Control device for motor

Abstract

A control device (20) for a motor (10) is provided, the motor (10) including a first coil and a second coil insulated from each other. The control device (20) includes a first circuit and a second circuit that switches a first process to a second process when a failure occurs in the first circuit. When a failure occurs in one of the first circuit and the second circuit, an external circuit generates an instruction for executing a process in which an operation amount calculated by the other of the first circuit and the second circuit is increased according to the number of control systems.

Description

Technical Field

[0001] The invention relates to a control device for a motor for steering a steering wheel. Background Art

[0002] A control device for controlling a motor that is a source of assist torque applied to a steering mechanism of a vehicle is known. For example, a control device described in Japanese Unexamined Patent Application Publication No. 2018-24335 (JP 2018-24335A) controls the supply of power to a motor including two systems of windings that are independent of each other. The control device includes two sets of drive circuits and a microprocessing unit (MPU) for corresponding to the windings of the two systems. The MPU of each system independently controls the supply of power to the windings of the corresponding system by controlling the drive circuit of the corresponding system.

[0003] The MPU of each system calculates the current command value for the coil of the corresponding system based on the detection result from the sensor of the corresponding system. When the sensor of the system is normal, the current command value calculated by the MPU of one system is shared by the MPUs of these systems. When an abnormality occurs in the sensor of one system, the current command value calculated by the MPU of another system is shared by the MPUs of these systems (Figures 9 and 10 thereof). Therefore, the supply of power to the winding of the abnormal system can be continuously performed. Summary of the invention

[0004] With the control device for a motor described in JP 2018-24335 A, it is possible to cope with an abnormality of a sensor belonging to one system. However, for example, when a situation occurs in which it is difficult to perform power supply control with the MPU of one system, only power supply to the winding of another system is performed. Therefore, when one system fails, there is a concern that the assist torque required for the motor is not obtained.

[0005] The present invention provides a control device for a motor, which can appropriately cope with failures of some of a plurality of systems.

[0006] According to a first aspect of the present invention, there is provided a control device for a motor that steers a steering wheel of a vehicle and includes a first coil and a second coil that are insulated from each other. The control device includes: a first circuit that calculates a first operation amount corresponding to a torque generated by the motor to feedback-control an angle that can be converted into a steering angle of the steering wheel and detected by a first sensor so that the angle becomes a target angle calculated by an external circuit, and the first circuit controls the supply of power to the first coil based on a value obtained by dividing the first operation amount according to the number of control systems; and a second circuit that calculates a second operation amount corresponding to the torque generated by the motor to feedback-control an angle detected by a second sensor so that the angle becomes a target angle, the second circuit selectively performs a first process and a second process, the first process is to control the supply of power to the second coil based on a value obtained by dividing the first operation amount according to the number of control systems, the second process is to control the supply of power to the second coil based on a value obtained by dividing the second operation amount according to the number of control systems, and when a failure occurs in the first circuit, the second circuit switches the first process to the second process. When one of the first circuit and the second circuit fails, the external circuit generates an instruction for executing a process of increasing the operation amount calculated by the other of the first circuit and the second circuit according to the number of control systems.

[0007] With this configuration, when one of the first circuit and the second circuit fails, the operation amount calculated by the other of the first circuit and the second circuit according to the instruction from the external circuit increases according to the number of control systems. Therefore, even when one of the first circuit and the second circuit fails, the total torque generated by the motor is ensured.

[0008] According to a second aspect of the present invention, there is provided a control device for a motor that steers a steering wheel of a vehicle and includes a first coil and a second coil that are insulated from each other. The control device includes: a first circuit that calculates a first operation amount corresponding to a torque generated by the motor to feedback-control an angle that can be converted into a steering angle of the steering wheel and detected by a first sensor so that the angle becomes a target angle calculated by an external circuit, and the first circuit controls the supply of power to the first coil based on a value obtained by dividing the first operation amount according to the number of control systems; and a second circuit that calculates a second operation amount corresponding to a torque generated by the motor to feedback-control an angle detected by a second sensor so that the angle becomes a target angle, and the second circuit controls the supply of power to the second coil based on a value obtained by dividing the second operation amount according to the number of control systems. When one of the first circuit and the second circuit fails, the external circuit generates an instruction for performing the following processing: increasing the operation amount calculated by the other of the first circuit and the second circuit according to the number of control systems.

[0009] With this configuration, when one of the first circuit and the second circuit fails, the operation amount calculated by the other of the first circuit and the second circuit according to the instruction from the external circuit increases according to the number of control systems. Therefore, even when one of the first circuit and the second circuit fails, the total torque generated by the motor is ensured.

[0010] In a control device for a motor, when communication with one of a first circuit and a second circuit is interrupted and when abnormality in mutual communication between the first circuit and the second circuit is identified through communication with the other of the first circuit and the second circuit, the external circuit can determine that one of the first circuit and the second circuit has failed and generate the instruction.

[0011] With this configuration, the external circuit can more quickly recognize a failure of one of the first circuit and the second circuit through communication with the first circuit and communication with the second circuit.

[0012] The control device for the motor may further include a monitoring circuit that monitors whether the abnormal state of the power supply voltage of at least the first circuit and the second circuit is maintained for a set time. In this case, when it is identified that one of the first circuit and the second circuit has a fault based on the monitoring result from the monitoring circuit, the first circuit and the second circuit may increase the operation amount of the other of the first circuit and the second circuit according to the number of control systems.

[0013] With this configuration, when a failure in one of the first circuit and the second circuit is identified based on at least the monitoring result of the power supply voltage of the first circuit and the second circuit, the operation amount of the other of the first circuit and the second circuit is increased according to the number of control systems. Therefore, even when a failure in one of the first circuit and the second circuit occurs, the total torque generated by the motor is ensured.

[0014] Here, the operation amount of the other of the first circuit and the second circuit does not increase until a set time has passed after the power supply voltage of one of the first circuit and the second circuit enters an abnormal state. Therefore, there is a concern that the total torque required for the motor is not ensured. Therefore, when a configuration for monitoring the power supply voltage of the first circuit and the second circuit is adopted, it is preferable to also adopt the above-mentioned configuration in which the external circuit recognizes a fault in one of the first circuit and the second circuit through communication with the first circuit and communication with the second circuit. Since the abnormality of the communication can be detected immediately, when one of the first circuit and the second circuit fails, the operation amount of the other of the first circuit and the second circuit increases immediately.

[0015] In the control device for the motor, the monitoring circuit can also monitor the mutual communication between the first circuit and the second circuit. In this case, when the instruction is generated and the mutual communication between the first circuit and the second circuit is identified to be normal based on the monitoring result, the first circuit and the second circuit may not adopt the instruction.

[0016] It is conceivable that the instruction is erroneously generated by an external device. When the mutual communication between the first circuit and the second circuit is proceeding normally, it can be said that the first circuit and the second circuit are operating normally. Therefore, with the control device, when an instruction is generated by an external circuit even when the mutual communication between the first circuit and the second circuit is normal, it is preferable not to adopt the instruction from the external circuit. With this configuration, it is prevented that the operation amount calculated by one of the first circuit and the second circuit increases according to the number of control systems due to an erroneous determination of the external circuit even if the first circuit and the second circuit are operating normally. Therefore, it is possible to prevent excessive output of the motor due to erroneous output of the instruction.

[0017] In the control device for a motor, when one of the first circuit and the second circuit increases its own operation amount according to the number of control systems in accordance with the instruction, the other of the first circuit and the second circuit can perform processing to reduce its own operation amount.

[0018] It is conceivable that the instruction is erroneously generated by an external device. In this case, there is a concern that even if the first circuit and the second circuit operate normally, the operation amount calculated by one of the first circuit and the second circuit will increase according to the number of control systems due to erroneous determination by the external circuit. In this regard, with this configuration, when one of the first circuit and the second circuit increases its operation amount according to the number of control systems in accordance with the instruction, the operation amount of the other of the first circuit and the second circuit decreases. Therefore, excessive output of the motor due to erroneous output of the instruction can be prevented.

[0019] In the control device for a motor, the first circuit or the second circuit, after having started executing the process according to the instruction, maintains a state of increasing its own operation amount according to the number of control systems when the instruction from the external circuit is interrupted.

[0020] For example, it is conceivable that the communication between the external circuit and the first circuit, the communication between the external circuit and the second circuit, or the mutual communication between the first circuit and the second circuit is unstable. In this case, it is possible to frequently switch between a state in which an instruction from the external circuit is supplied to the first circuit or the second circuit and a state in which the instruction is not supplied. In this respect, with this configuration, even if the instruction from the external circuit is interrupted, the first circuit or the second circuit maintains a state in which the amount of operation thereof is increased according to the number of control systems. Therefore, it is possible to prevent the operating state of the first circuit and the second circuit from frequently switching between a state in which a process based on an instruction is executed and a state in which a process based on an instruction is not executed.

[0021] In a control device for a motor, a first circuit may perform the following processing: a first auxiliary value for causing a motor to generate a steering assist force is calculated according to a steering state and the first auxiliary value is added to a first operating amount. In this case, the first circuit may perform the following processing: a first auxiliary correction value for offsetting the first operating amount is calculated according to a steering state and the first auxiliary correction value is added to the first operating amount, wherein the first operating amount is used to perform feedback control on the angle so that the angle becomes a target angle. The second circuit may perform the following processing: a second auxiliary value for causing a motor to generate a steering assist force is calculated according to a steering state and the second auxiliary value is added to a second operating amount. In this case, the second circuit may perform the following processing: a second auxiliary correction value for offsetting the second operating amount is calculated according to a steering state and the second auxiliary correction value is added to the second operating amount, wherein the second operating amount is used to perform feedback control on the angle so that the angle becomes a target angle.

[0022] With this configuration, when the first circuit and the second circuit perform feedback control on the angle that can be converted into the steering angle of the steering wheel so that the angle becomes the target angle and the driver's steering intervention occurs, the operation amount for performing feedback control on the angle that can be converted into the steering angle of the steering wheel so that the angle becomes the target angle is offset by the auxiliary correction value. Therefore, the motor generates an auxiliary force corresponding to the steering state. The driver's steering is assisted by the auxiliary force. When one of the first circuit and the second circuit is performing instruction-based processing, the operation amount calculated by the other of the first circuit and the second circuit increases according to the number of control systems. On the other hand, the auxiliary correction value calculated by the other of the first circuit and the second circuit is only a value corresponding to the steering state. Therefore, the operation amount calculated by the other of the first circuit and the second circuit cannot be fully offset. Therefore, the reaction force when the driver turns increases slightly. With this increase in reaction force, the driver can be aware of the abnormality of the control device.

[0023] In the control device for the motor, when one of the first circuit and the second circuit performs control according to the instruction, the other of the first circuit and the second circuit may increase the assist correction value calculated thereby according to the number of control systems.

[0024] With this configuration, when one of the first circuit and the second circuit is performing control based on an instruction generated by an external circuit and a steering intervention by the driver occurs, the assist correction value of the other of the first circuit and the second circuit is increased according to the number of control systems, and thus the operation amount of the other of the first circuit and the second circuit is appropriately offset. Therefore, when one of the first circuit and the second circuit is performing control based on an instruction generated by an external circuit and a steering intervention by the driver occurs, the motor generates an assist force corresponding to the assist value. Therefore, the steering of the driver can be appropriately assisted.

[0025] With the control device for a motor according to this aspect, it is possible to appropriately cope with failures of some of the plurality of systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like symbols represent like elements, and in which:

[0027] Figure 1 is a block diagram showing a control device for a motor according to a first embodiment;

[0028] Figure 2 is a diagram showing a part of a process performed by the control device for a motor according to the first embodiment when both systems are normal;

[0029] Figure 3 is a diagram showing a part of a process performed by the control device for a motor according to the first embodiment when a failure occurs in one of two systems; and

[0030] Figure 4 is a diagram showing a part of a process performed by the control device for a motor according to the second embodiment when a failure occurs in one of two systems. DETAILED DESCRIPTION

[0031] First embodiment

[0032] Hereinafter, a control device for a motor according to a first embodiment of the present invention will be described with reference to the accompanying drawings. Figure 1 As shown, the motor 10 is a power source for a steering actuator for steering a steering wheel of a vehicle. The steering shaft includes, for example, a steering shaft for steering the steering wheel and a pinion shaft rotating with the steering shaft. The torque generated by the motor 10 is transmitted to the steering shaft or the pinion shaft via a reduction gear mechanism. The steering wheel is connected to the pinion shaft via the steering shaft.

[0033] For example, a surface permanent magnet synchronous motor (SPMSM) is used as the motor 10 . The motor 10 includes a rotor 12 , a first stator coil 14 ( 1 ), and a second stator coil 14 ( 2 ). The motor 10 is controlled by a control device 20 .

[0034] The control device 20 controls torque as a control parameter of the motor 10. The control device 20 includes a first system circuit and a second system circuit. The first system circuit corresponds to the first stator coil 14 (1). The second system circuit corresponds to the second stator coil 14 (2).

[0035] The circuit of the first system includes a first inverter 22(1) and a first microcomputer 30(1). The first inverter 22(1) is connected to the first stator coil 14(1). The first microcomputer 30(1) controls the current flowing in the first stator coil 14(1) by outputting an operation signal MS(1) to the first inverter 22(1). The circuit of the second system includes a second inverter 22(2) and a second microcomputer 30(2). The second inverter 22(2) is connected to the second stator coil 14(2). The second microcomputer 30(2) controls the current flowing in the second stator coil 14(2) by outputting an operation signal MS(2) to the second inverter 22(2). The first microcomputer 30(1) and the second microcomputer 30(2) can communicate with each other via a communication line 42.

[0036] In the following description, when the first system and the second system are collectively represented, for example, in “the kth inverter 14 ( k ) is connected to the kth stator coil 14 ( k )”, a symbol “k” that may have a value of “1” or “2” is used.

[0037] The kth microcomputer 30(k) acquires the rotation angle θm(k) of the rotor 12 detected by the kth angle sensor 40(k) and the three-phase currents iu(k), iv(k) and iw(k) flowing in the kth stator coil 14(k). The values ​​of the currents iu(k), iv(k) and iw(k) may be detected, for example, as a voltage drop of a shunt resistor provided in a branch of the kth inverter 22(k).

[0038] The kth microcomputer 30(k) includes a CPU 32(k), a ROM 34(k), and a peripheral circuit 36(k). The CPU 32(k), the ROM 34(k), and the peripheral circuit 36(k) can communicate with each other via a local network 38(k). The peripheral circuit 36(k) includes a circuit for generating a clock signal for defining internal operations based on an external clock signal, a power supply circuit, and a reset circuit.

[0039] The first microcomputer 30(1) and the second microcomputer 30(2) can communicate with the main ECU 50 as an external circuit via the communication lines 54(1) and 54(2) and the communication lines 55(1) and 55(2). The first microcomputer 30(1) and the second microcomputer 30(2) receive the target angle θp* generated by the main ECU 50 via the communication lines 54(1) and 54(2).

[0040] The first microcomputer 30(1) and the second microcomputer 30(2) determine whether the mutual communication (hereinafter also referred to as "inter-microcomputer communication") between the first microcomputer 30(1) and the second microcomputer 30(2) is normal. For example, the first microcomputer 30(1) and the second microcomputer 30(2) periodically exchange predetermined data via the communication line 42, determine that the inter-microcomputer communication is normal when data exchange is possible, and determine that the inter-microcomputer communication is abnormal when data exchange is not possible. The first microcomputer 30(1) generates an electrical signal S1(1) indicating a determination result indicating whether the communication with the second microcomputer 30(2) is normal. The second microcomputer 30(2) generates an electrical signal S1(2) indicating a determination result indicating whether the communication with the first microcomputer 30(1) is normal.

[0041] The main ECU 50 comprehensively controls the control devices for various vehicle-mounted systems. The main ECU 50 acquires the optimal control method based on the vehicle state at that time, and instructs various vehicle-mounted control devices to perform individual control according to the acquired control method. The main ECU 50 intervenes in the control performed by the control device 20. The main ECU 50 switches its own automatic driving control function between on and off based on the operation of a switch (not shown) provided on the driver's seat or the like.

[0042] When the automatic driving control function of the main ECU 50 is turned on, the entity that operates the steering wheel is the main ECU 50, and the control device 20 performs steering control (automatic steering control) for steering the steering wheel by controlling the motor 10 based on the instruction from the main ECU 50. For example, the main ECU 50 calculates the target angle θp* as a command value for driving the vehicle along the target lane. The target angle θp* is a target steering angle required for driving the vehicle along the lane according to the driving state of the vehicle at that time, a target value of the rotation angle of the pinion shaft, or a target value of the rotation angle of the steering shaft. The rotation angle of the pinion shaft and the rotation angle of the steering shaft are angles that can be converted into the steering angle of the steering wheel.

[0043] The terminal voltage of the battery 52 installed in the vehicle is applied to the main ECU 50, the kth microcomputer 30(k) and the kth inverter 22(k). Here, the voltage of the battery 52 is applied to the kth microcomputer 30(k) via the relay 24(k). The relay 26(k) is provided between the kth inverter 22(k) and the kth stator coil 14(k).

[0044] In addition to the circuits of the first system and the circuits of the second system, the control device 20 also includes a monitoring circuit 44. The terminal voltage of the battery 52 is applied to the monitoring circuit 44. The monitoring circuit 44 receives the power supply voltage VB(1) of the first microcomputer 30(1) and the power supply voltage VB(2) of the second microcomputer 30(2), and determines whether the received power supply voltages VB(1) and VB(2) are normal. For example, when a state in which the power supply voltages VB(1) and VB(2) are less than a predetermined voltage threshold is maintained for a set time, the monitoring circuit 44 determines that the power supply voltages VB(1) and VB(2) are abnormal. The set time is set in consideration of preventing an erroneous determination by the monitoring circuit 44. Therefore, it is possible to prevent an instantaneous voltage drop from being determined as abnormal. The monitoring circuit 44 generates a first monitoring result signal S2, which indicates a monitoring result indicating whether the power supply voltages VB(1) and VB(2) are normal.

[0045] The monitoring circuit 44 also determines whether the communication between the first microcomputer 30(1) and the second microcomputer 30(2) is normal. The monitoring circuit 44 determines whether the communication between the first microcomputer 30(1) and the second microcomputer 30(2) is normal, for example, based on whether data is being exchanged between the first microcomputer 30(1) and the second microcomputer 30(2) via the communication line 42. The monitoring circuit 44 generates a second monitoring result signal S3 indicating whether the communication between the first microcomputer 30(1) and the second microcomputer 30(2) is normal. The first microcomputer 30(1) and the second microcomputer 30(2) receive the first monitoring result signal S2 and the second monitoring result signal S3 generated by the monitoring circuit 44.

[0046] The main ECU 50 detects whether the first microcomputer 30 ( 1 ) or the second microcomputer 30 ( 2 ) is normal based on whether the following two conditions A1 and A2 are satisfied.

[0047] <a1>The mutual communication between the first microcomputer 30 ( 1 ) and the second microcomputer 30 ( 2 ) via the communication line 42 is interrupted.

[0048] <a2>The communication with the first microcomputer 30 ( 1 ) via the communication line 55 ( 1 ) or the communication with the second microcomputer 30 ( 2 ) via the communication line 55 ( 2 ) is interrupted.

[0049] The main ECU 50 can identify whether the mutual communication between the first microcomputer 30(1) and the second microcomputer 30(2) via the communication line 42 is interrupted based on the electrical signal S1(1) transmitted from the first microcomputer 30(1) via the communication line 55(1) or the electrical signal S1(2) transmitted from the second microcomputer 30(2) via the communication line 55(2).

[0050] When the electrical signal S1(1) periodically generated by the first microcomputer 30(1) or the electrical signal S1(2) periodically generated by the second microcomputer 30(2) is not received, the main ECU 50 can identify whether the communication with the first microcomputer 30(1) or the communication with the second microcomputer 30(2) is interrupted.

[0051] When the communication with the first microcomputer 30(1) is interrupted and the mutual communication between the first microcomputer 30(1) and the second microcomputer 30(2) is recognized to be interrupted using the electrical signal S1(2), the main ECU 50 determines that the first microcomputer 30(1) is abnormal and the second microcomputer 30(2) is normal. When the communication with the second microcomputer 30(2) is interrupted and the mutual communication between the first microcomputer 30(1) and the second microcomputer 30(2) is recognized to be interrupted using the electrical signal S1(1), the main ECU 50 determines that the first microcomputer 30(1) is normal and the second microcomputer 30(2) is abnormal.

[0052] When determining that one of the first microcomputer 30(1) and the second microcomputer 30(2) is abnormal, the main ECU 50 generates a command S4 for a normal microcomputer of the first microcomputer 30(1) and the second microcomputer 30(2). The command S4 is a command for causing the normal microcomputer to increase the current supplied to the stator coil of the corresponding system.

[0053] Processing of kth microcomputer

[0054] The following will refer to Figure 2 The processing performed by the kth microcomputer 30(k) will be described. Figure 2 The illustrated processing is realized by causing the CPU 32(k) to execute a program stored in the ROM 34(k). In the following description, the processing executed by the first microcomputer 30(1) and the second microcomputer 30(2) are collectively denoted using "k".

[0055] The integration process M10(k) is a process of integrating the rotation angle θm(k) of the rotor 12. The conversion process M12(k) is a process of converting the output of the integration process M10(k) into the rotation angle θp(k) of the steering shaft by multiplying the output by a predetermined coefficient K. At the neutral position of the steering shaft corresponding to the driving state of the vehicle traveling straight ahead, the rotation angle θp(k) is zero, and the sign of the rotation angle θp(k) differs depending on whether the vehicle is turning right or left.

[0056] The feedback operation amount calculation process M20(k) is a process for calculating the feedback operation amount MFB(k), which is an operation amount for feedback-controlling the rotation angle θp(k) so that it becomes the target angle θp*. In the feedback operation amount calculation process M20(k), the feedback operation amount MFB(k) is calculated as the sum of the output value of the proportional element, the output value of the integral element, and the output value of the differential element. Specifically, the feedback operation amount calculation process M20(k) is as follows.

[0057] That is, the differential calculation process M22(k) is a process of calculating the difference between the rotation angle θp(k) and the target angle θp*. The proportional element M24(k) is a process of multiplying the difference between the rotation angle θp(k) as the output of the differential calculation process M22(k) and the target angle θp* by the proportional coefficient Kp. The integral element includes an integral gain multiplication process M26(k) and an integral process M28(k). The integral gain multiplication process M26(k) is a process of multiplying the difference between the rotation angle θp(k) as the output of the differential calculation process M22(k) and the target angle θp* by an integral gain Ki. The integral process M28(k) is a process of updating the integral value of the output of the integral gain multiplication process M26(k) and outputting the updated integral value of the output of the integral gain multiplication process M26(k). The differential element includes a differential gain multiplication process M30(k) and a differential process M32(k). The differential gain multiplication process M30(k) is a process of multiplying the difference between the rotation angle θp(k) as the output of the differential calculation process M22(k) and the target angle θp* by the differential gain Kd. The differential process M32(k) is a process of differentiating the output of the differential gain multiplication process M30(k). The addition process M34(k) is a process of calculating the sum of the output values ​​of the proportional element M24(k), the integral process M28(k), and the differential process M32(k), and outputting the calculated sum as the feedback operation amount MFB(k).

[0058] The feedforward operation amount calculation process M40(k) is a process for calculating the feedforward operation amount MFF(k), which is an operation amount for controlling the rotation angle θm(k) to make it a target angle θp*. In the feedforward operation amount calculation process M40(k), the larger the absolute value of the target angle θp* is, the feedforward operation amount MFF(k) having a larger absolute value is calculated. This calculation process can be realized, for example, by causing the CPU 32(k) to perform mapping calculation on the feedforward operation amount MFF(k) in a state in which mapping data with the target angle θp* as an input variable and the feedforward operation amount MFF(k) as an output variable is pre-stored in the ROM 34(k). Here, the mapping data is a set of data including discrete values ​​of the input variables and values ​​of the output variables corresponding to the values ​​of the input variables. In the mapping calculation, for example, when the value of the input variable matches one of the values ​​of the input variables of the mapping data, the value of the output variable of the corresponding mapping data is output as the calculation result. In the mapping calculation, when the value of the input variable does not match any value of the input variable in the mapping data, a value obtained by interpolation using a plurality of values ​​of the output variable included in the mapping data is output as a calculation result.

[0059] The addition process M42 (k) is a process of calculating a k-th operation amount MV (k) by adding the feedback operation amount MFB (k) and the feedforward operation amount MFF (k). The k-th operation amount MV (k) is a q-axis current command value.

[0060] The first operation signal generation process M44(1) is a process for calculating the operation signal MS(1) of the first inverter 22(1) using a value obtained by dividing the first operation amount MV(1) according to the number of control systems (two systems in this article). That is, the first operation signal generation process M44(1) is a process for calculating the operation signal MS(1) of the first inverter 22(1) so that the q-axis current flowing in the first stator coil 14(1) becomes "1 / 2" of the first operation amount MV(1) and outputting the calculated operation signal MS(1).

[0061] The selection process M50 is a process of selectively outputting one of the first operation amount MV(1) calculated in the addition process M42(1) and the second operation amount MV(2) calculated in the addition process M42(2) to the second operation signal generation process M44(2).

[0062] The second operation signal generation process M44(2) is a process for calculating the operation signal MS(2) of the second inverter 22(2) using a value obtained by dividing the first operation amount MV(1) or the second operation amount MV(2) selected in the selection process M50 according to the number of control systems (two control systems in this article). That is, in principle, the second operation signal generation process M44(2) is a process for calculating the operation signal MS(2) of the second inverter 22(2) so that the q-axis current flowing in the second stator coil 14(2) becomes "1 / 2" of the output of the selection process M50 and outputting the calculated operation signal MS(2).

[0063] The determination process M60 (k) is a process of determining whether the first microcomputer 30 (1) and the second microcomputer 30 (2) are operating normally. Specifically, the determination process M60 (k) executes the following three processes B1, B2, and B3.

[0064] <b1>A process of determining whether the power supply voltage VB(1) of the first microcomputer 30(1) and the power supply voltage VB(2) of the second microcomputer 30(2) are normal based on the first monitoring result signal S2 generated by the monitoring circuit 44.

[0065] <b2>A process of determining whether the mutual communication between the first microcomputer 30 ( 1 ) and the second microcomputer 30 ( 2 ) is normal based on the second monitoring result signal S3 generated by the monitoring circuit 44 .

[0066] <b3>When the instruction S4 is generated by the main ECU 50, a process of determining whether to execute the control based on the instruction S4 is performed based on the second monitoring result signal S3 generated by the monitoring circuit 44.

[0067] The selection process M62(k) is a process of selecting, based on the determination result from the determination process M60(k), one of the gains "0", "1", and "2" which are three fixed values stored in the ROM 34(k). In the selection process M62(k), when the determination result from the determination process M60(k) indicates that the power supply voltage VB(k) of the k-th microcomputer 30(k) of the corresponding system is normal, the gain "1" is selected. In the selection process M62(k), when the determination result from the determination process M60(k) indicates that the power supply voltage VB(k) of the k-th microcomputer 30(k) of the corresponding system is abnormal, the gain "0" is selected. In the selection process M62(k), when the determination result from the determination process M60(k) indicates that the power supply voltage VB(k) of a system other than the corresponding system is abnormal, the gain "2" is selected. In the selection process M62(k), when the determination result from the determination process M60(k) indicates that the control based on the instruction S4 is to be executed, the gain "2" is also selected.

[0068] The multiplication process M64(k) is a process of multiplying the gain selected in the selection process M62(k) by the feedback operation amount MFB(k) calculated in the addition process M34(k).

[0069] <Operation of the CPU 32(k)>

[0070] The operation of the CPU 32(k) will be described below.

[0071] As Figure 2 shown, when the following two determination results C1 and C2 are obtained in the determination process M60(1), the CPU 32(1) selects the gain "1" in the selection process M62(1).

[0072] <c1>The power supply voltage VB(1) of the first microcomputer 30(1) and the power supply voltage VB(2) of the second microcomputer 30(2) are normal.

[0073] <c2>The mutual communication between the first microcomputer 30 ( 1 ) and the second microcomputer 30 ( 2 ) is normal.

[0074] When the determination results C1 and C2 are obtained, the main ECU 50 basically does not generate the instruction S4. This is because the power supply voltage VB(k) of the CPU 32(k) is normal and the mutual communication between the first microcomputer 30(1) and the second microcomputer 30(2) is normal. Here, it is conceivable that the instruction S4 is erroneously generated because the main ECU 50 erroneously determines that one of the first microcomputer 30(1) and the second microcomputer 30(2) is abnormal. In this case, in the determination process M60(1), when the instruction S4 is generated by the main ECU 50 and the determination result C2 is obtained, it is determined that the instruction S4 will not be adopted.

[0075] When gain "1" is selected in the selection process M62(1), the value obtained by multiplying the feedback operation amount MFB(1) calculated in the addition process M34(1) by the gain "1" is used as the final feedback operation amount MFB(1). In the first operation signal generation process M44(1), an operation signal MS(1) for operating the first inverter 22(1) is generated so that the q-axis current flowing in the first stator coil 14(1) is "1 / 2" of the first operation amount MV(1). In addition, the CPU 32(1) outputs the first operation amount MV(1) reflecting the final feedback operation amount MFB(1) to the second microcomputer 30(2) via the communication line 42.

[0076] Similar to CPU 32(1), when two determination results C1 and C2 are obtained in determination processing M60(2), CPU 32(2) selects gain "1" in selection processing M62(2). When determination results C1 and C2 are obtained, CPU 32(2) adopts the first operation amount MV(1) output from CPU 32(1) in selection processing M50. Therefore, an operation signal MS(2) for operating the second inverter 22(2) is generated in the second operation signal generation processing M44(2) so that the q-axis current flowing in the second stator coil 14(2) is "1 / 2" of the first operation amount MV(1).

[0077] <A system failure: a system driver>

[0078] like Figure 3 As shown, when the following two determination results D1 and D2 are obtained in the determination process M60 ( 1 ), the CPU 32 ( 1 ) selects the gain “0” in the selection process M62 ( 1 ).

[0079] <d1>The power supply voltage VB(1) of the first microcomputer 30(1) is abnormal and the power supply voltage VB(2) of the second microcomputer 30(2) is normal.

[0080] <d2>The mutual communication between the first microcomputer 30 ( 1 ) and the second microcomputer 30 ( 2 ) is abnormal.

[0081] When the determination results D1 and D2 are obtained, the value obtained by multiplying the feedback operation amount MFB(1) calculated in the addition process M34(1) by the gain "0" is used as the final feedback operation amount MFB(1). In addition, when the determination results D1 and D2 are obtained, the CPU 32(1) switches the relays 24(1) and 26(1) from the closed state to the open state via the peripheral circuit 36(1).

[0082] Similar to the CPU 32(1), when the determination results D1 and D2 are obtained in the determination process M60(2), the CPU 32(2) adopts the second operation amount MV(2) in the selection process M50. When the determination results D1 and D2 are obtained in the determination process M60(2), the CPU 32(2) selects the gain "2" in the selection process M62(2). Therefore, the value of the final feedback operation amount MFB(2) used in the addition process M42(2) is twice the value of the feedback operation amount MFB(2) calculated in the addition process M34(2). That is, the decrease in the feedback operation amount MFB(1) is compensated by increasing the feedback operation amount MFB(2).

[0083] In the second operation signal generation process M44(2), an operation signal MS(2) for operating the second inverter 22(2) is generated so that the q-axis current flowing in the second stator coil 14(2) is "1 / 2" of the second operation quantity MV(2). The feedback operation quantity MFB(2) having a value twice that of the original feedback operation quantity MFB(2) calculated in the addition process M34(2) is reflected in the second operation quantity MV(2). Therefore, ultimately, an operation signal MS(2) for operating the second inverter 22(2) is generated so that the q-axis current flowing in the second stator coil 14(2) becomes the feedback operation quantity MFB(2) calculated in the addition process M34(2). That is, since power is not supplied to the first stator coil 14 (1), the q-axis current flowing in the second stator coil 14 (2) needs to be the second operation quantity MV (2) reflecting 100% of the feedback operation quantity MFB (2) calculated in the addition processing M34 (2) in order to control the rotation angle θp (2) to become the target angle θp*.

[0084] When the power supply voltage VB(1) of the first microcomputer 30(1) is normal and the power supply voltage VB(2) of the second microcomputer 30(2) is abnormal, the first microcomputer 30(1) and the second microcomputer 30(2) perform operations inverse to those when the power supply voltage VB(1) is abnormal and the power supply voltage VB(2) is normal.

[0085] Multiplication Mode

[0086] As described above, when a failure occurs in one of the circuits of the first system and the second system in the control device 20, the operation state of the control device 20 is shifted to a so-called one-system driving state in which the circuit of the normal system is used to control the supply of electric power to the motor 10. In the one-system driving state, it is possible to ensure that the motor 10 generates the required torque, but there is the following problem.

[0087] That is, when the state in which the power supply voltage VB(k) is less than the predetermined voltage threshold value is maintained for a set time, the monitoring circuit 44 determines that the power supply voltage VB(k) of the kth microcomputer 30(k) is abnormal. Therefore, until the set time has passed after the abnormality of the power supply voltage VB(k) has been detected and the abnormality has been determined, that is, until the operating state of the control device 20 is transferred to the one-system drive state after the abnormality of the power supply voltage VB(k) has been detected, the supply of power to the motor coil of the abnormal system is stopped and the state in which the feedback operation amount MFB(k) of the normal system is multiplied by a gain of "1" is maintained. In the kth operation signal generation process M44(k) of the normal system, an operation signal MS(k) for operating the kth inverter 22(k) is generated so that the q-axis current flowing in the kth stator coil 14(k) is "1 / 2" of the kth operation amount MV(k). Therefore, until the operating state of the control device 20 is transferred to the one-system drive state, the torque generated by the motor 10 is approximately half of the torque generated when both systems are normal. Therefore, the CPU 32(k) performs the following processing.

[0088] That is, when the following two determination results E1 and E2 are obtained in the determination process M60 ( 1 ), the CPU 32 ( 1 ) selects the gain “0” in the selection process M62 ( 1 ).

[0089] <e1>The mutual communication between the first microcomputer 30 ( 1 ) and the second microcomputer 30 ( 2 ) is abnormal.

[0090] <e2>The command S4 is generated by the main ECU 50 .

[0091] In the determination process M60 ( 1 ), when the command S4 is generated by the main ECU 50 and the mutual communication between the first microcomputer 30 ( 1 ) and the second microcomputer 30 ( 2 ) is abnormal, it is determined that the process based on the command S4 is to be executed.

[0092] Therefore, when the determination results E1 and E2 are obtained, the value obtained by multiplying the feedback operation amount MFB(1) calculated in the addition process M34(1) by the gain "0" is used as the final feedback operation amount MFB(1). In addition, when the determination results E1 and E2 are obtained, the CPU 32(1) switches the relays 24(1) and 26(1) from the closed state to the open state via the peripheral circuit 36(1).

[0093] Similar to the CPU 32(1), when the determination results E1 and E2 are obtained in the determination process M60(2), the CPU 32(2) adopts the second operation amount MV(2) in the selection process M50. When the determination results E1 and E2 are obtained in the determination process M60(2), the CPU 32(2) selects the gain "2" in the selection process M62(2). Therefore, the value of the final feedback operation amount MFB(2) used in the addition process M42(2) is twice the value of the feedback operation amount MFB(2) calculated in the addition process M34(2). That is, the decrease in the feedback operation amount MFB(1) is compensated by increasing the feedback operation amount MFB(2).

[0094] Therefore, the feedback operation amount MFB(2) having a value twice that of the original feedback operation amount MFB(2) calculated in the addition process M34(2) is reflected in the second operation amount MV(2). Therefore, in the second operation signal generation process M44(2), an operation signal MS(2) for operating the second inverter 22(2) is generated so that the q-axis current flowing in the second stator coil 14(2) becomes the original feedback operation amount MFB(2) calculated in the addition process M34(2).

[0095] When the power supply voltage VB(1) of the first microcomputer 30(1) is normal and the power supply voltage VB(2) of the second microcomputer 30(2) is abnormal, the first microcomputer 30(1) and the second microcomputer 30(2) perform operations inverse to those when the power supply voltage VB(1) is abnormal and the power supply voltage VB(2) is normal.

[0096] In this way, the feedback operation amount MFB(k) calculated in the feedback operation amount calculation process M20(k) of the normal system based on the instruction S4 from the main ECU 50 can be increased without particularly waiting for the state in which the power supply voltage of the microcomputer of the abnormal system is less than the predetermined voltage threshold value as the monitoring result from the monitoring circuit 44 to be maintained for a set time. Therefore, even when one of the first microcomputer 30(1) and the second microcomputer 30(2) fails, the motor 10 generates the same degree of torque as the torque generated when the microcomputers of both systems are normal in advance. That is, unlike the aforementioned one system driving state, when one of the first microcomputer 30(1) and the second microcomputer 30(2) fails, the period in which the torque generated by the motor 10 becomes about half of the original required torque is shortened.

[0097] Advantages of the First Embodiment

[0098] Therefore, according to the first embodiment, the following advantages can be obtained. (1) When one of the first microcomputer 30 (1) and the second microcomputer 30 (2) fails, the operation amount calculated by the other of the first microcomputer 30 (1) and the second microcomputer 30 (2) according to the instruction S4 from the main ECU 50 is increased according to the number of control systems. Therefore, even when one of the first microcomputer 30 (1) and the second microcomputer 30 (2) fails, the total torque generated by the motor 10 is ensured. Therefore, it is possible to more appropriately cope with a failure of one of the two systems.

[0099] (2) When an abnormality occurs in the power supply voltage of the microcomputer of one system, the microcomputer of the normal system increases the amount of current supplied to the stator coil of the normal system according to the instruction S4 from the main ECU 50 without waiting for the monitoring result from the monitoring circuit 44. Therefore, the motor 10 generates torque of the same degree as the total torque generated by the motor 10 in the normal state in advance. Here, the main ECU 50 detects the failure of one system based on the detection results indicating that the communication with the first microcomputer 30 (1) is interrupted, the communication with the second microcomputer 30 (2) is interrupted, and the communication between the microcomputers is interrupted, without monitoring the power supply voltage of the microcomputer. The interruption of communication can be detected immediately. Therefore, the main ECU 50 can detect the failure of one system at an earlier timing than the timing of the monitoring circuit 44 that uses the abnormality of the power supply voltage of one microcomputer as the abnormality determination condition. Therefore, when a failure occurs in one system, the period in which the torque generated by the motor 10 becomes half of the original required torque is greatly shortened. It is also possible to ensure the traceability of the rotation angle θp(k) to the target angle θp*.

[0100] (3) It is also conceivable that the main ECU 50 mistakenly determines that the microcomputer of one system is abnormal. Therefore, when the instruction S4 is generated by the main ECU 50 and the communication between the microcomputers is normal, the microcomputer of the other system determines that the processing based on the instruction S4 is not performed. This is because when the communication between the microcomputers is performed normally, it can be said that the first microcomputer 30 (1) and the second microcomputer 30 (2) are operating normally. The microcomputer of the other system determines that one system is normal, and performs the supply of power to the stator coil without following the instruction S4. Therefore, even if one system is normal, the amount of current supplied to the stator coil of the other system is prevented from becoming greater than the original required amount of current due to the erroneous determination of the main ECU 50. That is, it is possible to prevent excessive torque from being generated by the motor 10 due to the erroneous determination of the main ECU 50.

[0101] (4) When a system fails, the microcomputer of the normal system increases the amount of current supplied to the stator coil of the normal system according to the instruction S4 from the main ECU 50 without waiting for the monitoring result from the monitoring circuit 44. Here, it is conceivable that the main ECU 50 mistakenly determines the failure of the microcomputer of one system. In this case, there is a concern that even if the microcomputer of one system is normal, the amount of current supplied to the stator coil of the other system will become greater than the original required amount of current. Therefore, in the present embodiment, when the microcomputer of the other system performs power supply control based on the instruction S4 from the main ECU 50, the feedback operation amount MFB(k) calculated in the feedback operation amount calculation process M20(k) of the system determined to be abnormal is forcibly set to zero. Therefore, it is possible to prevent excessive torque from being generated by the motor 10 due to the erroneous determination of the main ECU 50.

[0102] (5) For example, it is conceivable that the communication state between the first microcomputer 30 (1) and the second microcomputer 30 (2) is unstable. In this case, for example, the determination result indicating whether the communication between the microcomputers is normal (the determination is performed by the monitoring circuit 44) may frequently change between normal and abnormal. When the instruction S4 is generated by the main ECU 50, there is a concern that the operating state of the control device 20 frequently switches between a state in which control based on the instruction S4 is performed and a state in which control based on the instruction S4 is not performed in the case where the determination result indicating whether the communication between the microcomputers is normal changes. In this regard, according to the present embodiment, the microcomputer of the normal system continues to perform control based on the instruction S4 in a period after the microcomputer of the normal system has started to perform control based on the instruction S4 until the end of the automatic driving or until the operating state is transferred to a system driving state (that is, until the period in which the monitoring circuit 44 is determined to detect an abnormality), regardless of the communication state between the microcomputers. Therefore, since frequent large changes in the amount of current supplied to the motor 10 are suppressed, the motor 10 can be operated stably.

[0103] Second embodiment

[0104] A control device for a motor according to a second embodiment will be described below. Figure 1 The first embodiment shown has the same configuration as that of the first embodiment, and is different from the first embodiment in the processing performed by the k-th microcomputer 30(k) when a system failure occurs. In the following description, when the processing performed by the first microcomputer 30(1) and the processing performed by the second microcomputer 30(2) are collectively represented, they are also described using the symbol "k".

[0105] like Figure 4 As shown, the basic assist value calculation process M70(k) is a process for calculating the basic assist value MI(k) based on the steering torque Th detected by the torque sensor provided in the steering shaft. The steering state of the driver is reflected in the steering torque Th. The basic assist value MI(k) is a q-axis current command value indicating the value of the amount of current to be supplied to the motor 10 in order to generate an assist force of appropriate magnitude based on the steering torque Th. The basic assist value calculation process M70(k) calculates the basic assist value MI(k) so that its absolute value increases as the absolute value of the steering torque Th increases. The driver's steering is assisted by the torque generated by the motor 10.

[0106] The assist correction value calculation process M72(k) is a process for calculating an assist correction value MC(k) based on the steering torque Th. The assist correction value MC(k) is used to cancel the feedback operation amount MFB(k) calculated in the feedback operation amount calculation process M20(k).

[0107] The multiplication process M74 ( k ) is a process of multiplying the auxiliary correction value MC(k) calculated in the auxiliary correction value calculation process M72 ( k ) by the gain (0, 1, or 2) calculated in the selection process M62 ( k ).

[0108] Advantages of the Second Embodiment

[0109] Therefore, according to the second embodiment, the following operations and advantages can be obtained. (6) When the control based on the instruction S4 from the main ECU 50 is being performed, the value of the feedback operation amount MFB(k) of the normal system calculated in the feedback operation amount calculation process M20(k) is twice the feedback operation amount MFB(k) in the normal state in which the instruction S4 is not generated. Therefore, when the control based on the instruction S4 from the main ECU 50 is being performed, there is a concern that the doubled feedback operation amount MFB(k) is not offset by using the assist correction value MC(k) calculated in the assist correction value calculation process M72(k) without any change. In this regard, according to the present embodiment, when the control based on the instruction S4 from the main ECU 50 is being performed, the assist correction value MC(k) of the normal system is doubled in the multiplication process M74(k). Therefore, the doubled feedback operation amount MFB(k) can be offset more appropriately. Therefore, when the control based on the instruction S4 is being performed and the driver operates the steering wheel, the motor 10 generates an assist force corresponding to the basic assist value MI(k). The driver's steering is assisted by the assist force. The steering feel given to the driver can be improved.

[0110] In addition, depending on product specifications, etc., a configuration may be adopted in which the k-th microcomputer 30(k) does not perform multiplication processing on the auxiliary correction value MC(k). With this configuration, when control based on the instruction S4 from the main ECU 50 is being performed, the auxiliary correction value MC(k) calculated in the auxiliary correction value calculation processing M72(k) is used without any change. That is, the auxiliary correction value MC(k) is only a value corresponding to the steering state. Therefore, the doubled feedback operation amount MFB(k) cannot be properly offset. Therefore, compared with the case in which control based on the instruction S4 from the main ECU 50 is being performed and multiplication processing is performed on the auxiliary correction value MC(k) or the automatic driving control function is turned off, the reaction (steering reaction force) from the steering wheel increases slightly. With this increase in reaction, the driver can be notified of the abnormality.

[0111] Other Implementations

[0112] The first embodiment and the second embodiment may be modified as follows. In the first embodiment and the second embodiment, when a system fails, the microcomputer of the normal system increases the amount of current supplied to the kth stator coil 14(k) by doubling the feedback operation amount MFB(k) according to the instruction S4 from the main ECU 50, but the output value of the proportional element, the output value of the integral element, and the output value of the differential element may be doubled individually.

[0113] In the first embodiment and the second embodiment, in the selection process M62(k), when the determination result in the determination process M60(k) indicates an abnormality in the power supply voltage VB(k) of the kth microcomputer 30(k) of the corresponding system, the feedback operation amount MFB(k) of the corresponding system is forcibly set to "0", but the operation of the feedback operation amount calculation process M20(k) may be stopped. When the determination result in the determination process M60(k) indicates an abnormality in the power supply voltage VB(k) of the kth microcomputer 30(k) of the corresponding system, the feedback operation amount MFB(k) may not be set to "0" as long as it is reduced.

[0114] The feedback operation amount MFB(k) is not limited to the sum of the output values ​​of the proportional element M24(k), the integral element, and the differential element. For example, the feedback operation amount MFB(k) may be the sum of the two output values ​​of the proportional element and the integral element. The feedback operation amount MFB(k) may be the sum of the two output values ​​of the integral element and the differential element. The feedback operation amount MFB(k) may be the output value of the integral element.

[0115] In the first and second embodiments, it is not necessary to calculate the k-th operation amount MV(k) based on the feedforward operation amount MFF(k). That is, the feedforward operation amount calculation process M40(k) may be omitted in the process executed by the CPU 32(k). In this case, the feedback operation amount MFB(k) calculated by the feedback operation amount calculation process M20(k) is used as the k-th operation amount MV(k).

[0116] For example, instead of adopting the kth microcomputer 30(k) including the CPU 32(k) as a software processing circuit that executes a program stored in a storage device, a dedicated hardware circuit such as an application specific integrated circuit (ASIC) specially provided for a specific application may be adopted as the control device 20. A configuration in which a software processing circuit and a dedicated hardware circuit are mixed may be adopted as the control device 20.

[0117] The number of control systems of the control device 20 only needs to be the same as the number of systems of the motor. For example, when the motor includes three systems of coils, the control device 20 may include three control systems. In this case, preferably, one of the multiple control systems of the control device 20 is used as a master system, and the other control systems are used as slave systems.

[0118] A configuration in which relays 26(1) and 26(2) are omitted may be adopted as control device 20. Control device 20 may control a motor as a driving source of a steer-by-wire actuator in which power transmission to the steering wheel is cut off.

[0119] In the first embodiment and the second embodiment, when both systems are normal, the second operation signal generation process M44 (2) uses the value obtained by dividing the first operation amount MV (1) selected in the selection process M50 according to the number of control systems to calculate the operation signal MS (2) of the second inverter 22 (2), but the operation signal can be calculated as follows. That is, when both systems are normal, the second operation signal generation process M44 (2) uses the second operation amount MV (2) to calculate the operation signal MS (2) of the second inverter 22 (2). In this case, the process of omitting the selection process M50 can be adopted as the process executed by the CPU 32 (2).

Claims

1. A control device (20) for a motor (10) which steers a steering wheel of a vehicle and comprises a first coil and a second coil which are insulated from each other, the control device (20) being characterized by comprising: a first circuit that calculates a first operation amount corresponding to a torque generated by the motor (10) to feedback-control an angle that can be converted into a steering angle of the steering wheel and detected by a first sensor so that the angle becomes a target angle calculated by an external circuit, and controls supply of electric power to the first coil based on a value obtained by dividing the first operation amount according to the number of control systems; as well as a second circuit that calculates a second operation amount corresponding to the torque generated by the motor (10) to perform feedback control on an angle detected by a second sensor so that the angle becomes the target angle, the second circuit selectively executing a first process for controlling the supply of power to the second coil based on a value obtained by dividing the first operation amount according to the number of control systems, and a second process for controlling the supply of power to the second coil based on a value obtained by dividing the second operation amount according to the number of control systems, and when a failure occurs in the first circuit, the second circuit switches the first process to the second process, wherein, when one of the first circuit and the second circuit fails, the external circuit generates an instruction for executing the following processing: increasing the operation amount calculated by the other of the first circuit and the second circuit according to the number of the control system, The device further comprises a monitoring circuit (44) for monitoring at least whether the abnormal state of the power supply voltage of the first circuit and the second circuit is maintained for a set time. wherein, when a failure is identified in one of the first circuit and the second circuit based on a monitoring result from the monitoring circuit (44), the first circuit and the second circuit increase the operation amount of the other of the first circuit and the second circuit according to the number of the control systems, The monitoring circuit (44) also monitors mutual communication between the first circuit and the second circuit; and When the instruction is generated and it is recognized based on the monitoring result that the mutual communication between the first circuit and the second circuit is normal, the first circuit and the second circuit do not adopt the instruction.

2. The control device (20) according to claim 1, characterized in that: When communication with one of the first circuit and the second circuit is interrupted and when abnormality in mutual communication between the first circuit and the second circuit is identified through communication with the other of the first circuit and the second circuit, the external circuit determines that one of the first circuit and the second circuit has failed and generates the instruction.

3. The control device (20) according to claim 1 or 2, characterized in that: When one of the first circuit and the second circuit increases its own operation amount according to the number of the control systems in accordance with the instruction, the other of the first circuit and the second circuit performs a process of reducing its own operation amount.

4. The control device (20) according to claim 1 or 2, characterized in that: The first circuit or the second circuit, after having started executing the process according to the instruction, maintains a state in which its own operation amount is increased according to the number of the control systems when the instruction from the external circuit is interrupted.

5. The control device (20) according to claim 1 or 2, characterized in that: The first circuit performs the following processing: a process of calculating a first assist value for causing the motor (10) to generate a steering assist force according to a steering state and adding the first assist value to the first operation amount, and a process of calculating a first assist correction value for offsetting the first operation amount according to the steering state and adding the first assist correction value to the first operation amount, wherein the first operation amount is used to feedback-control the angle so that the angle becomes the target angle; and The second circuit performs the following processing: calculating a second auxiliary value for causing the motor (10) to generate a steering auxiliary force according to the steering state and adding the second auxiliary value to the second operating amount, and calculating a second auxiliary correction value for offsetting the second operating amount according to the steering state and adding the second auxiliary correction value to the second operating amount, wherein the second operating amount is used to feedback control the angle so that the angle becomes the target angle.

6. The control device (20) according to claim 5, characterized in that When one of the first circuit and the second circuit performs control according to the instruction, the other of the first circuit and the second circuit increases the assist correction value calculated thereby according to the number of the control systems.

7. A control device (20) for a motor (10) which steers a steering wheel of a vehicle and comprises a first coil and a second coil which are insulated from each other, the control device (20) being characterized by comprising: a first circuit that calculates a first operation amount corresponding to a torque generated by the motor (10) to feedback-control an angle that can be converted into a steering angle of the steering wheel and detected by a first sensor so that the angle becomes a target angle calculated by an external circuit, and controls supply of electric power to the first coil based on a value obtained by dividing the first operation amount according to the number of control systems; as well as a second circuit that calculates a second operation amount corresponding to the torque generated by the motor (10) to perform feedback control on an angle detected by a second sensor so that the angle becomes the target angle, and controls the supply of electric power to the second coil based on a value obtained by dividing the second operation amount according to the number of the control systems, wherein, when one of the first circuit and the second circuit fails, the external circuit generates an instruction for executing the following processing: increasing the operation amount calculated by the other of the first circuit and the second circuit according to the number of the control system, The device further comprises a monitoring circuit (44) for monitoring at least whether the abnormal state of the power supply voltage of the first circuit and the second circuit is maintained for a set time. wherein, when a failure is identified in one of the first circuit and the second circuit based on a monitoring result from the monitoring circuit (44), the first circuit and the second circuit increase the operation amount of the other of the first circuit and the second circuit according to the number of the control systems, The monitoring circuit (44) also monitors mutual communication between the first circuit and the second circuit; and When the instruction is generated and it is recognized based on the monitoring result that the mutual communication between the first circuit and the second circuit is normal, the first circuit and the second circuit do not adopt the instruction.

8. The control device (20) according to claim 7, characterized in that When communication with one of the first circuit and the second circuit is interrupted and when abnormality in mutual communication between the first circuit and the second circuit is identified through communication with the other of the first circuit and the second circuit, the external circuit determines that one of the first circuit and the second circuit has failed and generates the instruction.

9. The control device (20) according to claim 7 or 8, characterized in that: When one of the first circuit and the second circuit increases its own operation amount according to the number of the control systems in accordance with the instruction, the other of the first circuit and the second circuit performs a process of reducing its own operation amount.

10. The control device (20) according to claim 7 or 8, characterized in that: The first circuit or the second circuit, after having started executing the process according to the instruction, maintains a state in which its own operation amount is increased according to the number of the control systems when the instruction from the external circuit is interrupted.

11. The control device (20) according to claim 7 or 8, characterized in that: The first circuit performs the following processing: a process of calculating a first assist value for causing the motor (10) to generate a steering assist force according to a steering state and adding the first assist value to the first operation amount, and a process of calculating a first assist correction value for offsetting the first operation amount according to the steering state and adding the first assist correction value to the first operation amount, wherein the first operation amount is used to feedback-control the angle so that the angle becomes the target angle; and The second circuit performs the following processing: calculating a second auxiliary value for causing the motor (10) to generate a steering auxiliary force according to the steering state and adding the second auxiliary value to the second operating amount, and calculating a second auxiliary correction value for offsetting the second operating amount according to the steering state and adding the second auxiliary correction value to the second operating amount, wherein the second operating amount is used to feedback control the angle so that the angle becomes the target angle.

12. The control device (20) according to claim 11, characterized in that When one of the first circuit and the second circuit performs control according to the instruction, the other of the first circuit and the second circuit increases the assist correction value calculated thereby according to the number of the control systems.

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