Control device for a vehicle

Abstract

A control device for a vehicle includes a plurality of control circuits configured to cooperatively or in combination control a control object by being activated with a power-on of the vehicle as a trigger. Each of the plurality of control circuits is configured to perform synchronous processing and power latch control. Each of the plurality of control circuits is configured to maintain an operation mode immediately before the vehicle is powered off, in a period in which the power latch control is being performed. Each of the plurality of control circuits is configured to not perform the synchronous processing for a predetermined period at the time of the power-on of the vehicle.

Description

Technical Field

[0001] This invention relates to a control device for vehicles. Background Technology

[0002] A so-called steer-by-wire system is known in which the power transmission between the steering wheel and the steering wheels is interrupted. For example, a steer-by-wire system described in Japanese Unexamined Patent Application Publication No. 2021-075182 (JP 2021-075182 A) includes a reaction actuator and a rotation actuator. The reaction actuator generates a steering reaction force, which is applied to the steering shaft. The rotation actuator generates a rotational force to rotate the steering wheels.

[0003] Each of the reaction actuator and the rotary actuator includes two redundantly configured control arithmetic units and two redundantly configured motor drive units. Each control arithmetic unit performs computational operations associated with the drive control of the motor. Each motor drive unit generates torque based on the drive signal generated by the corresponding control arithmetic unit.

[0004] The two control units of the first and second systems of the reaction actuator can communicate with each other and operate in coordination based on the information sent and received between the two control units. The two control units of the first and second systems of the rotary actuator can communicate with each other and operate in coordination based on the information sent and received between the two control units.

[0005] The control units of the first system of the reaction actuator and the first system of the rotary actuator can communicate with each other. Similarly, the control units of the second system of the reaction actuator and the second system of the rotary actuator can communicate with each other. These two control units of the first system and the two control units of the second system enable the corresponding motor drive units to jointly use information sent and received through inter-system communication to generate torque.

[0006] In related technologies, an electric power steering system that assists in the operation of the steering wheel is known. A control device for the electric power steering system causes an auxiliary motor to generate an auxiliary force based on the steering state of the steering wheel. For example, the control device described in Japanese Unexamined Patent Application Publication No. 2009-248850 (JP 2009-248850 A) performs power latching control to continuously execute control after the ignition key is turned off until a predetermined time has elapsed. When the steering wheel is operated while performing power latching control, motor-assisted steering is performed.

[0007] In the control device for an electric power steering system described in Japanese Unexamined Patent Application Publication No. 2020-108327 (JP 2020-108327 A), when the vehicle is powered off, after the supply of motor drive current is stopped, power latching control is performed to continuously perform temperature estimation operations for components on the board. The control device remains energized until a predetermined time has elapsed after the supply of motor drive current is stopped, or until the temperature of the components on the board becomes equal to or less than a predetermined value. Summary of the Invention

[0008] It is conceivable that in a steer-by-wire system comprising multiple systems, such as JP 2021-075182 A, power latching control as described in JP 2009-248850 A or JP 2020-108327 A would be implemented. In this case, the control processing unit would independently execute power latching control when the vehicle is powered off due to a trigger such as the operation of the ignition key. When the vehicle is powered on while power latching control is being executed, the control processing unit would determine whether the vehicle is powered on and restart the system after determining that the vehicle is powered on.

[0009] When the vehicle is powered on while power latch control is being performed, the timing of the vehicle's power-on detection by the control processing unit may be mismatched due to differences in wiring resistance, etc. Therefore, there is a possibility that the timing of the control processing unit's restart may also be mismatched. Consequently, the control processing unit that restarts earlier may perform an unintentional state transition by receiving pre-initialization information calculated by another control processing unit that is still performing power latch control.

[0010] According to one aspect of the present invention, a control device for a vehicle is provided. The control device for a vehicle includes a plurality of control circuits configured to coordinately or in combination control a controlled object by being activated upon power-on of the vehicle. Each of the plurality of control circuits is configured to perform synchronization processing and power latching control. Synchronization processing is a process of synchronizing the operating mode of the controlled object, determined based on its operating state, with each control object, and power latching control is a control that maintains a power supply for a defined period of time upon power-off of the vehicle. Each of the plurality of control circuits is configured to maintain the operating mode of the vehicle prior to power-off during the period in which power latching control is being performed. Each of the plurality of control circuits is configured not to perform synchronization processing for a predetermined period of time when the vehicle is powered on. The predetermined period of time is from the time the vehicle is powered on to the time when all control circuits of the plurality of control circuits are normally activated and capable of controlling the controlled object.

[0011] When the vehicle is powered on, there is a problem that the timing of the control circuit's recognition of the vehicle's power-on or the timing of the control circuit's activation may be mismatched due to differences in wiring resistance, etc. Therefore, for example, when the vehicle is powered on while power latch control is being performed, the following problem exists: the control circuit that starts earlier may perform an unintentional state transition by synchronizing the operating mode held in that control circuit with the pre-initialized operating mode held in another control circuit that is still performing power latch control.

[0012] In this regard, using this configuration, when the vehicle is powered on, multiple control circuits do not perform synchronization processing during the period from the time the vehicle is powered on until the time when all control circuits in the multiple control circuits are normally started and able to control the controlled object. Therefore, when the vehicle is powered on while power latching control is being performed, the control circuit that starts earlier will not synchronize the operating mode maintained in that control circuit with the operating mode maintained in another control circuit. Thus, unintentional state transitions by the control circuit that starts earlier can be prevented.

[0013] In a control device for a vehicle, the operating mode may include an operating mode when all control circuits in a plurality of control circuits are normal and an operating mode when one of the control circuits in a plurality of control circuits is abnormal.

[0014] For example, if a specific control circuit among multiple control circuits is determined to be in an abnormal state, and the vehicle is powered on again during the period of power latch-up control after a power outage, the specific control circuit can be in a state where it can return to normal operation. It is also conceivable that this specific control circuit starts earlier than another control circuit. In this case, when the specific control circuit synchronizes the operating mode of the controlled object held in its own mode with the abnormal operating mode held in another control circuit, it is possible that although the specific control circuit is in a state where it can return to normal operation, it can still control the controlled object based on the abnormal operating mode.

[0015] In this respect, this configuration ensures that during the period from when the vehicle is powered on until all control circuits in the multiple control circuits start normally and are able to control the controlled object, a specific control circuit does not synchronize the operating mode of the controlled object held in that specific control circuit with an abnormal operating mode held in another control circuit. Therefore, it prevents control circuits that start earlier from performing unintentional state transitions.

[0016] In a control device for a vehicle, the controlled object may include: a reaction motor comprising two winding systems and generating a steering reaction force applied to a steering wheel, wherein power transmission from the steering wheel to and from the rotating wheel is interrupted; and a rotation motor generating a rotational force for rotating the rotating wheel. Multiple control circuits may include: a first reaction control circuit configured to control the power supply to the first winding system of the reaction motor; a second reaction control circuit configured to control the power supply to the second winding system of the reaction motor; a first rotation control circuit configured to control the power supply to the first winding system of the rotation motor; and a second rotation control circuit configured to control the power supply to the second winding system of the rotation motor.

[0017] Using this configuration, for example, when the vehicle is powered on, the first reaction control circuit does not perform synchronization processing during the period between the time when all control circuits in the second reaction control circuit, the first rotation control circuit, and the second rotation control circuit (excluding the first reaction control circuit) are normally activated and able to control the reaction motor or rotation motor. The same applies to the second reaction control circuit, the first rotation control circuit, and the second rotation control circuit. Therefore, when the vehicle is powered on while power interlock control is being performed, the earlier-activated first reaction control circuit, second reaction control circuit, first rotation control circuit, or second rotation control circuit will not synchronize the operating mode of the reaction motor or rotation motor held therein with the operating mode held in the other control circuit. Thus, unintentional state transitions by the earlier-activated first reaction control circuit, second reaction control circuit, first rotation control circuit, and second rotation control circuit can be prevented.

[0018] In a control device for a vehicle, synchronization processing can be performed between a first reaction control circuit and a second reaction control circuit, between a first rotation control circuit and a second rotation control circuit, between a first reaction control circuit and a first rotation control circuit, and between a second reaction control circuit and a second rotation control circuit.

[0019] This configuration simplifies the signal path compared to a configuration where the first reaction control circuit, second reaction control circuit, first rotation control circuit, and second rotation control circuit perform synchronous processing with all other control circuits besides their respective control circuits. For example, it eliminates the need for communication lines between the first reaction control circuit and the second rotation control circuit, as well as between the second reaction control circuit and the first rotation control circuit.

[0020] In a control device for a vehicle, the controlled object may include: a reaction motor, which is the source of steering reaction force applied to a steering wheel, wherein power transmission from the steering wheel to and from the steering wheel is interrupted; and a rotation motor, which is the source of rotational force for rotating the steering wheel. Multiple control circuits may include: a reaction control circuit configured to control the reaction motor; and a rotation control circuit configured to control the rotation motor.

[0021] Using this configuration, when the vehicle is energized while power latching control is being executed and, for example, the reaction control circuit is activated earlier, the earlier-activated reaction control circuit does not synchronize the operating mode of the controlled object held in its reaction control circuit with the operating mode held in the rotation control circuit. Therefore, unintentional state transitions by the earlier-activated reaction control circuit can be prevented. The same applies to the rotation control circuit.

[0022] In a control device for a vehicle, the controlled object may include an auxiliary motor that generates an auxiliary force for assisting steering wheel operation. The auxiliary motor may include winding groups of a first system and winding groups of a second system. Multiple control circuits may include: a first auxiliary control circuit configured to control the power supply to the winding group of the first system; and a second auxiliary control circuit configured to control the power supply to the winding group of the second system.

[0023] Using this configuration, when the vehicle is powered on while power latching control is being executed and, for example, the first auxiliary control circuit starts earlier, the earlier-starting first auxiliary control circuit does not synchronize the operating mode of the auxiliary motor held in the first auxiliary control circuit with the operating mode held in the second auxiliary control circuit. Therefore, unintentional state transitions by the earlier-starting first auxiliary control circuit can be prevented. The same applies to the second auxiliary control circuit.

[0024] By using the control device for vehicles according to the present invention, unintentional state transitions when the vehicle is powered on can be suppressed while power latching control is being performed. Attached Figure Description

[0025] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, in which similar reference numerals denote similar elements, and in the drawings:

[0026] Figure 1 This is a diagram showing the configuration of a steer-by-wire system in which a control device for a vehicle according to the first embodiment is installed;

[0027] Figure 2This is a block diagram showing the reaction control device and the rotation control device according to the first embodiment;

[0028] Figure 3 This is a timing diagram showing the state transitions of the control circuit according to the comparative example;

[0029] Figure 4 This is a timing diagram showing the state transitions of the control circuit according to the first embodiment; and

[0030] Figure 5 This is a diagram showing the configuration of a control device for a vehicle according to a second embodiment. Detailed Implementation

[0031] First Implementation Method

[0032] The following describes a first embodiment of a steer-by-wire system that implements a control device for a vehicle.

[0033] like Figure 1 As shown, the vehicle's steering system 10 includes a steering shaft 12 connected to a steering wheel 11. The steering system 10 includes components in the vehicle's width direction (…). Figure 1 A rotating shaft 13 extends in the left-right direction. A rotating wheel 15 is connected to both ends of the rotating shaft 13 via a tie rod 14. When the rotating shaft 13 moves linearly, the rotation angle θw of the rotating wheel 15 changes. The steering shaft 12 and the rotating shaft 13 constitute the vehicle's steering mechanism. Figure 1 Only one rotating wheel 15 is shown in the image.

[0034] The steering system 10 includes a reaction motor 21 and a reduction gear mechanism 22. The reaction motor 21 is the source of the steering reaction force. The steering reaction force is a force acting in the opposite direction to the direction of operation of the steering wheel 11 operated by the driver. The rotation shaft of the reaction motor 21 is connected to the steering shaft 12 via the reduction gear mechanism 22. The torque of the reaction motor 21 is applied to the steering shaft 12 as the steering reaction force. By applying the steering reaction force to the steering wheel 11, an appropriate responsiveness can be given to the driver.

[0035] The reaction motor 21 is, for example, a three-phase brushless motor. The reaction motor 21 includes a first system winding group N11 and a second system winding group N12. The first system winding group N11 and the second system winding group N12 are wound on a common stator (not shown). The first system winding group N11 and the second system winding group N12 have the same electrical characteristics.

[0036] The steering system 10 includes a rotary motor 31 and a reduction gear mechanism 32. The rotary motor 31 is the source of rotational force. The rotational force refers to the force used to rotate the rotating wheel 15. The rotational shaft of the rotary motor 31 is connected to a pinion shaft 33 via the reduction gear mechanism 32. The pinion teeth 33a of the pinion shaft 33 mesh with the rack teeth 13b of the rotating shaft 13. The torque of the rotary motor 31 is applied as the rotational force to the rotating shaft 13 via the pinion shaft 33. The rotating shaft 13 moves in the vehicle width direction as the rotary motor 31 rotates.

[0037] The rotary motor 31 is, for example, a three-phase brushless motor. The rotary motor 31 includes a first system winding group N21 and a second system winding group N22. The first system winding group N21 and the second system winding group N22 are wound on a common stator (not shown). The first system winding group N21 and the second system winding group N22 have the same electrical characteristics.

[0038] The steering system 10 includes a reaction control device 40. The reaction control device 40 controls the drive of the reaction motor 21, which is the controlled object. The reaction control device 40 performs reaction control such that the reaction motor 21 generates a steering reaction force corresponding to the steering torque Th. The reaction control device 40 calculates the target steering reaction force based on the steering torque Th detected by the torque sensor 23, which is located in the steering shaft 12. The reaction control device 40 controls the power supply to the reaction motor 21 such that the actual steering reaction force applied to the steering shaft 12 reaches the target steering reaction force. The reaction control device 40 independently controls the power supply to the winding groups of two systems in the reaction motor 21.

[0039] The reaction control device 40 includes a first system circuit 41 and a second system circuit 42. The first system circuit 41 controls the power supply to the winding group N11 of the first system in the reaction motor 21 based on the steering torque Th detected by the torque sensor 23. The second system circuit 42 controls the power supply to the winding group N12 of the second system in the reaction motor 21 based on the steering torque Th detected by the torque sensor 23.

[0040] The steering system 10 includes a rotation control device 50. The rotation control device 50 controls the drive of the rotation motor 31, which is the controlled object. The rotation control device 50 performs rotation control based on the steering state, causing the rotation motor 31 to generate rotational force for rotating the wheel 15. The rotation control device 50 receives the steering angle θs detected by the steering angle sensor 24 and the travel Xw of the rotation shaft 13 detected by the travel sensor 34. The travel Xw is the displacement relative to the neutral position of the rotation shaft 13 and is a state variable reflecting the steering angle θw. The steering angle sensor 24 is disposed between the torque sensor 23 and the reduction gear mechanism 22 in the steering shaft 12. The travel sensor 34 is disposed near the rotation shaft 13.

[0041] The rotation control device 50 calculates the target rotation angle of the rotating wheel 15 based on the steering angle θs detected by the steering angle sensor 24. The rotation control device 50 calculates the rotation angle θw based on the stroke Xw of the rotating shaft 13 detected by the stroke sensor 34. The rotation control device 50 controls the power supply to the rotating motor 31 so that the rotation angle θw calculated based on the stroke Xw reaches the target rotation angle. The rotation control device 50 independently controls the power supply to the winding group of the second system in the rotating motor 31.

[0042] The rotation control device 50 includes a first system circuit 51 and a second system circuit 52. The first system circuit 51 controls the power supply to the winding group N21 of the first system in the rotation motor 31 based on the steering angle θs detected by the steering angle sensor 24 and the travel Xw of the rotating shaft 13 detected by the travel sensor 34. The second system circuit 52 controls the power supply to the winding group N22 of the second system in the rotation motor 31 based on the steering angle θs detected by the steering angle sensor 24 and the travel Xw of the rotating shaft 13 detected by the travel sensor 34.

[0043] A so-called electromechanical reaction actuator can be constructed by integrating the reaction control device 40 and the reaction motor 21. A so-called electromechanical rotary actuator can be constructed by integrating the rotation control device 50 and the rotation motor 31.

[0044] Power supply path

[0045] The power supply paths for the reaction control device 40 and the steering control device 50 will be described below. Various types of on-board devices, including the reaction control device 40 and the steering control device 50, are supplied with power from a DC power supply 60. The DC power supply 60 is, for example, a battery. Various types of sensors, including the torque sensor 23, the steering angle sensor 24, and the travel sensor 34, are supplied with power from the DC power supply 60.

[0046] The first system circuit 41 and second system circuit 42 of the reaction control device 40, and the first system circuit 51 and second system circuit 52 of the rotation control device 50 are connected to the DC power supply 60 via the vehicle's start switch SW. The start switch SW is, for example, an ignition switch or a power switch. The start switch SW operates when the vehicle's driving source, such as the engine, starts or stops. 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 system circuit 41 and second system circuit 42 of the reaction control device 40, and the first system circuit 51 and second system circuit 52 of the rotation control device 50. Turning on the start switch SW powers the vehicle. Turning off the start switch SW de-powers the vehicle.

[0047] The first system circuit 41 and the second system circuit 42 of the reaction control device 40, and the first system circuit 51 and the second system circuit 52 of the rotation control device 50 are connected to the DC power supply 60 via power relays 61, 62, 63 and 64. When power relays 61, 62, 63 and 64 are turned on, power from the DC power supply 60 is supplied via power relays 61, 62, 63 and 64 to the first system circuit 41 and the second system circuit 42 of the reaction control device 40, and the first system circuit 51 and the second system circuit 52 of the rotation control device 50.

[0048] The first system circuit 41 of the reaction control device 40 controls the on / off state of the power relay 61. When the start switch SW switches from the on state to the off state, the first system circuit 41 performs power latching control to keep the power relay 61 in the on state for a predetermined period of time. Therefore, the first system circuit 41 can still operate even after the start switch SW has been turned off. The first system circuit 41 can cut off the power supply to itself by switching the power relay 61 from the on state to the off state after the predetermined period of time has elapsed.

[0049] The first system circuit 41 detects the on / off state of the start switch SW, for example, by monitoring the voltage between the two ends of the start switch SW. When the voltage between the two ends of the start switch SW is less than a predetermined voltage threshold, the first system circuit 41 detects that the start switch SW has been turned on. When the voltage between the two ends of the start switch SW is equal to or greater than the predetermined voltage threshold, the first system circuit 41 detects that the start switch SW has been turned off.

[0050] The second system circuit 42 of the reaction control device 40 controls the on / off state of the power relay 62. Similar to the first system circuit 41, the second system circuit 42 performs power latching control. When the start switch SW switches from the on state to the off state, the second system circuit 42 keeps the power relay 62 in the on state for a predetermined period of time.

[0051] The first system circuit 51 of the rotation control device 50 controls the on / off state of the power relay 63. Similar to the first system circuit 41 of the reaction control device 40, the first system circuit 51 performs power latching control. When the start switch SW switches from the on state to the off state, the first system circuit 51 keeps the power relay 63 in the on state for a predetermined period of time.

[0052] The second system circuit 52 of the rotation control device 50 controls the on / off state of the power relay 64. Similar to the first system circuit 41 of the reaction control device 40, the second system circuit 52 performs power latching control. When the start switch SW switches from the on state to the off state, the second system circuit 52 keeps the power relay 64 in the on state for a predetermined period of time.

[0053] Among the components of the steering system 10, those components that need to operate even after the start switch SW is turned off, such as torque sensor 23, steering angle sensor 24, and travel sensor 34, are connected to the DC power supply 60 via at least one of power relays 61, 62, 63, and 64. Therefore, when the start switch SW is off and at least one of the power relays 61, 62, 63, and 64 is on, components such as torque sensor 23, steering angle sensor 24, and travel sensor 34 are continuously supplied with power.

[0054] Reaction control device

[0055] The configuration of the reaction control device 40 will be described in detail below. For example... Figure 2 As shown, the reaction control device 40 includes a first system circuit 41 and a second system circuit 42. The first system circuit 41 includes a first reaction control circuit 41A and a motor drive circuit 41B. The second system circuit 42 includes a second reaction control circuit 42A and a motor drive circuit 42B.

[0056] The first reaction control circuit 41A is composed of a processing circuit, which includes (1) one or more processors operating according to a computer program (software); (2) one or more special-purpose hardware circuits, such as application-specific integrated circuits (ASICs), that perform at least some of the various processes; or (3) a combination of the above. The processor includes a central processing unit (CPU). The processor includes memory such as random access memory (RAM) and read-only memory (ROM). The memory stores program code or commands configured to cause the CPU to perform processes. Memory, i.e., non-transitory computer-readable media, includes all available media that can be accessed by a general-purpose or special-purpose computer.

[0057] The first reaction control circuit 41A calculates the target steering reaction force to be generated by the reaction motor 21 based on the steering torque Th detected by the torque sensor 23, and calculates the first current command value of the winding group N11 of the first system based on the calculated target steering reaction force. Here, the first current command value is set to half (50%) of the current required by the reaction motor 21 to generate the target steering reaction force (100%). The first reaction control circuit 41A generates a drive signal (PWM signal) for the motor drive circuit 41B by performing current feedback control to make the actual current value supplied to the winding group N11 of the first system conform to the first current command value.

[0058] The motor drive circuit 41B is a PWM inverter, in which three branches corresponding to the three phases (U, V, and W) are connected in parallel with switching elements (e.g., two field-effect transistors (FETs) connected in series as branches, which are basic units). Based on the drive signal generated by the first reaction control circuit 41A, the motor drive circuit 41B converts DC power supplied from the DC power supply 60 into three-phase AC power by switching the phase switching elements. The three-phase AC power generated by the motor drive circuit 41B is supplied to the winding group N11 of the first system of the reaction motor 21 via power supply paths for each phase, including buses or cables. Therefore, the winding group N11 of the first system generates torque corresponding to the first current command value.

[0059] The second reaction control circuit 42A has essentially the same configuration as the first reaction control circuit 41A. The second reaction control circuit 42A calculates the target steering reaction force to be generated by the reaction 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 based on the calculated target steering reaction force. Here, the second current command value is set to half the amount of current required for the reaction motor 21 to generate the target steering reaction force. The second reaction control circuit 42A generates a drive signal for the motor drive circuit 42B by performing current feedback control to make the actual current value supplied to the winding group N12 of the second system conform to the second current command value.

[0060] Motor drive circuit 42B has essentially the same configuration as motor drive circuit 41B. Motor drive circuit 42B converts DC power supplied from DC power supply 60 into three-phase AC power based on a drive signal generated by second reaction control circuit 42A. The three-phase AC power generated by motor drive circuit 42B is supplied to the winding group N12 of the second system of reaction motor 21 via power supply paths including buses or cables for each phase. Therefore, the winding group N12 of the second system generates torque corresponding to the second current command value. The reaction motor 21 generates a total torque consisting of the torque generated by the winding group N11 of the first system and the torque generated by the winding group N12 of the second system.

[0061] Depending on the product specifications, a master-slave relationship may be established between the first system circuit 41 and the second system circuit 42 of the reaction control device 40. In this case, for example, the first system circuit 41 may act as the master, and the second system circuit 42 may act as the slave. Depending on the product specifications, the first system circuit 41 and the second system circuit 42 may have an equivalent relationship.

[0062] Rotation control device

[0063] The configuration of the rotation control device 50 will be described in detail below. For example... Figure 2 As shown, the rotation control device 50 includes a first system circuit 51 and a second system circuit 52. The first system circuit 51 includes a first rotation control circuit 51A and a motor drive circuit 51B. The second system circuit 52 includes a second rotation control circuit 52A and a motor drive circuit 52B.

[0064] The first rotation control circuit 51A has essentially the same configuration as the first reaction control circuit 41A. The first rotation control circuit 51A calculates the target rotation angle of the rotating wheel 15 based on the steering angle θs detected by the steering angle sensor 24. The rotation control device 50 calculates the rotation angle θw based on the stroke Xw of the rotating shaft 13 detected by the stroke sensor 34. The first rotation control circuit 51A calculates the target rotational force to be generated by the rotating motor 31 by executing angle feedback control to make the rotation angle θw calculated based on the stroke Xw conform to the target rotational angle, and calculates a third current command value for the winding group N21 of the first system of the rotating motor 31 based on the calculated value of the target rotational force. Here, the third current command value is set to half (50%) of the current required by the rotating motor 31 to generate the target rotational force (100%). The first rotation control circuit 51A generates a drive signal for the motor drive circuit 51B by executing current feedback control to make the actual current value supplied to the winding group N21 of the first system conform to the third current command value.

[0065] Motor drive circuit 51B has essentially 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 the drive signal generated by the first rotation control circuit 51A. The three-phase AC power generated by motor drive circuit 42B is supplied to the winding group N21 of the first system of the rotating motor 31 via power supply paths for each phase, including buses or cables. Therefore, the winding group N21 of the first system generates torque corresponding to the third current command value.

[0066] The second rotation control circuit 52A has essentially the same configuration as the first reaction control circuit 41A. The second rotation control circuit 52A calculates the target rotation angle of the rotating wheel 15 based on the steering angle θs detected by the steering angle sensor 24. The rotation control device 50 calculates the rotation angle θw based on the stroke Xw of the rotating shaft 13 detected by the stroke sensor 34. The second rotation control circuit 52A calculates the target rotational force to be generated by the rotating motor 31 by executing angle feedback control to make the rotation angle θw calculated based on the stroke Xw conform to the target rotational angle, and calculates the fourth current command value of the winding group N22 of the second system of the rotating motor 31 based on the calculated value of the target rotational force. Here, the fourth current command value is set to half (50%) of the current required for the rotating motor 31 to generate the target rotational force. The second rotation control circuit 52A generates a drive signal for the motor drive circuit 52B by executing current feedback control to make the actual current value supplied to the winding group N22 of the second system conform to the fourth current command value.

[0067] Motor drive circuit 52B has essentially 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 rotation control circuit 52A. The three-phase AC power generated by motor drive circuit 52B is supplied to the winding group N22 of the second system of rotation motor 31 via power supply paths including buses or cables for each phase. Therefore, the winding group N22 of the second system generates torque corresponding to the fourth current command value. Rotation motor 31 generates a total torque consisting of the torque generated by the winding group N21 of the first system and the torque generated by the winding group N22 of the second system.

[0068] Depending on the product specifications, a master-slave relationship may be established between the first system circuit 51 and the second system circuit 52 of the rotation control device 50. In this case, for example, the first system circuit 51 may act as the master, and the second system circuit 52 may act as the slave. Depending on the product specifications, the first system circuit 51 and the second system circuit 52 may have an equivalent relationship.

[0069] Communication path

[0070] The internal communication paths of the reaction control device 40 and the rotation control device 50, as well as the communication path between the reaction control device 40 and the rotation control device 50, will be described below.

[0071] like Figure 2 As shown, the first reaction control circuit 41A and the second reaction control circuit 42A send and receive information between themselves via communication line L1. The information includes anomaly information of the first reaction control circuit 41A, the second reaction control circuit 42A, or the motor drive circuit 41B or the motor drive circuit 42B. The information also includes values ​​of flags indicating various states. The first reaction control circuit 41A and the second reaction control circuit 42A coordinately control the drive of the reaction motor 21 based on the information sent and received between themselves.

[0072] The first rotation control circuit 51A and the second rotation control circuit 52A send and receive information between themselves via communication line L2. The information includes abnormal information from the first rotation control circuit 51A, the second rotation control circuit 52A, or the motor drive circuit 51B or the motor drive circuit 52B. The information also includes values ​​of flags indicating various states. The first rotation control circuit 51A and the second rotation control circuit 52A coordinately control the drive of the rotation motor 31 based on the information sent and received between themselves.

[0073] The first reaction control circuit 41A and the first rotation control circuit 51A send and receive information between themselves via communication line L3. The information includes abnormal information from the first reaction control circuit 41A, the first rotation control circuit 51A, or the motor drive circuit 41B or the motor drive circuit 51B. The information also includes values ​​of flags indicating various states. The first reaction control circuit 41A and the first rotation control circuit 51A coordinately control the drive of the rotation motor 31 based on the information sent and received between themselves.

[0074] The second reaction control circuit 42A and the second rotation control circuit 52A send and receive information between themselves via communication line L4. The information includes abnormal information from the second reaction control circuit 42A, the second rotation control circuit 52A, or the motor drive circuit 42B. The information also includes values ​​of flags indicating various states. The second reaction control circuit 42A and the second rotation control circuit 52A operate collaboratively based on the information sent and received between themselves.

[0075] Motor drive mode

[0076] The following describes the drive modes of the reaction motor 21 and the rotary motor 31. The drive modes include cooperative drive mode, independent drive mode, and single-system drive mode.

[0077] The cooperative drive mode is the drive mode when the first system circuit 41 and the first system circuit 51, as well as the second system circuit 42 and the second system circuit 52, are operating normally. The first system circuit 41 and the second system circuit 42 share information such as command values ​​and limit values, and cause both the first system winding group N11 and the second system winding group N12 of the reaction motor 21 to produce the same torque. Similarly, the first system circuit 51 and the second system circuit 52 share information such as command values ​​and limit values, and cause both the first system winding group N21 and the second system winding group N22 of the rotary motor 31 to produce the same torque.

[0078] Independent drive mode is the drive mode when the operation of one of the four control circuits (41A, 42A, 51A, and 52A) momentarily stops, the anomaly has not yet been determined, and there is a possibility of returning to normal operation. In independent drive mode, for example, when there is a possibility that the operation of one control circuit, which has stopped, will return to normal operation, the other three control circuits generate torque in the winding group corresponding to that control circuit based on the calculation results of the corresponding control circuit, without using information through inter-system communication.

[0079] The single-system drive mode is a drive mode used when an anomaly has been identified in one of the four control circuits (41A, 42A, 51A, and 52A) and there is no possibility of returning to normal operation without performing a reset process to power the vehicle back on. For example, when an anomaly is identified in the first reaction control circuit 41A or the first rotation control circuit 51A, the first reaction control circuit 41A and the first rotation control circuit 51A stop driving control of the reaction motor 21 and the rotation motor 31, and only the second system circuit 42 and the second system circuit 52 are used to generate torque in the reaction motor 21 and the rotation motor 31. Similarly, when an anomaly is identified in the second reaction control circuit 42A or the second rotation control circuit 52A, the second reaction control circuit 42A and the second rotation control circuit 52A stop driving control of the reaction motor 21 and the rotation motor 31, and only the first system circuit 41 and the first system circuit 51 are used to generate torque in the reaction motor 21 and the rotation motor 31.

[0080] State transition of control circuit

[0081] The following describes the state transitions of the control circuits (41A, 42A, 51A, and 52A). When the start switch SW is turned on, the control circuits perform start-up processing and initial checks. Start-up processing and initial checks are a series of processes required to start the steering system. Start-up processing and initial checks include, for example, hardware checks, initialization of the central processing unit (CPU), and initialization of variables and flags. While performing start-up processing and initial checks, the control state of the control circuits is the unassisted state. The unassisted state is the state where the control of the reaction motor 21 and the rotation motor 31 has not yet started. The control state is the operating state of the control circuits.

[0082] After the initial checks have been completed successfully, the control circuit transitions from the no-assistance state to the auxiliary start-up waiting state. The auxiliary start-up waiting state is the state that waits for the initial checks in all control circuits to complete successfully.

[0083] Once the initial checks in all control circuits have been completed normally, the control device can execute control of the reaction motor 21 or the steering motor 31. The control state of the control circuit transitions from the auxiliary start-up waiting state to the normal control state. The control circuit initiates normal control based on the steering state of the steering wheel 11 to generate steering reaction force and steering power. In the normal control state, the driving mode of the reaction motor 21 and the steering motor 31 is a cooperative drive mode. That is, in the normal control state, the control circuit causes torque to be generated by both the first system winding group N11 and the second system winding group N12 of the reaction motor 21, and causes torque to be generated by both the first system winding group N21 and the second system winding group N22 of the steering motor 31.

[0084] When the control circuit is in auxiliary start-up waiting state or normal control state and the predetermined abnormal determination condition is met, the control circuit switches from auxiliary start-up waiting state to independent drive mode or single system drive mode. When the control circuit is in independent drive mode and the predetermined return condition is met, the control circuit switches from independent drive mode to normal control state. When the control circuit is in independent drive mode and the predetermined abnormal determination condition is met, the control circuit switches from independent drive mode to single system drive mode.

[0085] When the start switch SW is turned off, the control circuit that is executing motor drive control in the control circuit performs power latching control. When the start switch SW is turned off, the vehicle stops.

[0086] For example, under normal control conditions, the control circuits (41A, 42A, 51A and 52A) perform power latching control after the start switch SW is turned off, and, for example, continue to perform temperature estimation operations on the components on the board.

[0087] For example, in a single-system drive mode state where an anomaly has been determined in the first reaction control circuit 41A or the first rotation control circuit 51A and the second system circuit 42 and the second system circuit 52 are being used to perform drive control on the reaction motor 21 and the rotation motor 31, the control circuits (42A and 52A) that perform motor drive control in the control circuit perform power latching control after the start switch SW is turned off, and, for example, continue to perform temperature estimation operation on the components on the board.

[0088] Examples of components include switching elements in motor drive circuits (41B, 42B, 51B, and 52B). The control circuit continues to supply power until a predetermined time has elapsed after the start switch SW has been turned off, or until the temperature of the components on the board, etc., becomes equal to or lower than a predetermined temperature. The predetermined temperature is a sufficiently low temperature.

[0089] When the temperature of components on the board becomes equal to or lower than a predetermined temperature, the control circuit stores the current temperature of the components in non-volatile memory and terminates the execution of power latch control. By executing power latch control, the control circuit can accurately determine the initial temperature of components on the board during subsequent normal control and appropriately execute overheat protection control. Overheat protection control is used to suppress overheating of components on the board by limiting reaction control or rotation control based on the temperature increase from the initial temperature of the components on the board.

[0090] Here, assume that during the period when power latching control is being performed after the start switch SW has been turned off, the start switch SW is turned back on. In this case, the following problem exists: When the start switch SW is turned on during the period of power latching control, the timing at which the control circuit recognizes the start switch SW's on-time may be mismatched due to differences in wiring resistance, etc. Therefore, there is a problem that the timing of the control circuit restart may be mismatched. Consequently, the control circuit that restarts earlier may perform an unintentional state transition because it receives pre-initialization information from another control circuit that is still performing power latching control.

[0091] Comparative examples of state transitions

[0092] The following will describe comparative examples of state transitions for control circuits (41A, 42A, 51A, and 52A). For example, the following description is based on the following premise.

[0093] That is, assuming that the vehicle has been de-energized after the malfunction of the first reaction control circuit 41A is determined, the drive of the motor by the first system circuit 41 and the first system circuit 51 has stopped, and the reaction motor 21 and the rotary motor 31 are driven by the second system circuit 42 and the second system circuit 52 in single-system drive mode. For example, by Figure 3 As indicated by the hyphen “-”, when the vehicle is powered off, the first reaction control circuit 41A and the first rotation control circuit 51A, as components of the first system (which is an abnormal system), do not perform power latching control and cease operation. The second reaction control circuit 42A and the second rotation control circuit 52A, as components of the second system (which is a normal system), perform power latching control. The second reaction control circuit 42A and the second rotation control circuit 52A maintain the operating mode of the reaction motor 21 and the rotation motor 31 before the vehicle is about to be powered off. Here, the operating mode of the reaction motor 21 and the rotation motor 31 before the vehicle is about to be powered off is the system 1 fault mode. The system 1 fault mode is the operating mode under the first system fault state. The first system fault state includes an abnormal state occurring in the first reaction control circuit 41A or the first rotation control circuit 51A.

[0094] Furthermore, the operating mode under the second system fault condition is the System 2 fault mode. The second system fault condition includes an abnormality occurring in the second reaction control circuit 42A or the second rotation control circuit 52A.

[0095] like Figure 3As shown in the timing diagram, when the vehicle is powered on again during the period of power latching control after a power outage (time T1), the first reaction control circuit 41A may be able to return to normal operation. The ability of the first reaction control circuit 41A to return to normal operation means that it can return to the cooperative drive mode, which is the drive mode when the first system circuits 41 and 51, as well as the second system circuits 42 and 52, are operating normally. For example, if an anomaly in the first reaction control circuit 41A has been determined to be due to temporary overheating of its components, and the temperature of the components of the first reaction control circuit 41A can be sufficiently reduced during the period from the determination of the anomaly until the vehicle is powered on again.

[0096] In this situation, it is conceivable that the first reaction control circuit 41A recognizes the vehicle's energization earlier than the other three control circuits (42A, 51A, and 52A). The other three control circuits do not recognize the vehicle's energization, and the second reaction control circuit 42A and the second rotation control circuit 52A continue to execute the power latching control ST5 as a mode of stop control. Figure 3 In the timing diagram, the state in which the control circuit recognizes that the vehicle is powered on is called "ON", and the state in which the control circuit does not recognize that the vehicle is powered on is called "OFF".

[0097] When it is determined that the vehicle is powered on, the first reaction control circuit 41A executes the start-up process ST1 and the initial check ST2, and then executes the auxiliary start-up waiting state ST3. The control state of the first reaction control circuit 41A changes from the no-assistance state CS1 through the auxiliary start-up waiting state CS2 to the independent drive mode state CS3. This is because the first reaction control circuit 41A and the second reaction control circuit 42A also synchronize the operating modes of the reaction motor 21 and the rotary motor 31.

[0098] That is, when as by Figure 3 When the control state transitions to the auxiliary start-up waiting state, as indicated by arrow D1, the first reaction control circuit 41A identifies the operating modes of the reaction motor 21 and the rotary motor 31, as identified by the second reaction control circuit 42A. Upon detecting a first system fault, the first reaction control circuit 41A initiates a stop control ST4 to halt its own operation and transitions its control state from the independent drive mode state CS3 to the non-auxiliary state CS4. The non-auxiliary state CS4 is a state where control over the reaction motor 21 and the rotary motor 31 is not performed. The first reaction control circuit 41A ultimately transitions to a sleep state, where it waits in a power-saving mode.

[0099] For example, when it is determined that the vehicle is powered on (time T2), the other three control circuits (42A, 51A, and 52A) begin processing ST1. When... Figure 3 When the control state indicated by arrow D2 has transitioned to the auxiliary start-up waiting state ST3, the second reaction control circuit 42A identifies the operating modes of the reaction motor 21 and the rotary motor 31 as identified by the first reaction control circuit 41A. When a fault is detected in the first system, the second reaction control circuit 42A switches its control state to the single-system drive mode using the second system, state CS5. In single-system drive mode, the second reaction control circuit 42A controls the drive of the reaction motor 21 (motor control ST6).

[0100] As by Figure 3 As indicated by arrow D3, for example, at the point when the startup process ST1 has been completed, the first rotation control circuit 51A identifies the operating modes of the reaction motor 21 and the rotation motor 31, which are identified by the first reaction control circuit 41A. When a first system fault is detected, the first rotation control circuit 51A initiates a stop control ST4 to halt its operation and changes its control state from the unassisted state CS1 to the non-assisted state CS4. The first rotation control circuit 51A eventually reaches a sleep state.

[0101] When as Figure 3 When the control state transitions to the auxiliary start-up waiting state CS2, as indicated by arrow D4, the second rotation control circuit 52A identifies the operating modes of the reaction motor 21 and the rotation motor 31, which were identified by the first rotation control circuit 51A. When a fault is detected in the first system, the second rotation control circuit 52A switches its control state to the single-system drive mode CS5 using the second system. In single-system drive mode, the second rotation control circuit 52A controls the drive of the rotation motor 31 (motor control ST6).

[0102] In this way, when the vehicle is powered on again during the period when power latching control is being performed after a power outage, the operating modes (System 1 fault mode) of the reaction motor 21 and the rotation motor 31 are synchronized among the control circuits (41A, 42A, 51A, and 52A). Therefore, although the first reaction control circuit 41A can return to normal operation, the control states of the second reaction control circuit 42A and the second rotation control circuit 52A unintentionally switch to a single-system drive mode using the second system.

[0103] Transition conditions of control state

[0104] Therefore, in this embodiment, the switching conditions for the control states of the control circuits (41A, 42A, 51A, and 52A) are set as follows: When the vehicle is powered on, from the time the vehicle is detected as powered on until all control circuits are normally activated and able to control the reaction motor 21 and the rotary motor 31, the control circuits do not perform the process of synchronizing the operating modes. The situations where the vehicle is powered on include, for example, the first time the vehicle is powered on while parked, and the situation where the vehicle is powered on again during a period when power latching control is being performed. If the vehicle is powered on again during a period when power latching control is being performed, and the operating modes of the motors (21 and 31) recognized by the corresponding control circuits are different from the operating modes of the motors recognized by other control circuits, the control circuits do not perform the process of synchronizing the operating modes until all control circuits are able to perform motor control.

[0105] Example of state transition

[0106] The state transitions of the control circuits (41A, 42A, 51A, and 52A) according to this embodiment will be described below. The assumptions are the same as those in the comparative example described above.

[0107] like Figure 4 As shown in the timing diagram, when the vehicle is powered on again during the period of power latching control after a power outage (time T1), the first reaction control circuit 41A can return to normal operation. The first reaction control circuit 41A recognizes that the vehicle is powered on earlier than the other three control circuits (42A, 51A, and 52A). The other three control circuits do not recognize that the vehicle is powered on, and the second reaction control circuit 42A and the second rotation control circuit 52A continue to execute power latching control ST5 as a mode of stop control.

[0108] When it is determined that the vehicle is powered on, the first reaction control circuit 41A executes the start-up process ST1 and the initial check ST2, and finally reaches the auxiliary start-up waiting state ST3. The control state of the first reaction control circuit 41A changes from the no-assistance state CS1 to the auxiliary start-up waiting state CS2. At this time, the operating mode of the motors (21 and 31) identified by the first reaction control circuit 41A is the normal mode. The normal mode is the normal operating mode of both the first system and the second system. On the other hand, the operating mode of the motors (21 and 31) identified by the second reaction control circuit 42A is the system 1 fault mode. In this way, the operating mode of the motors identified by the first reaction control circuit 41A is different from the operating mode of the motors identified by the second reaction control circuit 42A. However, during the auxiliary start-up waiting state CS2, the first reaction control circuit 41A does not perform the process of synchronizing the operating mode of the motors identified therein with the operating mode of the motors identified by the second reaction control circuit 42A. Therefore, the control state of the first reaction control circuit 41A remains in the auxiliary start-up waiting state CS2.

[0109] For example, when it is determined that the vehicle is powered on (time T2), the other three control circuits (42A, 51A, and 52A) begin processing ST1 and initial check ST2. At the moment when the initial check ST2, performed by the other three control circuits, is successfully completed, the control circuits (41A, 42A, 51A, and 52A) set the control state to normal control state CS6. The operating modes of the motors (21 and 31) identified by the control circuits (41A, 42A, 51A, and 52A) remain in the correct operating mode, i.e., synchronized with normal control state CS6. The first reaction control circuit 41A and the second reaction control circuit 42A control the drive of the reaction motor 21 in a cooperative drive mode, which is the drive mode in the normal state (motor control ST6). The first rotation control circuit 51A and the second rotation control circuit 52A control the drive of the rotation motor 31 in a cooperative drive mode (motor control ST6).

[0110] In this way, when the vehicle is restarted during a period of power latching control, even if the first reaction control circuit 41A, which is in a state capable of returning to normal operation, recognizes that the vehicle is powered on earlier than the other three control circuits (42A, 51A, and 52A), the control circuits (41A, 42A, 51A, and 52A) still start their operations as expected. Unlike the aforementioned comparative example, even if the first reaction control circuit 41A can return to normal operation, the operating modes of the reaction motor 21 and the rotary motor 31 will not unintentionally switch to the single-system drive mode using the second system.

[0111] When the vehicle is powered on again during the period when power latching control is being performed after the vehicle has been powered off in a state where an abnormality has been determined in a particular control circuit among the other three control circuits (42A, 51A and 52A), the particular control circuit operates in the same manner as the first reaction control circuit 41A.

[0112] Advantages of the first embodiment

[0113] Therefore, the following advantages can be achieved in this embodiment. When the vehicle is powered on again during the period when power latching control is being performed after a power outage, even if the operating mode of the identified motors (21 and 31) is different from the operating mode of the motors (21 and 31) identified by other control circuits, the control circuits (41A, 42A, 51A, and 52A) do not perform the process of synchronizing the operating modes. For example, when the vehicle is powered on again during the period when power latching control is being performed after a power outage in a state where an abnormality of a particular control circuit (41A) among the other three control circuits has been determined, that particular control circuit may be able to return to normal operation and identify that the vehicle has been powered on earlier than the other control circuits (42A, 51A, and 52A). In this case, during the period when it is in the auxiliary start waiting state while waiting for the initial check performed by the other control circuits (42A, 51A, and 52A) to complete normally, the particular control circuit (41A) does not perform the process of synchronizing the operating modes of the motors (21 and 31). Therefore, the motor operating mode recognized by the specific control circuit (41A) will not unintentionally switch to the motor operating mode recognized by other control circuits (42A, 51A, and 52A) (e.g., single-system drive mode). Therefore, the control circuits (41A, 42A, 51A, and 52A) initiate their operation normally. Thus, the drive of the reaction motor 21 and the rotary motor 31 can be appropriately controlled.

[0114] Synchronization processing is performed between the first reaction control circuit 41A and the second reaction control circuit 42A, between the first rotation control circuit 51A and the second rotation control circuit 52A, between the first reaction control circuit 41A and the first rotation control circuit 51A, and between the second reaction control circuit 42A and the second rotation control circuit 52A. Therefore, compared to a configuration where the control circuits (41A, 42A, 51A, and 52A) perform synchronization processing with all other control circuits except their corresponding control circuits, the signal paths can be simplified. For example, communication lines between the first reaction control circuit 41A and the second rotation control circuit 52A, and between the second reaction control circuit 42A and the first rotation control circuit 51A, are not required.

[0115] Second Implementation Method

[0116] The second embodiment of the control device for a vehicle implemented in the electric power steering system will now be described. Elements identical to those in the first embodiment will be indicated by the same reference numerals, and their detailed descriptions will be omitted.

[0117] In electric power steering systems Figure 1 The steering wheel 11 shown is mechanically connected to the rotating wheel 15. That is, the steering shaft 12, pinion shaft 33, and rotating shaft 13 serve as the power transmission path between the steering wheel 11 and the rotating wheel 15. When the rotating shaft 13 moves linearly as the steering wheel 11 is turned, the rotation angle θw of the rotating wheel 15 changes.

[0118] An electric power steering system includes an auxiliary motor and an auxiliary control unit. The auxiliary motor is positioned relative to... Figure 1 At the same location as the reaction motor 21 or the rotary motor 31 shown. The auxiliary motor generates an auxiliary force to assist in the operation of the steering wheel 11. The auxiliary force is a torque in the same direction as the steering direction of the steering wheel 11. The auxiliary control device controls the drive of the auxiliary motor, which is the controlled object.

[0119] like Figure 5 As shown, the auxiliary motor 70 includes a winding group N31 of a first system and a winding group N32 of a second system. The auxiliary control device 80 includes a first system circuit 81. The first system circuit 81 includes a first auxiliary control circuit 81A and a motor drive circuit 81B. The first auxiliary control circuit 81A controls the power supply to the winding group N31 of the first system. The first auxiliary control circuit 81A generates a drive signal for the motor drive circuit 81B based on the steering torque Th detected by the torque sensor 23.

[0120] 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 auxiliary control circuit 81A. The three-phase AC power generated by the motor drive circuit 81B is supplied to the winding group N31 of the first system of the auxiliary motor 70 via power supply paths for each phase, including buses or cables.

[0121] The auxiliary control device 80 includes a second system circuit 82. The second system circuit 82 includes a second auxiliary control circuit 82A and a motor drive circuit 82B. The second auxiliary control circuit 82A controls the power supply to the winding group N32 of the second system. The second auxiliary control circuit 82A generates a drive signal for the motor drive circuit 82B based on the steering torque Th detected by the torque sensor 23.

[0122] The motor drive circuit 82B converts the DC power supplied from the DC power supply 60 into three-phase AC power based on the drive signal generated by the second auxiliary control circuit 82A. The three-phase AC power generated by the motor drive circuit 82B is supplied to the winding group N32 of the second system of the auxiliary motor 70 via power supply paths for each phase, including busbars or cables.

[0123] The first auxiliary control circuit 81A and the second auxiliary control circuit 82A send and receive information between themselves via a communication line. The information includes anomaly information of the first auxiliary control circuit 81A, the second auxiliary control circuit 82A, or the motor drive circuit 81B or 82B. The information also includes the values ​​of various flags. The first auxiliary control circuit 81A and the second auxiliary control circuit 82A collaboratively control the drive of the auxiliary motor 70 based on the information sent and received between themselves.

[0124] The first auxiliary control circuit 81A and the second auxiliary control circuit 82A control the drive of the auxiliary motor in one of the following drive modes: cooperative drive mode, independent drive mode, and single-system drive mode, similar to the control circuits (41A, 42A, 51A, and 52A) according to the first embodiment. The control states of the first auxiliary control circuit 81A and the second auxiliary control circuit 82A change in the same manner as the control states of the control circuits (41A, 42A, 51A, and 52A) according to the first embodiment.

[0125] The first auxiliary control circuit 81A and the second auxiliary control circuit 82A perform power latching control while performing normal control for controlling the auxiliary motor in cooperative drive mode, so as to maintain power supply to it when the start switch SW is turned off, i.e., when the vehicle is powered off. When performing power latching control, the first auxiliary control circuit 81A and the second auxiliary control circuit 82A operate in the same manner as the control circuits (41A, 42A, 51A, 52A) according to the first embodiment.

[0126] In other words, when the vehicle is powered on, the first auxiliary control circuit 81A and the second auxiliary control circuit 82A do not perform the process of synchronizing the operating mode during the period from when the vehicle is recognized as powered on until all control circuits are started normally and can control the auxiliary motor.

[0127] If the vehicle is powered on again during a period when power latching control is in effect, the first auxiliary control circuit 81A will not perform synchronization processing for the operating modes, even if the operating mode of the auxiliary motor identified by the first auxiliary control circuit 81A differs from the operating mode of the auxiliary motor identified by the second auxiliary control circuit 82A. Similarly, if the vehicle is powered on again during a period when power latching control is in effect, the second auxiliary control circuit 82A will not perform synchronization processing for the operating modes, even if the operating mode of the auxiliary motor identified by the second auxiliary control circuit 82A differs from the operating mode of the auxiliary motor identified by the first auxiliary control circuit 81A.

[0128] For example, if the vehicle is powered on again during the period when power latching control is being performed after the vehicle has been powered down, and the first auxiliary control circuit 81A is determined to be malfunctioning, the first auxiliary control circuit 81A may be able to return to normal operation and recognize that the vehicle has been powered on earlier than the second auxiliary control circuit 82A. In this case, the first auxiliary control circuit 81A does not perform the synchronization process for the auxiliary motor's operating mode during the auxiliary start waiting state while waiting for the initial check of the second auxiliary control circuit 82A to be completed normally. Therefore, the operating mode of the auxiliary motor recognized by the first auxiliary control circuit 81A will not unintentionally change to the operating mode of the auxiliary motor recognized by the second auxiliary control circuit 82A (e.g., single-system drive mode). Therefore, the first auxiliary control circuit 81A and the second auxiliary control circuit 82A begin their operation normally.

[0129] If the vehicle is powered on again during the period when the power latch control is being performed after the vehicle power is cut off, and the second auxiliary control circuit 82A is determined to be abnormal, the second auxiliary control circuit 82A will operate in the same manner as the first auxiliary control circuit 81A.

[0130] Advantages of the second implementation method

[0131] Therefore, the following advantages can be achieved in the second embodiment. When the vehicle is powered on again during the period when power latching control is being performed after the vehicle has been powered off, even if the operating mode of the auxiliary motor recognized by the corresponding auxiliary control circuit is different from the operating mode of the auxiliary motor recognized by other control circuits, the first auxiliary control circuit 81A and the second auxiliary control circuit 82A do not perform the process of synchronizing their operating modes with the other operating mode. Therefore, the operating mode of the motor recognized by the first auxiliary control circuit 81A will not unintentionally change to the operating mode of the motor recognized by the second auxiliary control circuit 82A. The operating mode of the motor recognized by the second auxiliary control circuit 82A will not unintentionally change to the operating mode of the motor recognized by the first auxiliary control circuit 81A. Therefore, the first auxiliary control circuit 81A and the second auxiliary control circuit 82A start their operation normally. Therefore, the drive of the auxiliary motor can be properly controlled.

[0132] Other implementation methods

[0133] The first and second embodiments can be modified as follows. In the first embodiment, the reaction motor 21 and the rotation motor 31 include winding groups of two systems, but may also include winding groups of one system. In this case, the reaction control device 40 may include only one of the first system circuit 41 and the second system circuit 42. In this case, the rotation control device 50 may include only one of the first system circuit 51 and the second system circuit 52. The first reaction control circuit 41A or the second reaction control circuit 42A corresponds to the reaction control circuit in the claims. The first rotation control circuit 51A or the second rotation control circuit 52A corresponds to the rotation control circuit in the claims.

[0134] The vehicle control device is implemented in the steer-by-wire system of the first embodiment and in the electric power steering system of the second embodiment. However, the vehicle control device can also be implemented in, for example, a rearview mirror system that opens and closes together with a door lock. The vehicle control device can be implemented in all motor control devices that include redundant control circuitry and motor drive circuitry.

Claims

1. A control device for a vehicle, characterized in that... include: Multiple control circuits, configured to be activated by power-on of the vehicle, to coordinate or combine control of the controlled object. Each of the plurality of control circuits is configured to perform synchronization processing and power latching control. The synchronization processing is the process of synchronizing the operating modes of the controlled object, determined based on the operating state of the controlled object, with each other. The power latching control is a control used to maintain power supply for a limited period of time, triggered by a power outage of the vehicle. Each of the plurality of control circuits is configured to maintain the operating mode of the vehicle prior to the impending power loss during the period in which the power latch control is being executed, and Each of the plurality of control circuits is configured not to perform the synchronization process during a predetermined period when the vehicle is powered on. The predetermined period is from the time the vehicle is powered on to the time when all the control circuits in the plurality of control circuits start normally and are able to control the controlled object.

2. The control device for a vehicle according to claim 1, characterized in that, The operating modes include an operating mode when all the multiple control circuits are normal and an operating mode when one of the multiple control circuits is abnormal.

3. The control device for a vehicle according to claim 1 or 2, characterized in that, The controlled object includes: A reaction motor (21) comprising two winding systems and generating a steering reaction force, said steering reaction force being applied to a steering wheel (11), wherein power transmission from the steering wheel (11) to and from the rotating wheel (15) is interrupted; and A rotating motor (31) generates rotational force to rotate the rotating wheel (15); and The plurality of control circuits include: A first reaction control circuit (41A) is configured to control the power supply to the winding group of a first system of the reaction motor (21); The second reaction control circuit (42A) is configured to control the power supply to the winding group of the second system of the reaction motor (21); A first rotation control circuit (51A) is configured to control the power supply to the winding assembly of a first system of the rotation motor (31); and The second rotation control circuit (52A) is configured to control the power supply to the winding group of the second system of the rotation motor (31).

4. The control device for a vehicle according to claim 3, characterized in that, The synchronization process is performed between the first reaction control circuit (41A) and the second reaction control circuit (42A), between the first rotation control circuit (51A) and the second rotation control circuit (52A), between the first reaction control circuit (41A) and the first rotation control circuit (51A), and between the second reaction control circuit (42A) and the second rotation control circuit (52A).

5. The control device for a vehicle according to claim 1 or 2, characterized in that, The controlled object includes: A reaction motor (21), which is the source of the steering reaction force applied to the steering wheel (11), disconnects the power transmission from the steering wheel (11) to the rotating wheel (15) and from the rotating wheel (15); and A rotary motor (31) is the source of rotational force for rotating the rotary wheel (15), and The plurality of control circuits include: A reaction control circuit configured to control the reaction motor (21); and A rotation control circuit is configured to control the rotation motor (31).

6. The control device for a vehicle according to claim 1 or 2, characterized in that, The controlled object includes an auxiliary motor (70), which generates an auxiliary force to assist in the operation of the steering wheel (11). The auxiliary motor (70) includes a winding group of a first system and a winding group of a second system. The plurality of control circuits include: A first auxiliary control circuit (81A) is configured to control the power supply to the winding bank of the first system; and The second auxiliary control circuit (82A) is configured to control the power supply to the winding group of the second system.

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