Control device for a vehicle

Abstract

A control device for a vehicle is provided that includes a plurality of control circuits configured to control an object by starting in response to power-on of the vehicle, and configured to perform, in response to power-off of the vehicle, a power latch control for continuing to be supplied with power for a predetermined period of time. Each of the control circuits is configured to perform the starting after all the control circuits recognize the power-on of the vehicle in the case where the vehicle is powered on after the power latch control is being performed by the control circuits after the power-off of the vehicle.

Description

TECHNICAL FIELD

[0001] The present application relates to a control device for a vehicle. BACKGROUND

[0002] There is a so-called steer-by-wire steering system in which power transmission between a steering wheel and a steering wheel is cut off. For example, a steer-by-wire steering system described in Japanese Unexamined Patent Application Publication No. 2021-075182 (JP 2021-075182 A) includes a reaction actuator and a steering actuator. The reaction actuator generates a steering reaction force applied to a steering shaft. The steering actuator generates a steering force for turning a steering wheel.

[0003] Each of the reaction actuator and the steering actuator includes two control arithmetic units provided redundantly and two motor drive units provided redundantly. Each control arithmetic unit performs an arithmetic operation associated with drive control of a motor. Each motor drive unit generates a torque based on a drive signal generated by the corresponding control arithmetic unit.

[0004] The two control arithmetic units of the first system and the second system in the reaction actuator can communicate with each other and operate in cooperation based on information transmitted and received therebetween. The two control arithmetic units of the first system and the second system in the steering actuator can communicate with each other and operate in cooperation based on information transmitted and received therebetween.

[0005] The control arithmetic unit of the first system in the reaction actuator and the control arithmetic unit of the first system in the steering actuator can communicate with each other. The control arithmetic unit of the second system in the reaction actuator and the control arithmetic unit of the second system in the steering actuator can communicate with each other. The two control arithmetic units of the first system and the two control arithmetic units of the second system generally cause the corresponding motor drive units to generate a torque using information transmitted and received through inter-system communication.

[0006] There is an electric power steering system that assists operation of a steering wheel. A control device for the electric power steering system causes an assist motor to generate an assist force based on a steering state of the steering wheel. For example, a control device described in Japanese Unexamined Patent Application Publication No. 2009-248850 (JP 2009-248850 A) performs power latch control for continuously performing control until a predetermined time elapses after an ignition key has been turned off. In a case where the steering wheel is operated while the power latch control is performed, steering is assisted using the motor.

[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 for continuously performing operations such as temperature estimation for components on the board. The control device remains energized, that is, it continues to be supplied with power (i.e., continues to receive power supply) 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 power latching control, as described in JP 2009-248850 A or JP 2020-108327 A, would be implemented in a steer-by-wire system comprising multiple systems, such as JP 2021-075182 A. In this case, in response to a power outage caused by operation of the ignition key, the control arithmetic unit performs power latching control independently. If the vehicle is powered on while power latching control is being performed, the control arithmetic unit determines whether the vehicle is powered on and restarts the vehicle after determining that it is powered on.

[0009] When the vehicle is energized during power latching control, the timing at which the control arithmetic unit detects the vehicle's energization may be mismatched due to differences in wiring resistance, etc. Therefore, the timing of restarting the control arithmetic unit may also be mismatched. Consequently, the control arithmetic unit that restarts earlier may perform an unexpected state transition or output an unexpected arithmetic result by receiving pre-initialization information calculated by another control arithmetic unit still performing power latching control.

[0010] Specifically, when the vehicle is energized during power latch-up control, for example, each control arithmetic unit operates until it detects that the vehicle is energized (unlike the initial energization of the vehicle). Therefore, there is a high probability that each control arithmetic unit may output unexpected arithmetic results or execute unexpected state transitions. In steer-by-wire systems where power transmission between the steering wheel and steering wheels is cut off, when unexpected arithmetic results are output or unexpected state transitions are executed, the reaction actuator and steering actuator may not be properly controlled, potentially causing driver discomfort.

[0011] According to one aspect of the present invention, a control device for a vehicle is provided, the control device comprising a plurality of control circuits configured to activate in response to power-on of the vehicle to control a controlled object, and configured to perform power latching control for continuing to supply power for a predetermined time period in response to power-off of the vehicle. Each of the respective control circuits is configured to activate after all control circuits have detected power-on of the vehicle when power latching control is being performed after power-off of the vehicle.

[0012] With this configuration, when the vehicle is powered on while power latching control is in effect after a power outage, each control circuit starts up after the power-on is detected by all control circuits. Therefore, even if the control unit detects different times when the vehicle is powered on after a power outage and while power latching control is in effect, the start times of the control circuits can be matched.

[0013] In the control device according to this aspect, the control circuit can be configured to set the value of a flag based on the recognition result regarding whether the vehicle is energized. In this case, each of the various control circuits can be configured to determine whether all control circuits have recognized that the vehicle is energized based on the value of the flag.

[0014] Using this configuration, each control circuit can easily determine whether the vehicle's power supply has been recognized by all control circuits based on the value of the flag.

[0015] In the control device according to this aspect, the controlled object may include winding groups of two systems. The controlled object may include: a reaction motor that generates a steering reaction force applied to a steering wheel, the steering wheel being configured such that power transmission between the steering wheel and the steering wheels is interrupted; and a steering motor that generates a steering force for steering the steering wheels. In this case, the control circuit may include: a first reaction control circuit configured to control the power supply to the winding group of the first system in the reaction motor; a second reaction control circuit configured to control the power supply to the winding group of the second system in the reaction motor; a first steering control circuit configured to control the power supply to the winding group of the first system in the steering motor; and a second steering control circuit configured to control the power supply to the winding group of the second system in the steering motor.

[0016] Using this configuration, even when the vehicle is powered on while power latching control is being performed after a power outage, and the timing of the vehicle's power-on is different as detected by the first and second reaction control circuits, as well as the first and second steering control circuits, the timing of their start-up can be matched. The first and second reaction control circuits are configured to control the power supply to the reaction motor, and the first and second steering control circuits are configured to control the power supply to the steering motor. Therefore, the drive of the reaction motor and the steering motor can be appropriately controlled.

[0017] In the control device according to this aspect, the first reaction control circuit and the second reaction control circuit can be configured to perform a first mutual confirmation to verify whether the vehicle's power supply has been detected. The first steering control circuit and the second steering control circuit can be configured to perform a second mutual confirmation to verify whether the vehicle's power supply has been detected. The first reaction control circuit and the first steering control circuit can be configured to perform a third mutual confirmation to verify whether the first and second mutual confirmations have been successful, and are configured to determine that the vehicle's power supply has been detected by all control circuits when the first and second mutual confirmations have been successful. The second reaction control circuit and the second steering control circuit can be configured to perform a fourth mutual confirmation to verify whether the first and second mutual confirmations have been successful, and are configured to determine that the vehicle's power supply has been detected by all control circuits when the first and second mutual confirmations have been successful.

[0018] Compared to a configuration where each of the first and second reaction control circuits, as well as the first and second steering control circuits, mutually confirms the recognition result of the vehicle's energization using all other control circuits, this configuration simplifies the signal path. For example, no communication line is needed between the first reaction control circuit and the second steering control circuit, nor between the second reaction control circuit and the first steering control circuit.

[0019] In the control device according to this aspect, the controlled objects may include a reaction motor and a steering motor. The reaction motor is the source of the steering reaction force applied to the steering wheel, which is configured such that power transmission between the steering wheel and the steering wheels is interrupted. The steering motor is the source of the steering force for turning the steering wheels. In this case, the control circuit may include: a reaction control circuit configured to control the reaction motor; and a steering control circuit configured to control the steering motor. The reaction control circuit and the steering control circuit may be configured to mutually confirm whether the vehicle is powered on.

[0020] With this configuration, even if the vehicle is powered on while power latching control is in progress after a power outage, the timing of the reaction control circuit and the steering control circuit's power-on detection is different, allowing them to match their activation timings. Therefore, the drive of the reaction motor and the steering motor can be appropriately controlled.

[0021] In the control device according to this aspect, 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. In this case, the control circuit may include a first auxiliary control circuit and a second auxiliary control circuit, the first auxiliary control circuit being configured to control the power supply to the winding group of the first system, and the second auxiliary control circuit being configured to control the power supply to the winding group of the second system. The first and second auxiliary control circuits may be configured to mutually confirm whether vehicle power is detected.

[0022] Using this configuration, when the vehicle is powered on while power latching control is in progress after a power outage, both the first and second auxiliary control circuits activate after recognizing the vehicle's power-on. Therefore, even if the timing of the first and second auxiliary control circuits recognizing the vehicle's power-on differs, their activation timing can be matched. This allows for appropriate control of the auxiliary motor's drive.

[0023] In the control device according to this aspect, the control circuit can be configured to perform communication with an on-board system that performs processing to transition the vehicle to a drivable state. In this case, each of the control circuits can be configured to be allowed to communicate with the on-board system after all control circuits have detected the vehicle being powered on, in the event that the vehicle is powered on while power latching control is being performed after a power outage.

[0024] With this configuration, the control circuits cannot communicate with the onboard system when not all control circuits have detected the vehicle's power (i.e., the control circuits cannot communicate with the onboard system until all control circuits have detected the vehicle's power). Therefore, the likelihood of a control circuit that detects the vehicle's power earlier starting to communicate with the onboard system before all control circuits have detected the vehicle's power can be reduced.

[0025] In the control device according to this aspect, the control circuit can be configured to perform communication with an on-board system that performs processing to transition the vehicle to a drivable state, and the control circuit is configured to be allowed to communicate with the on-board system when the vehicle is powered on. The control circuit may include information indicating whether the on-board system is allowed to perform the processing. In this case, the control circuit can be configured to, as initialization processing for the information, change the content of the information from allowing the on-board system to perform the processing to disallowing the on-board system to perform the processing when the vehicle is powered off while performing control of the controlled object, and the control circuit can be configured to transmit the information to the on-board system when the vehicle is powered on again after a power outage and while power latching control is being performed.

[0026] When a vehicle is powered on while power latching control is in progress after a power outage, the following problem arises: the control circuit that detects the vehicle's power earlier may begin communicating with the onboard system before all other control circuits detect the power. In this case, the control circuit that detects the power earlier may send information to the onboard system instructing whether to allow the onboard system to perform processing to transition the vehicle to a drivable state. Here, the content of the information sent to the onboard system is changed to prohibit the onboard system from performing processing to transition the vehicle to a drivable state. Therefore, the likelihood of the onboard system starting to transition the vehicle to a drivable state before all other control circuits detect the power is reduced.

[0027] In the control device according to this aspect, the control circuit can be configured to perform communication with an on-board system that performs processing to transition the vehicle to a drivable state, and the control circuit can be configured to be allowed to communicate with the on-board system when the vehicle is powered on. The control circuit may include information indicating whether the on-board system is allowed to perform processing. In this case, the control circuit can be configured to retain the content of information set during the control of the controlled object when the vehicle is powered off while controlling the controlled object, such that the content is maintained to allow the on-board system to perform processing, and the control circuit is configured to transmit information to the on-board system when the vehicle is powered on while power latching control is being performed after a power outage. In this case, each of the control circuits can be configured to perform a process requesting the on-board system to ignore the information when the vehicle is powered on while power latching control is being performed after a power outage, and not all control circuits recognize the vehicle's power.

[0028] When a vehicle is powered on while power latching control is in progress after a power outage, the following problem arises: the control circuit that detects the vehicle's power earlier may begin communicating with the onboard system before all other control circuits detect the power. In this case, the control circuit that detects the power earlier may send information to the onboard system instructing whether to allow the onboard system to perform processing to transition the vehicle to a drivable state.

[0029] When power latching control is being executed, the information indicating whether the on-board system is allowed to perform the process of transitioning the vehicle to a drivable state is retained as it was set during the control of the controlled object—that is, the information used to allow the on-board system to perform the process of transitioning the vehicle to a drivable state. Therefore, the following problem exists: the on-board system may begin the process of transitioning the vehicle to a drivable state before all control circuits have recognized the vehicle's power-on.

[0030] In this respect, with this configuration, when the vehicle is powered on while power latching control is being performed after a power outage, if not all control circuits recognize the vehicle's power, the control circuit that recognizes the power earlier will execute a process requesting the onboard system to ignore the information previously transmitted to it. Therefore, the likelihood of the onboard system starting the process of transitioning the vehicle to a drivable state before all control circuits recognize the vehicle's power can be reduced.

[0031] Using the control device according to this aspect of the invention, even when the vehicle is powered on while power latching control is being performed, the timing of the control circuit startup can be matched. Attached Figure Description

[0032] 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 the same symbols denote the same elements, and in the drawings:

[0033] 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 provided.

[0034] Figure 2 This is a block diagram showing the reaction control device and steering control device according to the first embodiment;

[0035] Figure 3 This is a timing diagram showing the state transitions of the control circuit according to the first embodiment;

[0036] Figure 4 This is a diagram showing the configuration of a control device for a vehicle according to a second embodiment.

[0037] Figure 5 This is a timing diagram showing the state transitions of the control circuit according to the first comparison example;

[0038] Figure 6 This is a timing diagram showing the state transitions of the control circuit according to the second comparison example;

[0039] Figure 7 This is a timing diagram showing the first mode of state transition of the control circuit according to the third embodiment;

[0040] Figure 8 This is a timing diagram showing the second mode of state transition of the control circuit according to the third embodiment;

[0041] Figure 9 This is a timing diagram showing the first mode of state transition of the control circuit according to the fourth embodiment;

[0042] Figure 10 This is a timing diagram showing the second mode of state transition of the control circuit according to the fourth embodiment;

[0043] Figure 11 This is a timing diagram showing the first mode of state transition of the control circuit according to the fifth embodiment; and

[0044] Figure 12 This is a timing diagram showing the second mode of state transition of the control circuit according to the fifth embodiment. Detailed Implementation

[0045] First Implementation Method

[0046] The following describes a first embodiment of a control device for a vehicle implemented in a steering system with wire steering.

[0047] 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 steering shaft 13 extends in the left-right direction (as shown in the image). Steering wheels 15 are connected to both ends of the steering shaft 13 via connecting rods 14. When the steering shaft 13 moves linearly, the steering angle θw of the steering wheels 15 changes. The steering shafts 12 and 13 constitute the vehicle's steering mechanism. Figure 1 Only one steering wheel 15 is shown in the image.

[0048] The steering system 10 includes a reaction motor 21 and a reduction gear 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 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.

[0049] 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.

[0050] The steering system 10 includes a steering motor 31 and a reduction gear 32. The steering motor 31 is the source of steering force. Steering force is the force used to turn the steering wheel 15. The rotation shaft of the steering motor 31 is connected to a pinion shaft 33 via the reduction gear 32. The pinion teeth 33a of the pinion shaft 33 mesh with the rack teeth 13a of the steering shaft 13. The torque of the steering motor 31 is applied as steering force to the steering shaft 13 via the pinion shaft 33. The steering shaft 13 moves in the vehicle width direction as the steering motor 31 rotates.

[0051] The steering motor 31 is, for example, a three-phase brushless motor. The steering 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.

[0052] 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 the two systems in the reaction motor 21 according to each of the two systems in the reaction motor 21.

[0053] 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.

[0054] The steering system 10 includes a steering control unit 50. The steering control unit 50 controls the drive of the steering motor 31, which is the controlled object. The steering control unit 50 performs steering control based on the steering state to cause the steering motor 31 to generate a steering force that turns the steering wheels 15. The steering control unit 50 receives the steering angle θs detected by the steering angle sensor 24 and the travel Xw of the steering shaft 13 detected by the travel sensor 34. The travel Xw is the displacement relative to the neutral position of the steering 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 22 in the steering shaft 12. The travel sensor 34 is disposed near the steering shaft 13.

[0055] The steering control device 50 calculates the target steering angle of the steering wheel 15 based on the steering angle θs detected by the steering angle sensor 24. For example, the target steering angle can be obtained by multiplying the detected steering angle θs by a steering angle ratio. The steering angle ratio is the ratio of the steering angle θw to the steering angle θs. The steering angle ratio is a preset value based on product specifications, etc. The steering control device 50 calculates the steering angle θw based on the travel Xw of the steering shaft 13 detected by the travel sensor 34. The steering control device 50 controls the power supply to the steering motor 31 so that the steering angle θw calculated based on the travel Xw reaches the target steering angle. The steering control device 50 independently controls the power supply to the winding group of the second system in the steering motor 31.

[0056] The steering 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 steering motor 31 based on the steering angle θs detected by the steering angle sensor 24 and the travel Xw of the steering 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 steering motor 31 based on the steering angle θs detected by the steering angle sensor 24 and the travel Xw of the steering shaft 13 detected by the travel sensor 34.

[0057] A so-called mechanically and electrically integrated reaction actuator can be constructed by integrating the reaction control device 40 and the reaction motor 21. A so-called mechanically and electrically integrated steering actuator can be constructed by integrating the steering control device 50 and the steering motor 31.

[0058] Power supply path

[0059] The power supply paths for the reaction control unit 40 and the steering control unit 50 will be described below. Power is supplied from a direct current (DC) power source 60 located in the vehicle to various onboard devices, including the reaction control unit 40 and the steering control unit 50. The DC power source 60 is, for example, a battery. Power is also supplied from the DC power source 60 to various sensors, including the torque sensor 23, the steering angle sensor 24, and the travel sensor 34.

[0060] 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 steering 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 is operated when the vehicle's driving source, such as the engine, starts or stops. When the start switch SW is 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 steering control device 50. Turning on the start switch SW means supplying power to the vehicle. Turning off the start switch SW means de-energizing the vehicle.

[0061] 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 steering 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 circuits 41 and 42 of the reaction control device 40 and the first system circuits 51 and 52 of the steering control device 50.

[0062] 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 time period. Therefore, the first system circuit 41 can operate even after the start switch SW has been turned off. When the predetermined time period has elapsed, 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.

[0063] 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 is 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 is off.

[0064] 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 time period.

[0065] The first system circuit 51 of the steering 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 time period.

[0066] The second system circuit 52 of the steering 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 time period.

[0067] Among the components of the steering system 10, those components that need to operate even after the start switch SW is off (e.g., 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, even when the start switch SW is off, components such as torque sensor 23, steering angle sensor 24, and travel sensor 34 are continuously supplied with power when at least one of power relays 61, 62, 63, and 64 is on.

[0068] Reaction control device

[0069] 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.

[0070] The first reaction control circuit 41A comprises a processing circuit including (1) one or more processors operating according to a computer program (software), (2) one or more special-purpose hardware circuits (e.g., application-specific integrated circuits (ASICs)) performing at least some of the various processes, or (3) a combination thereof. 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 accessible by general-purpose or special-purpose computers.

[0071] 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 a first current command value for the winding group N11 of the first system based on the calculated target steering reaction force value. Here, the first current command value is set to half (50%) of the current amount (100%) required for the reaction motor 21 to generate the target steering reaction force. 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 consistent with the first current command value.

[0072] 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. Switching elements, such as two field-effect transistors (FETs) connected in series, serve as branches as basic units. The motor drive circuit 41B converts the DC power supplied from the DC power supply 60 into three-phase AC power by switching the phase switching elements based on the drive signal generated by the first reaction control circuit 41A. The three-phase AC power generated by the motor drive circuit 41B is supplied to the winding group N11 of the first system in the reaction motor 21 via a phase power supply path including a bus or cable. Therefore, the winding group N11 of the first system generates torque corresponding to the first current command value.

[0073] 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 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, which ensures that the actual current supplied to the winding group N12 of the second system matches the second current command value.

[0074] 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 second system winding group N12 in reaction motor 21 via a phase power supply path including a bus or cable. Therefore, the second system winding group N12 generates torque corresponding to the second current command value. Reaction motor 21 generates a total torque including the torque generated by the first system winding group N11 and the torque generated by the second system winding group N12.

[0075] Depending on the product specifications, a master-slave relationship can be configured 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 can act as the master circuit, and the second system circuit 42 can act as the slave circuit. Depending on the product specifications, the first system circuit 41 and the second system circuit 42 can have an equal relationship.

[0076] Steering control unit

[0077] The configuration of the steering control device 50 will be described in detail below. For example... Figure 2 As shown, the steering control device 50 includes a first system circuit 51 and a second system circuit 52. The first system circuit 51 includes a first steering control circuit 51A and a motor drive circuit 51B. The second system circuit 52 includes a second steering control circuit 52A and a motor drive circuit 52B.

[0078] The first steering control circuit 51A has essentially the same configuration as the first reaction control circuit 41A. The first steering control circuit 51A calculates the target steering angle of the steering wheel 15 based on the steering angle θs detected by the steering angle sensor 24. The steering control device 50 calculates the steering angle θw based on the travel Xw of the steering shaft 13 detected by the travel sensor 34. The first steering control circuit 51A calculates the target steering force to be generated by the steering motor 31 by executing angle feedback control to make the steering angle θw calculated based on the travel Xw consistent with the target steering angle, and calculates a third current command value for the winding group N21 of the first system in the steering motor 31 based on the calculated value of the target steering force. Here, the third current command value is set to half (50%) of the amount of current (100%) required for the steering motor 31 to generate the target steering force. The first steering control circuit 51A generates a drive signal for the motor drive circuit 51B by executing current feedback control to make the actual current value supplied to the winding group N21 of the first system consistent with the third current command value.

[0079] The motor drive circuit 51B has essentially the same configuration as the motor drive circuit 41B. The motor drive circuit 51B converts DC power supplied from the DC power supply 60 into three-phase AC power based on the drive signal generated by the first steering control circuit 51A. The three-phase AC power generated by the motor drive circuit 51B is supplied to the winding group N21 of the first system in the steering motor 31 via a power supply path including buses or cables. Therefore, the winding group N21 of the first system generates torque corresponding to the third current command value.

[0080] The second steering control circuit 52A has essentially the same configuration as the first reaction control circuit 41A. The second steering control circuit 52A calculates the target steering angle of the steering wheel 15 based on the steering angle θs detected by the steering angle sensor 24. The steering control device 50 calculates the steering angle θw based on the travel Xw of the steering shaft 13 detected by the travel sensor 34. The second steering control circuit 52A calculates the target steering force to be generated by the steering motor 31 by executing angle feedback control to make the steering angle θw calculated based on the travel Xw consistent with the target steering angle, and calculates a fourth current command value for the winding group N22 of the second system in the steering motor 31 based on the calculated value of the target steering force. Here, the fourth current command value is set to half (50%) of the amount of current required by the steering motor 31 to generate the target steering force. The second steering control circuit 52A generates a drive signal for the motor drive circuit 52B by executing current feedback control to make the actual current value supplied to the winding group N22 of the second system consistent with the fourth current command value.

[0081] 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 the drive signal generated by second steering 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 in steering motor 31 via a power supply path including buses or cables. Therefore, the winding group N22 of the second system generates torque corresponding to the fourth current command value. Steering motor 31 generates a total torque including 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.

[0082] Depending on the product specifications, the first system circuit 51 and the second system circuit 52 of the steering control device 50 can be configured in a master-slave relationship. In this case, for example, the first system circuit 51 can be used as the master circuit, and the second system circuit 52 can be used as the slave circuit. Depending on the product specifications, the first system circuit 51 and the second system circuit 52 can have an equal relationship.

[0083] Communication path

[0084] The following describes the internal communication paths of the reaction control device 40 and the steering control device 50, as well as the communication path between the reaction control device 40 and the steering control device 50.

[0085] like Figure 2As shown, the first reaction control circuit 41A and the second reaction control circuit 42A send and receive information between them via communication line L1. This information includes abnormal information regarding 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 the values ​​of various flags. 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 them.

[0086] The first steering control circuit 51A and the second steering control circuit 52A send and receive information between themselves via communication line L2. This information includes abnormal information regarding the first steering control circuit 51A, the second steering control circuit 52A, or the motor drive circuit 51B or the motor drive circuit 52B. The information also includes the values ​​of various flags. The first steering control circuit 51A and the second steering control circuit 52A coordinately control the drive of the steering motor 31 based on the information sent and received between them.

[0087] The first reaction control circuit 41A and the first steering control circuit 51A send and receive information between them via communication line L3. This information includes abnormal information regarding the first reaction control circuit 41A, the first steering control circuit 51A, or the motor drive circuit 41B or 51B. The information also includes the values ​​of various flags. Based on the information sent and received between them, the first reaction control circuit 41A and the first steering control circuit 51A collaboratively control the drive of the steering motor 31.

[0088] The second reaction control circuit 42A and the second steering control circuit 52A send and receive information between them via communication line L4. This information includes abnormal information regarding the second reaction control circuit 42A, the second steering control circuit 52A, or the motor drive circuit 42B. The information also includes the values ​​of various flags. The second reaction control circuit 42A and the second steering control circuit 52A operate collaboratively based on the information sent and received between them.

[0089] When an abnormality occurs in the first system circuits 41 and 51, which are components of the first system, the reaction motor 21 and the steering motor 31 are driven by the second system circuits 42 and 52, which are components of the second system. When an abnormality occurs in the second system circuits 42 and 52, which are components of the second system, the reaction motor 21 and the steering motor 31 are driven by the first system circuits 41 and 51, which are components of the first system.

[0090] For example, when an abnormality occurs in the first reaction control circuit 41A, the first reaction control circuit 41A stops operating, and the second reaction control circuit 42A continues to control the power supply to the winding group N12 of the second system in the reaction motor 21. In this case, the second reaction control circuit 42A can supply the winding group N12 of the second system with an amount of current corresponding to half (50%) of the amount of current required by the reaction motor 21 to generate the target steering reaction force. The second reaction control circuit 42A can also supply the winding group N12 of the second system with an amount of current greater than half of the amount of current required by the reaction motor 21 to generate the target steering reaction force. This depends on product specifications, etc. Only the torque generated by the winding group N12 of the second system in the reaction motor 21 is applied to the steering shaft 12 as the steering reaction force.

[0091] When an abnormality occurs in the first reaction control circuit 41A, the first steering control circuit 51A stops operating, and the second steering control circuit 52A continues to control the power supply to the winding group N22 of the second system in the steering motor 31. In this case, the second steering control circuit 52A can supply the winding group N22 of the second system with an amount of current corresponding to half (50%) of the amount of current required by the steering motor 31 to generate the target steering force. The second steering control circuit 52A can also supply the winding group N22 of the second system with an amount of current greater than half of the amount of current required by the steering motor 31 to generate the target steering force. This depends on product specifications, etc. Only the torque generated by the winding group N22 of the second system in the steering motor 31 is applied as the steering force to the steering shaft 13.

[0092] Similarly, when an anomaly occurs in the second reaction control circuit 42A, the second reaction control circuit 42A stops its operation, and the first reaction control circuit 41A continues to control the power supply to the winding group N11 of the first system in the reaction motor 21. When an anomaly occurs in the second reaction control circuit 42A, the second steering control circuit 52A stops its operation, and the first steering control circuit 51A continues to control the power supply to the winding group N21 of the first system in the steering motor 31.

[0093] When an anomaly occurs in the first steering control circuit 51A or the second steering control circuit 52A, similar to the case of an anomaly occurring in the first reaction control circuit 41A or the second reaction control circuit 42A, the power supply to the reaction motor 21 and the steering motor 31 continues to be controlled via the normal system. Similarly, in each of the cases where an anomaly occurs in the motor drive circuits 41B and 51B of the first system or in the motor drive circuits 42B and 52B of the second system, the power supply to the reaction motor 21 and the steering motor 31 also continues to be controlled via the normal system.

[0094] State transitions of control circuits

[0095] The state transitions of the control circuits (41A, 42A, 51A, and 52A) will be described below. Figure 3 As shown in the timing diagram, when the start switch SW is opened while in normal control mode (time T1), the first reaction control circuit 41A performs power latching control. Similar to the first reaction control circuit 41A, the second reaction control circuit 42A, the first steering control circuit 51A, and the second steering control circuit 52A also perform power latching control in response to the opening of the start switch SW.

[0096] Normal control is used to generate steering reaction force and steering force based on the steering state of steering wheel 11. In normal control, torque is generated by both the first system winding group N11 and the second system winding group N12 in the reaction motor 21, and torque is generated by both the first system winding group N21 and the second system winding group N22 in the steering motor 31. When the start switch SW is off, the vehicle stops.

[0097] The control circuits (41A, 42A, 51A, and 52A) perform power latching control after the start switch SW has been opened, and continue, for example, the operation of estimating the temperature of components on the board, etc. Examples of components include the switching elements of the motor drive circuits (41B, 42B, 51B, and 52B). The control circuits continue to be supplied with power (i.e., continue to receive power supply) until a predetermined time has elapsed after the start switch SW has been opened, 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.

[0098] When the temperature of components on the board reaches a predetermined temperature, the control circuit stores this temperature in non-volatile memory and terminates the 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 can appropriately execute overheat protection control. Overheat protection control is used to suppress overheating of components on the board by limiting reaction control or reversing control based on the temperature increase from the initial temperature of the components.

[0099] Here, it is assumed that the start switch SW is turned on again during the period when the power latch control is being executed after the start switch SW has been turned off. In this case, the following problem exists. That is, when the start switch SW is turned on during the period when the power latch control is being executed, the timing at which the first reaction control circuit 41A, the second reaction control circuit 42A, the first steering control circuit 51A, and the second steering control circuit 52A recognize the turn-on of the start switch SW may not match due to differences in wiring resistance or the like.

[0100] Examples of the timing at which the control circuits (41A, 42A, 51A, and 52A) recognize the turn-on of the start switch SW are as follows. That is, when the start switch SW is turned on during the period when the power latch control is being executed (time T2), the first reaction control circuit 41A recognizes the turn-on of the start switch SW at time T3. The second reaction control circuit 42A recognizes the turn-on of the start switch SW at time T4. The first steering control circuit 51A recognizes the turn-on of the start switch SW at time T5. The second steering control circuit 52A recognizes the turn-on of the start switch SW at time T6. The time relationship between the timings is the same as that represented by the relational expression (1).

[0101] T1 < T2 < T3 < T5 < T6 < T4……(1)

[0102] For example, "T1 < T2" means that time T2 is later than time T1.

[0103] Since the timing at which the control circuits (41A, 42A, 51A, and 52A) recognize the turn-on of the start switch SW is different in this way, there is a problem that the timing at which the control circuits start may be different. Therefore, in this embodiment, the control circuits execute the first mutual confirmation MC1, the second mutual confirmation MC2, the third mutual confirmation MC3, and the fourth mutual confirmation MC4 so that the timings at which they start match.

[0104] First mutual confirmation MC1

[0105] The first reaction control circuit 41A and the second reaction control circuit 42A execute the first mutual confirmation MC1 for mutually confirming whether the power-on of the vehicle has been recognized. Specifically, the first mutual confirmation is as follows.

[0106] The first reaction control circuit 41A sets the value of flag F11 based on the determination of whether the start switch SW has been turned on. When it is determined that the start switch SW is in the off state, the first reaction control circuit 41A sets the value of flag F11 to "0". When it is determined that the start switch SW has been turned on during the period of power latching control (time T3), the first reaction control circuit 41A sets the value of flag F11 to "1". The first reaction control circuit 41A sends the value of flag F11 to the second reaction control circuit 42A.

[0107] The second reaction control circuit 42A sets the value of flag F21 based on the determination of whether the start switch SW is turned on. When it is determined that the start switch SW is in the off state, the second reaction control circuit 42A sets the value of flag F21 to "0". When it is determined that the start switch SW has been turned on during the period of power latching control (time T4), the second reaction control circuit 42A sets the value of flag F21 to "1". The second reaction control circuit 42A sends the value of flag F21 to the first reaction control circuit 41A.

[0108] The first reaction control circuit 41A sets the value of flag F12 based on the values ​​of flags F11 and F21. The value of flag F12 indicates whether both the first reaction control circuit 41A and the second reaction control circuit 42A have recognized the activation of the start switch SW, i.e., whether the first mutual confirmation MC1 has been successful. When at least one of the values ​​of flags F11 and F21 is "0", the first reaction control circuit 41A sets the value of flag F12 to "0". This indicates that at least one of the first reaction control circuit 41A and the second reaction control circuit 42A has not recognized the activation of the start switch SW. When both the values ​​of flags F11 and F21 are "1", the first reaction control circuit 41A sets the value of flag F12 to "1". This indicates that both the first reaction control circuit 41A and the second reaction control circuit 42A have recognized the activation of the start switch SW. The first reaction control circuit 41A sends the value of flag F12 to the first steering control circuit 51A.

[0109] The second reaction control circuit 42A sets the value of flag F22 based on the values ​​of flags F11 and F21. Similar to flag F12, the value of flag F22 indicates whether both the first reaction control circuit 41A and the second reaction control circuit 42A have recognized the activation of the start switch SW, i.e., whether the first mutual confirmation MC1 has been successful. When at least one of the values ​​of flags F11 and F21 is "0", the second reaction control circuit 42A sets the value of flag F22 to "0". When both the values ​​of flags F11 and F21 are "1", the second reaction control circuit 42A sets the value of flag F22 to "1". The second reaction control circuit 42A sends the value of flag F22 to the second steering control circuit 52A.

[0110] Second mutual confirmation MC2

[0111] The first steering control circuit 51A and the second steering control circuit 52A perform a second mutual confirmation MC2 to mutually confirm whether the vehicle's power has been detected. Specifically, the second mutual confirmation is as follows.

[0112] The first steering control circuit 51A sets the value of flag F31 based on the determination of whether the start switch SW is turned on. When it is determined that the start switch SW is in the off state, the first steering control circuit 51A sets the value of flag F31 to "0". When it is determined that the start switch SW has been turned on during the period of power latching control (time T5), the first steering control circuit 51A sets the value of flag F31 to "1". The first steering control circuit 51A sends the value of flag F31 to the second steering control circuit 52A.

[0113] The second steering control circuit 52A sets the value of flag F41 based on the determination of whether the start switch SW is turned on. When it is determined that the start switch SW is in the off state, the second steering control circuit 52A sets the value of flag F41 to "0". When it is determined that the start switch SW has been turned on during the period when power latching control is being performed (time T6), the second steering control circuit 52A sets the value of flag F41 to "1". The second steering control circuit 52A sends the value of flag F41 to the first steering control circuit 51A.

[0114] The first steering control circuit 51A sets the value of flag F32 based on the values ​​of flags F31 and F41. The value of flag F32 indicates whether both the first steering control circuit 51A and the second steering control circuit 52A have recognized the activation of the start switch SW, i.e., whether the second mutual confirmation MC2 has been successful. When at least one of the values ​​of flags F31 and F41 is "0", the first steering control circuit 51A sets the value of flag F32 to "0". This indicates that at least one of the first steering control circuit 51A and the second steering control circuit 52A has not recognized the activation of the start switch SW. When both the values ​​of flags F31 and F41 are "1", the first steering control circuit 51A sets the value of flag F32 to "1". This indicates that both the first steering control circuit 51A and the second steering control circuit 52A have recognized the activation of the start switch SW. The first steering control circuit 51A sends the value of flag F32 to the first reaction control circuit 41A.

[0115] The second steering control circuit 52A sets the value of flag F42 based on the values ​​of flags F31 and F41. Similar to flag F32, the value of flag F42 indicates whether both the first steering control circuit 51A and the second steering control circuit 52A have successfully detected the activation of the start switch SW, i.e., whether the second mutual confirmation MC2 has been successfully completed. When at least one of the values ​​of flags F31 and F41 is "0", the second steering control circuit 52A sets the value of flag F42 to "0". When both the values ​​of flags F31 and F41 are "1", the second steering control circuit 52A sets the value of flag F42 to "1". The second steering control circuit 52A then sends the value of flag F42 to the second reaction control circuit 42A.

[0116] Third mutual confirmation MC3

[0117] The first reaction control circuit 41A and the first steering control circuit 51A execute a third mutual confirmation MC3 to verify whether the first mutual confirmation MC1 and the second mutual confirmation MC2 were successful. When the first mutual confirmation MC1 and the second mutual confirmation MC2 have been successful, the first reaction control circuit 41A and the first steering control circuit 51A determine that all control circuits (41A, 42A, 51A, and 52A) have recognized the vehicle's power supply. Specifically, the third mutual confirmation is as follows.

[0118] The first reaction control circuit 41A sets the value of flag F13 based on the values ​​of flags F12 and F32. The value of flag F13 indicates whether the start switch SW has been activated in all first reaction control circuits 41A, second reaction control circuit 42A, first steering control circuit 51A, and second steering control circuit 52A; that is, whether the first mutual confirmation MC1 and the second mutual confirmation MC2 have been successful. When at least one of the values ​​of flags F12 and F32 is "0", the first reaction control circuit 41A determines that at least one of the first mutual confirmation MC1 and the second mutual confirmation MC2 has failed, and sets the value of flag F13 to "0". When both the values ​​of flags F12 and F32 are "1", the first reaction control circuit 41A determines that the first mutual confirmation MC1 and the second mutual confirmation MC2 have been successful, and sets the value of flag F13 to "1". The first reaction control circuit 41A is activated in response to this setting (i.e., this setting acts as a trigger) (time T7).

[0119] The first steering control circuit 51A sets the value of flag F33 based on the values ​​of flags F12 and F32. Similar to flag F13, the value of flag F33 indicates whether all first reaction control circuits 41A, second reaction control circuit 42A, first steering control circuit 51A, and second steering control circuit 52A have recognized the activation of the start switch SW, i.e., whether the first mutual confirmation MC1 and the second mutual confirmation MC2 have been successful. When at least one of the values ​​of flags F12 and F32 is "0", the first steering control circuit 51A determines that at least one of the first mutual confirmation MC1 and the second mutual confirmation MC2 has failed, and sets the value of flag F33 to "0". When both the values ​​of flags F12 and F32 are "1", the first steering control circuit 51A determines that the first mutual confirmation MC1 and the second mutual confirmation MC2 have been successful, and sets the value of flag F33 to "1". The first steering control circuit 51A activates in response to this setting (time T7).

[0120] Fourth mutual confirmation MC4

[0121] The second reaction control circuit 42A and the second steering control circuit 52A execute a fourth mutual confirmation MC4 to verify whether the first mutual confirmation MC1 and the second mutual confirmation MC2 were successful. When the first mutual confirmation MC1 and the second mutual confirmation MC2 have been successful, the second reaction control circuit 42A and the second steering control circuit 52A determine that all control circuits (41A, 42A, 51A, and 52A) have recognized the vehicle's power supply. Specifically, this fourth mutual confirmation is as follows.

[0122] The second reaction control circuit 42A sets the value of flag F23 based on the values ​​of flags F22 and F42. Similar to flag F13, the value of flag F23 indicates whether all first reaction control circuits 41A, second reaction control circuit 42A, first steering control circuit 51A, and second steering control circuit 52A have recognized the activation of the start switch SW; that is, whether the first and second mutual confirmations have been successful. When at least one of the values ​​of flags F22 and F42 is "0", the second reaction control circuit 42A determines that at least one of the first and second mutual confirmations has failed and sets the value of flag F23 to "0". When both the values ​​of flags F22 and F42 are "1", the second reaction control circuit 42A determines that the first and second mutual confirmations have been successful and sets the value of flag F23 to "1". The second reaction control circuit 42A is activated in response to this setting (time T7).

[0123] The second steering control circuit 52A sets the value of flag F43 based on the values ​​of flags F22 and F42. Similar to flag F13, the value of flag F43 indicates whether all first reaction control circuits 41A, second reaction control circuit 42A, first steering control circuit 51A, and second steering control circuit 52A have recognized the activation of the start switch SW, i.e., whether the first and second mutual confirmations have been successful. When at least one of the values ​​of flags F22 and F42 is "0", the second steering control circuit 52A determines that at least one of the first and second mutual confirmations has failed and sets the value of flag F43 to "0". When both the values ​​of flags F22 and F42 are "1", the second steering control circuit 52A determines that the first and second mutual confirmations have been successful and sets the value of flag F43 to "1". The second steering control circuit 52A is activated in response to this setting (time T7).

[0124] In this way, when the start switch SW is turned on during the period when power latch control is being executed, the control circuits (41A, 42A, 51A, and 52A) start at the same timing (time T7). The control circuits execute an initial sequence upon startup and then transition to a state of performing normal control. The initial sequence is a series of procedures required to transition to system startup. These procedures include, for example, hardware checks, CPU initialization, and the initialization of variables or flags.

[0125] Advantages of the first embodiment

[0126] Therefore, according to the first embodiment, the following advantages can be achieved. (1-1) When the vehicle is powered on while power latching control is being performed after the vehicle has been powered off, each of the control circuits (41A, 42A, 51A, and 52A) performs a start-up (i.e., starts the start-up process) after the vehicle's power-on has been recognized by all control circuits. Therefore, when the vehicle is powered on while power latching control is being performed after the vehicle has been powered off, even if the timing of the control device recognizing the vehicle's power-on is different, the timing of the control circuit starting its start-up can be matched. Therefore, the drive of the reaction motor 21 and the steering motor 31 can be appropriately controlled.

[0127] (1-2) The control circuits (41A, 42A, 51A, and 52A) set the values ​​of flags (F11, F21, F31, and F41) based on the recognition results regarding whether the vehicle is powered on. Each of the control circuits can easily determine whether all control circuits have recognized the vehicle being powered on based on the value of the flag.

[0128] (1-3) The first reaction control circuit 41A and the second reaction control circuit 42A execute a first mutual confirmation MC1 to mutually confirm whether the vehicle's power-on has been identified by sending and receiving the values ​​of flags F11 and F21. The first steering control circuit 51A and the second steering control circuit 52A execute a second mutual confirmation MC2 to mutually confirm whether the vehicle's power-on has been identified by sending and receiving the values ​​of flags F31 and F41. The first reaction control circuit 41A and the first steering control circuit 51A execute a third mutual confirmation MC3 to mutually confirm whether the first mutual confirmation MC1 and the second mutual confirmation MC2 have been successful by sending and receiving the values ​​of flags F12 and F32. When the first mutual confirmation MC1 and the second mutual confirmation MC2 have been successful, the first reaction control circuit 41A and the first steering control circuit 51A determine that all control circuits have identified the vehicle's power-on. The second reaction control circuit 42A and the second steering control circuit 52A execute a fourth mutual confirmation MC4 to mutually confirm whether the first mutual confirmation MC1 and the second mutual confirmation MC2 were successful by sending and receiving the values ​​of flags F22 and F42. When the first mutual confirmation MC1 and the second mutual confirmation MC2 have been successful, the second reaction control circuit 42A and the second steering control circuit 52A determine that all control circuits have recognized that the vehicle is powered. Therefore, the signal path can be simplified compared to the case where each of the control circuits (41A, 42A, 51A, and 52A) mutually confirms the values ​​of flags (F11, F21, F31, and F41) with other control circuits. For example, a communication line is not required between the first reaction control circuit 41A and the second steering control circuit 52A, nor is a communication line required between the second reaction control circuit 42A and the first steering control circuit 51A.

[0129] Second Implementation Method

[0130] A second embodiment of a control device for a vehicle implemented in an 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 detailed descriptions thereof will be omitted.

[0131] In electric power steering systems Figure 1 The steering wheel 11 and steering wheel 15 are mechanically connected. That is, the steering shaft 12, pinion shaft 33, and steering shaft 13 serve as the power transmission path between the steering wheel 11 and the steering wheel 15. When the steering shaft 13 moves linearly as the steering wheel 11 turns, the steering angle θw of the steering wheel 15 changes.

[0132] An electric power steering system includes an auxiliary motor and auxiliary control units. The auxiliary motor is positioned in conjunction with... Figure 1At the same location as the reaction motor 21 or steering motor 31 shown, the auxiliary motor generates an auxiliary force to assist in the operation of the steering wheel 11. This 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.

[0133] like Figure 4 As shown, the auxiliary motor 70 includes a first system winding group N31 and a second system winding group N32. 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 first system winding group N31. 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.

[0134] 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 in the auxiliary motor 70 via the power supply path of the phase, including the bus or cable.

[0135] 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.

[0136] 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 in the auxiliary motor 70 via the power supply path of the phase, including the bus or cable.

[0137] The first auxiliary control circuit 81A and the second auxiliary control circuit 82A send and receive information between them via a communication line. This information includes abnormal information regarding 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 coordinately control the drive of the auxiliary motor 70 based on the information sent and received between them.

[0138] When the start switch SW is disconnected during normal control operation, the first auxiliary control circuit 81A performs power latching control to continue receiving power (i.e., continues to receive power). The first auxiliary control circuit 81A sets the value of flag F51 based on whether the start switch SW has been turned on. When it is determined that the start switch SW has been disconnected, the first auxiliary control circuit 81A sets the value of flag F51 to "0". When it is determined that the start switch SW was turned on during the period when power latching control is being performed, the first auxiliary control circuit 81A sets the value of flag F51 to "1". The first auxiliary control circuit 81A transmits the value of flag F51 to the second auxiliary control circuit 82A.

[0139] When the start switch SW is disconnected during normal control operation, the second auxiliary control circuit 82A performs power latching control to continue supplying power. The second auxiliary control circuit 82A sets the value of flag F61 based on whether the start switch SW has been turned on. When it is determined that the start switch SW has been disconnected, the second auxiliary control circuit 82A sets the value of flag F61 to "0". When it is determined that the start switch SW was turned on during the period of power latching control, the second auxiliary control circuit 82A sets the value of flag F61 to "1". The second auxiliary control circuit 82A transmits the value of flag F61 to the first auxiliary control circuit 81A.

[0140] The first auxiliary control circuit 81A and the second auxiliary control circuit 82A determine whether both the first auxiliary control circuit 81A and the second auxiliary control circuit 82A have recognized the activation of the start switch SW based on the values ​​of flag F51 and flag F61.

[0141] When at least one of the values ​​of flag F51 and flag F61 is “0”, the first auxiliary control circuit 81A and the second auxiliary control circuit 82A determine that at least one of the first auxiliary control circuit 81A and the second auxiliary control circuit 82A has not recognized the activation of the start switch SW.

[0142] When both flags F51 and F61 are "1", the first auxiliary control circuit 81A and the second auxiliary control circuit 82A determine that both have recognized the activation of the start switch SW. In response to this determination, the first auxiliary control circuit 81A and the second auxiliary control circuit 82A execute the start-up procedure.

[0143] In this manner, when the start switch SW is turned on during the period when power latching control is being performed, the first auxiliary control circuit 81A and the second auxiliary control circuit 82A perform their startup at the same timing. The first auxiliary control circuit 81A and the second auxiliary control circuit 82A execute an initial sequence upon startup and then transition to the state of performing normal control.

[0144] Advantages of the second implementation method

[0145] Therefore, the following advantages can be achieved in the second embodiment. (2-1) When the vehicle is powered on while power latching control is being performed after the vehicle has been powered off, the first auxiliary control circuit 81A and the second auxiliary control circuit 82A execute their startup (i.e., begin their startup process) after both have detected the vehicle's power-on. Therefore, even if the timing of the first auxiliary control circuit 81A and the second auxiliary control circuit 82A detecting the vehicle's power-on is different, the timing of their startup can be matched. As a result, the drive of the auxiliary motor 70 can be appropriately controlled.

[0146] (2-2) The first auxiliary control circuit 81A and the second auxiliary control circuit 82A set the values ​​of flags F51 and F61 based on the determination of whether the vehicle is powered on. The first auxiliary control circuit 81A and the second auxiliary control circuit 82A can easily determine whether both the first auxiliary control circuit 81A and the second auxiliary control circuit 82A have identified the vehicle as powered on by checking the values ​​of flags F51 and F61.

[0147] Third Implementation Method

[0148] The following describes a third embodiment of a control device for a vehicle implemented in a steering system with wire steering. This embodiment essentially has the same characteristics as... Figures 1 to 3 The structure shown is the same as that of the first embodiment. Elements that are the same as those in the first embodiment will be indicated by the same reference numerals, and detailed descriptions thereof will be omitted.

[0149] like Figure 1 As shown, the reaction control device 40 is connected to the vehicle system 72 via an in-vehicle network 71. The in-vehicle network 71 is, for example, a controller area network (CAN). The reaction control device 40 and the vehicle system 72 send and receive information via the in-vehicle network 71. The steering control device 50 is connected to the vehicle system 72 via the in-vehicle network 71. The steering control device 50 and the vehicle system 72 send and receive information via the in-vehicle network 71.

[0150] The vehicle system 72 includes, for example, a steering lock control device, a shift lock control device, a transmission control device, and an instrument control device. The steering lock control device controls the operation of the steering lock mechanism. The steering lock mechanism is a mechanism that restricts the rotation of the steering wheel 11. The steering lock control device controls the operation of the steering lock mechanism so that the steering wheel 11 is unlocked when the ignition switch SW is turned on. The process of unlocking the steering wheel 11 is a process of changing the vehicle to a drivable state. The steering lock control device controls the operation of the steering lock mechanism so that the steering wheel 11 is locked when the ignition switch SW is turned off.

[0151] The shift lock control device controls the operation of the shift lock mechanism. The shift lock mechanism is a mechanism used to restrict the operation of the shift lever using a locking member. The shift lock control device controls the operation of the shift lock mechanism so that when the shift lever is in the parking range and the brake pedal is depressed, the shift lever is unlocked when the start switch SW is turned on. Unlocking the shift lever is a process that allows the vehicle to be moved to a drivable state. The shift lock control device also controls the operation of the shift lock mechanism so that when the shift lever is in the parking position, the shift lever is locked when the start switch SW is turned off.

[0152] The drivetrain control unit controls the operation of the vehicle. More specifically, the drivetrain control unit controls the vehicle's drivetrain. The drivetrain includes a driving source for the vehicle's propulsion and a power transmission mechanism. Examples of driving sources include an internal combustion engine and a motor. The power transmission mechanism is the mechanism that transmits power generated by the driving source to the drive wheels. When the start switch SW is turned on, the drivetrain control unit performs predetermined start-up preparations. Start-up preparations include initial checks, such as hardware checks, CPU initialization, variable or flag initialization, and processes necessary to start the vehicle's drivetrain. After start-up preparations are complete, the drivetrain control unit starts the drivetrain. The process of starting the drivetrain is the process of transitioning the vehicle to a state where it can be driven.

[0153] The instrument cluster controls the activation of indicator lights on the instrument panel. These indicator lights include warning lights configured to alert the driver of any abnormality or malfunction related to vehicle operation, and warning lights configured to warn or alert the driver if they fail to perform the correct operation. The warning lights emit different colors according to the alarm level. For example, red indicates an abnormality requiring immediate inspection. Yellow indicates an abnormality requiring timely inspection. Green indicates normal operation.

[0154] When the source voltage supplied via the start switch SW has a value within a predetermined operating voltage range, the first reaction control circuit 41A can perform communication via the vehicle network 71. The operating voltage range is the range of source voltages required for the operation of the control circuits (41A, 42A, 51A, and 52A) including the first reaction control circuit 41A. The operating voltage range is set, for example, based on the viewpoint of ensuring reliable communication. When the source voltage supplied via the start switch SW reaches a value within the operating voltage range, the first reaction control circuit 41A transmits various information to the vehicle system 72 via the vehicle network 71. The second reaction control circuit 42A, the first steering control circuit 51A, and the second steering control circuit 52A perform the same processing as that performed by the first reaction control circuit 41A.

[0155] This information includes, for example, the following five indicators (A1) to (A5): (A1) Communication Allow indicator F71; (A2) First Unlock Allow indicator F72; (A3) Second Unlock Allow indicator F73; (A4) Start Allow indicator F74; and (A5) Instrument Notification indicator F75. The Communication Allow indicator F71 indicates whether communication via the vehicle network 71 is permitted. The first reaction control circuit 41A sets the value of the Communication Allow indicator F71 based on whether the source voltage supplied via the start switch SW is within the operating voltage range. When the source voltage supplied via the start switch SW is within the operating voltage range, the first reaction control circuit 41A sets the value of the Communication Allow indicator F71 to "Allow". When the value of the Communication Allow indicator F71 is set to "Allow", it means that communication by the control circuits (41A, 42A, 51A, and 52A) via the vehicle network 71 is permitted. When the voltage of the power supplied via the start switch SW is outside the operating voltage range, the first reaction control circuit 41A sets the value of the communication enable flag F71 to "disable". When the value of the communication enable flag F71 is set to "disable", it means that communication via the vehicle network 71 is not allowed for the control circuits (41A, 42A, 51A and 52A).

[0156] The first unlock permission flag F72 indicates whether the steering lock control device is allowed to unlock the steering wheel 11. The first reaction control circuit 41A sets the value of the first unlock permission flag F72 based on whether the ignition switch SW has been turned on. Here, when the source voltage supplied via the ignition switch SW is within the operating voltage range, the first reaction control circuit 41A determines that the ignition switch SW has been turned on. When the source voltage supplied via the ignition switch SW is outside the operating voltage range, the first reaction control circuit 41A determines that the ignition switch SW has been turned off.

[0157] When the ignition switch SW is turned on, the first reaction control circuit 41A sets the value of the first unlocking permission flag F72 to "allow". When the first unlocking permission flag F72 is set to "allow", it means that the steering lock control device is allowed to unlock the steering wheel 11. When the ignition switch SW is turned off, the first reaction control circuit 41A sets the value of the first unlocking permission flag F72 to "disallow". When the first unlocking permission flag F72 is set to "disallow", it means that the steering lock control device is not allowed to unlock the steering wheel 11.

[0158] The second unlock permission flag F73 indicates whether the shift lock control device is allowed to unlock the shift lever. The first reaction control circuit 41A sets the value of the second unlock permission flag F73 based on whether the charging of the DC power supply 60 is complete. For example, when the charging power of the DC power supply 60 is greater than 90% of the full charge power, the first reaction control circuit 41A determines that the charging of the DC power supply 60 is complete. When the charging power of the DC power supply 60 is equal to or less than 90% of the full charge power, the first reaction control circuit 41A determines that the charging of the DC power supply 60 is not yet complete.

[0159] When the DC power supply 60 has finished charging, the first reaction control circuit 41A sets the value of the second unlocking permission flag F73 to "allow". When the second unlocking permission flag F73 is set to "allow", it means that the shift lock control device is allowed to unlock the shift lever. When the DC power supply 60 has not finished charging, the first reaction control circuit 41A sets the value of the second unlocking permission flag F73 to "disallow". When the second unlocking permission flag F73 is set to "disallow", it means that the shift lock control device is not allowed to unlock the shift lever.

[0160] The start-allow flag F74 indicates whether starting the drivetrain is permitted. The first reaction control circuit 41A sets the value of the start-allow flag F74 based on whether the execution of the initial sequence has been completed. When the execution of the initial sequence has been completed, the first reaction control circuit 41A sets the value of the start-allow flag F74 to "allow". When the value of the start-allow flag F74 is set to "allow", it means that the drivetrain control device is allowed to start the drivetrain. When the execution of the initial sequence has not yet been completed, the first reaction control circuit 41A sets the value of the start-allow flag F74 to "prohibit". When the value of the start-allow flag F74 is set to "prohibit", it means that the drivetrain control device is not allowed to start the drivetrain.

[0161] The instrument cluster indicator F75 displays information indicating the operational status of the four control circuits (41A, 42A, 51A, and 52A) in the steer-by-wire system. When all control circuits are operating normally, the control circuit sets the value of instrument cluster indicator F75 to "Normal." When at least one control circuit malfunctions or fails to activate, the control circuit sets the value of instrument cluster indicator F75 to "Abnormal." For example, when braking (or disconnection) of the power supply path to a specific control circuit is detected, the control circuit sets the value of instrument cluster indicator F75 to "Abnormal."

[0162] The second reaction control circuit 42A, the first steering control circuit 51A, and the second steering control circuit 52A are similar to the first reaction control circuit 41A in that the values ​​of the flags (F71 to F75) are set.

[0163] Not all four control circuits (41A, 42A, 51A, and 52A) have the function of setting the values ​​of the enable flags (F72, F73, and F74). That is, the function of setting the enable flags can be assigned to a control circuit for execution by the control circuit. In this case, there may be control circuits that do not have the function of setting the enable flags.

[0164] For example, only the second reaction control circuit 42A may have the function of setting the values ​​of the first unlock permission flag F72 and the second unlock permission flag F73. The second reaction control circuit 42A and the first steering control circuit 51A may have the function of setting the value of the start permission flag F74. Only the first steering control circuit 51A may have the function of setting the value of the instrument notification flag F75. All control circuits may have the function of setting the value of the communication permission flag F71.

[0165] Therefore, even when the start switch SW is turned on, the vehicle will not transition to a drivable state until the reaction control device 40 and steering control device 50 reach a state capable of normal control after completing the execution of the initial sequence. In other words, unlocking the steering wheel 11 and gearshift lever, as well as starting the transmission system, are not permitted until a state capable of normal control is reached. Thus, it is possible to prevent the vehicle from transitioning to a drivable state when normal control cannot be performed by the reaction control device 40 and steering control device 50. The vehicle can begin driving in a state that is safer for the driver, i.e., a state where the vehicle can steer in the direction the driver desires. A first comparative example of the state transition of the control circuit.

[0166] The following will describe a first comparative example of the state transitions of the control circuits (41A, 42A, 51A, and 52A).

[0167] like Figure 5As shown in the timing diagram, under normal control conditions (time T11), when the start switch SW is open, the control circuit performs power latching control. When the start switch SW is open, the level of the source voltage supplied to the control circuit (41A, 42A, 51A, and 52A) via the power supply path including the start switch SW switches changes from "Hi" to "Lo". "Hi" indicates that the source voltage is greater than the lower limit of the operating voltage range and less than the upper limit of the operating voltage range. "Lo" indicates that the source voltage is equal to or less than the lower limit of the operating voltage range. When the source voltage level changes from "Hi" to "Lo", the value of the communication enable flag F71 changes from "Enabled" to "Disabled".

[0168] During power latching control, the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, the start permission flag F74, and the instrument notification flag F75 remain the same as those set during normal control operations performed before the start switch SW was opened. In other words, the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, and the start permission flag F74 remain "permitted." The value of the instrument notification flag F75 remains "normal." For example, when the start of the control circuits (41A, 42A, 51A, and 52A) has been confirmed, i.e., when all control circuits have recognized the opening of the start switch SW, the values ​​of the flags (F72, F73, F74, and F75) are reset.

[0169] When the start switch SW is off, the steering lock control device uses the steering lock mechanism to switch the state of the steering wheel 11 from the unlocked state to the locked state.

[0170] When the start switch SW is off, the shift lock control device uses the shift lock mechanism to switch the shift lever from the unlocked state to the locked state.

[0171] When the start switch SW is turned off, the drivetrain control device switches the drivetrain's state from "ready to start" to "ready to stop". "Ready to start" indicates that the drivetrain's start preparation is complete and the drivetrain is ready to start. "Ready to stop" indicates that the drivetrain's operation has stopped.

[0172] When the start switch SW is off, the instrument control unit switches the indicator light on the instrument panel that indicates the status of the steer-by-wire system from the on state, which indicates normal operation of the steer-by-wire system, to the off state, which indicates the stop state of the steer-by-wire system.

[0173] Here, it is assumed that after the start switch SW is turned off, it is turned back on during the period of power latching control (time T12). In this case, the following problems exist: the timing by which the control circuits (41A, 42A, 51A, and 52A) detect the turn-on of the start switch SW may be mismatched due to differences in wiring resistance, etc. There may be cases where a specific control circuit within the control circuits (41A, 42A, 51A, and 52A) fails to detect the turn-on of the start switch SW due to an interruption (i.e., disconnection or disconnection) in the power supply path to that specific control circuit. The power supply path includes the power supply to the start switch SW.

[0174] In the event of such an event, the following problem arises. For example, suppose that during the period from when the start switch SW is turned off until it is turned back on during the execution of power latching control (time T11 to time T12), an interruption occurs in the power supply path to a specific control circuit. This power supply path includes the start switch SW. In such a case, source voltage is not supplied to the specific control circuit via the start switch SW. Therefore, the specific control circuit cannot recognize the turn on of the start switch SW. The specific control circuit will not activate.

[0175] Therefore, it is impossible for all four control circuits (41A, 42A, 51A, and 52A) to simultaneously detect the activation of the start switch SW. The control circuits continue to perform power latching control without starting. After a predetermined time period elapses from the point when the start switch SW is deactivated, the control circuits stop power latching control and transition to a sleep state (time T13). Sleep is a state in which the control circuits temporarily suspend their operation and wait in a power-saving state. When transitioning to the sleep state, the control circuits send information indicating the transition to the sleep state to the vehicle system 72 via the vehicle network 71.

[0176] When the start switch SW is turned on during power latching control, source voltage is supplied to three of the four control circuits (41A, 42A, 51A, and 52A) excluding the specific control circuit via the power supply path including the start switch SW. When the source voltage supplied with the turn switch SW reaches a value within the operating voltage range, the three control circuits excluding the specific control circuit set the value of the communication permission flag F71 to "permitted".

[0177] During the execution of power latching control, three control circuits, excluding the specific control circuit, maintain the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, the start permission flag F74, and the instrument notification flag F75 at the same values ​​set during normal control performed before the start switch SW is opened. That is, the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, and the start permission flag F74 are set to "permitted," and the value of the instrument notification flag F75 is set to "normal."

[0178] Therefore, when the value of the communication permission flag F71 is switched from "prohibited" to "permitted" during the execution of power latch control, three control circuits, except for the specific control circuit, send the values ​​of flags (F72, F73, F74, and F75) to the vehicle system 72 via the vehicle network 71. Thus, the steering lock control device can perform the process of unlocking the steering wheel 11. The shift lock control device can perform the process of unlocking the shift lever. The drivetrain control device can perform the process of starting the drivetrain.

[0179] Therefore, even if the four control circuits (41A, 42A, 51A, and 52A) in the steering-by-wire system fail to activate, the vehicle can still be brought to a drivable state. Specifically, the process is as follows.

[0180] The steering lock control device is set to "allowed" based on the value of the first unlock permission flag F72, and uses the steering lock mechanism to switch the steering wheel 11 from the locked state to the unlocked state.

[0181] The shift lock control device is set to "permitted" based on the value of the second unlock permission flag F73, and uses the shift lock mechanism to switch the shift lever from the locked state to the unlocked state.

[0182] When the start switch is turned on, the drivetrain control unit begins the predetermined start preparation. Start preparation includes processes such as initial checks required to start the drivetrain. When start preparation is complete, the drivetrain switches from the "ready to disconnect" state to the "ready to connect" state. That is, the drivetrain transitions to a state where it can be started. The drivetrain control unit starts the drivetrain based on the value of the start permission flag F74 being set to "permitted".

[0183] The instrument control unit, based on the value of the instrument notification flag F75 being set to "normal", switches the indicator light on the instrument panel that indicates the status of the steer-by-wire system from the off state, indicating the steer-by-wire system is stopped, to the on state, indicating the steer-by-wire system is operating normally.

[0184] In this way, with the four control circuits in the steering-by-wire system not activated, the steering wheel 11 and gear shift lever are unlocked and the start of the transmission system is permitted, thereby changing the vehicle to a state where the vehicle can drive.

[0185] When the vehicle network 71 receives information indicating that the control circuit is transitioning to a sleep state, or when communication between the control circuit and the instrument cluster control unit is interrupted, the instrument cluster control unit switches the state of the indicator lights. For example, the instrument cluster control unit switches the state of the indicator lights from a state indicating normal operation of the steer-by-wire system to a red on state (i.e., the red light is illuminated). After the control circuit completes the power latch-up control, the driver can visually identify any abnormalities in the steer-by-wire system.

[0186] Even if the timing mismatch of the start switch SW being turned on is detected by the four control circuits (41A, 42A, 51A, and 52A), the same event as an interruption in the power supply path to the specific control circuit, including the start switch SW, will occur. That is, the control circuit that detected the start switch SW being turned on earlier will send the values ​​of flags (F72, F73, F74, and F75) to the vehicle system 72 via the vehicle network 71. Therefore, even if the four control circuits in the steering-by-wire system are not activated, the vehicle may still transition to a drivable state.

[0187] Even when the configuration that assigns the function of setting the values ​​of the permission flags (F72, F73, and F74) to the control circuit for execution by the control circuit is adopted, the same event as the interruption that occurs in the power supply path for a specific control circuit, including the start switch SW, will occur.

[0188] For example, if only the second reaction control circuit 42A has the function of setting the values ​​of the first unlocking permission flag F72 and the second unlocking permission flag F73, it is assumed that the second reaction control circuit 42A recognizes the activation of the start switch SW before the other three control circuits. In this case, the second reaction control circuit 42A sends the values ​​of the first unlocking permission flag F72 and the second unlocking permission flag F73 to the vehicle system 72 via the vehicle network 71. Therefore, even if the four control circuits in the steering-by-wire system are not activated, the steering wheel 11 and the gear shift lever may still be unlocked. The same event occurs if an interruption occurs in the power supply path to a specific control circuit other than the second reaction control circuit 42A, which includes the start switch SW.

[0189] For example, if the second reaction control circuit 42A and the first steering control circuit 51A have the function of setting the value of the start permission flag F74, it is assumed that the second reaction control circuit 42A or the first steering control circuit 51A recognizes the activation of the start switch SW before the other three control circuits. In this case, the second reaction control circuit 42A or the first steering control circuit 51A sends the value of the start permission flag F74 to the vehicle system 72 via the vehicle network 71. Therefore, even if the four control circuits in the steering-by-wire system are not activated, the vehicle's drivetrain may still be activated. The same event occurs if an interruption occurs in the power supply path to a specific control circuit other than the second reaction control circuit 42A or the first steering control circuit 51A, which includes the start switch SW.

[0190] Second comparison example of state transitions in control circuits

[0191] The following is a second comparative example describing the state transitions of the control circuits (41A, 42A, 51A, and 52A).

[0192] like Figure 6 As shown in the timing diagram, a situation may arise where, during normal control operations before the start switch SW is immediately de-energized, a specific control circuit cannot recognize the activation of the start switch SW due to an interruption in the power supply path to that circuit. This power supply path includes the start switch SW. In this case, when the start switch SW is re-energized during the period of power latching control after it has been de-energized, a situation arises... Figure 5 The events shown in the first comparison example are the same events.

[0193] Therefore, even if the four control circuits in the steering-by-wire system are not activated, the vehicle may still transition to a drivable state. In configurations where the functions of setting the values ​​of permission flags (F72, F73, and F74) are assigned to the control circuits for execution by the control circuits, for example, the following problem exists: That is, even if the four control circuits in the steering-by-wire system are not activated, the steering wheel 11 and gearshift lever may be unlocked, or the drivetrain may be activated.

[0194] When an interruption in the power supply path to a specific control circuit is detected during normal control operations performed before the start switch SW is disconnected, the control circuit sets the value of the instrument notification flag F75 to "abnormal". Based on the "abnormal" value of the instrument notification flag F75, the instrument control unit switches the state of the indicator light to, for example, the yellow ON state (i.e., the yellow light is on).

[0195] During the power latching control process after the start switch SW is disconnected, the value of the instrument notification flag F75 remains set to "abnormal". Therefore, when the start switch SW is reconnected during the power latching control period and the value of the communication permission flag F71 is set to "permission", the instrument control unit switches the indicator light to the yellow on state based on the fact that the value of the instrument notification flag F75 is set to "abnormal".

[0196] During the period when the start switch SW is in the off state, the instrument control device will switch the indicator light to the off state (off state). For example, in Figure 5 The first comparison example shown and Figure 6 As shown in the second comparative example, when the four control circuits in the steering-by-wire system are not activated, it is preferable not to change the vehicle to a drivable state or to perform the process of changing the vehicle to a drivable state. This is because there is no reaction control and steering control based on the steering state of the steering wheel 11, and therefore it is impossible to change the vehicle's driving direction to the direction desired by the driver.

[0197] Therefore, in this embodiment, the reaction control device 40 and the steering control device 50 are configured as follows. When all five of the following conditions B1 to B5 are met, the control circuits (41A, 42A, 51A, and 52A) set the value of the communication permission flag F71 to "permitted". Conditions B1 to B5 constitute the communication permission conditions. The communication permission conditions are those conditions that enable the control circuits to determine whether to permit communication via the vehicle network 71.

[0198] Condition B1 is the condition where the value of the communication permission flag F71 is set to "prohibited". Condition B2 is the condition where the value of the vehicle power flag F76 is set to "on". Condition B3 is the condition where the source voltage is greater than the lower limit of the operating voltage range.

[0199] Condition B4 is the condition where the source voltage is less than the upper limit of the operating voltage range. Condition B5 is the condition that conditions B1 to B4 are continuously satisfied for a set period of time or longer. The vehicle power-on indicator F76 indicates whether all control circuits have recognized the activation of the start switch SW. The control circuits... Figure 3 The first mutual confirmation MC1, the second mutual confirmation MC2, the third mutual confirmation MC3, and the fourth mutual confirmation MC4 mutually confirm whether they have recognized the start switch SW as closed, i.e., whether they have recognized the vehicle's power. When it is determined that at least one of the control circuits has not recognized the start switch SW as closed, the control circuit sets the value of the vehicle power indicator F76 to "disconnected". When it is determined that all control circuits have recognized the start switch SW as closed, the control circuit sets the value of the vehicle power indicator F76 to "connected".

[0200] Conditions B3 and B4 are used to determine whether the source voltage identified by the control device is within the operating voltage range. Condition B5 is set, for example, to prevent the value of the communication permission flag F71 from being incorrectly set to "permitted" when conditions B1 to B4 are instantaneously met.

[0201] Therefore, once it is determined that all four control circuits have recognized the activation of the start switch SW, each control circuit can communicate via the vehicle network 71.

[0202] The first mode of state transition of the control circuit

[0203] The first mode of state transition of the control circuit (41A, 42A, 51A and 52A) according to this embodiment will now be described.

[0204] Here, it is assumed that during the execution of power latching control, an interruption occurs in the power supply path to the specific control circuit during the period from the time the start switch SW is turned off to the time the start switch SW is turned on again. This power supply path includes the start switch SW. Therefore, the source voltage is not supplied to the specific control circuit via the start switch SW. Consequently, the specific control circuit cannot recognize the turn on of the start switch SW. The specific control circuit will not activate.

[0205] like Figure 7 As shown in the timing diagram, when the start switch SW is disconnected under normal control conditions (time T11), the control circuit performs power latching control. When the start switch SW is disconnected, the source voltage level switches from "Hi" to "Lo". Therefore, when the start switch SW is disconnected, the control circuit switches the value of the vehicle power-on flag F76 from "On" to "Off". The control circuit also switches the value of the communication permission flag F71 from "Permission" to "Disable".

[0206] During the execution of power latching control, the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, the start permission flag F74, and the instrument notification flag F75 are maintained at the same values ​​set in the normal control state before the start switch SW is opened. That is, the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, and the start permission flag F74 remain "permitted," while the value of the instrument notification flag F75 remains "normal."

[0207] When the start switch SW is turned on during power latching control (time T12), source voltage is supplied to three of the four control circuits (41A, 42A, 51A, and 52A) except for the specific control circuit via the power supply path including the start switch SW. Since the power supply to the specific control circuit via the start switch SW is cut off, the specific control circuit cannot recognize the turn on of the start switch SW. Therefore, a situation will not occur where all four control circuits (41A, 42A, 51A, and 52A) have recognized the turn on of the start switch SW.

[0208] Therefore, even if the source voltage level actually switches from "Lo" to "Hi" due to the activation of the start switch SW during the execution of power latch control, the control circuit still keeps the value of the vehicle power-on flag F76 "off". Since the above-mentioned communication activation determination conditions, namely conditions B2 and B5, are not met, the control circuit keeps the value of the communication permission flag F71 "prohibited".

[0209] Since communication via the vehicle network 71 is not permitted, the three control circuits other than the specific control circuit will not send the values ​​of the flags (F72, F73, F74 and F75) to the vehicle system 72 via the vehicle network 71.

[0210] Therefore, the steering lock control device will not initiate the process of unlocking the steering wheel 11. The steering lock control device keeps the steering wheel 11 in the locked state. The shift lock control device will not initiate the process of unlocking the shift lever. The shift lock control device keeps the shift lever in the locked state. The drivetrain control device will not initiate the process of activating the drivetrain. The drivetrain control device keeps the drivetrain in the "ready to disengage" state, that is, the operation of the drivetrain has stopped.

[0211] Therefore, if the four control circuits (41A, 42A, 51A and 52A) in the online steering system fail to activate, the vehicle will not transition to a drivable state.

[0212] When the ignition switch SW is turned on, the instrument cluster control switches the indicator light from the off state to, for example, the red on state. This is because, even when the ignition switch SW is on, the instrument cluster control cannot communicate with the control circuitry. The driver can immediately visually identify any abnormalities in the steer-by-wire system without waiting for the power latch-up control executed by the control circuitry to complete.

[0213] This also applies to situations where the timing of the four control circuits (41A, 42A, 51A, and 52A) recognizing the activation of the start switch SW is mismatched. In other words, the control circuit that has already recognized the activation of the start switch SW earlier will not send the values ​​of the flags (F72, F73, F74, and F75) to the vehicle system 72 via the vehicle network 71. This is because communication via the vehicle network 71 is not permitted until all four control circuits have recognized the activation of the start switch SW. Therefore, in the case of the four control circuits in the steering-by-wire system not being activated, the vehicle will not transition to a drivable state.

[0214] This also applies when the function of setting the values ​​of the permission flags (F72, F73, and F74) is assigned to the control circuit for execution by the control circuit. For example, if only the second reaction control circuit 42A has the function of setting the values ​​of the first unlock permission flag F72 and the second unlock permission flag F73, assume that the second reaction control circuit 42A recognizes the activation of the start switch SW before the other three control circuits. In this case, the second reaction control circuit 42A will not send the values ​​of the first unlock permission flag F72 and the second unlock permission flag F73 to the vehicle system 72 via the vehicle network 71. Therefore, if the four control circuits in the steering-by-wire system are not activated, the steering wheel 11 and the gear shift lever will not be unlocked. Furthermore, this also applies when an interruption occurs in the power supply path to a specific control circuit other than the second reaction control circuit 42A. This power supply path includes the start switch SW.

[0215] For example, if the second reaction control circuit 42A and the first steering control circuit 51A have the function of setting the value of the start permission flag F74, assume that the second reaction control circuit 42A or the first steering control circuit 51A recognizes the activation of the start switch SW before the other three control circuits. In this case, the second reaction control circuit 42A or the first steering control circuit 51A will not send the value of the start permission flag F74 to the vehicle system 72 via the vehicle network 71. Therefore, if the four control circuits in the steering-by-wire system are not activated, the vehicle's drivetrain will not start. Furthermore, this also applies to situations where an interruption occurs in the power supply path to a specific control circuit other than the second reaction control circuit 42A or the first steering control circuit 51A. The power supply path includes the power supply path to the start switch SW.

[0216] Second mode of state transition of control circuit

[0217] The second mode of state transition of the control circuit (41A, 42A, 51A and 52A) according to this embodiment will now be described.

[0218] like Figure 8As shown in the timing diagram, a situation may arise where, during normal control operations before the start switch SW is immediately de-energized, the specific control circuit cannot recognize the start switch SW being activated due to an interruption in the power supply path to the specific control circuit. The power supply path includes the start switch SW. In this case, when the start switch SW is re-energized during the period of power latching control after it has been de-energized, the control circuit executes... Figure 7 The processing is the same as in the first mode shown.

[0219] Therefore, if the four control circuits in the steering-by-wire system are not activated, the vehicle will not transition to a drivable state. This also applies when the function of setting the values ​​of the permission flags (F72, F73, and F74) is assigned to the control circuits for execution by the control circuits. In other words, if the control circuits in the steering-by-wire system are not activated, the steering wheel 11 and gearshift lever will not be unlocked, and the drivetrain will not be activated.

[0220] Advantages of the third implementation method

[0221] Therefore, the following advantages can be achieved in the third embodiment. (3-1) When the start switch SW is turned on, each of the four control circuits (41A, 42A, 51A, and 52A) performs a start-up (i.e., starts the start-up process) after all control circuits have recognized the turn on of the start switch SW. When the start switch SW is turned on, communication via the vehicle network 71 is not allowed until all four control circuits have recognized the turn on of the start switch SW. Therefore, in the case where there is a control circuit that has not recognized the turn on of the start switch SW, the other control circuits that have recognized the turn on of the start switch SW cannot send the values ​​of the flags (F72, F73, F74, and F75) to the vehicle system 72. Therefore, when the control circuit in the steering-by-wire system is not activated, it is possible to prevent the vehicle from changing to a state where the vehicle can be driven, or to prevent the execution of the process that would change the vehicle to a state where the vehicle can be driven.

[0222] (3-2) When the start switch SW is turned on and the instrument control unit cannot communicate with the control circuit, the instrument control unit switches the indicator light from the off state to the red on state. The red on state indicates that an abnormality has occurred in the steer-by-wire system. Therefore, the driver can immediately visually identify the abnormality in the steer-by-wire system without waiting for the power latch-up control in the control circuit to complete.

[0223] Fourth Implementation Method

[0224] The following describes a fourth embodiment of a control device for a vehicle implemented with a steer-by-wire system. This embodiment essentially has the same characteristics as... Figures 1 to 3The configuration is the same as in the first embodiment shown. Elements that are the same as in the first embodiment will be indicated by the same reference numerals, and their detailed descriptions will be omitted.

[0225] The difference between this embodiment and the third embodiment lies in the processing performed by the control circuits (41A, 42A, 51A, and 52A) when the start switch SW is off. The control circuits initialize the values ​​of the flags sent to the vehicle system 72 when all three conditions C1 to C3 are met. The flags sent to the vehicle system 72 include a first unlock permission flag F72, a second unlock permission flag F73, a start permission flag F74, and an instrument notification flag F75.

[0226] Condition C1 is the condition where the value of the stop control flag F77 is set to "stop". Condition C2 is the condition where the value of the vehicle power-off flag F78 is set to "disconnect". Condition C3 is the condition where the value of the communication permission flag F71 is set to "prohibit".

[0227] The control stop flag F77 indicates whether the control circuit has stopped the reaction control or steering control. When the reaction control or steering control has not stopped, the control circuit sets the value of the control stop flag F77 to "not stopped". When the reaction control or steering control has stopped, the control circuit sets the value of the control stop flag F77 to "stopped".

[0228] The vehicle power failure indicator F78 indicates whether all control circuits have detected the ignition switch SW being disconnected. The control circuits then... Figure 3 The first mutual confirmation MC1, the second mutual confirmation MC2, the third mutual confirmation MC3, and the fourth mutual confirmation MC4 shown mutually confirm whether they have detected the start switch SW being open, i.e., whether they have detected the vehicle's power being cut off. When it is determined that at least one of the control circuits has not detected the start switch SW being open, the control circuit sets the value of the vehicle power-off flag F78 to "on". When it is determined that all control circuits have detected the start switch SW being open, the control circuit sets the value of the vehicle power-off flag F78 to "off".

[0229] The communication permission flag F71 indicates whether communication via the vehicle network 71 is permitted. When all five conditions B1 to B5 are met, the control circuit sets the value of the communication permission flag F71 to "permitted". When the start switch SW is off, the control circuit sets the value of the communication permission flag F71 to "prohibited".

[0230] As an initialization process, the control circuit sets the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, and the start permission flag F74 to "disable". As an initialization process, the control circuit switches the value of the instrument notification flag F75 to a value corresponding to the current state of the steer-by-wire system.

[0231] The first mode of state transition of the control circuit

[0232] The first mode of state transition of the control circuit (41A, 42A, 51A and 52A) according to this embodiment will now be described.

[0233] Here, it is assumed that during the execution of power latching control, an interruption occurs in the power supply path to the specific control circuit during the period from the time the start switch SW is turned off to the time the start switch SW is turned on again. This power supply path includes the start switch SW. Therefore, the source voltage is not supplied to the specific control circuit via the start switch SW. Consequently, the specific control circuit cannot recognize the turn on of the start switch SW. The specific control circuit does not activate.

[0234] like Figure 9 As shown in the timing diagram, when the start switch SW is disconnected under normal control conditions (time T11), the control circuit performs power latching control. When the start switch SW is disconnected, the source voltage level switches from "Hi" to "Lo". Therefore, the control circuit stops the reaction control or steering control and switches the value of the control stop flag F77 from "not stopped" to "stopped". The control circuit switches the value of the vehicle power-off flag F78 from "on" to "off". The control circuit switches the value of the communication permission flag F71 from "permitted" to "prohibited".

[0235] When all three conditions C1 to C3 are met, the control circuit initializes the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, the start permission flag F74, and the instrument notification flag F75. Specifically, the control circuit switches the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, and the start permission flag F74 from "permitted" to "prohibited." The control circuit then switches the value of the instrument notification flag F75 to the value corresponding to the current state of the steering-by-wire system. Here, because an interruption occurs in the power supply path to the specific control circuit, the value of the instrument notification flag F75 is set to "abnormal." Alternatively, the value of the instrument notification flag F75 can be set to a more specific value, such as "yellow light request," instead of "abnormal."

[0236] When the start switch SW is turned on again during the period of power latching control after the start switch SW has been turned off (time T12), the source voltage is not supplied to the specific control circuit via the power supply path including the start switch SW. Therefore, the specific control circuit cannot recognize the turn on of the start switch SW. The specific control circuit does not start.

[0237] Source voltage is supplied to three control circuits, excluding the specific control circuit, via a power supply path including the start switch SW. When the supplied source voltage reaches a value within the operating voltage range due to the activation of the start switch SW, the three control circuits, excluding the specific control circuit, set the value of the communication permission flag F71 to "permitted". Therefore, the three control circuits, excluding the specific control circuit, can perform communication via the vehicle network 71.

[0238] When the value of the communication permission flag F71 is switched from "prohibited" to "permitted", three control circuits other than the specific control circuit send the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, the start permission flag F74 and the instrument notification flag F75 to the vehicle system 72 via the vehicle network 71.

[0239] However, the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, and the start permission flag F74 have been set to "disabled" through initialization. Therefore, the steering lock control device will not initiate the process of unlocking the steering wheel 11. The steering lock control device keeps the steering wheel 11 in the locked state. The shift lock control device will not initiate the process of unlocking the shift lever. The shift lock control device keeps the shift lever in the locked state. The drivetrain control device will not initiate the process of starting the drivetrain. The drivetrain control device keeps the drivetrain in the "ready to disengage" state, that is, the operation of the drivetrain has stopped.

[0240] Therefore, if the four control circuits (41A, 42A, 51A and 52A) in the online steering system fail to activate, the vehicle will not transition to a drivable state.

[0241] When the instrument cluster indicator F75 is set to "abnormal," the instrument cluster control switches the indicator light from off to yellow on. The driver can immediately visually identify the abnormality in the steer-by-wire system without waiting for the power latch-up control executed by the control circuitry to complete.

[0242] This also applies to situations where the timing of the four control circuits (41A, 42A, 51A, and 52A) recognizing the activation of the start switch SW is mismatched. In other words, the following problem exists: the control circuit that recognizes the activation of the start switch SW earlier may send the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, the start permission flag F74, and the instrument notification flag F75 to the vehicle system 72 via the vehicle network 71. However, the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, and the start permission flag F74 have already been initialized to "disabled". Therefore, if the four control circuits in the steering-by-wire system are not activated, the vehicle will not transition to a drivable state.

[0243] This also applies when the function of setting the values ​​of the permission flags (F72, F73, and F74) is assigned to the control circuit for execution by the control circuit. For example, if only the second reaction control circuit 42A has the function of setting the values ​​of the first unlock permission flag F72 and the second unlock permission flag F73, suppose the second reaction control circuit 42A recognizes the activation of the start switch SW before the other three control circuits. In such a case, the following problem exists: the second reaction control circuit 42A may send the values ​​of the first unlock permission flag F72 and the second unlock permission flag F73 to the vehicle system 72 via the vehicle network 71. However, the values ​​of the first unlock permission flag F72 and the second unlock permission flag F73 have already been initialized to "disabled". Therefore, if the four control circuits in the steering-by-wire system are not activated, the steering wheel 11 and the gear shift lever will not be unlocked. Furthermore, this also applies when an interruption occurs in the power supply path to a specific control circuit other than the second reaction control circuit 42A. The power supply path is the power supply path that includes the start switch SW.

[0244] For example, if the second reaction control circuit 42A and the first steering control circuit 51A have the function of setting the value of the start permission flag F74, suppose the second reaction control circuit 42A or the first steering control circuit 51A recognizes the activation of the start switch SW before the other three control circuits. In such a case, the following problem exists: the second reaction control circuit 42A or the first steering control circuit 51A may send the value of the start permission flag F74 to the vehicle system 72 via the vehicle network 71. However, the value of the start permission flag F74 has already been initialized to "disabled". Therefore, if the four control circuits in the steering-by-wire system are not activated, the vehicle's drivetrain will not start. Furthermore, this also applies to situations where an interruption occurs in the power supply path to a specific control circuit other than the second reaction control circuit 42A or the first steering control circuit 51A. The power supply path includes the power supply path to the start switch SW.

[0245] Second mode of state transition of control circuit

[0246] The second mode of state transition of the control circuit (41A, 42A, 51A and 52A) according to this embodiment will now be described.

[0247] like Figure 10 As shown in the timing diagram, during normal control operations prior to the start switch SW being open, the power supply to a specific control circuit may be interrupted due to a disruption in the power supply path to that circuit. The power supply path includes the start switch SW. When the start switch SW is open in this state and all three conditions C1 to C3 are met, the control circuit initializes the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, the start permission flag F74, and the instrument notification flag F75.

[0248] In other words, the control circuit switches the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, and the start permission flag F74 from "permitted" to "prohibited". The control circuit also switches the value of the instrument notification flag F75 to the value corresponding to the current state of the steer-by-wire system. Here, because an interruption occurs in the power supply path to the specific control circuit, the value of the instrument notification flag F75 is set to "abnormal".

[0249] If the start switch SW is turned back on during the period of power latching control after the start switch SW has been turned off, the control circuit will execute the same... Figure 9 The processing is the same as in the first mode shown. That is, when the value of the communication permission flag F71 switches from "prohibited" to "permitted", three control circuits other than the specific control circuit send the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, the start permission flag F74 and the instrument notification flag F75 to the vehicle system 72 via the vehicle network 71.

[0250] However, the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, and the start permission flag F74 have been initialized to "prohibited". Therefore, in the case that the four control circuits in the steering-by-wire system are not activated, the vehicle will not transition to a drivable state. This also applies when the function of setting the values ​​of the permission flags (F72, F73, and F74) is assigned to the control circuits for execution by the control circuits. In other words, in the steering-by-wire system, when the control circuits are not activated, the steering wheel 11 and the gear shift lever will not be unlocked, and the drivetrain will not be activated.

[0251] Advantages of the fourth implementation method

[0252] Therefore, the following advantages can be achieved in the fourth embodiment. (4-1) When the start switch SW is off, the control circuits (41A, 42A, 51A and 52A) initialize the values ​​of the first unlock permission flag F72, the second unlock permission flag F73 and the start permission flag F74. That is, the control device sets the values ​​of the first unlock permission flag F72, the second unlock permission flag F73 and the start permission flag F74 to "prohibited".

[0253] Here, if the start switch SW is turned on again during the period of power latching control after the start switch SW has been turned off, and there is a control circuit that has not yet recognized the turn of the start switch SW, the control circuit will not activate in the steering system by wire. However, other control circuits that have recognized the turn of the start switch SW may send the values ​​of the permission flags (F72, F73, and F74) to the vehicle system 72.

[0254] At this time, since the values ​​of the permission flags (F72, F73, and F74) have been set to "prohibited," the steering wheel 11 and gear shift lever are not unlocked, and the transmission system is not activated. Therefore, when the control circuit of the drive-by-wire system is not activated, it is possible to prevent the vehicle from transitioning to a drivable state, or to prevent the execution of processes that would transition the vehicle to a drivable state.

[0255] (4-2) When the start switch SW is open, the control circuits (41A, 42A, 51A, and 52A) initialize the value of the instrument notification flag F75. That is, the control circuits switch the value of the instrument notification flag F75 to a value corresponding to the current state of the steer-by-wire system. For example, if an interruption in the power supply path to a specific control circuit is detected at the time the start switch SW is open, the control circuit sets the value of the instrument notification flag F75 to "abnormal". If the start switch SW is re-engaged during the period of power latching control after the start switch SW is open, the control circuit that detects the re-engagement of the start switch SW sends the value of the instrument notification flag F75 to the vehicle system 72. When the value of the instrument notification flag F75 has been set to "abnormal", the instrument control unit switches the indicator light from the off state to the on state indicating an abnormality in the steer-by-wire system. The on state indicating an abnormality is, for example, the yellow light on state. Therefore, the driver can immediately visually identify the abnormality of the steer-by-wire system without waiting for the power latching control executed by the control circuit to complete.

[0256] Fifth Implementation Method

[0257] The following describes a fifth embodiment of a control device for a vehicle implemented with a steer-by-wire system. This embodiment essentially has the same characteristics as... Figures 1 to 3The configuration is the same as in the first embodiment shown. Elements that are the same as in the first embodiment will be indicated by the same reference numerals, and their detailed descriptions will be omitted.

[0258] The difference between this embodiment and the third embodiment lies in the processing performed by the control circuits (41A, 42A, 51A, and 52A) when the start switch SW is turned on. When the start switch SW is turned on, the control circuits set the value of the start status flag F79. The start status flag F79 indicates whether all control circuits have recognized the turn on of the start switch SW. The control circuits... Figure 3 The first mutual confirmation MC1, the second mutual confirmation MC2, the third mutual confirmation MC3, and the fourth mutual confirmation MC4 shown mutually confirm whether they have recognized the activation of the start switch SW, i.e., whether they have recognized the vehicle's power supply. When it is determined that at least one of the control circuits has not recognized the activation of the start switch SW, the control circuit sets the value of the start status flag F79 to "not start". When the value of the start status flag F79 is set to "not start", this means that the control circuit in the drive-by-wire system is not activated. When it is determined that all control circuits have recognized the activation of the start switch SW, the control circuit sets the value of the start status flag F79 to "start". When the value of the start status flag F79 is set to "start", this means that the control circuit in the drive-by-wire system can be activated.

[0259] The first mode of state transition of the control circuits (41A, 42A, 51A, and 52A) according to this embodiment will now be described. Here, it is assumed that during the execution of power latching control, an interruption occurs in the power supply path to the specific control circuit during the period from the time the start switch SW is turned off to the time the start switch SW is turned on again. This power supply path includes the start switch SW. Therefore, the source voltage is not supplied to the specific control circuit via the start switch SW. Consequently, the specific control circuit cannot recognize the turn-on of the start switch SW. The specific control circuit will not start.

[0260] like Figure 11 As shown in the timing diagram, when the start switch SW is disconnected under normal control conditions (time T11), the control circuit performs power latching control. When the start switch SW is disconnected, the source voltage level switches from "Hi" to "Lo". When the source voltage level switches from "Hi" to "Lo", the control circuit switches the value of the communication permission flag F71 from "Permission" to "Disable".

[0261] During the execution of power latching control, the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, the start permission flag F74, and the instrument notification flag F75 are maintained at the same values ​​set during normal control before the start switch SW is opened. That is, the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, and the start permission flag F74 are maintained at "permission". The value of the instrument notification flag F75 is maintained at "normal". The value of the start status flag F79 is maintained at "start".

[0262] When the start switch SW is turned on again during the period of power latching control after the start switch SW has been turned off (at time T12), no source voltage is supplied to the specific control circuit via the power supply path including the start switch SW. Therefore, the specific control circuit cannot recognize the turn on of the start switch SW. Consequently, the specific control circuit will not start.

[0263] Source voltage is supplied to three control circuits other than the specific control circuit via a power supply path including the start switch SW. Here, since the specific control circuit cannot recognize the start switch SW being turned on, there will not be a situation where all control circuits recognize the start switch SW being turned on. Therefore, the three control circuits other than the specific control circuit set the value of the start status flag F79 to "not start".

[0264] When the supply voltage reaches a value within the operating voltage range due to the activation of the start switch SW, the three control circuits, excluding the specific control circuit, set the value of the communication permission flag F71 to "permitted". Therefore, the three control circuits, excluding the specific control circuit, can perform communication via the vehicle network 71.

[0265] When the value of the communication permission flag F71 switches from "prohibited" to "permitted", three control circuits, excluding the specific control circuit, send the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, the start permission flag F74, the instrument notification flag F75, and the start status flag F79 to the vehicle system 72 via the vehicle network 71. The process of sending the value of the start status flag F79, which is set to "not start", to the vehicle system 72 is a process for requesting the vehicle system 72 to ignore the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, and the start permission flag F74.

[0266] Therefore, when the value of the start status flag F79 is set to "not start", the vehicle system 72 ignores the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, and the start permission flag F74. That is, even if the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, and the start permission flag F74 are set to "permitted", the vehicle system 72 will not operate.

[0267] In other words, the steering lock control device does not perform the process of unlocking the steering wheel 11. Therefore, the steering wheel 11 remains in the locked state. The shift lock control device does not perform the process of unlocking the shift lever. Therefore, the shift lever remains in the locked state. The drivetrain control device does not perform the process of starting the drivetrain. Therefore, the drivetrain remains in the stopped state.

[0268] Therefore, if the four control circuits (41A, 42A, 51A and 52A) in the online steering system fail to activate, the vehicle will not transition to a drivable state.

[0269] When the ignition switch SW is turned on and the ignition status indicator F79 is set to "not started," the instrument cluster control will switch the indicator light from the off state to, for example, the red on state. This is because when the ignition status indicator F79 is set to "not started," it indicates that the control circuitry of the steer-by-wire system cannot be activated. The driver can immediately visually identify the malfunction of the steer-by-wire system without waiting for the power latch-up control executed by the control circuitry to complete.

[0270] This also applies to situations where the timing of the four control circuits (41A, 42A, 51A, and 52A) recognizing the activation of the start switch SW is mismatched. In other words, the following problem exists: a control circuit that has recognized the activation of the start switch SW earlier may send the values ​​of flags (F72, F73, F74, F75, and F79) to the vehicle system 72 via the vehicle network 71. However, when a control circuit has not recognized the activation of the start switch SW, the value of the start status flag F79 is set to "not start". Therefore, even if the permission flags (F72, F73, and F74) set to "permitted" are sent to the vehicle system 72, the vehicle system 72 will not operate. Therefore, if the four control circuits in the steering-by-wire system are not activated, the vehicle will not transition to a drivable state.

[0271] This also applies when the function of setting the values ​​of the permission flags (F72, F73, and F74) is assigned to the control circuit for execution by the control circuit. For example, if only the second reaction control circuit 42A has the function of setting the values ​​of the first unlock permission flag F72 and the second unlock permission flag F73, suppose the second reaction control circuit 42A recognizes the activation of the start switch SW before the other three control circuits. In such a case, the following problem exists: the second reaction control circuit 42A may send the values ​​of the first unlock permission flag F72 and the second unlock permission flag F73 to the vehicle system 72 via the vehicle network 71.

[0272] However, when a control circuit fails to recognize the activation of the start switch SW, the start status flag F79 is set to "not start". Therefore, even if the value of the first unlock permission flag F72, set to "permitted", is sent to the vehicle system 72, the steering lock control device does not perform the process of unlocking the steering wheel 11. Even if the value of the second unlock permission flag F73, set to "permitted", is sent to the vehicle system 72, the shift lock control device does not perform the process of unlocking the shift lever. Therefore, when none of the four control circuits in the steering-by-wire system are activated, the steering wheel 11 is not unlocked and the shift lever is not unlocked. Furthermore, this also applies to situations where an interruption occurs in the power supply path to a specific control circuit other than the second reaction control circuit 42A. This power supply path includes the start switch SW.

[0273] For example, if the second reaction control circuit 42A and the first steering control circuit 51A have the function of setting the value of the start permission flag F74, assume that the second reaction control circuit 42A or the first steering control circuit 51A recognizes the activation of the start switch SW before the other three control circuits. In such a case, the following problem exists: the second reaction control circuit 42A or the first steering control circuit 51A may send the value of the start permission flag F74 to the vehicle system 72 via the vehicle network 71.

[0274] However, when a control circuit fails to recognize the activation of the start switch SW, the start status flag F79 is set to "not start". Therefore, even if the start permission flag F74, set to "permitted", is sent to the vehicle system 72, the drivetrain control unit does not perform any operation of the drivetrain. Thus, the drivetrain will not start if the four control circuits in the steering-by-wire system are not activated. Furthermore, this also applies to situations where an interruption occurs in the power supply path to a specific control circuit other than the second reaction control circuit 42A or the first steering control circuit 51A. This power supply path includes the start switch SW.

[0275] Second mode of state transition of control circuit

[0276] The second mode of state transition of the control circuit (41A, 42A, 51A and 52A) according to this embodiment will now be described.

[0277] like Figure 12 As shown in the timing diagram, a situation may arise where, during normal control operations prior to the start switch SW being opened, a specific control circuit cannot recognize the start switch SW being turned on due to an interruption in the power supply path to that circuit. The power supply path includes the start switch SW. In this case, when the start switch is opened, the control circuit performs... Figure 11 The process is the same as in the first mode shown. That is, if at least one of the control circuits does not detect the start switch SW being open, the control circuit sets the value of the start status flag F79 to "not start".

[0278] Therefore, when the four control circuits in the steering-by-wire system are not activated, the vehicle will not transition to a drivable state. This also applies when the function of setting the values ​​of the permission flags (F72, F73, and F74) is assigned to the control circuits for execution by the control circuits. In other words, when the control circuits in the steering-by-wire system are not activated, the steering wheel 11 and gearshift lever will not be unlocked, and the powertrain will not be activated.

[0279] Advantages of the fifth implementation method

[0280] Therefore, the following advantages can be achieved in the fifth embodiment. When the start switch SW is turned on and there is at least one control circuit that does not recognize the turn on of the start switch SW, the control circuits (41A, 42A, 51A, and 52A) set the value of the start status flag F79 to "not start". When the value of the start status flag F79 is set to "not start", the vehicle system 72 ignores the values ​​of the first unlock permission flag F72, the second unlock permission flag F73, and the start permission flag F74. Therefore, it is possible to prevent the vehicle from changing to a drivable state when the control circuit in the steering-by-wire system is not activated, or to avoid performing the process of changing the vehicle to a drivable state.

[0281] (5-2) When the start switch SW is turned on and the start status indicator F79 is set to "not start", the instrument control unit switches the indicator light from the off state to the red light on state. This is because when the start status indicator F79 is set to "not start", it indicates that the control circuit of the steer-by-wire system cannot be started. Therefore, the driver can immediately visually identify the abnormality in the steer-by-wire system without waiting for the power latch-up control in the control circuit to complete.

[0282] Other implementation methods

[0283] The aforementioned embodiments can be modified as follows. In the first embodiment and the third to fifth embodiments, the initial sequence executed by the control circuits (41A, 42A, 51A and 52A) at startup may include midpoint learning processing and steering angle synchronization processing.

[0284] The midpoint learning process is the process of learning the steering wheel 11's neutral steering position. The steering system 10 includes a stop mechanism configured to limit the rotation of the steering wheel 11 to provide a limit on the steering angle of the steering wheel 11. The stop mechanism limits the steering range of the steering wheel 11 to, for example, less than 360°. The reaction control device 40 controls the reaction motor 21 to operate the steering wheel 11 to a first operating end and then return it to a second operating end. Thereafter, the reaction control device 40 calculates the midpoint of the steering angle based on the rotation angle of the reaction motor 21 at the start and end points of the return operation of the steering wheel 11. The midpoint of the steering angle corresponds to the motor midpoint, which is the rotational position of the reaction motor 21 when the steering wheel 11 is in the neutral steering position. The reaction control device 40 stores the midpoint of the steering angle or the motor midpoint as the steering neutral steering position of the steering wheel 11 in a memory.

[0285] Here, when the information about the steering neutral position stored in the memory is lost, the reaction control device 40 learns the steering neutral position of the steering wheel 11. This time corresponds, for example, to the point when the vehicle is first powered on after the battery is newly attached to the vehicle. This is because when the battery is removed from the vehicle for replacement, the information about the steering neutral position stored in the memory of the reaction control device 40 is lost because no power is supplied to the reaction control device 40.

[0286] Depending on product specifications, the reaction control device 40 can perform midpoint learning processing when the vehicle is powered on, and can also perform midpoint learning processing when the reliability of information about the steering neutral position stored in the memory decreases.

[0287] Steering angle synchronization processing is the process of correcting the rotational position of the steering wheel 11. When the rotational position of the steering wheel 11 is different from the rotational position corresponding to the steering position of the steering wheel 15, the reaction control device 40 drives the reaction motor 21 so that the rotational position of the steering wheel 11 reaches the rotational position corresponding to the steering position of the steering wheel 15.

[0288] For example, when the vehicle is powered off, the reaction control device 40 stores the steering angle θs detected before the power was cut off as a reference steering angle. The reference steering angle is used to determine whether the steering wheel 11 rotates during the period when the vehicle is powered off. If the steering angle θs after the vehicle is powered on does not match the reference steering angle, the reaction control device 40 calculates the difference between the steering angle θs after the vehicle is powered on and the reference steering angle and controls the power supply to the reaction motor 21 so that the difference is canceled out.

[0289] The reaction control device 40 can calculate the difference between the steering angle θs after the vehicle is energized and the value obtained by multiplying the steering angle θw after the vehicle is energized by the reciprocal of the steering angle ratio, and control the power supply to the reaction motor 21 so that the difference is canceled out.

[0290] In the first embodiment, the reaction motor 21 and the steering 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 steering control device 50 may include only one of the first system circuit 51 and the second system circuit 52. Here, for example, when the reaction control device 40 includes only the first system circuit 41, the steering control device 50 may include only the first system circuit 51. The first reaction control circuit 41A sets the value of flag F11 based on the determination result regarding whether the start switch SW is turned on. The first steering control circuit 51A sets the value of flag F31 based on the determination result regarding whether the start switch SW is turned on. When both the values ​​of flag F11 and flag F31 are "1", the first reaction control circuit 41A and the first steering control circuit 51A determine that both have identified that the start switch SW is turned on. The first reaction control circuit 41A and the first steering control circuit 51A are activated in response to this determination. Therefore, even if the vehicle is energized during power latching control after the vehicle has been de-energized, the activation timing of the first reaction control circuit 41A and the first steering control circuit 51A can be matched, even if their timings for recognizing the vehicle's energization differ. This also applies to cases where the reaction control device 40 includes only the second system circuit 42 and the steering control device 50 includes only the second system circuit 52. Therefore, the drive of the reaction motor and the steering motor can be appropriately controlled. The first reaction control circuit 41A or the second reaction control circuit 42A is an example of a reaction control circuit. The first steering control circuit 51A or the second steering control circuit 52A is an example of a steering control circuit. This configuration can be applied to the third to fifth embodiments.

[0291] In the first embodiment, the control circuits (41A, 42A, 51A, and 52A) can determine whether all control circuits have recognized the vehicle's power supply by using the values ​​of mutual confirmation flags (F11, F21, F31, and F41). In this case, the first reaction control circuit 41A and the second steering control circuit 52A are configured to send and receive information via a communication line. This configuration can be applied to the third through fifth embodiments.

[0292] In the first embodiment, a specific control circuit in the control circuits (41A, 42A, 51A, and 52A) determines whether all control circuits have recognized the vehicle's power supply by verifying the values ​​of flags in other control circuits. The specific control circuit notifies the other control circuits of the determination result regarding whether all control circuits have recognized the vehicle's power supply. In this case, the first reaction control circuit 41A and the second steering control circuit 52A, or the second reaction control circuit 42A and the first steering control circuit 51A, are configured such that they can send and receive information via a communication line. This configuration can be applied to the third through fifth embodiments.

[0293] In the first embodiment, a vehicle control device is implemented in a steering system with wire steering. In the second embodiment, a vehicle control device is implemented in an electric power steering system, but it can also be implemented in a door mirror system, for example, that opens and closes together with a door lock. The vehicle control device can be implemented in all vehicle systems requiring synchronization of state transitions among multiple control circuits. The event used to trigger the synchronization of state transitions is not limited to the energization of the vehicle. In the third to fifth embodiments, similar to the first and second embodiments, the vehicle control device can be implemented in all vehicle systems requiring synchronization of state transitions among multiple control circuits.

Claims

1. A control device for a vehicle, characterized in that... include: Multiple control circuits are configured to activate in response to power-on of the vehicle to control the controlled object, and to perform power latching control in response to power-off of the vehicle to continue to be supplied with power for a predetermined period of time. Each of the plurality of control circuits is configured to: mutually confirm whether the vehicle has been powered on while the power latching control is being performed after the vehicle has been powered off, and execute the start-up after all control circuits have recognized the vehicle being powered on.

2. The control device according to claim 1, characterized in that: The plurality of control circuits are configured to set the value of the flag based on the recognition result regarding whether the vehicle is powered on; and Each of the plurality of control circuits is configured to determine, based on the value of the flag, whether all control circuits have recognized that the vehicle is powered on.

3. The control device according to claim 1 or 2, characterized in that: The controlled object includes the winding groups of two systems; The controlled object includes A reaction motor (21) generates a force towards the steering wheel (11). The applied steering reaction force, the steering wheel (11) is configured to disconnect the power transmission between the steering wheel (11) and the steering wheels, and Steering motor (31), the steering motor generates a steering force for turning the steering wheels; as well as The plurality of control circuits include A first reaction control circuit is configured to control the power supply to the winding group of a first system in the reaction motor (21). A second reaction control circuit is configured to control the power supply to the winding group of the second system in the reaction motor (21). A first steering control circuit, configured to control the supply of power to the winding group of a first system in the steering motor (31), and A second steering control circuit is configured to control the supply of power to the winding group of a second system in the steering motor (31).

4. The control device according to claim 3, characterized in that: The first reaction control circuit and the second reaction control circuit are configured to perform a first mutual confirmation to confirm whether the vehicle is energized; The first steering control circuit and the second steering control circuit are configured to perform a second mutual confirmation to confirm whether the vehicle is energized; The first reaction control circuit and the first steering control circuit are configured to perform a third mutual confirmation to verify whether the first and second mutual confirmations have been successful, and are configured to determine that the vehicle's power-on has been recognized by all control circuits when the first and second mutual confirmations have been successful; and The second reaction control circuit and the second steering control circuit are configured to perform a fourth mutual confirmation to verify whether the first mutual confirmation and the second mutual confirmation have been successful, and are configured to determine that the vehicle’s power has been recognized by all control circuits when the first mutual confirmation and the second mutual confirmation have been successful.

5. The control device according to claim 1 or 2, characterized in that: The controlled objects include a reaction motor (21) and a steering motor (31). The reaction motor (21) is the source of the steering operation reaction force applied to the steering wheel (11), which is configured such that the power transmission between the steering wheel (11) and the steering wheel is cut off. The steering motor (31) is the source of the steering force for turning the steering wheel. The plurality of control circuits include a reaction control circuit and a steering control circuit, the reaction control circuit being configured to control the reaction motor (21) and the steering control circuit being configured to control the steering motor (31); and The reaction control circuit and the steering control circuit are configured to mutually confirm whether the vehicle is powered on.

6. The control device according to claim 1 or 2, characterized in that: The controlled object includes an auxiliary motor (70) that generates an auxiliary force for assisting 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 and a second auxiliary control circuit, wherein the first auxiliary control circuit is configured to control the power supply to the winding group of the first system, and the second auxiliary control circuit is configured to control the power supply to the winding group of the second system. as well as The first auxiliary control circuit and the second auxiliary control circuit are configured to mutually confirm whether the vehicle is powered on.

7. The control device according to claim 1 or 2, characterized in that: The plurality of control circuits are configured to communicate with an onboard system (72), which performs processing to change the vehicle to a drivable state; and Each of the plurality of control circuits is configured to, when the vehicle is powered on while the power latching control is being performed after the vehicle is powered off, be allowed to communicate with the vehicle system (72) after all control circuits have detected that the vehicle is powered on.

8. A control device for a vehicle, characterized in that... include: Multiple control circuits are configured to activate in response to power-on of the vehicle to control the controlled object, and to perform power latching control in response to power-off of the vehicle to continue to be supplied with power for a predetermined period of time. Each of the plurality of control circuits is configured to, when the vehicle is powered on while the power latching control is being executed after the vehicle has been powered off, execute a start-up operation after all control circuits detect the power-on of the vehicle. The plurality of control circuits are configured to perform communication with the vehicle system (72), which performs processing to change the vehicle to a driving state, and the plurality of control circuits are configured to be allowed to communicate with the vehicle system (72) when the vehicle is powered on. The plurality of control circuits include information indicating whether the vehicle system (72) is permitted to perform the processing; and The plurality of control circuits are configured to: when the vehicle is powered off while control of the controlled object is being performed, as an initialization process for the information, change the content of the information from allowing the vehicle system (72) to perform the processing to disallowing the vehicle system (72) from performing the processing; and the plurality of control circuits are configured to transmit the information to the vehicle system (72) when the vehicle is powered on while the power latching control is being performed after the vehicle is powered off.

9. A control device for a vehicle, characterized in that... include: Multiple control circuits are configured to activate in response to power-on of the vehicle to control the controlled object, and to perform power latching control in response to power-off of the vehicle to continue to be supplied with power for a predetermined period of time. Each of the plurality of control circuits is configured to, when the vehicle is powered on while the power latching control is being executed after the vehicle has been powered off, execute a start-up operation after all control circuits detect the power-on of the vehicle. The plurality of control circuits are configured to perform communication with the vehicle system (72), which performs processing to change the vehicle to a driving state, and the plurality of control circuits are configured to be allowed to communicate with the vehicle system (72) when the vehicle is powered on. The plurality of control circuits include information indicating whether the vehicle system (72) is permitted to perform the processing; The plurality of control circuits are configured to: when the vehicle is powered off while control of the controlled object is being performed, maintain the content of the information set during the control of the controlled object, such that the content is maintained to allow the vehicle system (72) to perform the processing; and the plurality of control circuits are configured to transmit the information to the vehicle system (72) when the vehicle is powered on while the power latch control is being performed after the vehicle is powered off; and Each of the plurality of control circuits is configured to, when the vehicle is powered on while the power latching control is being performed after the vehicle is powered off, perform a process to request the vehicle system (72) to ignore the information if not all of the control circuits recognize that the vehicle is powered on.

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