CN113098363A

CN113098363A - Control apparatus and control method

Info

Publication number: CN113098363A
Application number: CN202011535195.1A
Authority: CN
Inventors: 星野宏树
Original assignee: Nidco Smart Motion Co ltd
Current assignee: Nidco Smart Motion Co ltd; Nidec Mobility Corp
Priority date: 2019-12-23
Filing date: 2020-12-23
Publication date: 2021-07-09
Also published as: JP7203003B2; DE102020134718A1; JP2021098471A

Abstract

A control device, comprising: first and second motors that share and output a driving force; and first and second control systems that control the respective motors, each control system including an abnormality detection unit that detects an abnormality of the own system and the other system, a control unit that supplies a current for outputting a driving force to the motors, a shunt resistor, and a variable amplification unit. The variable amplifying unit amplifies a potential difference between both ends of the shunt resistor by using a first amplification factor in a case where abnormality of the own system and another system is not detected. The variable amplifying unit amplifies the potential difference by using a second amplification factor smaller than the first amplification factor in a case where the abnormality of the own system is not detected and the abnormality of the other system is detected.

Description

Control apparatus and control method

Technical Field

One or more embodiments of the present invention relate to a control apparatus and a control method, and more particularly, to a control apparatus having a redundant system and a control method thereof.

Background

There is known a technique relating to a control apparatus which has a redundant system and can continue control even if an abnormality occurs. For example, patent document 1 discloses an electric power steering apparatus in which a plurality of motors that assist a steering force are provided to increase the distribution amount of the assist steering force given to a normal motor and reduce the burden on a driver when at least one of the plurality of motors fails. The electric power steering apparatus includes a target current distribution unit that increases distribution of an assist steering force applied to a normal motor when at least one of the plurality of motors fails, and reduces a burden on a driver by increasing a distribution amount of the assist steering force given to the normal motor. Further, a current limit value setting unit that sets current limit values of the plurality of motors is included, and when at least one of the plurality of motors fails, the current limit value setting unit sets a current limit value of the normal motor as the current limit value at the time of the failure, and the target current distribution unit distributes the motor current via the current distribution determination unit to which the current limit value at the time of the failure is input, according to the current limit value at the time of the failure, thereby maximizing the capacity of the normal motor.

Patent document 1: JP-A-2004-129402

Disclosure of Invention

In the related art, when one multi-phase motor fails, the distribution amount of the assist steering force applied to the normal motor is increased, and the current limit value of the normal motor is set to increase the distribution amount of the driving force. However, such a control apparatus that controls the multiphase motor generally has an amplifier circuit for amplifying a potential difference in order to detect a current flowing through each phase of the multiphase motor. The amplifier circuit normally amplifies the detected potential difference by a predetermined amplification factor, but when an attempt is made to increase the dispensing amount of a normal multiphase motor, the amplifier circuit may saturate, and if saturated, an accurate current cannot be detected.

One or more embodiments of the present invention have been made in view of such circumstances, and an object thereof is to provide a control apparatus and a control method in which, in a control system that controls a multiphase motor having a redundant system, an amplifier circuit does not saturate even in the case where an abnormality occurs in one system and the share amount of the driving force of the other multiphase motor increases.

One or more embodiments of the present invention provide a control apparatus including: a first motor and a second motor that share and output a driving force for driving a load; a first control system that controls the first motor; and a second control system that controls the second motor. Each of the first control system and the second control system includes: an abnormality detection unit that detects an abnormality of its own system and detects a state of another system; a control unit that supplies a current for outputting a driving force to the motor; a shunt resistor provided for measuring the current; and a variable amplifying unit that amplifies a potential difference between both ends of the shunt resistor by using the first amplification factor or a second amplification factor smaller than the first amplification factor. The variable amplifying unit amplifies the potential difference by using the first amplification factor in a case where the abnormality of the own system is not detected by the abnormality detecting unit and the abnormality of the state of the other system is not detected. The variable amplifying unit amplifies the potential difference by using the second amplification factor in a case where the abnormality of the own system is not detected by the abnormality detecting unit and the state of the other system is detected as abnormal.

Accordingly, it is possible to provide a control apparatus capable of, in a case where a state abnormality of another system is detected, amplifying a potential difference by using an amplification factor smaller than that at the time of normal in a system where no abnormality is detected, thereby expanding a dynamic range of an amplifier circuit at the time of abnormality while maintaining detection accuracy at the time of normal.

Further, in each of the first control system and the second control system, the control unit may supply the electric motor with a current for outputting a driving force shared by the own system, the driving force being calculated by using a sharing ratio changed according to a detection result of the abnormality detecting unit. In the case where the abnormality detecting unit does not detect the abnormality of the own system and does not detect that the state of the other system is abnormal, the sharing ratio may be set to a predetermined first ratio, and the variable amplifying unit may amplify the potential difference by using the first amplification factor. In the case where the abnormality detection unit detects an abnormality of the own system, the sharing ratio may be set to zero. In the case where the abnormality detecting unit does not detect the abnormality of the own system and detects that the state of the other system is abnormal, the sharing ratio may be set to a ratio obtained by adding at least a part of the sharing ratio of the other system to the first ratio, and the variable amplifying unit may amplify the potential difference by using the second amplification factor.

Accordingly, in the case where the state abnormality of the other system is detected, the share ratio of the system in which the abnormality is not detected is set to a ratio obtained by adding at least a part of the share ratio of the system in which the abnormality is detected to the share ratio in the normal state, so that the share amount of the driving force of the multiphase motor of the normal system can be increased in the abnormal state, and the burden on the driver can be reduced.

One or more embodiments of the present invention provide a control method of a control apparatus including: a first motor and a second motor that share and output a driving force for driving a load; a first control system that controls the first motor; and a second control system that controls the second motor, the control method including: amplifying a potential difference at a predetermined position of a current for outputting a driving force to the motor by using a first amplification factor in a case where an abnormality of the own system is not detected and a state abnormality of another system is not detected; and amplifying the potential difference by using a second amplification factor smaller than the first amplification factor in the system in which the abnormality is not detected, in a case where the abnormality of the own system is not detected and the state of the other system is detected as the abnormality.

Accordingly, it is possible to provide a control method capable of expanding the dynamic range of the amplifier circuit at the time of abnormality while maintaining the detection accuracy at the time of abnormality by amplifying the potential difference using an amplification factor smaller than that at the time of abnormality in a system in which abnormality is not detected, in the case where abnormality of the state of another system is detected.

As described above, according to one or more embodiments of the present invention, in a control system that controls a multi-phase motor having a redundant system, even in the case where an abnormality occurs in one system and the share amount of the driving force of another multi-phase motor increases, it is possible to provide a control apparatus and a control method in which an amplifier circuit is not saturated.

Drawings

Fig. 1 is a block configuration diagram of a control apparatus according to a first embodiment of the present invention.

Fig. 2 is an enlarged configuration diagram of a variable amplifying unit of the control apparatus according to the first embodiment of the present invention.

Fig. 3 is a block configuration diagram of a variable amplifying unit of the control apparatus according to the first embodiment of the present invention.

Fig. 4 is a flowchart of a control apparatus according to a first embodiment of the present invention.

Detailed Description

Hereinafter, one or more embodiments of the present invention will be described with reference to the accompanying drawings.

First embodiment

Referring to fig. 1, a control apparatus 1 according to the present embodiment will be described. The control device 1 is an electric power steering control device that controls the first electric motor MT 1/the second electric motor MT2 used in electric power steering (not shown) mounted on a vehicle. Each of the first motor MT 1/the second motor MT2 is a three-phase motor, is provided with two windings in one rotor, and is a two-system redundant motor. The first motor MT 1/the second motor MT2 is not limited thereto, and may be a motor that is redundant to two systems by using two motors including one winding in one rotor. The first electric motor MT1 and the second electric motor MT2 share and output a driving force for driving a steering mechanism (load) of the vehicle. In addition to the steering mechanism of the vehicle of the present embodiment, the load is, for example, a solenoid valve or the like in an electronically controlled brake (control device) in a redundant system associated with automobile electronization.

The control apparatus 1 has redundant systems so as to correspond to motors that are redundant in both systems, because control continues even when an abnormality occurs in any system. The control apparatus 1 includes a first control system 110 corresponding to the system-1 system 100 for the first motor MT1, and a second control system 210 corresponding to the system-2 system 200 for the second motor MT 2. The first and

second control systems

110 and 210 are powered by the common battery VBAT to acquire a steering state from the torque/angle sensor, and respectively drive the first and second electric motors MT1 and MT2 to generate an assist force for power steering.

The first control system 110 includes: two torque sensor signal input circuits that acquire signals from torque/angle sensors for detecting torque and a rotation angle of a steering; two MR sensors that acquire the rotation angle of the rotor obtained from a magnet provided on the rotation shaft of the rotor of the first motor MT1 (second motor MT 2); a microcomputer 111 that acquires signals of a torque sensor signal input circuit, an MR sensor, and the like, and controls rotation of the first motor MT 1; a pre-driver 112 that generates a PWM signal from a control signal of the microcomputer 111; and a bridge circuit 130 that drives the first motor MT1 by a PWM signal. Incidentally, the MR sensor is a magnetoresistive sensor. The microcomputer 111, the pre-driver 112, and the bridge circuit 130 together constitute a control unit that supplies a current for outputting a driving force for rotationally driving the first motor MT1 to the first motor MT 1.

A torque sensor that detects steering torque, which is important information of electric power steering, is redundant. The torque sensor signal input circuit to which the torque sensor signal is input is also redundant. Similarly, the MR sensor itself is also redundant in that it acquires a signal of the rotation angle of the first electric motor MT1, which is important information for electric power steering. If there is no abnormality, the output signals from the redundant torque sensor signal input circuits are designed to be identical. Similarly, the output signals from the redundant MR sensors are designed to be identical in that if there is no anomaly, it detects the same status information of the vehicle. Based on signals obtained from these circuits and the like, the microcomputer 111 calculates a Pulse Width Modulation (PWM) duty value for turning on and off a semiconductor element provided in each phase circuit of the bridge circuit 130. The pre-driver 112 outputs a PWM signal for driving the bridge circuit 130 based on the PWM duty value. The bridge circuit 130 drives rotation of the first motor MT1 existing outside the first control system 110.

The microcomputer 111 includes an abnormality detection unit 120 that detects an abnormality of the first control system 110. The abnormality detection unit 120 detects an abnormality of the first control system 110 as its own system, and detects a state of the second control system 210 as another system. For example, in the case where the torque value applied to the steering is different as the output values of the two torque sensor signal input circuits in the first control system 110, or in the case where the voltage values that vary according to the rotation of the first electric motor MT1 are different as the output values of the two MR sensors, the abnormality detecting unit 120 detects that an abnormality occurs in the torque/angle sensor, the torque sensor signal input circuit, the MR sensor, and the like of the system-1 system 100 in the first control system 110.

The abnormality detection unit 120 may also detect the presence or absence of an abnormality by comparing, for example, an input voltage value from the power supply circuit of the first control system 110, an output voltage value to the terminal of the first electric motor MT1, or the like, with a predetermined threshold value. For example, when a detection value of the voltage value is acquired at the terminal of the first electric motor MT1, the abnormality detection unit 120 compares the detection value with a predetermined threshold value, and detects that there is an abnormality in the first control system 110, for example, in the case where the detection value exceeds the threshold value. Similarly, when a detection value of the voltage value is acquired at the terminal of the power supply circuit, the abnormality detection unit 120 compares the detection value with a predetermined threshold value, and detects that there is an abnormality in the first control system 110, for example, in a case where the detection value is smaller than the threshold value.

The microcomputer 111 of the first control system 110 and the microcomputer 211 of the second control system 210 appropriately exchange information in the respective systems. The abnormality detection unit 120 detects a state of presence or absence of an abnormality in the system 2 system 200 via the microcomputer 211 of the second control system 210. The information exchanged by the microcomputer 111 of the first control system 110 and the microcomputer 211 of the second control system 210 may be information indicating that an abnormality is detected in any configuration element or information indicating that an abnormality is not detected in all configuration elements in its own system, or may be information indicating which configuration element detects an abnormality in its own system.

The bridge circuit 130 is a bridge circuit configured by connecting phase circuits CU/CV/CW in parallel corresponding to respective phases U/V/W of the three-phase first motor MT 1. The bridge circuit is an inverter circuit that receives control from the predriver 112 for outputting PWM signals to each phase. The bridge circuit 130 is connected from the power supply circuit to the positive electrode side via a power supply line, and is grounded via a ground line. Each phase circuit CU/CV/CW of the bridge circuit 130 includes, in series, a high-potential-side switching element provided on the power supply line side, a low-potential-side switching element provided on the ground line side, and a shunt resistor 140 provided on the most ground line side. As the high-potential side switching element and the low-potential side switching element, a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) is generally used.

The drain of the high-potential side switching element is connected to the power supply line. Further, the source of the high-potential side switching element is connected to the drain of the low-potential side switching element. The source of the low-potential-side switching element is connected to the ground line via a shunt resistor 140. The PWM signal generated by the pre-driver 112 is input to the gates of the high-potential side switching element and the low-potential side switching element, and the source-drain thereof is turned on/off. The connection points of the high-potential side switching element and the low-potential side switching element are respectively connected to the phases of the first motor MT1, power is supplied to the first motor MT1 by on/off of each switching element, and the control unit rotationally drives the first motor MT 1.

The shunt resistor 140 is provided on the low potential side (ground side) from the low potential side switching element, and is provided for detecting a current supplied from the bridge circuit 130 to each phase of the first motor MT 1. In general, the first motor MT1 is supplied with driving power by exciting a sine wave. At this time, since feedback for controlling the current value of each phase U/V/W is required, a shunt resistor 140 is provided to perform current detection of each phase in each phase circuit CU/CV/CW. In general, since the resistance value of the shunt resistor is small and the potential difference of the shunt resistor 140 flowing the current of each phase is small, it is fed back to the microcomputer 111 via the amplifier circuit. The first control system 110 includes a variable amplifying unit 150 which will be described later as an amplifier circuit.

The microcomputer 111 receives as inputs a phase current value obtained from the shunt resistor 140, a steering torque value obtained from a torque sensor signal input circuit, a vehicle speed from an electronic control unit (ECU, not shown) obtained via a CAN transceiver, a rotation angle of the first electric motor MT1 obtained from an MR sensor, and the like. The microcomputer 111 calculates a target current command value from a steering torque value applied to the steering by the driver at the time of the driver's vehicle speed. For example, the microcomputer 111 performs calculation with reference to a predetermined table (T-I map) in which a steering torque value and a target current command value are associated with each vehicle speed. Further, the microcomputer 111 performs feedback of the phase current value detected by the shunt resistor 140 to a target current command value, and the first electric motor MT1 calculates a command current for each phase corresponding to the assist force to be applied to the steering, and outputs it to the pre-driver 112.

The variable amplifying unit 150 will be described with reference to fig. 2. The variable amplifying unit 150 receives as input the voltage value across the shunt resistor 140 of each phase circuit CU/CV/CW. The variable amplification unit 150 detects and amplifies a current value of each phase circuit CU/CV/CW based on the voltage values at both ends, and outputs the current detection value of each phase as feedback to the microcomputer 111. Further, in the case where the abnormality detection unit 120 detects an abnormality, the variable amplification unit 150 receives a gain setting signal from the microcomputer 111.

The variable amplifying unit 150 will be described in detail with reference to fig. 3. The variable amplification unit 150 includes an amplifier circuit U151, an amplifier circuit V152, an amplifier circuit W153, and a switch controller 154. The amplifier circuit U151 receives the voltage across the shunt resistor 140 in the phase circuit CU, and outputs the current detection value of the phase circuit CU. The amplifier circuit V152 receives the voltage across the shunt resistor 140 in the phase circuit CV, and outputs a current detection value of the phase circuit CV. The amplifier circuit W153 receives the voltage across the shunt resistor 140 in the phase circuit CW and outputs the current detection value of the phase circuit CW.

The amplifier circuit U151 includes one operational amplifier and two gain circuits. One gain circuit is a circuit in which resistors 5K Ω and 100K Ω and a switch S1 are connected in series, and the other gain circuit is a circuit in which resistors 5K Ω and 50K Ω and a switch S2 are connected in series. When the switch S1 is closed and the switch S2 is open, the amplification factor of the amplifier circuit U151 is 20, whereas when the switch S1 is open and the switch S2 is closed, the amplification factor is 10. These resistance values and amplification factors are examples, and are appropriately determined to suit the system. The amplifier circuit V152 and the amplifier circuit W153 have the same configuration as the amplifier circuit U151.

The switch controller 154 receives a gain setting signal from the microcomputer 111 and inputs the gain setting signal to the amplifier circuit U151, the amplifier circuit V152, and the amplifier circuit W153. The gain setting signal is a signal for setting opening and closing of the switch S1 and the switch S2 in the amplifier circuit U151, the amplifier circuit V152, and the amplifier circuit W153. The microcomputer 111 sets the switch S1 closed and the switch S2 open, or the switch S1 open and the switch S2 closed by gain setting signals in the amplifier circuit U151, the amplifier circuit V152, and the amplifier circuit W153. That is, the microcomputer 111 sets the amplification factors of the amplifier circuit U151, the amplifier circuit V152, and the amplifier circuit W153 to 20 or 10 by the gain setting signal. Therefore, the variable amplifying unit 150 outputs, as the current detection value, a current value obtained by amplifying the potential difference across the shunt resistor 140 to two different amplification factors. In other words, the variable amplifying unit 150 outputs a current value obtained by amplifying the potential difference between the both ends of the shunt resistor 140 by the first amplification factor or the second amplification factor smaller than the first amplification factor.

The second control system 210 includes: two torque sensor signal input circuits that acquire signals from torque/angle sensors for detecting torque and a rotation angle of a steering; two MR sensors that acquire the rotation angle of the rotor obtained from a magnet provided on the rotation shaft of the rotor of the second motor MT2 (first motor MT 1); a microcomputer 211 that acquires signals from a torque sensor signal input circuit, an MR sensor, and the like to control the rotation of the second motor MT 2; a pre-driver 212 that generates a PWM signal from a control signal of the microcomputer 211; a bridge circuit 230 that drives the second motor MT2 by a PWM signal; a shunt resistor 240 provided for measuring a current of each phase; and a variable amplifying unit 250 that amplifies the potential difference across the shunt resistor 240 by a predetermined amplification factor. These configuration elements are the same as the corresponding configuration elements in the first control system 110 described above, and the description thereof will be omitted.

The first control system 110 and the second control system 210 in the control apparatus 1 share the driving force output from one rotor by controlling the currents flowing through the two different windings in the system. The share ratio is generally equal (when normal), and is the first control system 110: second control system 210 — 50: 50 (first ratio). As will be described later, the sharing ratio is changed according to the detection result of the abnormality detection unit 120. The first and

second control systems

110 and 210 supply currents for outputting driving forces, which are calculated by themselves using the sharing ratios, to the first and second electric motors MT1 and MT2, respectively.

The control flow of the control apparatus 1 will be described with reference to fig. 4. The control flow is executed in the first control system 110 and the second control system 210. Hereinafter, an example of the execution of the first control system 110 will be described. In S100, the microcomputer 111 initially sets the first control system 110 at the timing of ignition on or the like of the vehicle. The microcomputer 111 outputs a gain setting signal for closing the switch S1 and opening the switch S2 by this initial setting with respect to the variable amplifying unit 150. Therefore, the amplification factors of the amplifier circuit U151, the amplifier circuit V152, and the amplifier circuit W153 are set to 20.

In S102, the abnormality detection unit 120 of the microcomputer 111 diagnoses whether a failure has occurred in the first control system 110 as its own system. As described above, the abnormality detection unit 120 diagnoses the presence or absence of a fault based on information from the torque sensor signal input circuit or the like associated with the system 1 system 100. In S104, the abnormality detection unit 120 reads a state as to whether a failure has occurred in the second control system 210 as another system via the microcomputer 211.

In S106, in the case where the microcomputer 111 detects the presence of an abnormality in the first control system 110 as its own system, the process ends without executing the following steps. That is, in the case where there is an abnormality in its own system, the microcomputer 111 does not control the first motor MT1 of the system 1 system 100. The microcomputer 111 supplies the first motor MT1 with a current for outputting the driving force shared by its own system, which is calculated by using a predetermined sharing ratio with another system, and in the case where the abnormality detection unit 120 detects an abnormality of its own system, the sharing ratio is set to 0.

On the other hand, in the case where no abnormality is detected in its own system, in S108, if no abnormality is detected in the other system, in S110, the microcomputer 111 performs control calculation of the first motor MT1 of the system 1 system 100 and drives the first motor MT1 through the pre-driver 112 and the bridge circuit 130. That is, in the case where no abnormality is detected in both the first control system 110 and the second control system 210 (at the time of normality), both systems drive each motor at a predetermined sharing ratio (first ratio), and detect a current for driving each motor at an amplification factor that is initially set.

In S108, in the case where it is detected that there is an abnormality in the second control system 210 as another system, in S200 the microcomputer 111 changes the amplification factor. Specifically, in S202, the microcomputer 111 sets the amplification factor of the potential difference across the shunt resistor 140 for detecting the current flowing through each phase of the bridge circuit 130 of the first control system 110 as its own system from 20 to 10. In S204, the microcomputer 111 outputs a gain setting signal for opening the switch S1 and closing the switch S2 with respect to the variable amplifying unit 150.

Therefore, in the case where the abnormality detecting unit 120 does not detect the abnormality of the first control system 110 as its own system and does not detect the abnormality of the state of the second control system 210 as another system, the variable amplifying unit 150 amplifies the potential difference by using the predetermined amplification factor (first amplification factor) that is initially set. Further, in the case where the abnormality detecting unit 120 does not detect an abnormality of its own system and detects a state abnormality of the other system, the variable amplifying unit 150 of the system in which the abnormality is not detected amplifies the potential difference by using an amplification factor (second amplification factor) smaller than the predetermined amplification factor that is initially set. Accordingly, in a system in which an abnormality is not detected in the case where an abnormality is detected in the state of another system, by amplifying the potential difference using an amplification factor smaller than that in normal time, it is made possible to widen the dynamic range of the amplifier circuit in the case of an abnormality while maintaining the detection accuracy in normal time.

After the amplification factor is changed to be smaller than that at the normal time, in S300 the microcomputer 111 changes the mode (output increase mode) to increase the output of the first motor MT1 of the system 1 system 100. The output increase mode is a mode in which the command current of each phase output from the microcomputer 111 to the pre-driver 112 is uniformly increased in all phases. Therefore, the assist force that the first electric motor MT1 must impart to the steering increases. The output increase mode is enabled, for example, by amplifying the command current or switching the T-I diagram (torque-current diagram).

After entering the output increasing mode, in S110 the microcomputer 111 performs control calculation of the first motor MT1 of the system 1 system 100 and drives the first motor MT1 through the pre-driver 112 and the bridge circuit 130. That is, for example, in the case where an abnormality is detected in the second control system 210, the first control system 110 drives the first motor MT1 in the output increasing mode, and detects a current for driving the first motor MT1 with a changed amplification factor. This process is repeated until the ignition switch is turned off (S112).

In the control device 1, generally, the control is performed with a certain margin with respect to the rated value of the first electric motor MT 1/the second electric motor MT 2. For example, if the rating of the first/second electric motors MT 1/MT 2 is 70A, the control device 1 normally controls at a current of up to 50A. In the control apparatus 1 having the redundant system, in the case where an abnormality occurs in the second control system 210 and the output of the second electric motor MT2 is exhausted, the assist force applied to the steering by the first electric motor MT1 and the second electric motor MT2 is halved, but the first electric motor MT1 of the first control system 110 that normally operates is supplied with, for example, a current of 70A/50A 1.4 times the rated limit, thereby increasing the assist force to be applied to the steering.

As described above, in the control apparatus 1, even if an abnormality occurs in the second control system 210, the normal first control system 110 can increase the assist force to be applied to the steering and reduce the burden on the driver by adding at least a part of the share ratio of the second control system 210 for outputting the share ratio of the driving force shared by itself to the share ratio at the normal time, and can avoid saturation of the amplifier circuit by amplifying the phase current by an amplification factor smaller than that at the normal time even in the case where the share amount is increased.

If the first motor of the first control system that is operating normally continues to be driven around 70A of the rated value, it may become high in temperature due to heat generation. In this case, a value smaller than the initially required current value may be controlled to the upper limit. A third amplification factor suitable for the upper limit of the current value is set in the variable amplification unit 150. Alternatively, the upper limit value may gradually decrease as time elapses, and may return to the first load ratio after a predetermined period of time. In this case, the amplification factor also gradually decreases. In this way, when a system abnormality occurs, the assist force of steering is suddenly reduced to half, thereby reducing the risk of a driver error and allowing the driver to notice the abnormality of the system.

The above also applies to the control method for controlling the control device 1. In a control method of a control apparatus 1 including a first electric motor MT1 and a second electric motor MT2 that share and output a driving force for driving a steering mechanism (load) of a vehicle, a first control system 110 that controls the first electric motor MT1, and a second control system 210 that controls the second electric motor MT2, the method includes: amplifying, by the two systems, a potential difference at a predetermined position of a current for outputting a driving force to the motor using a predetermined amplification factor (first amplification factor) in a case where an abnormality of its own system is not detected and a state abnormality of the other system is not detected; and in the case where an abnormality of its own system is not detected and a state abnormality of another system is detected, the potential difference is amplified by using an amplification factor (second amplification factor) smaller than a predetermined amplification factor in the system in which the abnormality is not detected.

Accordingly, it is possible to provide a control method capable of expanding a dynamic range without saturating the amplifier circuit at the time of abnormality while maintaining the detection accuracy at the time of abnormality by amplifying the potential difference using an amplification factor smaller than that at the time of abnormality in the system in which abnormality is not detected, in the case where abnormality in the state of another system is detected.

The present invention is not limited to the illustrated embodiments, and may be performed by structures without departing from the scope of the content described in each of the claims. That is, although the present invention has been particularly shown and described with respect to particular embodiments, it will be understood by those skilled in the art that various changes in the number and in another detailed configuration may be made to the above-described embodiments without departing from the scope of the technical concept and objects of the present invention.

Claims

1. A control device, comprising:

a first motor and a second motor that share and output a driving force for driving a load;

a first control system that controls the first motor; and

a second control system for controlling the second motor,

wherein each of the first control system and the second control system comprises:

an abnormality detection unit detecting an abnormality of its own system and detecting a state of another system,

a control unit that supplies a current for outputting a driving force to the motor,

a shunt resistance provided for measuring the current; and

a variable amplifying unit amplifying a potential difference between both ends of the shunt resistor by using a first amplification factor or a second amplification factor smaller than the first amplification factor,

wherein the variable amplifying unit amplifies the potential difference by using the first amplification factor in a case where the abnormality detecting unit does not detect an abnormality of its own system and does not detect a state abnormality of another system, and

wherein the variable amplifying unit amplifies the potential difference by using a second amplification factor in a case where the abnormality detecting unit does not detect the abnormality of the own system and detects that the state of the other system is abnormal.

2. The control device according to claim 1, wherein,

wherein, in each of the first control system and the second control system,

the control unit supplies to the motor a current for outputting a driving force shared by the own system, the driving force being calculated by using a sharing ratio changed according to a detection result of the abnormality detecting unit,

in the case where the abnormality of the own system is not detected by the abnormality detecting unit and the state of the other system is not detected as abnormal, the sharing ratio is set to a predetermined first ratio, and the variable amplifying unit amplifies the potential difference by using the first amplification factor,

in the case where the abnormality of the own system is detected by the abnormality detecting unit, the sharing ratio is set to zero, and

in a case where the abnormality detecting unit does not detect the abnormality of the own system and detects that the state of the other system is abnormal, the sharing ratio is set to a ratio obtained by adding at least a part of the sharing ratio of the other system to the first ratio, and the variable amplifying unit amplifies the potential difference by using the second amplification factor.

3. The control device according to claim 2, wherein,

wherein the first ratio is 50%.

4. The control device according to claim 2 or 3,

wherein, in each of the first control system and the second control system,

in the case where the abnormality detecting unit does not detect the abnormality of the own system and detects that the state of the other system is abnormal, the control unit continues to supply the electric motor with a current calculated by using a ratio obtained by adding at least a part of the sharing ratio of the other system to the first ratio, then subtracts the sharing ratio from the first ratio, and the variable amplifying unit amplifies the potential difference by using a third amplification factor larger than the first amplification factor and corresponding to a current value of the subtraction ratio.

5. The control device according to claim 2 or 3,

wherein, in each of the first control system and the second control system,

in a case where the abnormality detecting unit does not detect the abnormality of the own system and detects that the state of the other system is abnormal, the control unit continues to supply the electric motor with a current calculated by using a ratio obtained by adding at least a part of the sharing ratio of the other system to the first ratio, and after a predetermined period of time, the sharing ratio is set to the first ratio, and the variable amplifying unit amplifies the potential difference by using the first amplification factor after the predetermined period of time.

6. The control apparatus according to any one of claims 1 to 3,

wherein the load is a steering mechanism of a vehicle, and

wherein the control device is an electric power steering control device.

7. A control method of a control apparatus, the control apparatus comprising: a first motor and a second motor that share and output a driving force for driving a load; a first control system that controls the first motor; and a second control system that controls the second motor, the control method including:

amplifying a potential difference at a predetermined position of a current for outputting a driving force to the motor by using a first amplification factor in a case where an abnormality of the own system is not detected and a state abnormality of another system is not detected; and

in the case where an abnormality of the own system is not detected and the state of the other system is detected as an abnormality, the potential difference is amplified by using a second amplification factor smaller than the first amplification factor in the system where the abnormality is not detected.