Vehicle control system and vehicle control apparatus

Abstract

This vehicle control system includes: a vehicle device including an actuator; a drive unit that drives the actuator; and a control unit including a plurality of processors configured to acquire the operation states of the actuator and the drive unit, generate drive commands for controlling the drive unit according to input operation information, perform self-diagnosis, and output results of the self-diagnosis, and a command selection unit that selects, from among the drive commands generated by the plurality of processors, a drive command generated by any one processor having a normal result of the self-diagnosis and outputs the selected drive command to the drive unit.

Description

Vehicle control system and vehicle control device

[0001] The present invention relates to a vehicle control system and a vehicle control device for controlling on-vehicle equipment mounted on a vehicle such as an automobile, and particularly relates to a redundant vehicle control system and a redundant vehicle control device having a plurality of processors.

[0002] In vehicles such as automobiles, as a steering device that controls the traveling direction of the vehicle, a steering device that performs steering control by operating a steering mechanism provided in the vehicle using the driving force of a motor is generally used. Conventionally, in a steering device, a steering wheel operated by a driver is linked to a steering mechanism via a steering shaft. For example, even when a control device, a motor or the like included in the steering device fails, it is still possible to continue steering the vehicle by operating the steering wheel.

[0003] On the other hand, in recent years, a technology called steer-by-wire (SBW), which eliminates the mechanical connection between the steering wheel and the steering mechanism, has been put into practical use. In SBW, the operation amount of the steering wheel is transmitted as an electrical signal to a steering device that steers wheels, and the steering device controls the steering mechanism based on the steering amount. In SBW, since there is no mechanical connection between the steering wheel and the steering mechanism, there is a risk that the vehicle cannot be steered if the steering control device fails. Regarding such safety and reliability issues, for example, Patent Document 1 discloses an electric power steering device in which an actuator that operates a steering mechanism and a control device that controls the actuator are made redundant, and steering can be continued even if any one of the plurality of actuators or control devices fails.

[0004] International Publication No. WO 2023 / 281990

[0005] The electric power steering system described in Patent Document 1 includes first and second actuators connected in parallel to drive a steering mechanism, first and second control devices each having a processor (MCU) to control these two actuators, and a third control device capable of switching and transmitting the control output between the first and second actuators. As a result, if the processor of the first or second control device that normally controls the actuators fails, the third control device can take over the processing of the failed control device, thereby maintaining the capability of the steering control device and continuing steering control. However, for example, if the processors of any two of the three control devices fail, even if the pre-drivers and inverters of those two control devices are normal, only one of the two actuators can be controlled, resulting in a halving of the steering device's output and a decrease in steering capability.

[0006] Furthermore, since the third control unit only begins processing after a failure is detected in the other control units, there is a slight delay between the occurrence of a failure and the transition to control by the third control unit, which could potentially cause a temporary interruption of actuator control.

[0007] In view of the problems in the prior art described above, the object of the present invention is to enable the vehicle to continue steering without reducing the performance of the vehicle equipment by allowing control to be quickly taken over by another processor when one of the multiple processors fails.

[0008] In one preferred embodiment, the vehicle control system according to the present invention comprises: a vehicle device having an actuator; a drive unit that drives the actuator; a plurality of processors configured to acquire the operating state of the actuator and the drive unit, generate drive commands for controlling the drive unit according to input operation information, perform a self-diagnosis and output the results of the self-diagnosis; and a control unit comprising a command selection unit that selects a drive command generated by any one of the processors whose self-diagnosis results are normal from among the drive commands generated by the plurality of processors and outputs it to the drive unit.

[0009] Furthermore, from another perspective, in one preferred embodiment, the vehicle control device according to the present invention is a vehicle control device for controlling a drive unit that drives an actuator having a vehicle device, and comprises a plurality of processors configured to acquire the operating state of the actuator and the drive unit, generate drive commands for controlling the drive unit according to input operation information, perform a self-diagnosis and output the result of the self-diagnosis, and a command selection unit that selects a drive command generated by any one of the processors whose self-diagnosis result is normal from among the drive commands generated by the plurality of processors and outputs it to the drive unit.

[0010] According to the present invention, if any one of the multiple processors is in a healthy state, actuator control can be quickly continued, and control of the vehicle equipment can be continued without degrading its capabilities. Other problems solved by the present invention and novel features will become apparent from the description and drawings herein.

[0011] This is a schematic diagram showing the configuration of one embodiment of the steering system. This is a schematic block diagram showing the logical configuration of the steering control device. This is a schematic block diagram showing the logical configuration of the command selection unit. This is a flowchart for explaining the overview of the operation of the command selection unit. This is a flowchart outlining the processing performed by the MCU. This is a flowchart showing the control flow of the relays on the steering device side. This is a flowchart showing the control flow of the relays on the reaction force generating device side.

[0012] Hereinafter, representative embodiments of the present invention will be described with reference to the drawings. The embodiments and drawings described below are illustrative examples for explaining the present invention, and have been omitted or simplified as appropriate for clarity of explanation. Furthermore, please note that in order to facilitate understanding of the invention, the position, size, shape, and extent of each component shown in the drawings may not necessarily represent them precisely. In each drawing, parts having the same configuration and / or function are denoted by the same reference numeral. In addition, in the following description, unless particularly necessary, redundant explanations of parts having the same configuration and / or function will be omitted.

[0013] Figure 1 is a schematic diagram showing the configuration of one embodiment of a steering system as an example of a vehicle control system according to the present invention. The steering system of this embodiment is mounted on a vehicle such as an automobile (not shown) and used to steer the steering wheels (generally the front wheels) provided on that vehicle. As shown in Figure 1, the steering system of this embodiment is composed of a steering device 10 and a reaction force generating device 20 as vehicle equipment, and a steering control device 30 that controls these devices.

[0014] The steering system 10 is comprised of a motor 11, a reduction gear 12, a pinion shaft 13, a steering rod 14, and a steering angle detection device 15.

[0015] The motor 11 is a brushless type motor driven by U, V, and W three-phase AC power. In this embodiment, the motor 11 has two sets of U, V, and W three-phase windings, and windings supplied with the same phase power are connected in parallel to each other. A reduction gear 12 is connected to the output shaft of the motor 11, and the rotational output of the motor 11 is transmitted to the pinion shaft 13 via the reduction gear 12, thereby rotating the pinion shaft 13. The motor 11 is equipped with a rotation angle sensor 16 that detects the rotational position (rotation angle) of the rotor.

[0016] A pinion gear 17 is formed on the pinion shaft 13. The pinion gear 17 is configured to mesh with a rack gear 18 provided on the steering rod 14, and the rotational motion of the pinion shaft 13 is transmitted to the steering rod 14 via the pinion gear 17 and rack gear 18, causing the steering rod 14 to move linearly in its longitudinal direction (left-right direction in Figure 1). The steering rod 14 is connected to the wheels 40 at both ends via tie rods 50. The linear motion of the steering rod 14 is transmitted to the wheels 40 via the tie rods 50, causing the wheels 40 to steer.

[0017] The steering angle detection device 15 is, for example, installed on the pinion shaft 13, and detects the rotation angle of the pinion shaft 13 corresponding to the steering angle of the wheel 40 as the actual steering angle.

[0018] In this embodiment, a rack-and-pinion mechanism using a pinion gear 17 and a rack gear 18 is used to convert the rotational output of the motor 11 into linear motion of the steering rod 14. However, other mechanisms, such as a so-called ball screw mechanism, may be used instead of the rack-and-pinion mechanism.

[0019] The reaction force generating device 20 comprises a steering angle detection device 21 and a motor 22, and is mounted on a steering shaft 65 connected to a steering wheel 60 operated by the driver in the passenger compartment of a vehicle (not shown). The reaction force generating device 20 can generate a reaction torque that is a rotational force in the opposite direction to the rotational torque of the steering shaft 65 caused by the operation of the steering wheel 60, and apply it to the steering shaft 65.

[0020] The steering angle detection device 21 is attached to the steering shaft 65 and can detect the rotation angle of the steering shaft 65, which rotates in conjunction with the operation of the steering wheel, as the steering angle or steering amount. In other words, together with the steering wheel 60, the steering angle detection device 21 functions as an operation input device that receives operation input from the driver and inputs the steering angle information as operation information to the steering control device 30.

[0021] The motor 22 has an output shaft connected to the steering shaft 65 and generates a reaction torque that serves as a steering reaction force, which is applied to the steering shaft 65. In this embodiment, the motor 22 is a brushless type motor equipped with a U, V, and W three-phase winding set and driven by U, V, and W three-phase AC power. The motor 22, like the motor 11, is equipped with a rotation angle sensor 23 that detects the rotational position of the rotor.

[0022] The steering control device 30 controls the steering of the wheels 40 by controlling the motor 11 based on the actual steering angle detected by the steering angle detection device 15 and the steering angle of the steering wheel 60 detected by the steering angle detection device 21. The steering control device 30 also acquires a target value for the reaction torque to be applied to the steering shaft 65 based on the steering angle detected by the steering angle detection device 21 and information such as vehicle speed obtained via an in-vehicle network, such as a CAN (Controller Area Network), and controls the motor 22 to generate a steering reaction force.

[0023] The steering system of this embodiment can be configured as an SBW system in which the steering device 10 and the steering shaft 65 are mechanically separated. A clutch mechanism may be provided between the steering shaft 65 and the pinion shaft 13, for example, to mechanically connect the steering shaft 65 and the pinion shaft 13. With such a configuration, for example, if the steering device 10 fails, the steering shaft 65 and the pinion shaft 13 can be connected, allowing the wheels 40 to be steered using the steering force from operating the steering wheel, and thus enabling continued steering.

[0024] The reaction force generating device 20 and the steering control device 30 are connected by a cable (not shown), and information detected by the steering angle detection device 21 and the rotation angle sensor 23 is sent to the steering control device 30 via the cable, and the motor 22 is driven by the steering control device 30.

[0025] Figure 2 is a schematic block diagram showing the logical configuration of the steering control device 30.

[0026] The steering control device 30 converts DC power supplied from a power source such as a battery into U, V, and W three-phase AC power and supplies it to the actuator motors 11 and 22, thereby controlling the motors 11 and 22. The steering control device 30 includes an electronic control unit 31, a drive unit 32 that drives motor 11, and a drive unit 33 that drives motor 22.

[0027] The electronic control unit 31 includes three MCUs (microcontroller units) 200a, 200b, and 200c as processors for controlling the motor 11 and the motor 22. Hereafter, when it is not necessary to distinguish between these three MCUs 200a, 200b, and 200c individually, the alphabetical subscripts may be omitted and they will be referred to as MCU200. The same applies to the other components below. The electronic control unit 31 also includes command selection units 220 and 221 that select and output control signals output from the three MCUs 200.

[0028] The drive unit 32 includes inverters 210a and 210b that supply power to each of the two winding sets of the motor 11, pre-drivers 230a, 230b, and 230c for driving these inverters, and relays 240a, 240b, 240c, and 240d that selectively connect the outputs of the pre-drivers 230 to the inverter 210. Similarly, the drive unit 33 includes an inverter 211 that supplies power to the motor 22, pre-drivers 231a and 231b for driving the inverter 211, and relays 241a and 241b that selectively connect the outputs of the pre-drivers 231 to the inverter 211.

[0029] In this embodiment, the electronic control unit 31 and the drive unit 32, and the pre-driver 231 and relay 241 of the drive unit 33 are housed in a housing attached to the motor 11, and the inverter 211 is located on the reaction force generating device 20 side. The relay 241 and the inverter 211 are connected remotely by a cable. This configuration allows for miniaturization of the reaction force generating device 20 and secures space in the vehicle interior where the reaction force generating device is located. Alternatively, the electronic control unit 31 and the drive unit 33 may be housed in separate housings, with the drive unit 33 located on the reaction force generating device 20 side and connected by a cable. Alternatively, the drive unit 33 and the command selection unit 221 may be housed in the same housing and located on the reaction force generating device 20 side, with the MCU 200 and the command selection unit 221 connected by a cable.

[0030] Furthermore, with respect to the steering device 10, the pre-driver 230 and relay 240 of the drive unit 32 may be housed in the same housing as the electronic control unit 31, and the relay 240 and inverter 210 may be connected by a cable. Alternatively, the drive unit 32 and the electronic control unit 31 may be housed in separate housings and connected by a cable, or the drive unit 32 and the command selection unit 220 may be housed in a separate housing from the MCU 200, and the MCU 200 and the command selection unit 220 may be connected by a cable.

[0031] The MCU 200 is equipped with an arithmetic unit such as a CPU (Central Processing Unit), a storage device such as RAM or flash memory, and peripheral devices for inputting and outputting various signals to the MCU 200. The MCU 200 realizes various functions as a steering control device 30 by executing a program stored in the storage device with its arithmetic unit. The MCU 200 may be equipped with one or more arithmetic units. In addition to being implemented in software using a program, the functions of the steering control device 30 may also be implemented in hardware using FPGAs (Field-Programmable Gate Arrays) or ASICs (Application-Specific Integrated Circuits).

[0032] The MCU 200 is configured to generate and output a first PWM command as a drive command to be given to three redundant pre-drivers 230a, 230b, and 230c that drive the inverters 210a and 210b. The first PWM command output from the MCU 200 is input to the command selection unit 220. The MCU 200 also performs self-diagnosis during its operation, and if any malfunction is detected, it outputs a diagnostic signal indicating an error state to notify the command selection unit 220.

[0033] The command selection unit 220 refers to the diagnostic signals of each MCU 200 and selects a first PWM command to be given to the pre-driver 230 from among the first PWM commands output from the three MCUs 200, and outputs the selected first PWM command to the three pre-drivers 230. The command selection unit 220 also outputs a selection signal to the MCU 200 that output the selected first PWM command to indicate that it has been selected.

[0034] The pre-driver 230 receives the first PWM command selected by the command selection unit 220 and generates and outputs a PWM signal to drive the inverter 210. The outputs of the three pre-drivers 230 are selectively input to one or both of the inverters 210a by four relays 240a, 240b, 240c, and 240d.

[0035] Each inverter 210 converts the DC power supplied from a battery (not shown) into U, V, and W three-phase AC power and supplies it to the motor 11. The AC power output from inverter 210a is supplied to one of the two winding sets provided by the motor 11, and the AC power output from inverter 210b is supplied to the other winding set. As a result, even if a failure occurs in one inverter or winding set, the motor 11 can still be operated by the other inverter or winding set, and the steering function can be maintained.

[0036] The inverter 210 is equipped with a current sensor that detects the current supplied to the motor 11. The motor current information, which is the detection result, is sent to each MCU 200 via the signal line 250 through the relay 240 and pre-driver 230. In addition, the rotational position information, which is the output of the rotation angle sensor 16 provided on the motor 11, is also sent to each MCU 200 via the signal line 260. The motor current and rotational position information is used in each MCU 200 to generate the first PWM command.

[0037] The MCU 200 is also configured to generate and output a second PWM command, which is given to two redundant pre-drivers 231 to drive the inverter 211 that supplies power to the motor 22. The second PWM command, like the first PWM command, is selected by the command selection unit 221 and supplied to the pre-drivers 231. Diagnostic signals supplied to the command selection unit 220 are also supplied to the command selection unit 221 and are referenced when selecting the second PWM command.

[0038] The pre-drivers 231a and 231b are connected to the inverter 211 via relays 241a and 241b, respectively. The PWM signals output from the pre-drivers 231a and 231b are selectively supplied to the inverter 211 by relay 241.

[0039] Like inverter 210, inverter 211 converts DC power supplied from a battery (not shown) into U, V, and W three-phase AC power according to the PWM signal supplied from the pre-driver 231 and supplies it to the motor 22. Inverter 211, like inverter 210, is equipped with a current sensor to detect the current supplied to the motor 22. The motor current information detected by inverter 211 is provided to each MCU 200 via signal line 251 through relay 241 and pre-driver 231. In addition, the rotational position information detected by the rotation angle sensor 23 of the motor 22 is provided to each MCU 200 via signal line 261.

[0040] The MCU 200 is configured to receive information from the steering angle detection device 15 and the steering angle detection device 21, as well as information such as vehicle speed. This information is used together with the motor current and rotational position information mentioned above to generate the first PWM command and the second PWM command.

[0041] Figure 3 is a schematic block diagram showing the logical configuration of the command selection unit 220. As shown in Figure 3, the command selection unit 220 is composed of a selection logic unit 300, a PWM command selection switch 310, a circuit error detection unit 320, and a redundant output selection switch 330.

[0042] Diagnostic signals are input to the selection logic unit 300 from MCUs 200a, 200b, and 200c via signal lines 340a, 340b, and 340c, respectively. For the signal line 340, for example, "1" is output by the MCU 200 if the MCU 200 is normal, and "0" is output by the MCU 200 if any abnormality occurs in the MCU 200. The selection logic unit 300 may include, for example, a logic circuit configured to select the MCU 200 with the highest predetermined priority from among the MCUs 200 determined to be operating normally based on the diagnostic signals.

[0043] The selection logic unit 300 is configured to notify the selected MCU 200 of a selection signal indicating that it has been selected via the signal line 350a, 350b, or 350c. For example, the selection logic unit 300 outputs "1" to the signal line 350 connected to the selected MCU 200, and outputs "0" to the signal line 350 connected to the unselected MCU 200. For example, assuming that the MCU 200b is selected by the selection logic unit 300, "1" is output to the signal line 350b, and "0" is output to the signal line 350a and the signal line 350c.

[0044] First PWM commands are input to the PWM command selection switch 310 from MCUs 200a, 200b, and 200c via signal lines 360a, 360b, and 360c, respectively. A switching signal corresponding to the selection result is also input from the selection logic unit 300 to the PWM command selection switch 310. The PWM command selection switch 310 is configured to select and output one of the three input first PWM commands in accordance with the switching signal.

[0045] The circuit error detection unit 320 is provided accompanying the selection logic unit 300, and monitors whether the operation of the selection logic unit 300 is properly performed. The circuit error detection unit 320 has, for example, a logic circuit equivalent to that of the selection logic unit 300, and can be configured to compare the equivalent logic circuit with the processing result of the selection logic unit 300, and determine whether the operation of the selection logic unit 300 is appropriate based on whether the comparison result matches or does not match.

[0046] A first PWM command output by a PWM command selection switch 310 and a first PWM command predetermined as a redundant output are input to a redundant output selection switch 330. In the present embodiment, the first PWM command output by an MCU 200c is used as a redundant output, and the first PWM command transmitted via a signal line 360c is input to the redundant output selection switch 330 together with the PWM command selection switch 310. The redundant output selection switch 330 is configured to output the first PWM command output from the PWM command selection switch 310 during normal operation, and output the first PWM command input from the signal line 360c instead of the output from the PWM command selection switch 310 when an abnormality of the selection logic unit 300 is detected by a circuit error detection unit 320.

[0047] The first PWM command output from the redundant output selection switch 330 is input to three pre-drivers 230a, 230b, 230c, and is used for controlling an inverter 210.

[0048] In the present embodiment, the first PWM command output from the MCU 200c having the lowest priority is used as a redundant output. The MCU 200c with the lowest priority has a lower cumulative processing load than other MCUs, and is considered to have a lower probability of failure than other MCUs. Therefore, more reliable backup operation can be expected.

[0049] FIG. 4 is a flowchart for explaining an outline of the operation of the command selection unit 220. In FIG. 4, the MCU 200a is denoted as "M1", the MCU 200b is denoted as "M2", and the MCU 200c is denoted as "M3". In the following description, it is assumed that the priority of the MCUs 200 is set in the order of the MCU 200a, the MCU 200b, and the MCU 200c.

[0050] First, the command selection unit 220 uses the diagnostic signal of the MCU 200a input via the signal line 340a to determine whether the MCU 200a with the highest priority is operating normally, using the selection logic unit 300 (step S100). If it is determined that the MCU 200a is operating normally, the circuit error detection unit determines whether the logic of the selection logic unit 300, which determined that the MCU 200a is operating normally, is operating normally (S105). If the logic of the MCU 200a is normal, the first PWM command output from the MCU 200a is selected as the first PWM command supplied to the pre-driver 230 (step S110).

[0051] If it is determined in step S100 that there is an abnormality in the operation of MCU 200a, the selection logic unit 300 determines whether the diagnostic signal on signal line 340a indicates an abnormality in MCU 200a and the diagnostic signal on signal line 340b indicates that MCU 200b is functioning normally (step S115). If it is determined that there is an abnormality in MCU 200a and MCU 200b is functioning normally, the circuit error detection unit 320 determines whether the logic used in step S115 is functioning normally (S120). If it is determined that the logic is functioning normally, the first PWM command output from MCU 200b is selected as the first PWM command supplied to the pre-driver 230 (step S125).

[0052] If the judgment result in step S115 is negative, the selection logic unit 300 determines whether the diagnostic signals on signal lines 340a and 340b indicate abnormalities in MCUs 200a and 200b, and whether the diagnostic signal on signal line 340c indicates that MCU 200c is functioning normally (step S130). If abnormalities are found in MCUs 200a and 200b, and MCU 200c is functioning normally, the circuit error detection unit 320 determines whether the logic used in the judgment in step S130 is functioning normally (step S135). If it is determined that the logic is functioning normally, the first PWM command output from MCU 200c is selected as the first PWM command supplied to the pre-driver 230 (step S140).

[0053] When a first PWM command used in step S110, S125, or S140 is selected, the PWM command selection switch 310 is switched by the selection logic unit 300 to output the selected first PWM. In addition, a selection signal indicating that the first PWM command has been selected is notified to the MCU 200 that generates the selected first PWM command via the signal line 350 (step S145).

[0054] On the other hand, if an abnormality in the logic operation is detected in any of steps S105, S120, or S135, the circuit error detection unit 320 selects the redundant output as the first PWM command to be output (S150). In this case, the redundant output selection switch 330 is switched so that the redundant output (in this embodiment, the first PWM command supplied from the MCU 200c via the signal line 360c) is output as the first PWM command supplied to the pre-driver 230. In this case as well, similar to step S145, a selection signal indicating that the first PWM command to be used as the redundant output is selected is output to the MCU 200 (in this embodiment, the MCU 200c) that outputs the first PWM command to be used as the redundant output (step S155).

[0055] The command selection unit 221 is configured similarly to the command selection unit 220 shown in Figure 3, except that it has two pre-drivers 230 connected to the output of the redundant output selection switch 330, and can be configured to perform the same operation as shown in Figure 4. For this reason, a detailed explanation is omitted here.

[0056] Figure 5 is a flowchart illustrating the general processing performed by the MCU 200. In this embodiment, the same processing is performed by each MCU 200 regardless of whether or not it is selected as a PWM command supplied to the pre-driver 230.

[0057] When the ignition switch (not shown) is turned on and the MCU 200 is started, it performs a self-diagnosis to determine whether there are any malfunctions in its operation and whether it is operating normally (step S200), and determines whether its operation is normal or not (step S205). In step S205, if the self-diagnosis determines that some malfunction has occurred and the operation is not normal, the MCU 200 outputs a diagnostic signal indicating an abnormal state, notifies the command selection units 220 and 221 of the occurrence of the abnormality, and terminates processing (step S210).

[0058] If the operating state is determined to be normal in step S205, the MCU 200 receives information output from the steering angle detection device 15, the steering angle detection device 21 sensors, the rotation angle sensors 16 and 23, and the current sensor of the inverter 210 (step S215). Based on the received information, it generates a first PWM command for controlling the motor 11 and a second PWM command for controlling the motor 22. The specific method for generating the first and second PWM commands is publicly known and is not directly related to the characteristic features of this embodiment, so a detailed explanation is omitted here (step S220).

[0059] Subsequently, the MCU 200 checks whether it has received a selection signal from the command selection unit 220 on the steering device 10 side indicating the selection of the first PWM command (step S225). If a selection signal is received, the MCU 200 controls the relays 240 on the steering device 10 side, i.e., relays 240a, 240b, 240c, and 240d, to selectively supply the PWM signals output from the pre-drivers 230a, 230b, and 230c to the inverters 210a and 210b (step S230).

[0060] Next, the MCU 200 checks whether it has received a selection signal from the command selection unit 221 on the reaction force generating device 20 side indicating the selection of the second PWM command. If it is determined in step S225 that it has not received a selection signal from the command selection unit 220, the processing in step S230 is skipped and the processing in this step is performed (step S235).

[0061] If it is determined in step S235 that a selection signal has been received, the MCU 200 controls the relays 240 on the reaction force generating device 20 side, i.e., relays 241a and 241b, to selectively supply the PWM signals output from the pre-drivers 231a and 231b to the inverter 211 and terminate the process (step S240). On the other hand, if it is determined in step S235 that a selection signal has not been received from the command selection unit 221, the process in step S240 is not performed, and the MCU 200 terminates the process.

[0062] The above series of processes are periodically activated and executed while the ignition switch is on, and the steering device 10 and the reaction force generating device 20 continue to operate.

[0063] Figure 6 is a flowchart showing the control flow of the relay 240 on the steering device 10 side that is performed in step S230. In this embodiment, in the initialization process immediately after the ignition switch is turned on, relays 240a and 240d are set to ON, and relays 240b and 240c are set to OFF.

[0064] In controlling the relay 240, the MCU 200 first acquires the operating status of each pre-driver 230 on the steering device 10 side, namely pre-drivers 230a, 230b, and 230c (step S300). Based on the acquired operating status, the MCU 200 determines whether the pre-driver 230a is operating normally (step S305).

[0065] If the pre-driver 230a is operating normally, the MCU 200 checks whether the relay 240b is ON or OFF (step S310). If the relay 240b is ON, it turns the relay 240b OFF, disconnecting the connection between the pre-driver 230b and the inverter 210a. If it is determined in step S310 that the relay 240b is OFF, this step is skipped (step S315). Then, the MCU 200 turns the relay 240a ON, connects the output of the pre-driver 230a to the inverter 210a, and controls the inverter 210a with the PWM signal output from the pre-driver 230a (step S320).

[0066] On the other hand, if an abnormality in the pre-driver 230a is detected in step S305, the MCU 200 turns off the relay 240a and disconnects the connection between the pre-driver 230a and the inverter 210a (step S325).

[0067] Next, the MCU 200 determines whether the pre-driver 230b is functioning correctly based on the operating status acquired in step S300 (step S330). If there is an abnormality in the pre-driver 230b, the MCU 200 proceeds directly to the process in step S345.

[0068] If the pre-driver 230b is operating normally, the next step is to check if the relay 240c is in the off state and if the connection between the pre-driver 230b and the inverter 210b is interrupted (step S335). If the relay 240c is off and the connection between the pre-driver 230b and the inverter 2210b is interrupted, the MCU 200 turns on the relay 240b and connects the output of the pre-driver 230b to the inverter 210a. If it is determined in step S335 that the relay 240c is in the on state, the pre-driver 230b is connected to the inverter 210 and the inverter 210b is already being controlled by the pre-driver 230b, so this step is skipped (step S340).

[0069] The MCU 200 then checks whether the pre-driver 230c is operating normally based on the operating status acquired in step S300 (step S345).

[0070] If the pre-driver 230c is operating normally, the MCU 200 checks whether the relay 240c is ON or OFF (step S350). If the relay 240c is ON, it turns off the relay 240c, disconnecting the connection between the pre-driver 230b and the inverter 210b. If it is determined in step S310 that the relay 240c is OFF, this step is skipped (step S355). Then, the MCU 200 turns on the relay 240d, connects the output of the pre-driver 230c to the inverter 210b, and terminates the relay switching control so that the inverter 210b is controlled by the PWM signal output from the pre-driver 230c (step S360).

[0071] On the other hand, if an abnormality in the pre-driver 230c is detected in step S345, the MCU 200 turns off the relay 240d to disconnect the connection between the pre-driver 230c and the inverter 210b (step S365).

[0072] Next, the MCU 200 determines whether the pre-driver 230b is operating normally based on the operating status acquired in step S300. If there is an abnormality in the pre-driver 230b, the MCU 200 terminates the relay switching control (step S370). If the pre-driver 230b is operating normally, the MCU 200 then checks whether the relay 240b is in the off state and whether the connection between the pre-driver 230b and the inverter 210a is interrupted. If it is determined that the relay 240b is in the on state, it means that the pre-driver 230b is connected to the inverter 210a and the inverter 210a is already being controlled by the pre-driver 230b, so the MCU 200 terminates the relay switching control (step S375).

[0073] If it is determined in step S375 that relay 240b is off and the connection between pre-driver 230b and inverter 2210a is interrupted, the MCU 200 turns on relay 240c to connect the output of pre-driver 230b to inverter 210b and terminates the relay switching control (step S380).

[0074] Figure 7 is a flowchart showing the control flow of the relay 241 on the reaction force generating device 20 side performed in step S240. In this embodiment, the pre-driver 231a is used as the primary pre-driver and the pre-driver 231b is used as the secondary pre-driver. Therefore, in the initialization process immediately after the ignition switch is turned on, relay 241a is set to ON and relay 241b is set to OFF.

[0075] In controlling the relay 241, the MCU 200 acquires the operating status of each pre-driver 231 on the reaction force generating device 20 side, namely pre-drivers 231a and 231b (step S400). Based on the acquired operating status, the MCU 200 first determines whether the pre-driver 231a is operating normally (step S405).

[0076] If the pre-driver 231a is operating normally, the MCU 200 checks whether the relay 241b is ON or OFF (step S410). If the relay 241b is ON, it turns the relay 241b OFF, disconnecting the connection between the pre-driver 231b and the inverter 211. If it is determined in step S410 that the relay 241b is OFF, this step is skipped (step S415). The MCU 200 then turns the relay 241a ON, connecting the output of the pre-driver 231a to the inverter 211, so that the inverter 211 is controlled by the PWM signal output from the pre-driver 231a (step S420).

[0077] On the other hand, if an abnormality in the pre-driver 231a is detected in step S405, the MCU 200 turns off the relay 241a to disconnect the connection between the pre-driver 231a and the inverter 211 (step S425).

[0078] Next, the MCU 200 determines whether the pre-driver 231b is functioning correctly based on the operating status acquired in step S400. If there is an abnormality in the pre-driver 231b, the MCU 200 terminates the relay switching control (step S430).

[0079] If the pre-driver 230b is functioning correctly, the relay 241b is turned on to connect the output of the pre-driver 231b to the inverter 211 and the process ends (step S340).

[0080] In this embodiment, as described above, one PWM command is selected from among the PWM commands output from multiple MCUs according to a predetermined priority order, and the selected PWM command is supplied to multiple pre-drivers that drive multiple inverters that supply power to each of the multiple redundant winding sets of the motor. Therefore, if any one of the multiple MCUs is in a healthy state, power can be continuously supplied to the multiple winding sets, and steering control can be continued without reducing the capacity of the steering device.

[0081] Multiple MCUs generate PWM commands regardless of their selected state. Therefore, even if a failure occurs in the selected MCU, steering control can be continued simply by switching the PWM command in the command selection unit, minimizing the control interruption time due to the failure.

[0082] Furthermore, in this embodiment, since multiple MCUs each perform both the control of the steering control device and the control of the reaction force generating device, it is possible to implement redundant control of each with a small number of MCUs. Compared to the case where separate MCUs are used for the steering control device and the reaction force generating device to provide redundancy for each, the overall number of MCUs can be reduced, making it possible to miniaturize the steering system.

[0083] In the embodiment described above, only the motor in the steering device has redundant winding sets. However, the motor in the reaction force generating device can also be made redundant in the same way as the motor in the steering device by providing it with multiple winding sets.

[0084] In the embodiment described above, three MCUs are used, but the number of MCUs is not limited to three; it may be two, four or more. Also, in the embodiment described above, each MCU controls both the steering device and the reaction force generating device, but as in the prior art, separate MCUs may be used for controlling the steering device and the reaction force generating device, respectively.

[0085] Furthermore, although the above-described embodiment used an SBW system as an example, which eliminates the mechanical connection between the steering wheel and the steering device, the steering control device can be similarly configured not only in SBW systems but also in conventional steering systems where the steering wheel and the steering device are mechanically connected. Alternatively, instead of a steering wheel or reaction force generating device, an operation input device such as a joystick may be used as the operation input device, and the steering device may be controlled in accordance with the operation input to the operation input device.

[0086] Although the present invention has been described above using representative embodiments as examples, the present invention is not limited thereto and can be implemented in various ways without departing from the spirit of the invention as described in the claims. Furthermore, the embodiments described above are explained in detail for the purpose of clearly illustrating the present invention and are not necessarily limited to those having all the configurations described.

[0087] 10... Steering device, 20... Reaction force generating device, 11, 22... Motor, 12... Reducer, 13... Pinion shaft, 14... Steering rod, 15... Steering angle detection device, 16, 23... Rotation angle sensor, 17... Pinion gear, 18... Rack gear, 21... Steering angle detection device, 30... Steering control device, 40... Wheel, 50... Tie rod, 60... Steering wheel, 65... Steering shaft, 200a 200b, 200c...MCU, 220, 221...Command selection unit, 230a, 230b, 230c, 231a, 231b...Pre-driver, 240a, 240b, 240c, 240d, 241a, 241b...Relay, 210a, 210b, 211...Inverter, 300...Selection logic unit, 310...PWM command selection switch, 320...Circuit error detection unit, 330...Redundant output selection switch

Claims

1. A vehicle control system comprising: a vehicle device having an actuator; a drive unit for driving the actuator; a plurality of processors configured to acquire the operating status of the actuator and the drive unit, generate drive commands for controlling the drive unit according to input operation information, perform a self-diagnosis and output the results of the self-diagnosis; and a control unit comprising a command selection unit that selects a drive command generated by any one of the processors whose self-diagnosis results are normal from among the drive commands generated by the plurality of processors and outputs it to the drive unit.

2. The vehicle control system according to claim 1, wherein the command selection unit has a selection logic unit configured to select a drive command to be output from among the drive commands generated by a processor whose self-diagnosis result is normal, according to a predetermined priority order.

3. The vehicle control system according to claim 2, wherein the command selection unit has an error detection unit that detects a malfunction in the selection logic unit, and is configured to output the drive command generated by a predetermined processor among the plurality of processors when the malfunction is detected by the error detection unit.

4. The vehicle control system according to claim 3, wherein the predetermined processor is the processor with the lowest priority.

5. The vehicle control system according to claim 1, wherein the command selection unit is configured to send a selection signal to the one processor that generated the drive command to be output to the drive unit, indicating that it has been selected.

6. The vehicle control system according to claim 1, wherein the control unit and the drive unit are each housed in separate housings, and the control unit and the drive unit are connected via a cable.

7. The vehicle control system according to claim 1, wherein the command selection unit is housed together with the drive unit in a housing different from the plurality of processors, and the plurality of processors and the command selection unit are connected via a cable.

8. The vehicle control system according to claim 1, wherein the vehicle equipment includes a reaction force generating device having a first actuator for applying a reaction force to a steering wheel and a steering device having a second actuator for applying a steering force to a wheel, the drive unit includes a first drive unit having a first inverter for supplying power to the first actuator and a second drive unit having a second inverter for supplying power to the second actuator, each of the plurality of processors is configured to generate drive commands for driving the first inverter and the second inverter, respectively, based on the amount of steering of the steering wheel input as the operation information, and the command selection unit includes a first selection unit for selecting a drive command generated by the plurality of processors for driving the first inverter and a second selection unit for selecting a drive command generated for driving the second inverter.

9. The vehicle control system according to claim 8, wherein the control unit, the first drive unit, and the second drive unit are each housed in different housings, and the control unit and the first drive unit, and the control unit and the second drive unit, are connected by cables.

10. The vehicle control system according to claim 8, wherein the plurality of processors are housed in a first housing, the first selection unit is housed in a second housing together with the first drive unit, the second selection unit is housed in a third housing together with the second drive unit, and the plurality of processors and the first selection unit, and the plurality of processors and the second selection unit are connected by cables.

11. A vehicle control device for controlling a drive unit that drives an actuator of a vehicle device, comprising: a plurality of processors configured to acquire the operating status of the actuator and the drive unit, generate drive commands for controlling the drive unit according to input operation information, perform a self-diagnosis and output the results of the self-diagnosis; and a command selection unit that selects a drive command generated by any one of the processors whose self-diagnosis results are normal from among the drive commands generated by the plurality of processors and outputs it to the drive unit.

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