Motor control device

Abstract

To provide a motor control device that enables a load observer to accurately estimate a load.SOLUTION: A motor control device is applied to a system in which windings, drive circuits, and control units of an electric motor that imparts torque to a steering system are organized into multiple systems. The control unit of each system is capable of communicating with each other, and the control unit in each system includes a load observer that estimates a load acting on the steering system using a feedback value related to current or torque, and a calculation unit that calculates a command value for driving at least the drive circuit in that system out of all the drive circuits in all the systems using the load estimated by the load observer in that system. At the time of normal circumstances, the feedback value of each system is calculated based on a feedback value according to the sum of the currents flowing through the windings of all the systems.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a control device for an electric motor for steering angle control. [Background technology]

[0002] Patent Document 1 below discloses an electric drive unit that includes a first system electric drive device and a second system electric drive device to provide redundancy to the system. The first system electric drive device includes a first control device, a first drive circuit, a first winding, a first current detector, and a first position detector. The second system electric drive device includes a second control device, a second drive circuit, a second winding, a second current detector, and a second position detector.

[0003] Each control device has a function of calculating a torque command value based on a higher-level signal from a higher-level controller, a steering torque signal, vehicle conditions, etc. Each control device also has a function of calculating a current command value to be applied to the corresponding winding based on the torque command value, a current feedback value from a current detector, a position feedback value from a position detector, etc., so that the electric drive device generates a torque equal to the torque command value. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 122562 [Patent Document 2] International Publication No. 2023 / 286169 Summary of the Invention [Problem to be solved by the invention]

[0005] Electric power steering systems (hereinafter sometimes referred to as "redundant EPS") have been developed in which windings, drive circuits, and control units (microcomputers) are arranged in multiple systems.

[0006] In a redundant EPS, if a load observer that estimates the load acting on the steering system is provided in each system, even if the feedback value of each system is input to the load observer in the corresponding system, there is a risk that each load observer will not be able to accurately estimate the load acting on the steering system.

[0007] An object of the present disclosure is to provide a motor control device that enables a load observer to accurately estimate the load acting on a steering system in a system that includes an electric motor that applies torque to a steering system and has multiple windings, drive circuits, and control units.

[0008] An object of the present disclosure is to provide a motor control device that enables a load observer to accurately estimate the load acting on a steering system in a system that includes an electric motor that applies torque to a steering system and has a dual-system winding, drive circuit, and control unit. [Means for solving the problem]

[0009] One embodiment of the present disclosure provides a motor control device that is applied to a system in which windings, drive circuits, and control units of an electric motor that imparts torque to a steering system are organized into multiple systems, wherein the control units of each system are capable of communicating with each other, and the control unit in each system includes a load observer that estimates the load acting on the steering system using a feedback value related to current or torque, and a calculation unit that calculates a command value for driving at least the drive circuit in that system out of all the drive circuits in all systems using the load estimated by the load observer in that system, and wherein under normal circumstances, the feedback value of each system is calculated based on a feedback value corresponding to the sum of the currents flowing through the windings of all systems.

[0010] In this configuration, in a system including an electric motor that applies torque to the steering system and in which windings, drive circuits, and control units are arranged in multiple systems, the load observer can accurately estimate the load acting on the steering system.

[0011] One embodiment of the present disclosure relates to an electric motor that applies torque to a steering system, the electric motor including two winding systems, i.e., a first system winding and a second system winding; a first drive circuit for supplying power to the first system winding; a second drive circuit for supplying power to the second system winding; a first control unit that controls the first drive circuit; and a second control unit that controls the second drive circuit, the second control unit being capable of mutual communication with the first control unit, wherein the first control unit includes a first load observer that estimates a load acting on the steering system using a first feedback value related to current or torque, and a second control unit that controls the first drive circuit and the second drive circuit using the load estimated by the first load observer. and a first calculation unit that calculates a first command value for driving at least the first drive circuit of two drive circuits, wherein the second control unit includes a second load observer that estimates a load acting on the steering system using a second feedback value related to current or torque, and a second calculation unit that calculates a second command value for driving the second drive circuit using the load estimated by the second load observer, wherein under normal circumstances, both the first feedback value and the second feedback value are calculated based on both a feedback value corresponding to the current flowing in the first system winding and a feedback value corresponding to the current flowing in the second system winding.

[0012] In this configuration, in a system including an electric motor that applies torque to the steering system and in which the windings, drive circuit, and control unit are arranged in two systems, the load observer can accurately estimate the load acting on the steering system. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram showing a schematic configuration of a redundant EPS to which a motor control device according to an embodiment of the present disclosure is applied. [Figure 2] FIG. 2 is a block diagram for explaining the electrical configuration of the motor control ECU. [Figure 3]FIG. 3 is a block diagram for explaining the functional configuration of the first microcomputer and the second microcomputer, and the communication of information between the two microcomputers. [Figure 4] FIG. 4 is a block diagram showing a first modified example of the first calculation unit. [Figure 5] FIG. 5 is a block diagram showing a second modified example of the first calculation unit. [Figure 6] FIG. 6 is a block diagram showing a third modified example of the first calculation unit. DETAILED DESCRIPTION OF THE INVENTION

[0014] [Description of the embodiments of the present disclosure] One embodiment of the present disclosure provides a motor control device that is applied to a system in which windings, drive circuits, and control units of an electric motor that imparts torque to a steering system are organized into multiple systems, wherein the control units of each system are capable of communicating with each other, and the control unit in each system includes a load observer that estimates the load acting on the steering system using a feedback value related to current or torque, and a calculation unit that calculates a command value for driving at least the drive circuit in that system out of all the drive circuits in all systems using the load estimated by the load observer in that system, and wherein under normal circumstances, the feedback value of each system is calculated based on a feedback value corresponding to the sum of the currents flowing through the windings of all systems.

[0015] In this configuration, in a system including an electric motor that applies torque to the steering system and in which windings, drive circuits, and control units are arranged in multiple systems, the load observer can accurately estimate the load acting on the steering system.

[0016] In one embodiment of the present disclosure, when communication between the control units of at least two systems becomes impossible, the control unit of each system calculates the feedback value based only on the feedback value corresponding to the current flowing through the winding of that system.

[0017] One embodiment of the present disclosure relates to an electric motor that applies torque to a steering system, the electric motor including two winding systems, i.e., a first system winding and a second system winding; a first drive circuit for supplying power to the first system winding; a second drive circuit for supplying power to the second system winding; a first control unit that controls the first drive circuit; and a second control unit that controls the second drive circuit, the second control unit being capable of mutual communication with the first control unit, wherein the first control unit includes a first load observer that estimates a load acting on the steering system using a first feedback value related to current or torque, and a second control unit that controls the first drive circuit and the second drive circuit using the load estimated by the first load observer. and a first calculation unit that calculates a first command value for driving at least the first drive circuit of two drive circuits, wherein the second control unit includes a second load observer that estimates a load acting on the steering system using a second feedback value related to current or torque, and a second calculation unit that calculates a second command value for driving the second drive circuit using the load estimated by the second load observer, wherein under normal circumstances, both the first feedback value and the second feedback value are calculated based on both a feedback value corresponding to the current flowing in the first system winding and a feedback value corresponding to the current flowing in the second system winding.

[0018] In this configuration, in a system including an electric motor that applies torque to the steering system and in which the windings, drive circuit, and control unit are arranged in two systems, the load observer can accurately estimate the load acting on the steering system.

[0019] In one embodiment of the present disclosure, when communication between the first control unit and the second control unit becomes impossible, the first control unit calculates the first feedback value based only on a feedback value corresponding to the current flowing through the first system winding, and the second control unit calculates the second feedback value based only on a feedback value corresponding to the current flowing through the second system winding. Detailed Description of Embodiments of the Present Disclosure Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0020] FIG. 1 is a schematic diagram showing a schematic configuration of a redundant EPS to which a motor control device according to an embodiment of the present disclosure is applied.

[0021] The redundant EPS 1 includes a steering wheel (handle) 2 as a steering member for steering the vehicle, a steering mechanism 4 that steers steered wheels 3 in conjunction with the rotation of the steering wheel 2, and a steering assist mechanism 5 that assists the driver in steering. The steering wheel 2 and the steering mechanism 4 are mechanically connected via a steering shaft 6 and an intermediate shaft 7.

[0022] The steering shaft 6 includes an input shaft 8 connected to the steering wheel 2 and an output shaft 9 connected to the intermediate shaft 7. The input shaft 8 and the output shaft 9 are connected via a torsion bar 10 so as to be capable of relative rotation.

[0023] The steering mechanism 4 is made up of a rack-and-pinion mechanism including a pinion shaft 13 and a rack shaft 14 as a steering shaft. The steered wheels 3 are connected to each end of the rack shaft 14 via tie rods 15 and knuckle arms (not shown). The pinion shaft 13 is connected to the intermediate shaft 7. The pinion shaft 13 rotates in conjunction with the steering of the steering wheel 2. A pinion 16 is connected to the tip of the pinion shaft 13.

[0024] The rack shaft 14 extends linearly in the left-right direction of the vehicle. A rack 17 that meshes with the pinion 16 is formed in the middle of the rack shaft 14 in the axial direction. The pinion 16 and the rack 17 convert the rotation of the pinion shaft 13 into axial movement of the rack shaft 14. By moving the rack shaft 14 in the axial direction, the steered wheels 3 can be steered.

[0025] When the steering wheel 2 is steered (rotated), this rotation is transmitted to the pinion shaft 13 via the steering shaft 6 and the intermediate shaft 7. The rotation of the pinion shaft 13 is then converted into axial movement of the rack shaft 14 by the pinion 16 and the rack 17. As a result, the steered wheels 3 are steered.

[0026] The steering assist mechanism 5 includes an electric motor 18 for generating a steering assist force (assist torque), and a reducer 19 for amplifying the output torque of the electric motor 18 and transmitting it to the steering mechanism 4. The reducer 19 is made up of a worm gear mechanism including a worm gear 20 and a worm wheel 21 that meshes with the worm gear 20. The reducer 19 is housed in a gear housing 22 that serves as a transmission mechanism housing.

[0027] In the following, the reduction ratio (gear ratio) of the reducer 19 may be expressed as N. The reduction ratio N is determined by the rotation angle of the worm wheel 21, that is, the worm wheel angle θ ww The worm gear angle θ is the rotation angle of the worm gear 20 relative to the wg The ratio (θ wg / θ ww )

[0028] The worm gear 20 is rotationally driven by an electric motor 18. In addition, the worm wheel 21 is connected to the output shaft 9 so as to be integrally rotatable therewith.

[0029] The motor torque generated by the electric motor 18 is expressed as a positive value if it is a torque that rotates the output shaft 9 in the left steering direction, and is expressed as a negative value if it is a torque that rotates the output shaft 9 in the right steering direction.

[0030] When the worm gear 20 is rotationally driven by the electric motor 18, the worm wheel 21 is rotationally driven, and motor torque is applied to the steering shaft 6, causing the steering shaft 6 (output shaft 9) to rotate. The rotation of the steering shaft 6 is then transmitted to the pinion shaft 13 via the intermediate shaft 7. The rotation of the pinion shaft 13 is converted into axial movement of the rack shaft 14, thereby turning the steered wheels 3. In other words, by rotating the worm gear 20 with the electric motor 18, steering assistance by the electric motor 18 and steering of the steered wheels 3 become possible.

[0031] The electric motor 18 is provided with a rotation angle sensor 23 for detecting the rotation angle of the rotor of the electric motor 18. The rotation angle of the rotor of the electric motor 18 is expressed, for example, as a positive value for the amount of rotation from the neutral position in the left steering direction, and as a negative value for the amount of rotation from the neutral position in the right steering direction.

[0032] The torque applied to the output shaft 9 (an example of a drive target of the electric motor 18) includes the motor torque from the electric motor 18 and a disturbance torque T lc Disturbance torque T other than the motor torque lc includes steering torque, road load torque (road reaction torque), friction torque, etc. Disturbance torque T lc is an example of a "load acting on the steering system" in the present disclosure.

[0033] The steering torque is a torque applied to the output shaft 9 from the steering wheel 2 side by a force applied to the steering wheel 2 by the driver, a force generated by steering inertia, or the like.

[0034] The road load torque is a torque applied to the output shaft 9 from the steered wheels 3 via the rack shaft 14 due to the self-aligning torque generated in the tires, forces generated by the suspension and tire-wheel alignment, frictional forces of the rack-and-pinion mechanism, etc.

[0035] 2, the electric motor 18 includes a first winding system 18A and a second winding system 18B. The electric motor 18 is controlled by a motor control ECU 201. An output signal of the rotation angle sensor 23 is input to the motor control ECU 201.

[0036] Fig. 2 is a block diagram for explaining the electrical configuration of the motor control ECU 201. Fig. 3 is a block diagram for explaining the functional configuration of the first microcomputer 30A and the second microcomputer 30B and the communication of information between the two microcomputers.

[0037] The motor control ECU 201 includes a first system unit 202 and a second system unit 203. The first system unit 202 includes a first microcomputer 30A, a first drive circuit (inverter circuit) 51A that is controlled by the first microcomputer 30A and supplies power to the first system winding 18A of the electric motor 18, and a current (hereinafter referred to as "first actual current I") that flows through the first system winding 18A. m1 The first microcomputer 30A is an example of the "controller" or "first control unit" in the present disclosure.

[0038] The first microcomputer 30A includes a CPU and memory (ROM, RAM, non-volatile memory, etc.), and functions as a plurality of functional processing sections by executing predetermined programs, including a first actual torque calculation section 31A, a first feedback value calculation section 32A, a first actual steering angle calculation section 33A, a first load observer 34A, a first calculation section 35A, a third coefficient multiplication section 36A, a first torque control section 37A, and a first monitoring section 38A.

[0039] The first actual torque calculation unit 31A calculates the first actual current I m1 is multiplied by the torque constant of the electric motor 18 to obtain the actual motor torque T m1 The actual motor torque T m1 By multiplying this by the reduction ratio N, the first actual torque N·T acting on the output shaft 9 is obtained.m1 Calculates the first actual torque N·T m1 is an example of "a feedback value according to the current flowing through the winding of the system (first system)" or "a feedback value according to the current flowing through the winding of the first system" in the present disclosure.

[0040] The first feedback value calculation unit 32A calculates a first feedback value FB1 related to current or torque, which is input to the first load observer 34A. The first feedback value calculation unit 32A includes a first coefficient multiplication unit 39A, a second coefficient multiplication unit 40A, and a first addition unit 41A. The first coefficient multiplication unit 39A calculates a first actual torque N·T m1 The second coefficient multiplication unit 40A multiplies the second actual torque N·T given from the second system unit 203 by the first coefficient K1. m2 The first adder 41A multiplies the multiplication result K1·N·T of the first coefficient multiplier 39A. m1 , the multiplication result K2·N·T of the second coefficient multiplication unit 40A m2 By adding the first feedback value FB1 (= K1·N·T m1 +K2·N·T m2 ) is calculated.

[0041] The first actual steering angle calculation unit 33A calculates the rotor rotation angle θ based on the output of the rotation angle sensor 23. m The rotor rotation angle θ m is divided by the reduction ratio N to obtain the first actual steering angle θ, which is the rotation angle of the output shaft 9. m Calculates / N.

[0042] The first load observer 34A calculates the first feedback value FB1 and the first actual steering angle θ m / N is used to generate disturbance torque T lc Hereinafter, the disturbance torque estimated value calculated by the first load observer 34A is referred to as the "first disturbance torque estimated value ^T lc1 As the first load observer 34A, for example, the disturbance torque estimator (64) shown in FIGS. 5 and 7 of WO 2023 / 286169 can be used.

[0043] The first calculation unit 35A calculates the first disturbance torque estimate value ^T lc1 The motor torque command value T m1,cmd (hereinafter referred to as "first motor torque command value T m1,cmd The first motor torque command value T m1,cmd is an example of a "command value" or a "first command value" in the present disclosure.

[0044] The first calculation unit 35A calculates, for example, a first disturbance torque estimate value ^T lc1 The value obtained by multiplying this by -1 is the first motor torque command value T m1,cmd This allows the first disturbance torque estimate ^T lc1 The torque to cancel out this is the first motor torque command value T m1,cmd It is calculated as:

[0045] The third coefficient multiplication unit 36A multiplies the first motor torque command value T m1,cmd is multiplied by the third coefficient K3 to obtain the torque command value for the first system K3·T m1,cmd Calculate the following.

[0046] The first torque control unit 37A calculates the torque command value K3·T for the first system by controlling the motor torque generated in the electric motor 18 by the current flowing through the first system winding 18A. m1,cmd The first driving circuit 51A is driven so that the value approaches .

[0047] As the first torque control unit 37A, for example, the torque control unit (55) shown in FIGS. 2 and 8 of International Publication No. 2023 / 286169 can be used. In this case, the first torque control unit 37A controls the torque command value K3·T for the first system to be given to the first torque control unit 37A. m1,cmd The first torque control unit 37A calculates a first system current command value by dividing the first actual current I m1 is feedback controlled so that it approaches the current command value for the first system.

[0048] The first monitoring unit 38A monitors the state of each part of the first system unit 202. As will be described later, a second monitoring unit 38B that monitors the state of each part of the second system unit 203 is provided within the second system unit 203. The first monitoring unit 38A is communicably connected to the second monitoring unit 38B. This allows the first monitoring unit 38A to grasp the state of each part of the second system unit 203. The first monitoring unit 38A sets the values ​​of the first coefficient K1, the second coefficient K2, and the third coefficient K3 according to the state of each part of the first system unit 202 and the state of each part of the second system unit 203.

[0049] The second system unit 203 includes a second microcomputer 30B, a second drive circuit 51B that is controlled by the second microcomputer 30B and supplies power to the second system winding 18B of the electric motor 18, and a current (hereinafter referred to as "second actual current I") that flows through the second system winding 18B. m2 and a second current detection circuit 52B for detecting a current difference between the first and second terminals of the power supply 51 and the power supply 52.

[0050] The second microcomputer 30B is an example of the "controller" or "second controller" in the present disclosure. The first microcomputer 30A and the second microcomputer 30B are capable of communicating with each other.

[0051] The second microcomputer 30B includes, as functional processing units, a second actual torque calculation unit 31B, a second feedback value calculation unit 32B, a second actual steering angle calculation unit 33B, a second load observer 34B, a second calculation unit 35B, a sixth coefficient multiplication unit 36B, a second torque control unit 37B, a second monitoring unit 38B, and a switch 42.

[0052] The second actual torque calculation unit 31B calculates the second actual current I m2 is multiplied by the torque constant of the electric motor 18 to obtain the actual motor torque T m2 The actual motor torque T m2 By multiplying this by the reduction ratio N, the second actual torque N·T acting on the output shaft 9 is obtained. m2 Calculates the second actual torque N·T m2is an example of "a feedback value according to the current flowing through the winding of the system (second system)" or "a feedback value according to the current flowing through the winding of the second system" in the present disclosure.

[0053] The second feedback value calculation unit 32B calculates a second feedback value FB2 related to current or torque, which is input to the second load observer 34B. The second feedback value calculation unit 32B includes a fourth coefficient multiplication unit 39B, a fifth coefficient multiplication unit 40B, and a second addition unit 41B. The fourth coefficient multiplication unit 39B multiplies the second actual torque N·T m2 The fifth coefficient multiplication unit 40B multiplies the first actual torque N·T given by the first system unit 202 by a fourth coefficient K4. m1 The second adder 41B multiplies the multiplication result K4·N·T of the fourth coefficient multiplier 39B. m2 , the multiplication result K5·N·T of the fifth coefficient multiplication unit 40B m1 By adding the second feedback value FB2 (=K4·N·T m2 +K5·N·T m1 ) is calculated.

[0054] The second actual steering angle calculation unit 33B calculates the rotor rotation angle θ based on the output of the rotation angle sensor 23. m The rotor rotation angle θ m is divided by the reduction ratio N to obtain the second actual steering angle θ, which is the rotation angle of the output shaft 9. m Calculates / N.

[0055] The second load observer 34B calculates the second feedback value FB2 and the second actual steering angle θ m / N, the disturbance torque T lc Hereinafter, the disturbance torque estimated value calculated by the second load observer 34B is referred to as the "second disturbance torque estimated value ^T lc2 As the second load observer 34B, for example, the disturbance torque estimator (64) shown in FIGS. 5 and 7 of WO 2023 / 286169 can be used.

[0056] The second calculation unit 35B calculates the second disturbance torque estimate value ^T lc2 The motor torque command value T m2,cmd (hereinafter referred to as "second motor torque command value T m2,cmd The second motor torque command value T m2,cmd is an example of a "command value" or a "second command value" in the present disclosure.

[0057] The second calculation unit 35B calculates, for example, the second disturbance torque estimated value ^T lc2 The value obtained by multiplying this by -1 is the second motor torque command value T m2,cmd This allows the second disturbance torque estimate ^T lc2 The torque to cancel out this is the second motor torque command value T m2,cmd It is calculated as:

[0058] The switch 42 is connected to the first motor torque command value T calculated by the first calculation unit 35A. m1,cmd and the second motor torque command value T calculated by the second calculation unit 35B. m2,cmd The switch 42 inputs the first motor torque command value T m1,cmd and the second motor torque command value T m2,cmd Select one of them and output it.

[0059] The sixth coefficient multiplication unit 36B multiplies the motor torque command value (first motor torque command value T m1,cmd or second motor torque command value T m2,cmd ) by the sixth coefficient K6 to obtain the torque command value for the second system K6·T m1,cmd or K6·T m2,cmd Calculate the following.

[0060] The second torque control unit 37B calculates the motor torque generated in the electric motor 18 by the current flowing through the second system winding 18B as a second system torque command value K6·T m1,cmd or K6·T m2,cmd The second driving circuit 51B is driven so that the value approaches .

[0061] As the second torque control unit 37B, for example, the torque control unit (55) shown in FIGS. 2 and 8 of International Publication No. 2023 / 286169 can be used. In this case, the second torque control unit 37B controls the torque command value K6·T m1,cmd or K6·T m2,cmd The second torque control unit 37B calculates a second system current command value by dividing the second actual current I m2 is feedback controlled so that the current command value for the second system approaches the current command value for the second system.

[0062] The second monitoring unit 38B monitors the state of each unit in the second system unit 203. The second monitoring unit 38B is communicably connected to the first monitoring unit 38A. This allows the second monitoring unit 38B to grasp the state of each unit in the first system unit 202. The second monitoring unit 38B sets the values ​​of the fourth coefficient K4, the fifth coefficient K5, and the sixth coefficient K6 according to the state of each unit in the second system unit 203 and the state of each unit in the first system unit 202, and controls the switch 42.

[0063] The coefficient multiplication units 36A, 39A, 40A, 36B, 39B, and 40B and the switch 42 are controlled according to the states of the first system unit 202 and the second system unit 203. This switches the drive mode of the electric motor. In this embodiment, there are four drive modes for the electric motor, and these modes are switched according to the states of the first system unit 202 and the second system unit 203. Each drive mode will be described below.

[0064] (1) First coordinated drive mode: A drive mode that is set when the first system unit 202 and the second system unit 203 are in a normal state and communication is possible between the microcomputers 30A and 30B.

[0065] In this case, the first coefficient K1, the second coefficient K2, the fourth coefficient K4, and the fifth coefficient K5 are set to 1. The third coefficient K3 and the sixth coefficient K6 are set to 0.5. The switch 42 controls the first motor torque command value T m1,cmd and the second motor torque command value T m2,cmd Among these, the first motor torque command value T m1,cmd is selected and output.

[0066] As a result, the first feedback value calculation unit 32A outputs (N·T m1 +N·T m2 ) is output from the second feedback value calculation unit 32B. m1 +N·T m2 ) is output. In other words, in this case, the first feedback value FB1 and the second feedback value FB2 are equal.

[0067] As a result, the first load observer 34A calculates (N·T m1 +N·T m2 ) and the first actual steering angle θ m / N, the first disturbance torque estimate ^T lc1 The second load observer 34B calculates (N·T m1 +N·T m2 ) and the second actual steering angle θ m / N, the second disturbance torque estimate ^T lc2 Calculate the following.

[0068] The first calculation unit 35A and the second calculation unit 35B each calculate a first disturbance torque estimated value ^T lc1 and the second disturbance torque estimate ^T lc2 The first motor torque command value T m1,cmd and the second motor torque command value T m2,cmd Calculate the following.

[0069] The third coefficient multiplication unit 36A in the first system unit 202 calculates the first motor torque command value T m1,cmdThe switch 42 outputs half of the first motor torque command value T m1,cmd Therefore, the sixth coefficient multiplication unit 36B in the second system unit 203 selects and outputs the second motor torque command value T m2,cm Instead, the first motor torque command value T m1,cmd As a result, cooperative driving by the first system section 202 and the second system section 203 is realized.

[0070] In this case, the first load observer 34A calculates the first disturbance torque estimate value ^T using the first feedback value FB1 corresponding to the actual motor torque generated by the electric motor 18. lc1 Therefore, the first disturbance torque estimate ^T lc1 This allows accurate calculation of the appropriate motor torque command value for the first system, T m1,cmd / 2 and the motor torque command value T m2,cmd / 2 is obtained.

[0071] In the first coordinated drive mode, the switch 42 controls the second motor torque command value T m2,cmd In this case, the sixth coefficient multiplication unit 36B in the second system unit 203 may be controlled to select and output the second motor torque command value T m2,cm 1 / 2 of this is output as the motor torque command value for the second system.

[0072] (2) Second cooperative drive mode: A drive mode that is set when the first system unit 202 and the second system unit 203 are in a normal state but communication between the microcomputers 30A and 30B is not possible.

[0073] In this case, the first coefficient K1 and the fourth coefficient K4 are set to 2. The second coefficient K2 and the fifth coefficient K5 are set to 0. The third coefficient K3 and the sixth coefficient K6 are set to 0.5. The switch 42 controls the first motor torque command value T m1,cmd and the second motor torque command value T m2,cmd Among these, the second motor torque command value T m2,cmdis selected and output.

[0074] As a result, the first feedback value calculation unit 32A outputs 2N·T m1 The second feedback value calculation unit 32B outputs a first feedback value FB1 corresponding to 2N·T m2 A second feedback value FB2 corresponding to the above is output.

[0075] As a result, the first load observer 34A calculates 2N·T m1 The first feedback value FB1 and the first actual steering angle θ m / N, the first disturbance torque estimate ^T lc1 The second load observer 34B calculates 2N·T m2 The second feedback value FB2 and the second actual steering angle θ m / N to obtain the second disturbance torque estimate ^T lc2 Calculate the following.

[0076] The first calculation unit 35A calculates the first disturbance torque estimate value ^T lc1 The first motor torque command value T m1,cmd The second calculation unit 35B calculates the second disturbance torque estimated value ^T lc2 Using this, the second motor torque command value T m2,cmd Calculate the following.

[0077] Further, the third coefficient multiplication unit 36A in the first system unit 202 calculates the first motor torque command value T m1,cmd The sixth coefficient multiplier 36B in the second system unit 203 outputs half of the second motor torque command value T m2,cmd As a result, cooperative driving by the first system section 202 and the second system section 203 is realized.

[0078] Although communication between the first system unit 202 and the second system unit 203 has stopped, if it is assumed that the first system unit 202 and the second system unit 203 are operating normally, then 2N·T m1The first feedback value FB1 and 2N T m2 The second feedback value FB2, which corresponds to the actual motor torque generated by the electric motor 18, is a feedback value corresponding to the actual motor torque generated by the electric motor 18. Therefore, the first load observer 34A and the second load observer 34B can accurately estimate the disturbance torque. As a result, an appropriate first system motor torque command value T m1,cmd / 2 and the motor torque command value T m2,cmd / 2 is obtained.

[0079] (3) First single-system drive mode: A drive mode that is set when one of the first system unit 202 and the second system unit 203 has failed and communication between the microcomputers 30A and 30B is possible.

[0080] A fault is one that causes the power supply to the corresponding system winding to be stopped.

[0081] For example, if the second system unit 203 has failed, the first coefficient K1 is set to 1, the second coefficient K2 is set to 0, and the third coefficient K3 is set to 1. The fourth coefficient K4 and the fifth coefficient K5 may retain their values ​​before the failure, or may be set to other values. The sixth coefficient K6 is set to 0. Note that since the second system unit 203 has failed, the second actual torque calculated by the second actual torque calculation unit 31B is 0, and therefore the second coefficient K2 may be 1.

[0082] As a result, the first feedback value calculation unit 32A outputs N·T m1 As a result, the first load observer 34A outputs a first feedback value FB1 corresponding to N·T m1 The first feedback value FB1 and the first actual steering angle θ m / N, the first disturbance torque estimate ^T lc1 Calculate the following.

[0083] The first calculation unit 35A calculates the first disturbance torque estimate value ^T lc1 The first motor torque command value T m1,cmdThe third coefficient multiplication unit 36A calculates the first motor torque command value T m1,cmd is output as the motor torque command value for the first system. This allows one-system driving by only the first system unit 202 to be realized.

[0084] In this case, the first load observer 34A calculates a first feedback value FB1 (=N·T) corresponding to the actual motor torque generated by the electric motor 18. m1 ) to obtain the first disturbance torque estimate ^T lc1 Therefore, the first disturbance torque estimate ^T lc1 This allows accurate calculation of the appropriate motor torque command value for the first system, T m1,cmd is obtained.

[0085] When the first system unit 202 is faulty, the fourth coefficient K4 is set to 1, the fifth coefficient K5 is set to 0, and the sixth coefficient K6 is set to 1. The first coefficient K1, the second coefficient K2, and the third coefficient K3 may be kept at their values ​​before the fault, or may be set to other values. Also, the switch 42 controls the first motor torque command value T m1,cmd and the second motor torque command value T m2,cmd Among these, the second motor torque command value T m2,cmd Since the first system unit 202 has failed, the first actual torque calculated by the first actual torque calculation unit 31A is 0, and therefore the fifth coefficient K5 may be 1.

[0086] In this case, the sixth coefficient multiplication unit 36B multiplies the second motor torque command value T m2,cmd is output as the motor torque command value for the second system. This allows one-system driving by only the second system unit 203 to be realized.

[0087] In this case, the second load observer 34B calculates a second feedback value FB2 (=N·T) corresponding to the actual motor torque generated by the electric motor 18. m2 ) to obtain the second disturbance torque estimate ^T lc2 Therefore, the second disturbance torque estimate ^T lc2This allows accurate calculation of the appropriate motor torque command value for the second system T m2,cmd is obtained.

[0088] (4) Second one-system drive mode: A drive mode that is set when one of the first system unit 202 and the second system unit 203 fails and communication between the microcomputers 30A and 30B is not possible.

[0089] For example, if the second system unit 203 is faulty, the first coefficient K1 is set to 1, the second coefficient K2 is set to an arbitrary value, and the third coefficient K3 is set to 1. The fourth coefficient K4, the fifth coefficient K5, and the sixth coefficient K6 may retain their values ​​before the fault or may be set to other values.

[0090] As a result, the first feedback value calculation unit 32A outputs N·T m1 As a result, the first load observer 34A outputs a first feedback value FB1 corresponding to N·T m1 The first feedback value FB1 and the first actual steering torque θ m / N, the first disturbance torque estimate ^T lc1 Calculate the following.

[0091] The first calculation unit 35A calculates the first disturbance torque estimate value ^T lc1 The first motor torque command value T m1,cmd The third coefficient multiplication unit 36A calculates the first motor torque command value T m1,cmd is output as the motor torque command value for the first system. This allows one-system driving by only the first system unit 202 to be realized.

[0092] In this case, the first load observer 34A calculates a first feedback value FB1 (=N·T) corresponding to the actual motor torque generated by the electric motor 18. m2 ) to obtain the first disturbance torque estimate ^T lc1 Therefore, the first disturbance torque estimate ^T lc1 This allows an appropriate motor torque command value for the first system to be obtained.

[0093] When the first system unit 202 is faulty, the fourth coefficient K4 is set to 1, the fifth coefficient K5 is set to an arbitrary value, and the sixth coefficient K6 is set to 1. The first coefficient K1, the second coefficient K2, and the third coefficient K3 may be kept at their values ​​before the fault, or may be set to other values. Also, the switch 42 controls the first motor torque command value T m1,cmd and the second motor torque command value T m2,cmd Among these, the second motor torque command value T m2,cmd is selected and output.

[0094] In this case, the sixth coefficient multiplication unit 36B multiplies the second motor torque command value T m2,cmd is output as the motor torque command value for the second system. This allows one-system driving by only the second system unit 203 to be realized.

[0095] In this case, the second load observer 34B calculates a second feedback value FB2 (=N·T) corresponding to the actual motor torque generated by the electric motor 18. m2 ) to obtain the second disturbance torque estimate ^T lc2 Therefore, the second disturbance torque estimate ^T lc2 This allows an appropriate motor torque command value for the second system to be obtained.

[0096] Next, modifications of the calculation units 35A and 35B will be described. The configuration of the modification of the second calculation unit 35B is similar to the configuration of the modification of the first calculation unit 35A, so only the modification of the first calculation unit 35A will be described below.

[0097] FIG. 4 is a block diagram showing the configuration of a first modified example of the first calculation unit 35A.

[0098] The first calculation unit 35A1 according to the first modification receives the first disturbance torque estimated value ^T lc1 In addition, the first actual steering angle θ mIn this example, the target value is an automatic steering command value θ for automatic steering control (driving assistance control). ad is.

[0099] Automatic steering command value θ ad is the target value of the steering angle for automatically driving the vehicle along the target trajectory. ad is expressed as the amount of rotation (rotation angle) from the neutral position of the output shaft 9, and for example, the amount of rotation from the neutral position in the left steering direction is expressed as a positive value, and the amount of rotation from the neutral position in the right steering direction is expressed as a negative value. The automatic steering control (driving support control) may be, for example, lane keeping assist (LKA) control for keeping the vehicle within the lane, or lane centering assist (LCA) control for driving the vehicle along the center of the lane.

[0100] The first calculation unit 35A1 includes a first feedback control unit 71A, a first disturbance torque compensation unit 72A, and a first reduction ratio division unit 73A.

[0101] The first feedback control unit 71A is configured to adjust the actual steering angle θ m / N is the automatic steering command value θ ad The first feedback control unit 71A includes a first angle deviation calculation unit 74A and a first PD control unit 75A.

[0102] The first angle deviation calculation unit 74A calculates the automatic steering command value θ ad and the first actual steering angle θ m / N and deviation Δθ(=θ ad -θ m / N). The first load observer 34A calculates the actual steering angle θ m / N estimate^θ m / N, the first angle deviation calculation unit 74A calculates the automatic steering command value θ ad and the actual steering angle estimate ^θ m / N deviation (θ ad -^θ m / N) may be calculated as the angle deviation Δθ.

[0103] The first PD control unit 75B performs a PD calculation (proportional differential calculation) on the angle deviation Δθ calculated by the first angle deviation calculation unit 74A, thereby obtaining a feedback control torque T fb Calculate the feedback control torque T fb is given to the first disturbance torque compensation section 72A.

[0104] The first disturbance torque compensation unit 72A calculates the feedback control torque T fb First disturbance torque estimate ^T lc1 By subtracting c1,cmd (=T fb -^T lc ) is calculated. As a result, the first steering torque command value T c1,cmd (torque command value for output shaft 9) is obtained.

[0105] First steering torque command value T c1,cmd is given to the first reduction ratio division unit 73A. The first reduction ratio division unit 73A calculates the first steering torque command value T c1,cmd is divided by the reduction ratio N to obtain the first motor torque command value T m1,cmd This first motor torque command value T m1,cmd is given to the third coefficient multiplication unit 36A (see FIG. 2).

[0106] Fig. 5 is a block diagram showing the configuration of a second modified example of the first calculation unit 35A. In Fig. 5, parts corresponding to those in Fig. 4 are denoted by the same reference numerals as in Fig. 4.

[0107] The first calculation unit 35A2 according to the second modification receives the first disturbance torque estimated value ^T lc1 In addition, the first actual steering angle θ m In this example, the target value is an automatic steering command value θ for automatic steering control (driving assistance control). ad is.

[0108] The first calculation unit 35A2 includes a first feedback control unit 71A, a first feedforward control unit 76A, a first torque addition unit 77A, a first disturbance torque compensation unit 72A, and a first reduction ratio division unit 73A.

[0109] The first feedback control unit 71A has a configuration similar to that of the first feedback control unit 71A in FIG. 4, and ad and actual steering angle θ m / N and deviation Δθ(=θ ad -θ m / N), the feedback control torque T fb Calculate the feedback control torque T fb is given to the first torque addition unit 77A.

[0110] The first feedforward control unit 76A is provided to compensate for a delay in response due to the inertia of the electric power steering system 1, thereby improving the response of the control. The first feedforward control unit 76A includes a first angular acceleration calculation unit 78A and a first inertia multiplication unit 79A. The first angular acceleration calculation unit 78A calculates an automatic steering command value θ ad By differentiating twice, the target angular acceleration d 2 θ ad / dt 2 Calculate the following.

[0111] The first inertia multiplication unit 79A multiplies the target angular acceleration d calculated by the first angular acceleration calculation unit 78A by 2 θ ad / dt 2 is multiplied by the inertia J of the electric power steering system 1 to obtain the feedforward control torque T ff (=J·d 2 θ ad / dt 2 The inertia J is calculated from, for example, a physical model of the electric power steering system 1. The feedforward control torque T ff is given to the first torque addition unit 77A as an inertia compensation value.

[0112] The first torque addition unit 77A calculates the feedback control torque T fb to the feedforward control torque T ff By adding fb +T ff ) is calculated.

[0113] The first disturbance torque compensator 72A calculates the basic torque command value (T fb +T ff ) to the first disturbance torque estimate ^T lc1 By subtracting c1,cmd (=T fb -^T lc ) is calculated. As a result, the first steering torque command value T c1,cmd (torque command value for output shaft 9) is obtained.

[0114] First steering torque command value T c1,cmd is given to the first reduction ratio division unit 73A. The first reduction ratio division unit 73A calculates the first steering torque command value T c1,cmd is divided by the reduction ratio N to obtain the first motor torque command value T m1,cmd This first motor torque command value T m1,cmd is given to the third coefficient multiplication unit 36A (see FIG. 2).

[0115] Fig. 6 is a block diagram showing the configuration of a third modified example of the first calculation unit 35A. In Fig. 6, parts corresponding to those in Fig. 5 are denoted by the same reference numerals as in Fig. 5.

[0116] When the first calculation unit 35A3 according to the third modification is applied, the torque sensor 12 is disposed near the torsion bar 10, as shown by the dashed line in Fig. 1. The torque sensor 12 calculates the steering torque (torsion bar torque) T applied to the steering wheel 2 based on the amount of relative rotational displacement between the input shaft 8 and the output shaft 9. d The steering torque T detected by the torque sensor 12 dFor example, the torque for steering left is detected as a positive value, and the torque for steering right is detected as a negative value, and the larger the absolute value, the larger the magnitude of the steering torque.

[0117] The first calculation unit 35A3 according to the third modification receives the first disturbance torque estimated value ^T lc1 In addition, the first actual steering angle θ m / N and a target value is also given from a higher-level ECU (not shown). d In this example, the target value is the automatic steering command value θ ad is.

[0118] The first calculation unit 35A3 includes a first assist torque command value setting unit 81A, a first manual steering command value generation unit 82A, a first integrated angle command value calculation unit 83A, a first feedback control unit 71A, a first feedforward control unit 76A, a first torque addition unit 77A, a first disturbance torque compensation unit 72A, and a first reduction ratio division unit 73A.

[0119] The first assist torque command value setting unit 81A sets a first assist torque command value T as1 The first assist torque command value setting unit 81A sets the steering torque T d Based on this, the first assist torque command value T as1 Set.

[0120] First assist torque command value T as1 is set to a positive value when the electric motor 18 is to generate a steering assist force for steering to the left, and is set to a negative value when the electric motor 18 is to generate a steering assist force for steering to the right. as1 is the steering torque T d The steering torque T dThe first assist torque command value T as1 is the steering torque T d The larger the absolute value of the first assist torque command value setting unit 81A, the larger the absolute value of the second assist torque command value setting unit 81B. For example, the assist torque command value setting unit (51) shown in FIG. 2 of WO 2023 / 286169 can be used as the first assist torque command value setting unit 81A.

[0121] When the driver operates the steering wheel 2, the first manual steering command value generating unit 82A calculates a steering angle (more precisely, a rotation angle of the output shaft 9) corresponding to the steering wheel operation as a first manual steering command value θ md1 The first manual steering command value generating unit 82A is provided to set the steering torque T d and the first assist torque command value T set by the first assist torque command value setting unit 81A. as1 and the first manual steering command value θ md1 Generate.

[0122] The first manual steering command value generating unit 82A can use, for example, the manual steering command value generating unit (52) shown in FIG. 2 of International Publication No. 2023 / 286169. In this case, the first manual steering command value generating unit 82A calculates the first manual steering command value θ by solving the differential equation of the following formula (1): md1 Calculate the following.

[0123] J c ·d 2 θ md1 / dt 2 =T d +T as1 -k θ md1 -c(dθ md1 / dt)…(1) In equation (1), J c is the preset inertia of the lower column, and T d is the steering torque detected by the torque sensor 12, and T as1 is the first assist torque command value T set by the first assist torque command value setting unit 81A. as1where k is a preset spring constant and c is a preset viscous damping coefficient.

[0124] The first integrated angle command value calculation unit 83A calculates the automatic steering command value θ given from the upper ECU. ad , the first manual steering command value θ md1 is added to obtain the first integrated angle command value θ int1 The first integrated angle command value θ int1 is given to the first feedback control section 71A and the first feedforward control section 76A.

[0125] The first feedback control section 71A has a configuration similar to that of the first feedback control section 71A in Fig. 4. However, the first feedback control section 71A has an automatic steering command value θ ad Instead, the first integrated angle command value θ int1 The first feedback control unit 71A receives the first integrated angle command value θ int1 and actual steering angle θ m / N and deviation Δθ(=θ int1 -θ m / N), the feedback control torque T fb Calculate the feedback control torque T fb is given to the first torque addition unit 77A.

[0126] The first feedforward control unit 76A has a configuration similar to that of the first feedforward control unit 76A in Fig. 5. However, the first feedforward control unit 76A does not include an automatic steering command value θ ad Instead, the first integrated angle command value θ int1 The first feedforward control unit 76A receives the first integrated angle command value θ int1 The second derivative value d 2 θ int1 / dt 2 is multiplied by the inertia J of the electric power steering system 1 to obtain a first feedforward control torque T ff (=J·d 2 θ int1 / dt 2) is calculated. The first feedforward control torque T ff is given to the first torque addition unit 77A as an inertia compensation value.

[0127] The first torque addition unit 77A calculates the feedback control torque T fb to the feedforward control torque T ff By adding fb +T ff ) is calculated.

[0128] The first disturbance torque compensator 72A calculates the basic torque command value (T fb +T ff ) to the first disturbance torque estimate ^T lc1 By subtracting c1,cmd (=T fb -^T lc ) is calculated. As a result, the first steering torque command value T c1,cmd (torque command value for output shaft 9) is obtained.

[0129] First steering torque command value T c1,cmd is given to the first reduction ratio division unit 73A. The first reduction ratio division unit 73A calculates the first steering torque command value T c1,cmd is divided by the reduction ratio N to obtain the first motor torque command value T m1,cmd This first motor torque command value T m1,cmd is given to the third coefficient multiplication unit 36A (see FIG. 2).

[0130] 6, the first feedforward control unit 76A may be omitted. In this case, the feedback control torque T calculated by the first feedback control unit 71A is fb is the basic target torque.

[0131] Although the embodiments and modifications of the present disclosure have been described above, the present disclosure can also be embodied in other forms.

[0132] In the above-described embodiment and modified example, the first actual current I detected by the first current detection circuit 52A m1 The first actual torque N·T is calculated based on m1 is set as the "feedback value according to the current flowing through the first system winding" in the present disclosure (see the first actual torque calculation unit 31A). However, the calculation result K3·T of the third coefficient multiplication unit 36A m1,cmd is multiplied by the reduction ratio N, which is N·K3·T m1,cmd may be set as the "feedback value according to the current flowing through the first system winding" in the present disclosure. In this case, N·K3·T m1,cmd is provided to the first coefficient multiplier 39A and the fifth coefficient multiplier 40B.

[0133] Similarly, the calculation result K6·T of the sixth coefficient multiplication unit 36B m1,cmd (or K6·T m2,cmd ) multiplied by the reduction ratio N, N·K6·T m1,cm (or K6·T m2,cmd ) may be set as the "feedback value according to the current flowing through the secondary system winding" in the present disclosure. In this case, N·K6·T m1,cm (or K6·T m2,cmd ) is provided to the fourth coefficient multiplier 39B and the second coefficient multiplier 40A.

[0134] Alternatively, a value T1 obtained by multiplying a first-system current command value calculated in first torque control unit 37A by a torque constant and then multiplying the result by the reduction ratio N may be set as the "feedback value according to the current flowing through the first-system winding" in the present disclosure. In this case, T1 is provided to first coefficient multiplier 39A and fifth coefficient multiplier 40B. Similarly, a value T2 obtained by multiplying a second-system current command value calculated in second torque control unit 37B by a torque constant and then multiplying the result by the reduction ratio N may be set as the "feedback value according to the current flowing through the second-system winding." In this case, T2 is provided to fourth coefficient multiplier 39B and second coefficient multiplier 40A.

[0135] In the above embodiment, the control amount distribution ratio (K3:K6 or K6:K3) between the two systems is 1:1 in the first coordinated drive mode and the second coordinated drive mode, but the control amount distribution ratio between the two systems may be other than that (m:n). However, the condition m+n=1 must be satisfied. For example, when m:n=3:2, m=3 / 5 and n=2 / 5 are set.

[0136] Specifically, in the first coordinated drive mode, for example, K1, K2, K4, and K5 are set to 1. Then, K3 is set to m, and K6 is set to n. As a result, the control amount distribution ratio between the first system unit 202 and the second system unit 203 becomes m:n.

[0137] In the second coordinated drive mode, for example, K1=1 / m, K2=0, K4=1 / n, and K5=0 are set. Then, K3 is set to m, and K6 is set to n. As a result, the control amount distribution ratio between the first system unit 202 and the second system unit 203 becomes m:n.

[0138] In addition, while the above-described embodiment shows an example in which the present disclosure is applied to motor control of a column-type EPS, the present disclosure can also be applied to motor control of EPS other than column-type EPS.The present disclosure can also be applied to control of an electric motor for steering angle control and an electric motor for reaction force control in a steer-by-wire system.

[0139] Furthermore, in the above embodiment, an electric power steering system in which the windings, drive circuits, and control units are divided into two systems has been described, but the present disclosure can also be applied to an electric power steering system in which the windings, drive circuits, and control units are divided into three or more systems.

[0140] In this case, under normal circumstances, the feedback value related to the current or torque used in the load observer of each system is calculated based on a feedback value corresponding to the sum of the currents flowing through the windings (system windings) of all systems. On the other hand, when communication between the microcomputers (controllers) of at least two systems becomes impossible, the microcomputer of each system calculates the feedback value related to the current or torque used in the load observer of that system based only on the feedback value corresponding to the current flowing through the winding (system winding) of that system.

[0141] Although the embodiments of the present disclosure have been described in detail, these are merely specific examples used to clarify the technical content of the present disclosure, and the present disclosure should not be construed as being limited to these specific examples, and the scope of the present disclosure is limited only by the appended claims. [Explanation of symbols]

[0142] 18...electric motor, 18A, 18B...windings, 30A, 30B...microcomputer, 31A, 31B...actual torque calculation unit, 32A, 32B...feedback value calculation unit, 33A, 33B...actual steering angle calculation unit, 34A, 34B...load observer, 35A, 35B...calculation unit, 36A...third coefficient multiplication unit, 36B...sixth coefficient multiplication unit, 37A, 37B...torque control unit, 38A, 38B...monitoring unit, 39A...first coefficient multiplication unit, 39B...fourth coefficient multiplication unit, 40A...second coefficient multiplication unit, 40B...fifth coefficient multiplication unit, 41A, 41B...addition unit, 42...switch, 51A, 51B...drive circuit, 52A, 52B...current detection circuit, 201...motor control ECU, 202...first system unit, 203...second system unit

Claims

1. A motor control device applied to a system in which windings, drive circuits, and control units of an electric motor that applies torque to a steering system are systemized in multiple systems, The control units of each system are capable of communicating with each other, the control unit in each system includes a load observer that estimates a load acting on the steering system using a feedback value related to current or torque, and a calculation unit that calculates a command value for driving at least the drive circuit in that system among all the drive circuits in all systems, using the load estimated by the load observer in that system; In a normal state, the feedback value of each system is calculated based on a feedback value corresponding to a sum of currents flowing through windings of all systems.

2. When communication between the control units of at least two systems becomes impossible, 2. The motor control device according to claim 1, wherein the control unit of each of the systems calculates the feedback value based only on a feedback value corresponding to a current flowing through a winding of that system.

3. an electric motor that applies torque to a steering system, the electric motor having two winding systems, i.e., a first winding system and a second winding system; a first drive circuit for supplying power to the first system winding; a second drive circuit for supplying power to the second system winding; a first control unit that controls the first drive circuit; a second control unit that controls the second drive circuit and is capable of mutual communication with the first control unit; The first control unit a first load observer that estimates a load acting on the steering system using a first feedback value related to a current or a torque; a first calculation unit that calculates a first command value for driving at least the first drive circuit of the first drive circuit and the second drive circuit using the load estimated by the first load observer, The second control unit is a second load observer that estimates a load acting on the steering system using a second feedback value related to current or torque; a second calculation unit that calculates a second command value for driving the second drive circuit using the load estimated by the second load observer, a motor control device wherein, under normal circumstances, the first feedback value and the second feedback value are both calculated based on both a feedback value corresponding to a current flowing through the first system winding and a feedback value corresponding to a current flowing through the second system winding.

4. When communication between the first control unit and the second control unit becomes impossible, the first control unit calculates the first feedback value based only on a feedback value corresponding to a current flowing through the first system winding; The motor control device according to claim 3 , wherein the second control unit calculates the second feedback value based only on a feedback value corresponding to a current flowing through the second system winding.

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