that varies cosineally with respect to the rotation angle of steering motor 31. Rotation detection circuits 51C, 52C calculate the rotation direction and number of rotations of steering motor 31 based on the sine signal and cosine signal.

[0069] Rotation detection circuits 51C and 52C plot coordinates (cosθb, sinθb), which are a pair of sine and cosine signal values, on an orthogonal coordinate system of "cosθb" and "sinθb," ​​and detect the rotation direction of steering motor 31 based on the transition of the quadrant in which the plotted coordinates are located. "θb" is the rotation angle of steering motor 31. Rotation detection circuits 51C and 52C determine the quadrant in which the plotted coordinates are located based on the positive and negative values ​​of "sinθb" and "cosθb." When the coordinates transition, for example, from the first quadrant to the second quadrant, rotation detection circuits 51C and 52C determine that the rotation direction of steering motor 31 is forward. Furthermore, when the coordinates transition, for example, from the first quadrant to the fourth quadrant, rotation detection circuits 51C and 52C determine that the rotation direction of steering motor 31 is reverse.

[0070] Rotation detection circuits 51C, 52C have counters. Rotation detection circuits 51C, 52C increase or decrease a count value by a fixed value each time the quadrant in which the coordinates (cos θb, sin θb), which are a set of sine and cosine signal values, are located, changes. The fixed value is a positive natural number such as 1 or 2. When the rotation direction of steering motor 31 is forward, rotation detection circuits 51C, 52C increase the count value by a fixed value each time the coordinates change by one quadrant. When the rotation direction of steering motor 31 is reverse, rotation detection circuits 51C, 52C decrease the count value by a fixed value each time the coordinates change by one quadrant. Rotation detection circuits 51C, 52C detect the number of rotations of steering motor 31 based on the count value.

[0071] The first turning control circuit 51A detects abnormalities in the two rotation detection circuits 51C, 52C by comparing the count values ​​of the two rotation detection circuits 51C, 52C. When the count values ​​of the two rotation detection circuits 51C, 52C match, the first turning control circuit 51A determines that the two rotation detection circuits 51C, 52C are normal. When the count values ​​of the two rotation detection circuits 51C, 52C do not match, the first turning control circuit 51A determines that either one of the two rotation detection circuits 51C, 52C or both of the two rotation detection circuits 51C, 52C are abnormal.

[0072] The second turning control circuit 52A determines whether or not there is an abnormality in the two rotation detection circuits 51C, 52C in the same manner as the first turning control circuit 51A. (A3) First steering control circuit 51A is connected to stroke sensor 34. First steering control circuit 51A receives an electrical signal generated by stroke sensor 34. Stroke sensor 34 is used to detect the absolute axial position of steered shaft 13. Stroke sensor 34 may be of a type that is provided on pinion shaft 33, for example. This type of stroke sensor 34 detects the rotation angle of pinion shaft 33 as an absolute angle. The rotation angle of pinion shaft 33 can be converted into the stroke of steered shaft 13 or the rotation angle of steering motor 31.

[0073] Depending on the product specifications, the second turning control circuit 52A may not be connected to the stroke sensor 34. In this case, the second turning control circuit 52A cannot receive the electrical signal generated by the stroke sensor 34.

[0074] (A4) The first steering control circuit 51A has a function to detect a battery reset. A battery reset occurs when the power supply from the DC power supply 60, such as a battery, is interrupted. The first steering control circuit 51A detects a battery reset, for example, when the power from the DC power supply 60 is interrupted. The second steering control circuit 52A, like the first steering control circuit 51A, has a function to detect a battery reset.

[0075] (A5) When first turning control circuit 51A is started, for example, in the cases of B1 to B3 below, the accuracy of the count numbers of rotation detection circuits 51C and 52C cannot be guaranteed. B1. When a battery reset occurs When the power from DC power supply 60 is cut off, rotation detection circuits 51C, 52C cannot count the number of rotations of steering motor 31.

[0076] B2: When an abnormality is detected in rotation detection circuits 51C, 52C: In this case, it is unclear whether the number of rotations of steering motor 31 is a correct value. B3. When it is not possible to determine an abnormality in rotation detection circuits 51C, 52C: In this case, it is unclear whether the number of rotations of steering motor 31 is a correct value.

[0077] Therefore, in the cases of B1 to B3, first steering control circuit 51A uses the detection result of stroke sensor 34 to calculate an offset angle based on the neutral position of steering shaft 13. The neutral position is the position of steering shaft 13 when the vehicle is traveling straight ahead. The offset angle is the stroke of steering shaft 13 based on the neutral position of steering shaft 13, or the rotation angle of pinion shaft 33. First steering control circuit 51A transmits the offset angle to second steering control circuit 52A via communication line L2. First steering control circuit 51A stores the offset angle, and calculates the rotation angle of steering motor 31 as an absolute angle based on the offset angle.

[0078] (A6) In cases other than B1 to B3 above, first turning control circuit 51A uses the offset angle stored at the time of startup to calculate the rotation angle of turning motor 31 as an absolute angle. <State of steering control device 50> Next, the state of the steering control device 50 will be described.

[0079] As shown in FIG. 3, the state of the steering control device 50 is indicated by, for example, the following items (C1) to (C6). C1. Communication between microcontrollers C2. Driving state C3. Battery Reset C4.TC initial status flag C5.Whether or not TC comparison was performed C6.TC initial state judgment result (C1) Inter-microcomputer communication is communication between first turning control circuit 51A and second turning control circuit 52A. The state of inter-microcomputer communication includes normal and abnormal.

[0080] (C2) The drive state includes the drive state of first steering control circuit 51A and the drive state of second steering control circuit 52A. "Main" in FIG. 3 indicates first steering control circuit 51A, which is the master. "Sub" in FIG. 3 indicates second steering control circuit 52A, which is the slave. The drive state includes the cooperative drive mode, independent drive mode, single-system drive mode, and stop. Stop includes a stop caused by a failure in the non-rotation angle system and a stop caused by a failure in the rotation angle system.

[0081] A failure in the non-rotation angle system is an abnormality in equipment that does not affect the calculation of the rotation angle of turning motor 31, such as the rotation angle sensor of turning motor 31 and rotation detection circuits 51C, 52C. A failure in the non-rotation angle system includes a case where an abnormality is determined after the rotation angle of turning motor 31 has been calculated as an absolute angle, and a case where an abnormality is determined before the rotation angle of turning motor 31 is calculated as an absolute angle. A failure in the rotation angle system is an abnormality in equipment that affects the calculation of the rotation angle of turning motor 31, such as the rotation angle sensor of turning motor 31 and rotation detection circuits 51C, 52C.

[0082] (C3) Battery Reset indicates whether a battery reset has occurred. "Reset" in FIG. 3 indicates that a battery reset has occurred. A hyphen "-" in FIG. 3 indicates that a battery reset has not occurred.

[0083] (C4) The TC initial status flag indicates whether the two rotation detection circuits 51C, 52C are normal. When the first turning control circuit 51A determines that the two rotation detection circuits 51C, 52C are normal, it sets the value of the TC initial status flag to "normal." When the value of the TC initial status flag is set to "normal," the rotation detection circuits 51C, 52C are usable. When the first turning control circuit 51A determines that either one of the two rotation detection circuits 51C, 52C is abnormal, it sets the value of the TC initial status flag to "invalid." When the value of the TC initial status flag is set to "invalid," the rotation detection circuits 51C, 52C cannot be used. A hyphen "-" in FIG. 3 indicates that it does not need to be taken into consideration.

[0084] When the value of the TC initial state flag is "normal", first steering control circuit 51A uses the stored offset angle to calculate the rotation angle of steering motor 31 as an absolute angle. When the value of the TC initial state flag is "invalid", first steering control circuit 51A uses the detection result of stroke sensor 34 to calculate an offset angle based on the neutral position of steering shaft 13. First steering control circuit 51A uses the calculated offset angle to calculate the rotation angle of steering motor 31 as an absolute angle.

[0085] (C5) Whether or not TC comparison is performed indicates whether or not comparison processing is performed on the count values ​​of the two rotation detection circuits 51C and 52C. "Yes" in FIG. 3 indicates that comparison processing is performed on the count values ​​of the two rotation detection circuits 51C and 52C. "No" in FIG. 3 indicates that comparison processing is not performed on the count values ​​of the two rotation detection circuits 51C and 52C.

[0086] For example, if first steering control circuit 51A starts in single-system mode while second steering control circuit 52A is stopped, it is not possible to compare the count values ​​of two rotation detection circuits 51C, 52C. In this case, it is not possible to detect an abnormality in rotation detection circuits 51C, 52C. For this reason, the detection result of stroke sensor 34 is used to calculate an offset angle based on the neutral position of steered shaft 13. First steering control circuit 51A uses the calculated offset angle to calculate the rotation angle of steering motor 31 as an absolute angle.

[0087] However, after the rotation angle of steering motor 31 is calculated as an absolute angle using the stored offset angle, for example, second steering control circuit 52A may stop due to a non-rotation angle system failure. In this case, the status of whether TC comparison has been performed will be "performed."

[0088] (C6) The TC initial state determination result indicates whether or not the number of rotations of steering motor 31 was continuously counted by rotation detection circuits 51C, 52C while the vehicle power supply was off. "Continuous" in FIG. 3 indicates that rotation detection circuits 51C, 52C were counting continuously. "Discontinuous" in FIG. 3 indicates that rotation detection circuits 51C, 52C were not counting continuously. A hyphen "-" in FIG. 3 indicates that it does not need to be taken into consideration.

[0089] For example, when a battery reset occurs, rotation detection circuits 51C, 52C cannot count the number of rotations of steering motor 31. As a result, the TC initial state determination result becomes "discontinuous." When the TC initial state determination result becomes "discontinuous," the accuracy of the count numbers of rotation detection circuits 51C, 52C cannot be guaranteed. Therefore, when the TC initial state determination result becomes "discontinuous," the detection result of stroke sensor 34 is used to calculate an offset angle based on the neutral position of steering shaft 13. First steering control circuit 51A uses the calculated offset angle to calculate the rotation angle of steering motor 31 as an absolute angle.

[0090] When all of the following four conditions (D1) to (D4) are satisfied, first turning control circuit 51A uses the stored offset angle to calculate the rotation angle of turning motor 31 as an absolute angle.

[0091] D1. Battery reset has not occurred. The value of the D2.TC initial status flag is "normal." D3.TC comparison is "Yes".

[0092] D4. The TC initial state judgment result is "continuous." When at least one of the four conditions (D1) to (D4) is not satisfied, first steering control circuit 51A uses the detection result of stroke sensor 34 to calculate an offset angle based on the neutral position of steered shaft 13. First steering control circuit 51A uses the calculated offset angle to calculate the rotation angle of steering motor 31 as an absolute angle.

[0093] The second steering control circuit 52A basically operates in the same manner as the first steering control circuit 51A. However, the steering control device 50 has the following concerns.

[0094] As shown in the bottom row of Figure 3, there may be a situation where the first steering control circuit 51A, which is the master, does not start up when the vehicle power supply is turned on. If the first steering control circuit 51A is maintained in a stopped state, the second steering control circuit 52A, which is the slave, would normally start up in, for example, a single-system mode.

[0095] However, because first steering control circuit 51A is stopped, it is not possible to determine whether there is an abnormality in rotation detection circuits 51C, 52C. For this reason, second steering control circuit 52A needs to use the detection result of stroke sensor 34 to calculate the offset angle based on the neutral position of steered shaft 13, and therefore the rotation angle of steering motor 31, as an absolute angle. However, if second steering control circuit 52A is not configured to incorporate the detection result of stroke sensor 34, second steering control circuit 52A will not be able to calculate the offset angle, and therefore the rotation angle of steering motor 31, as an absolute angle. Therefore, there is a concern that second steering control circuit 52A may not be able to start up.

[0096] This phenomenon may occur, for example, when the vehicle power supply is turned on in a state where the power supply line that supplies power to first turning control circuit 51A is disconnected. Therefore, in this embodiment, the following configuration is adopted.

[0097] When the vehicle power supply is turned on, if the first steering control circuit 51A, which is the master, does not start up, the second steering control circuit 52A, which is the slave, compares the rotation angle of the steering motor 31 stored the last time the vehicle power supply was turned off with the rotation angle of the steering motor 31 calculated from the stored offset angle.

[0098] When the absolute value of the difference between the rotation angle of steering motor 31 stored the last time the vehicle power was turned off and the rotation angle of steering motor 31 calculated from the offset angle is equal to or less than a predetermined threshold value, second steering control circuit 52A determines that no abnormality has occurred in rotation detection circuits 51C, 52C. In this case, second steering control circuit 52A is started using the rotation angle of steering motor 31 calculated from the offset angle. This is because there is a concern that if control is executed based on the rotation angle of steering motor 31 stored the last time the vehicle power was turned off, deviations in detection errors of the rotation angle sensor of steering motor 31 will be accumulated.

[0099] That is, as shown in the bottom row of Figure 3, when the second steering control circuit 52A, which is the slave, starts up in single-system mode, if it is confirmed that there are no abnormalities in the rotation detection circuits 51C, 52C, the value of the TC initial state flag of the second steering control circuit 52A is considered to be "normal" and the second steering control circuit 52A starts up.

[0100] However, it is assumed that, under normal vehicle use conditions, events that cause a change in the steering angle θw, such as jacking up the vehicle, do not occur. When the absolute value of the difference between the rotation angle of steering motor 31 stored the last time the vehicle power was turned off and the rotation angle of steering motor 31 calculated from the offset angle exceeds a predetermined threshold value, second steering control circuit 52A determines that there is a risk of an abnormality occurring in rotation detection circuits 51C, 52C. In this case, second steering control circuit 52A does not start up.

[0101] This is for the following reason. That is, if, during the period from when the vehicle power is turned off to when it is turned on again, the absolute value of the difference between the rotation angle of steering motor 31 stored when the vehicle power was last turned off and the rotation angle of steering motor 31 calculated when the vehicle power is turned on this time exceeds a threshold value, there is a risk of vehicle deviation. Vehicle deviation is, for example, deviation of a vehicle that should normally proceed straight.

[0102] <When vehicle power is off: Processing procedure of second steering control circuit 52A> Next, the processing procedure of second steering control circuit 52A when the vehicle power supply is turned off will be described.

[0103] As shown in the flowchart of Figure 4, when the vehicle power supply is turned off, second steering control circuit 52A stores the rotation angle of steering motor 31 at that time. The rotation angle is an absolute angle. Second steering control circuit 52A determines whether the rotation angle of steering motor 31 has been successfully stored (step S101).

[0104] For example, when no rotation angle system failure has occurred in its own system before the execution of power latch control, and when no error has occurred in writing to memory, second turning control circuit 52A determines that the rotation angle of turning motor 31 has been successfully stored (YES in step S101). In this case, second turning control circuit 52A also stores that the stored rotation angle of turning motor 31 will be usable the next time it is started. After a predetermined execution period of power latch control has elapsed, second turning control circuit 52A turns off the power (step S102).

[0105] When a rotation angle system failure occurs in its own system before the execution of power latch control, or when a writing error to memory is detected, second turning control circuit 52A determines that the rotation angle of turning motor 31 has not been stored correctly (NO in step S101). In this case, second turning control circuit 52A also stores the fact that the stored rotation angle of turning motor 31 will not be usable at the next start-up (step S103). Second turning control circuit 52A turns off the power supply after a predetermined execution period of power latch control has elapsed (step S102).

[0106] <When vehicle power is on: Processing procedure of second steering control circuit 52A> Next, the processing procedure of second steering control circuit 52A when the vehicle power supply is turned on will be described.

[0107] As shown in the flowchart of Figure 5, when the vehicle power supply is turned on, second steering control circuit 52A reads out the rotation angle of steering motor 31 stored in memory. The rotation angle is the rotation angle of steering motor 31 stored in memory the previous time the vehicle power supply was turned off. The rotation angle is an absolute angle. Second steering control circuit 52A determines whether the rotation angle of steering motor 31 was successfully read out (step S201).

[0108] If second steering control circuit 52A is able to read out the rotation angle of steering motor 31 normally (YES in step S201), and its own drive mode is single-system drive mode, it regards its own TC initial state flag as "normal." At this time, second steering control circuit 52A calculates the rotation angle of steering motor 31 (step S202). Second steering control circuit 52A uses the stored offset angle to calculate the rotation angle of steering motor 31 as an absolute angle.

[0109] Next, if the rotation angle of steering motor 31 read from memory is usable, second steering control circuit 52A compares the rotation angle of steering motor 31 read from memory with the rotation angle of steering motor 31 calculated in the previous step S202. Second steering control circuit 52A determines whether the comparison result is normal (step S203).

[0110] When the absolute value of the difference between the rotation angle of steering motor 31 read from memory and the rotation angle of steering motor 31 calculated in the previous step S202 is equal to or less than a predetermined threshold value, second steering control circuit 52A determines that the comparison result is normal (YES in step S203). The fact that the comparison result is normal also means that two rotation detection circuits 51C, 52C are normal.

[0111] When the comparison result is normal, the second turning control circuit 52A starts to execute normal control, which is control in a single-system mode. When the absolute value of the difference between the rotation angle of steering motor 31 read from memory and the rotation angle of steering motor 31 calculated in the previous step S202 exceeds a predetermined threshold value, second steering control circuit 52A determines that the comparison result is abnormal (NO in step S203). When the comparison result is abnormal, second steering control circuit 52A determines that start-up is not possible (S205) and ends the processing. Start-up is not possible is a state in which start-up is not possible.

[0112] It should be noted that if the second turning control circuit 52A is unable to read out the rotation angle of the turning motor 31 normally (NO in step S201), it also determines that start-up is not possible (S205) and ends the process.

[0113] <Detection error of rotation angle sensor> Next, the detection error of the rotation angle sensor of the steering motor 31 will be described. Here, the following items (E1) to (E5) are assumed.

[0114] (E1) During the period when the vehicle power supply is on and during the period when the vehicle power supply is off, the rotation angle of steering motor 31 does not change from its true value of 0°. The rotation angle is an absolute angle. (E2) The rotation detection circuits 51C and 52C are normal.

[0115] (E3) The normal variation of the rotation angle sensor signal is, for example, ±α°. (E4) If the variation in the rotation angle sensor of the steering motor 31 is within the allowable range of vehicle deflection, the second steering control circuit 52A can be activated.

[0116] (E5) The allowable range of vehicle deflection is the range within which the rotation angle of steering motor 31 detected by the rotation angle sensor can be determined to be normal, and is, for example, ±2α°. The allowable range is set based on the variation in the rotation angle stored in memory when the vehicle power is off and the variation in the rotation angle calculated the next time the vehicle power is turned on.

[0117] The following three cases F1 to F3 will be considered. F1. Vehicle power on: Nth time As shown in Figure 6(a), when the rotation angle of steering motor 31 stored in memory is 0°, which is the true value, and the rotation angle of steering motor 31 calculated at startup is α°, the calculated rotation angle of steering motor 31 is within the allowable range of vehicle deflection, specifically a value of "-2α° or more and 2α° or less". Therefore, second steering control circuit 52A can be started.

[0118] E2. Vehicle power on: N+1th time As shown in Figure 6(b), when the rotation angle of steering motor 31 stored in memory is α° and the rotation angle of steering motor 31 calculated at start-up is -α°, the rotation angle of steering motor 31 is within the allowable range of vehicle deflection, specifically a value of "-α° or more and 3α° or less". Therefore, second steering control circuit 52A can be started.

[0119] E3. Vehicle power on: N+2 times As shown in Figure 6(c), when the rotation angle of steering motor 31 stored in memory is -α° and the rotation angle of steering motor 31 calculated at start-up is α°, the rotation angle of steering motor 31 is within the allowable range of vehicle deflection, specifically a value of "-3α° or more and α° or less". Therefore, second steering control circuit 52A can be started.

[0120] In this way, even if the maximum error is taken between the rotation angle of the steering motor 31 stored in memory when the vehicle power is off and the rotation angle of the steering motor 31 calculated the next time the vehicle power is turned on, the detection error of the rotation angle of the steering motor 31 does not accumulate.

[0121] <Effects of the first embodiment> The first embodiment provides the following advantages. (1-1) When the vehicle power is turned on, the second steering control circuit 52A is configured to be activated when the absolute value of the difference between the absolute rotation angle of the steering motor 31 stored the previous time the vehicle power was turned off and the absolute rotation angle of the steering motor 31 calculated the current time the vehicle power is turned on is equal to or less than a predetermined threshold value, even if an abnormality is detected in one of the two rotation detection circuits 51C, 52C when the vehicle power is turned on, or even if it is not possible to determine whether there is an abnormality in the two rotation detection circuits 51C, 52C.

[0122] When the absolute value of the difference between the absolute rotation angle of steering motor 31 stored when the vehicle power was off and the absolute rotation angle of steering motor 31 calculated when the vehicle power was turned on this time is equal to or less than a predetermined threshold value, it can be said that rotation detection circuits 51C, 52C are normal. In other words, if first steering control circuit 51A, which is the master, does not start when the vehicle power is turned on, second steering control circuit 52A, which is the slave, can start properly as long as the steering angle θw has not changed due to the application of an external force while parking, for example. Motor drive is controlled by second steering control circuit 52A.

[0123] The first steering control circuit 51A may be configured to operate in the same manner as the second steering control circuit 52A. (1-2) Steering device 10 has stroke sensor 34 that detects the absolute axial position of steered shaft 13. When the vehicle power is on, if it is detected that an abnormality has occurred in one of two rotation detection circuits 51C, 52C, or if it is not possible to determine whether or not an abnormality exists in two rotation detection circuits 51C, 52C, first steering control circuit 51A can calculate the absolute rotation angle of steering motor 31 using the detection result of stroke sensor 34.

[0124] (1-3) When the vehicle power is turned on, if the first master steering control circuit 51A does not start, the second steering control circuit 52A can be started using the rotation angle of the steering motor 31 stored in memory when it is confirmed that there are no abnormalities in the rotation detection circuits 51C, 52C.

[0125] (1-4) It is required that the steering motor 31 be started as much as possible, even if only one system is used. This requirement can be met. <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 reference numerals are used to designate the same components as those in the first embodiment, and detailed descriptions thereof will be omitted.

[0126] The electric power steering device is configured by mechanically connecting steering wheel 11 and steered wheels 15 shown in Fig. 1 above. That is, steering shaft 12, pinion shaft 33 and steered shaft 13 function as a power transmission path between steering wheel 11 and steered wheels 15. When steering wheel 11 is steered, steered shaft 13 moves linearly, thereby changing the steered angle θw of steered wheels 15.

[0127] 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 to assist 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.

[0128] 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.

[0129] The motor drive circuit 81B converts the DC power supplied from the DC power supply 60 into three-phase AC power based on the 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 by bus bars, cables, or the like.

[0130] 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.

[0131] 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 by bus bars, cables, or the like.

[0132] 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 about 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.

[0133] First assist control circuit 81A basically has the same configuration as first steering control circuit 51A shown in Figure 2. Second assist control circuit 82A basically has the same configuration as second steering control circuit 52A shown in Figure 2. Like the control circuits (41A, 42A, 51A, 52A) in the first embodiment, first assist control circuit 81A and second assist control circuit 82A control the drive of assist motor 70 in one of the cooperative drive mode, independent drive mode, and single-system drive mode.

[0134] There is a master-slave relationship between the first circuit system 81 and the second circuit system 82 of the reaction force control device 40. In this case, for example, the first circuit system 81 functions as the master, and the second circuit system 82 functions as the slave.

[0135] When the vehicle power supply is turned on, if the first assist control circuit 81A, which is the master, does not start up, the second assist control circuit 82A, which is the slave, performs the same operation as the second assist control circuit 82A in the first embodiment.

[0136] The second assist control circuit 82A compares the rotation angle of the assist motor 70 stored when the vehicle power was last turned off with the rotation angle of the assist motor 70 calculated from the stored offset angle.

[0137] The second assist control circuit 82A determines that no abnormality has occurred in the rotation detection circuits 51C, 52C when the absolute value of the difference between the rotation angle of the assist motor 70 stored the last time the vehicle power was turned off and the rotation angle of the assist motor 70 calculated from the offset angle is equal to or less than a predetermined threshold value. In this case, the second assist control circuit 82A is activated using the rotation angle of the assist motor 70 calculated from the offset angle.

[0138] That is, as shown in the bottom row of Figure 3, when the slave second assist control circuit 82A starts up in single-system mode, if it is confirmed that there are no abnormalities in the rotation detection circuits 51C, 52C, the value of the TC initial state flag of the second assist control circuit 82A is considered to be "normal" and the second assist control circuit 82A starts up.

[0139] When the difference between the rotation angle of assist motor 70 stored the last time the vehicle power was turned off and the rotation angle of assist motor 70 calculated from the offset angle exceeds a predetermined threshold, second assist control circuit 82A determines that there is a possibility of an abnormality occurring in rotation detection circuits 51C, 52C. In this case, second steering control circuit 52A does not start.

[0140] Therefore, according to the second embodiment, in addition to the effects (1-1) to (1-3) of the first embodiment, the following effects can be obtained. (2-1) The assist motor 70 is required to be started as much as possible, even if only one system is used. This requirement can be met. [Explanation of symbols]

[0141] 10...Steering device (mechanical device) 11...Steering wheel 13...Steering shaft (component) 15...Steering wheel 31...Steering motor 51A...First steering control circuit 52A...Second steering control circuit 70...Assist motor 81A...First assist control circuit 82A...Second assist control circuit 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 assist motor

Claims

1. a two-system control circuit that independently controls power supply to the winding groups of a motor having two systems of winding groups; a two-system rotation detection circuit for detecting the number of rotations of the motor; The control circuit has a function of calculating an absolute rotation angle of the motor using the number of rotations of the motor, and when the power is turned off, stores the absolute rotation angle of the motor at that time, and when the power is turned on, starts up after confirming that both of the two systems of rotation detection circuits are normal, The vehicle control device is configured to, when power is turned on, determine that the rotation detection circuit of its own system is normal and start up, even if an abnormality is detected in one of the two rotation detection circuits or even if it is not possible to determine whether there is an abnormality in either of the two rotation detection circuits, if the absolute value of the difference between the absolute rotation angle of the motor stored when power was last turned off and the absolute rotation angle of the motor calculated when power is turned on this time is equal to or less than a predetermined threshold value.

2. the two control circuits are configured to exchange the number of rotations of the motor detected by the rotation detection circuit of their own system with each other, and to determine whether there is an abnormality in the rotation detection circuits of the two systems by comparing the number of rotations of the motor detected by the rotation detection circuits of the two systems; The two control circuits have a master-slave relationship, with the control circuit of the first system functioning as a master and the control circuit of the second system functioning as a slave, Cases where an abnormality in the two rotation detection circuits cannot be determined include a case where the control circuit of the first system does not start when the power is turned on, 2. The vehicle control device according to claim 1, wherein the control circuit of the second system is configured to determine that the rotation detection circuit of its own system is normal and to start up when the absolute value of the difference between the absolute rotation angle of the motor stored when the power was last turned off and the absolute rotation angle of the motor calculated when the power was turned on this time is equal to or less than a predetermined threshold value, even if the control circuit of the first system does not start up when the power is turned on.

3. the motor is a drive source of a mechanical device, and the mechanical device has a sensor that detects an absolute position of a component that is linked to the motor; Only the control circuit of the first system is connected to the sensor, 3. The vehicle control device according to claim 1, wherein the control circuit of the first system is configured to execute, when power is turned on, a process of calculating an absolute rotation angle of the motor using the absolute positions of the components detected through the sensors, and a process of transmitting the absolute positions of the components detected through the sensors to the control circuit of the second system, if an abnormality is detected in one of the rotation detection circuits of the two systems or if an abnormality in the rotation detection circuits of the two systems cannot be determined.

4. the mechanical device is a steering device of a vehicle; The component is a steering shaft that steers steered wheels of a vehicle, 4. The vehicle control device according to claim 3, wherein the sensor is a stroke sensor that detects an absolute axial position of the steered shaft.

5. The motor is a steering motor that generates a steering force for steering steered wheels of a vehicle, The two control circuits are a first steering control circuit that controls power supply to the winding group of the first system of the steering motor; 5. The vehicle control device according to claim 4, further comprising: a second steering control circuit that controls power supply to the winding group of the second system of the steering motor.

6. the motor is an assist motor that generates an assist force to assist in the operation of the steering wheel, The two control circuits are a first assist control circuit that controls power supply to the winding group of the first system of the assist motor; 5. The vehicle control device according to claim 4, further comprising: a second assist control circuit that controls power supply to the winding group of the second system of the assist motor.

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