Motor control device and electric power steering device

Abstract

A motor control device is provided that enables the application of steering assist force early when the vehicle is started. Specifically, when the first microprocessor (18) has sent an instruction value (A2) (alternative value) from the second microprocessor (19) after the initial diagnosis of the first system (1000) is completed, it receives the instruction value (A2) (alternative value) sent from the second microprocessor (19), corrects the instruction value (A1) (second instruction value) by making the received instruction value (A2) (specific alternative value (A2')) gradually approach the instruction value (A1) (second instruction value) calculated by the first microprocessor (18), sends the instruction value (A1') as the corrected instruction value (A1) (second instruction value) to the second microprocessor (19), and limits the absolute value of the instruction value (A1') to gradually increase from "0" to below the upper limit of a predetermined set value, and drives the first motor drive unit (26) of the first system (1000) based on the limited instruction value (A1') (target current instruction value (Ir)).

Description

Technical Field

[0001] This invention relates to motor control devices and electric power steering devices. Background Technology

[0002] Conventionally, for example, a motor control device has been proposed, comprising: a main control unit that performs current control on one winding of an electric motor having two windings; and a slave control unit that performs current control on the other winding (see, for example, Patent Document 1). In the motor control device described in Patent Document 1, the main control unit calculates command values ​​from the two control units, performs current control on one winding based on the calculated command values, and sends the command values ​​to the slave control unit, which then performs current control on the other winding based on the sent command values.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent No. 7027808 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] Typically, in a motor control unit, initial diagnostics begin when the driver operates the ignition switch upon vehicle startup. After the initial diagnostics are completed, control of the electric motor commences. Therefore, in a motor control unit having a master control unit and a slave control unit, the configuration is such that initial diagnostics begin separately in both the master and slave control units, and control of the electric motor begins after the initial diagnostics in both units are completed. That is, after the initial diagnostics in the master and slave control units are completed, control of the electric motor begins, and steering assist force is applied to the steering system.

[0008] The purpose of this invention is to provide a motor control device and an electric power steering device that can initiate the application of steering assistance force early when the vehicle is started.

[0009] Methods for solving problems

[0010] To achieve the above objectives, one aspect of the present invention provides a motor control device (a) for controlling the drive of an electric motor having multiple winding groups, the motor control device comprising: (b) multiple drive circuits that supply power to the winding groups; and (c) multiple control units that generate control signals for driving the drive circuits based on command values; (d) when a set of components including correspondingly formed winding groups, drive circuits, and control units is defined as a first system, and another set of components is defined as a second system, (e) a first control unit serving as the control unit of the first system calculates a command value for the first control unit and a command value for the second control unit serving as the control unit of the second system, drives the drive circuit of the first system based on the calculated first command value, and sends the calculated second command value, which is the command value of the second control unit, to the second control unit; (f) the second control unit receives the second command value sent from the first control unit and drives the drive circuit of the second system based on the received second command value; and (g) the second control unit further comprises: a diagnostic completion detection unit that detects the completion of the initial diagnostic of the first system; and (h) a substitution value calculation unit that calculates the second command value. (i) If the initial diagnosis of the first system is not detected by the diagnosis completion detection unit when the initial diagnosis of the second system is completed, the drive circuit of the second system is driven based on the substitution value calculated by the substitution value calculation unit, and the substitution value is sent to the first control unit. Then, when the diagnosis completion detection unit detects that the initial diagnosis of the first system is completed, the drive circuit of the second system is driven based on the second instruction value sent from the first control unit. (j) If the first control unit has already sent a substitution value from the second control unit when the initial diagnosis of the first system is completed, the first control unit receives the substitution value sent from the second control unit, corrects the second instruction value calculated by the first control unit in such a way that the specific substitution value received as the substitution value gradually approaches the second instruction value calculated by the first control unit, sends the corrected second instruction value to the second control unit, and corrects the first instruction value calculated by the first control unit in such a way that the specific substitution value gradually approaches the first instruction value calculated by the first control unit, limits the absolute value of the corrected first instruction value to gradually increase from "0" to below the upper limit of a predetermined set value, and drives the drive circuit of the first system based on the limited first instruction value.

[0011] In addition, the main feature of another aspect of the electric power steering device of the present invention is that it includes: (a) the motor control device described above; and (b) an electric motor controlled by the motor control device, and (c) a steering assist force applied to the vehicle's steering system by means of the electric motor.

[0012] Invention Effects

[0013] According to one aspect of the present invention, a motor control device and an electric power steering device are provided that enable the application of steering assistance force to begin early when the vehicle is started. Attached Figure Description

[0014] Figure 1 This is a diagram showing the overall structure of the electric power steering device according to the first embodiment.

[0015] Figure 2 This is a diagram showing the internal structure of the electronic control unit.

[0016] Figure 3 This is a diagram illustrating the operation of the electronic control unit.

[0017] Figure 4 This is a diagram illustrating the operation of the electronic control unit.

[0018] Figure 5 This diagram illustrates the operation of the electric power steering system in the first mode.

[0019] Figure 6 This is a diagram showing the operation of the electric power steering system in the second or fourth mode.

[0020] Figure 7 This is a diagram showing the operation of the electric power steering system in the third mode.

[0021] Figure 8 This diagram shows the operation of the electric power steering system after switching to the fourth mode.

[0022] Figure 9 This is a diagram showing the structure of the cross-attenuation section in modified example (1).

[0023] Figure 10 This is a diagram showing the operation of the electronic control unit in variant (1).

[0024] Figure 11 This is a diagram showing the operation of the electronic control unit in variant (1).

[0025] Figure 12 This is a diagram showing the operation of the second instruction value generation unit in variant example (2).

[0026] Figure 13 This is a diagram showing the operation of the electric power steering device in variant (2).

[0027] Figure 14 This is a diagram showing the operation of the first microprocessor in variant (3). Detailed Implementation

[0028] The inventors have repeatedly studied a motor control device capable of initiating steering assist force application early upon vehicle startup, and considered a structure in which the control unit of the master control unit and the slave control unit, whose initial diagnosis is completed first, begins controlling the electric motor without waiting for the initial diagnosis of the other control unit to complete. However, in this structure, if the initial diagnosis of the slave control unit is completed before that of the master control unit, and the slave control unit alone performs electric motor control, the motor output of the electric motor may change drastically when the master control unit completes its initial diagnosis and begins controlling the electric motor based on the command value calculated by the master control unit. This drastic change in the steering assist force applied to the steering system may cause discomfort to the driver.

[0029] Hereinafter, an example of a motor control device and an electric power steering device according to an embodiment of the present invention will be described with reference to the accompanying drawings. Furthermore, the embodiments shown below are examples of apparatuses and methods for embodying the technical concept of the present invention, and the structure, arrangement, etc., of the constituent components of the technical concept of the present invention are not limited to the following descriptions. Various modifications can be made to the technical concept of the present invention within the scope of the claims as defined in the claims.

[0030] Furthermore, while the following description illustrates the application of this invention to electric power steering systems, the invention is not limited to applications in electric power steering systems and can be applied to various other uses. For example, it can be applied to electric braking systems or to drive mechanisms for indirect actuators used in driving robots.

[0031] The embodiments of the present invention will be described in the following order.

[0032] 1. Overall structure of electric power steering system

[0033] 2. Operation of the electric power steering system

[0034] 3. Variations

[0035] [1. Overall Structure of Electric Power Steering System]

[0036] Figure 1 This is a diagram showing the overall structure of the electric power steering device 100 according to the first embodiment. (See diagram below.) Figure 1As shown, the steering shaft 2 of the steering wheel 1 is connected to the steering wheels 8L and 8R via a reduction gear 3, universal joints 4a and 4b, a pinion rack mechanism 5, and tie rods 6a and 6b, and via wheel hub units 7a and 7b. The pinion rack mechanism 5 has a pinion 5a that transmits steering force from the universal joint 4b and a rack 5b that meshes with the pinion 5a. The pinion rack mechanism 5 uses the rack 5b to convert the steering force transmitted to the pinion 5a into straight-line motion in the vehicle width direction.

[0037] Additionally, a first torque sensor 9 and a second torque sensor 10 are installed on the steering shaft 2 to detect the driver's steering torque Th, and a steering angle sensor 11 to detect the steering angle θh of the steering wheel 1. Here, the steering torque Th detected by the first torque sensor 9 and the second torque sensor 10 are slightly different values ​​due to individual differences in the sensors.

[0038] Furthermore, the electric motor 12, which provides steering assistance to the steering system, is connected to the steering shaft 2 via a reduction gear 3. For example, a multiphase motor with multiple winding groups can be used as the electric motor 12. In the first embodiment, it is illustrated that the electric motor 12 has a first system coil 13 and a second system coil 14 wound within the same motor housing (see reference). Figure 2 This refers to a three-phase motor with two winding groups that rotate a rotor shared by the coils of both systems. In other words, it becomes a double-wound motor with two sets of three-phase winding groups having identical electrical characteristics.

[0039] Additionally, power is supplied from the battery 15 to the electronic control unit (ECU) 200 that controls the electric power steering device 100, and an ignition key signal is input from the ignition switch 16.

[0040] Additionally, the electronic control unit 200 is connected to a vehicle CAN (Controller Area Network) 17, from which it receives various vehicle information. For example, it receives vehicle speed Vh information detected by a speed sensor (not shown) from the vehicle CAN 17. Based on the steering torque Th detected by the first torque sensor 9 and the second torque sensor 10, the steering angle θh detected by the steering angle sensor 11, and the vehicle speed Vh received from the vehicle CAN 17, the electronic control unit 200 transmits the information via an inverter (in... Figure 2 The first motor drive unit 26 and the second motor drive unit 37 in the middle perform PWM (Pulse Width Modulation) control on the electric motor 12.

[0041] The electronic control unit 200 includes, for example, a computer with peripheral components such as a first microprocessor 18 (broadly referred to as a "control unit," "first control unit," or "main control unit"), a second microprocessor 19 (broadly referred to as a "control unit," "second control unit," or "slave control unit"), and a storage unit 20. The first microprocessor 18 and the second microprocessor 19 can be, for example, a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit). The storage unit 20 can be, for example, a semiconductor storage unit, a magnetic storage unit, or an optical storage unit. Examples of such storage units include registers, cache memory, ROM (Read Only Memory) used as main storage, and RAM (Random Access Memory). The functions of the electronic control unit 200 described below are implemented, for example, by the first microprocessor 18 and the second microprocessor 19 of the electronic control unit 200 executing computer programs stored in the storage unit 20. Furthermore, the storage unit 20 stores various data required for the execution of computer programs such as the first gain G1 and the second gain G2, which will be described later.

[0042] Figure 2 This is a diagram showing the internal structure of the electronic control unit 200. (Example) Figure 2 As shown, the electronic control unit 200 includes a first initial diagnostic unit 21, a first command value generation unit 22, a cross-attenuation unit 23, a first output limiting unit 24, a first current control unit 25, a first motor drive unit 26 (broadly referred to as a "drive circuit"), a first voltage detection unit 27, a first current detection unit 28, a first temperature detection unit 29, a first rotation angle detection unit 30, and a first power supply unit 31. The first initial diagnostic unit 21 to the first current control unit 25 are implemented by the first microprocessor 18 executing computer programs stored in the storage unit 20. In addition, the first initial diagnostic unit 21 to the first power supply unit 31, together with the first torque sensor 9 and the first system coil 13, constitute a set of components for controlling the drive of the electric motor 12 (hereinafter also referred to as "first system 1000"). That is, the first system 1000 is a set of components including the first system coil 13, the first motor drive unit 26, and the first microprocessor 18, which are formed correspondingly to each other.

[0043] Similarly, the electronic control unit 200 includes a second initial diagnostic unit 32, a second instruction value generation unit 33 (generally referred to as a "substitution value calculation unit"), a diagnostic completion detection unit 34, a second output limiting unit 35, a second current control unit 36, a second motor drive unit 37 (generally referred to as a "drive circuit"), a second voltage detection unit 38, a second current detection unit 39, a second temperature detection unit 40, a second rotation angle detection unit 41, and a second power supply unit 42. The second initial diagnostic unit 32 to the second current control unit 36 ​​are implemented by the second microprocessor 19 executing computer programs stored in the storage unit 20. Furthermore, the second initial diagnostic unit 32 to the second power supply unit 42, together with the second torque sensor 10 and the second system coil 14, constitute a set of components for controlling the drive of the electric motor 12 (hereinafter also referred to as "second system 2000"). That is, the second system 2000 is a set of components including the second system coil 14, the second motor drive unit 37, and the second microprocessor 19, which are formed correspondingly to each other. In addition, the first microprocessor 18 and the second microprocessor 19 can communicate with each other (send and receive data) via bus 43.

[0044] Furthermore, as described later, when the initial diagnosis of the first system 1000 is completed but the initial diagnosis of the second system 2000 is not completed, the electronic control unit 200 enters a first mode in which only the first system 1000 performs drive control of the electric motor 12. Then, when the initial diagnosis of the second system 2000 is completed, it switches to a second mode in which both the first system 1000 and the second system 2000 perform drive control of the electric motor 12. On the other hand, when the initial diagnosis of the second system 2000 is completed but the initial diagnosis of the first system 1000 is not completed, the electronic control unit 200 enters a third mode in which only the second system 2000 performs drive control of the electric motor 12. Then, when the initial diagnosis of the first system 1000 is completed, it switches to a fourth mode in which both the first system 1000 and the second system 2000 perform drive control of the electric motor 12.

[0045] The first initial diagnostic unit 21 performs an initial diagnostic of the first system 1000. For example, the initial diagnostic can be a diagnostic performed when the vehicle is started, i.e., a diagnostic to verify whether each component constituting the first system 1000 is operating normally. For example, a method can be used where, when the driver operates the ignition switch 16, it is determined whether the output values ​​of the first voltage detection unit 27, the first current detection unit 28, the first temperature detection unit 29, the first rotation angle detection unit 30, the first torque sensor 9, etc., are appropriate values ​​relative to a predetermined reference such as the command value A1 set by the first command value generation unit 22. The action (calculation) performed by the first system 1000 to apply steering assist force stops before the initial diagnostic of the first system 1000 is completed and begins after the initial diagnostic of the first system 1000 is completed.

[0046] When the first initial diagnostic unit 21 completes the initial diagnostic of the first system 1000, the first command value generation unit 22 calculates the target steering torque based on the steering torque Th output from the first torque sensor 9, the vehicle speed Vh received from the vehicle CAN 17, the steering angle θh output from the steering angle sensor 11, and the steering angular velocity ωh calculated based on the steering angle θh. The target steering torque is the total amount of steering assist force that assists the driver in steering the steering wheel 1. Furthermore, the first command value generation unit 22 converts the calculated target steering torque into a current command value Ir0. For example, the q-axis current command value and the d-axis current command value can be used as the current command value Ir0. Additionally, the first command value generation unit 22 assigns the converted current command value Ir0 to the first system 1000 and the second system 2000, setting the current command value used in the first system 1000 (hereinafter also referred to as the "first command value") and the current command value used in the second system 2000 (hereinafter also referred to as the "second command value"). Figure 2 In the example shown, the first instruction value and the second instruction value are each set to half the current instruction value Ir0, thus becoming the same instruction value A1. The instruction value A1 is output to the cross-attenuation unit 23. That is, the first instruction value generation unit 22 calculates the instruction value A1 (first instruction value) of the first microprocessor 18 and the instruction value A1 (second instruction value) of the second microprocessor 19.

[0047] The cross-attenuation unit 23 includes a first multiplier 44, a second multiplier 45, and an adder 46. The first gain G1 used in the first multiplier 44 and the second gain G2 used in the second multiplier 45 are set to values ​​in the range of 0 and below 1.

[0048] When the first initial diagnostic unit 21 completes the initial diagnostic of the first system 1000, the second multiplier 45 multiplies the instruction value A2 sent from the second instruction value generation unit 33 or the instruction value A2 received when the first instruction value generation unit 22 starts calculating the instruction value A1 (hereinafter also referred to as "specific substitution value A2") with the second gain G2, and calculates the multiplication result (hereinafter also referred to as "second multiplication result"). Specifically, if the second multiplier 45 does not send the instruction value A2 (substitution value) from the second microprocessor 19 when the initial diagnostic of the first system 1000 is completed (hereinafter also referred to as "first state"), it sets the value of the second gain G2 to "0", and multiplies the instruction value A2 with the second gain G2 to calculate G2. A2 is the result of the second multiplication. The "first state" occurs when the initial diagnosis of the first system 1000 is completed before the initial diagnosis of the second system 2000.

[0049] On the other hand, when the initial diagnosis of the first system 1000 is completed and the instruction value A2 (substitute value) from the second microprocessor 19 is sent (hereinafter also referred to as the "second state"), the second multiplier 45 gradually changes the value of the second gain G2 from "1" to "0" over time. In addition, the specific substitute value A2' is multiplied by the second gain G2 to calculate G2. A2' is the second multiplication result. The "second state" is generated in the third mode where the initial diagnosis of the second system 2000 is completed before the initial diagnosis of the first system 1000, and only the second system 2000 performs drive control of the electric motor 12. Therefore, in the case where the initial diagnosis of the first system 1000 is completed before the second system 2000 performs drive control of the electric motor 12, the second multiplication result G2... A2' gradually changes from "A2'" to "0". The result of the second multiplication is output to adder 46.

[0050] As a method for setting the specific alternative value A2', for example, one approach is to receive the instruction value A2 sent from the second microprocessor 19 and use the received instruction value A2 as the specific alternative value A2' when switching from the third mode to the fourth mode, in which the electric motor 12 is driven and controlled by both the first system 1000 and the second system 2000, after the initial diagnosis of the first system 1000 is completed. Furthermore, in the first embodiment, when the second gain G2 is gradually changed from "1" to "0", the amount of change in the second gain G2 is kept constant for each change. Therefore, when the diagnosis of the first system 1000 is completed, as described later, the time required for the output of the cross-attenuation section 23 to reach the instruction value A1 from the specific alternative value A2' can be set to a constant value (e.g., 50 μs).

[0051] When the first initial diagnostic unit 21 completes the initial diagnostic of the first system 1000, the first multiplier 44 multiplies the instruction value A1 (which serves as both the first instruction value and the second instruction value) set by the first instruction value generation unit 22 with the first gain G1, and calculates the multiplication result (hereinafter also referred to as "the first multiplication result G1"). A1). The value of the first gain G1 is set, for example, to G1 = 1 - G2. Thus, when the initial diagnosis is completed in the first state, the first multiplication result G1 A1 becomes "A1". Furthermore, in the case of the second state, the first multiplication result G1 A1 gradually changes from "0" to "A1". The result of the first multiplication is G1. A1 is output to adder 46.

[0052] When the first initial diagnostic unit 21 completes the initial diagnostic of the first system 1000, the adder 46 multiplies the first multiplication result G1. The result of multiplying A1 and the second product is G2. A2 or G2 Add A2' to calculate the sum (hereinafter also referred to as "instruction value A1'"). Thus, when the initial diagnosis is completed in the first state, the instruction value A1' becomes "A1". In addition, when in the second state, the instruction value A1' gradually changes from "specific substitute value A2'" to "A1". That is, when in the second state, the instruction value A1 is corrected in a way that gradually approaches the instruction value A1 (first instruction value, second instruction value) calculated by the first instruction value generation unit 22 from the specific substitute value A2', thus becoming the instruction value A1'. The instruction value A1' (corrected first instruction value, second instruction value) is output to the first output limiting unit 24 and sent to the second microprocessor 19. In other words, the first microprocessor 18 is configured to add the instruction value A1 calculated by the first instruction value generation unit 22 in sequence with the specific substitute value A2' at a predetermined ratio G1:G2 to obtain the sum value (G1:G2). A1+G2 A2') is sent as instruction value A1' and sequentially sent to the second microprocessor 19. Additionally, the first microprocessor 18 is configured such that the proportion of instruction value A1 is such that its sum (G1) A1 and G2 The ratio G1:G2 changes by starting with "0" and then gradually increasing from "0".

[0053] Furthermore, as described above, in the first embodiment, the case where the "first instruction value" and the "second instruction value" are the same instruction value A1 is illustrated. Therefore, in the description of the adder 46 described above, the "first instruction value" and the "second instruction value" are recorded together as "instruction value A1 (first instruction value, second instruction value)" and "instruction value A1' (corrected first instruction value, second instruction value)". In contrast, if the instruction value A1 representing the "first instruction value", the instruction value A1 representing the "second instruction value", the instruction value A1' representing the "corrected first instruction value", and the instruction value A1' representing the "corrected second instruction value" are recorded separately, the description of the adder 46 can also be expressed as follows. "That is, in the second state, the instruction value A1 (first instruction value) is corrected in a manner that gradually approaches the instruction value A1 (first instruction value) calculated by the first instruction value generation unit 22 from a specific substitution value A2', becoming the instruction value A1'. The instruction value A1' (corrected first instruction value) is output to the first output limiting unit 24. In addition, the instruction value A1 (second instruction value) is corrected in a manner that gradually approaches the instruction value A1 (second instruction value) calculated by the first instruction value generation unit 22 from a specific substitution value A2', becoming the instruction value A1'. The instruction value A1' (corrected second instruction value) is sent to the second microprocessor 19."

[0054] The first output limiting unit 24 sets the target current command value Ir by limiting the absolute value of the command value A1' (corrected first command value) output from the cross-attenuation unit 23 to a predetermined upper limit value U1 or lower. For example, "U1" replaces the command value A1' exceeding "U1", and "-U1" replaces the command value A1' below "-U1". Furthermore, when the first initial diagnostic unit 21 completes the initial diagnostic of the first system 1000, the first output limiting unit 24 first sets the absolute value of the upper limit value U1 to "0", and then gradually increases it from "0" to the predetermined set value. Thus, the target current command value Ir of the first system 1000 immediately becomes "0" immediately after the initial diagnostic of the first system 1000 is completed, and then gradually changes from "0" to the command value A1'. Therefore, for example, when switching from the third mode to the fourth mode, the steering assist force of the first system 1000 immediately after the switch can be set to "0", and the target current command value Ir can be gradually increased, thereby suppressing abrupt changes in motor output. Furthermore, the amount of change in the upper limit value U1 during each change is set constant so that the time required to reach the "set value" is constant (e.g., 1 second). Additionally, the first output limiting unit 24 can set the set value to a lower value than if the temperature of the electric motor 12 or the first motor drive unit 26 detected by the first temperature detection unit 29 is higher than a predetermined temperature. The target current command value Ir is output to the first current control unit 25.

[0055] The first current control unit 25 generates a voltage control command value Vref based on the deviation between the current value Im of the first system coil 13 (received from feedback) and the target current command value Ir, using feedback control such as PI (proportional-integral) control. For example, the current value Im can be the q-axis current iq and d-axis current id obtained by converting the phase currents of each phase A, B, and C of the first system coil 13. Similarly, the voltage control command value Vref can be the voltage command values ​​of each phase A, B, and C. Furthermore, based on the generated voltage control command value Vref, the first current control unit 25 generates a gate signal (PWM signal) for driving the first motor drive unit 26 (e.g., an inverter). In other words, the first current control unit 25 generates a PWM signal (control signal) to drive the first motor drive unit 26 based on the target current command value Ir (the limited command value A1).

[0056] With this structure, when the initial diagnosis of the first system 1000 is completed in the first state (i.e., the initial diagnosis of the first system 1000 is completed before the initial diagnosis of the second system 2000), the first microprocessor 18 enters the first mode, sets the instruction value A1 calculated by the first instruction value generation unit 22 as the instruction value A1' (=A1), and starts driving the first motor drive unit 26 of the first system 1000 based on the instruction value A1' (the corrected first instruction value). Additionally, the first microprocessor 18 sends the instruction value A1' (the corrected second instruction value) to the second microprocessor 19. Then, when the initial diagnosis of the second system 2000 is completed, it switches to the second mode, and the first microprocessor 18 continues to generate the instruction value A1' (=A1), and continues to drive the first motor drive unit 26 by the first system 1000 based on the instruction value A1'. Furthermore, in the second mode, as described later, the second microprocessor 19 of the second system 2000 executes the driving of the second motor drive unit 37.

[0057] On the other hand, if the first microprocessor 18 is in the second state when the initial diagnosis of the first system 1000 is completed (i.e., the initial diagnosis of the second system 2000 is completed before the initial diagnosis of the first system 1000), it switches from the third mode to the fourth mode, such as... Figure 3 As shown, the instruction value A1 is corrected by gradually approaching the instruction value A1 calculated by the first instruction value generation unit 22 from a specific substitution value A2', and the corrected instruction value A1 (instruction value A1') is output to the first output restriction unit 24. In addition, the instruction value A1' is sent to the second microprocessor 19. Figure 3 This is a diagram illustrating the operation of the electronic control unit 200. Figure 3 (a) is a graph showing the relationship between instruction value and time. Figure 3 (b) is a graph showing the relationship between gain and time. Figure 3 (c) is a diagram showing the case where the instruction value is immediately switched from A2 to A1. Additionally, in the fourth mode, as... Figure 4 As shown, the first microprocessor 18 restricts the instruction value A1' to gradually increase from "0" to below the upper limit value U1 of a predetermined set value, thus becoming the target current instruction value Ir, and drives the first motor drive unit 26 of the first system 1000 based on the target current instruction value Ir. Figure 4 This is a diagram illustrating the operation of the electronic control unit 200. Figure 4 (a) is a graph showing the relationship between the target current command value Ir, the upper limit value U1 and time for the first system. Figure 4(b) is a graph showing the relationship between the target current command value Ir, the upper limit value U2, and time for the second system. Furthermore, in the fourth mode, as described later, the second microprocessor 19 of the second system 2000 executes the driving of the second motor drive unit 37.

[0058] The first motor drive unit 26 is a drive circuit that supplies power to the first system coil 13. Driven by a PWM signal output from the first microprocessor 18, the first motor drive unit 26 supplies current (electricity) to the first system coil 13 of the electric motor 12 such that the deviation between the current value Im of the first system coil 13 and the target current command value Ir is "0". That is, the first motor drive unit 26 is driven based on the PWM signal (a signal based on the limited command value A1'). For example, an inverter can be used as the first motor drive unit 26.

[0059] The first voltage detection unit 27 detects the voltage of the first motor drive unit 26. The first current detection unit 28 detects the phase current of each phase of the first system coil 13. The first temperature detection unit 29 detects the temperature of the electric motor 12 or the first motor drive unit 26. The first rotation angle detection unit 30 detects the rotation angle θm of the electric motor 12. The detected voltage, phase current, temperature, and rotation angle θm are output to the first microprocessor 18.

[0060] The first power supply unit 31 is located between the battery 15 and the first microprocessor 18 and the first motor drive unit 26. Based on a control signal output from the first microprocessor 18, it connects or disconnects the battery 15 from the first microprocessor 18 and the first motor drive unit 26. This starts or stops the power supply from the battery 15 to the first microprocessor 18 and the first motor drive unit 26. For example, a relay can be used as the first power supply unit 31.

[0061] The second initial diagnostic unit 32 performs an initial diagnostic of the second system 2000. For example, the initial diagnostic can be a diagnostic performed when the vehicle is started, i.e., a diagnostic to verify whether the various components constituting the second system 2000 are operating normally. For example, a method can be used where, when the driver operates the ignition switch 16, it is determined whether the output values ​​of the second voltage detection unit 38, the second current detection unit 39, the second temperature detection unit 40, the second rotation angle detection unit 41, the second torque sensor 10, etc., are appropriate values ​​relative to a predetermined reference such as the command value A2 set by the second command value generation unit 33. The action (calculation) performed by the second system 2000 to apply steering assist force stops before the initial diagnostic of the second system 2000 is completed and begins after the initial diagnostic of the second system 2000 is completed.

[0062] When the second initial diagnostic unit 32 completes the initial diagnostic of the second system 2000, the second command value generation unit 33 calculates a replacement value (a replacement value for the second command value, hereinafter also referred to as "command value A2") for the command value A1 sent from the first command value generation unit 22. Specifically, the second command value generation unit 33 calculates the target steering torque based on the steering torque Th output from the second torque sensor 10, the vehicle speed Vh received from the vehicle CAN 17, the steering angle θh output from the steering angle sensor 11, and the steering angular velocity ωh calculated based on the steering angle θh. Furthermore, the second command value generation unit 33 converts the calculated target steering torque into a current command value Ir0. The converted current command value Ir0 is then assigned to the first system 1000 and the second system 2000, setting a first command value used in the first system 1000 and a second command value used in the second system 2000. Figure 2 The example illustrates a case where the first command value and the second command value are each set to half the current command value Ir0, thus becoming the same command value A2. Command value A2 is output to the second output limiting unit 35.

[0063] Here, the steering torque Th output from the first torque sensor 9 and the steering torque Th output from the second torque sensor 10 are not exactly the same due to individual differences in the sensors. Therefore, depending on the different steering torque Th, the command value A1 calculated by the first command value generation unit 22 and the command value A2 calculated by the second command value generation unit 33 are slightly different values.

[0064] The diagnostic completion detection unit 34 detects the completion of the initial diagnostics of the first system 1000. As described above, if the initial diagnostics of the first system 1000 is not completed, the first microprocessor 18 does not begin the calculation of instruction value A1', nor does it begin sending instruction value A1'. Therefore, the diagnostic completion detection unit 34 determines, for example, whether instruction value A1' is sent sequentially from the first microprocessor 18. If it is sent sequentially, it determines that the initial diagnostics of the first system 1000 is completed; if instruction value A1' is not sent, it determines that the initial diagnostics of the first system 1000 is not completed. The detection result is output to the second instruction value generation unit 33 and the second output limiting unit 35.

[0065] The second output limiting unit 35 sets the target current command value Ir by limiting the absolute value of the instruction value A1' sent from the first microprocessor 18 or the instruction value A2 output from the second instruction value generation unit 33 to a predetermined upper limit value U2 or lower. Specifically, when the diagnostic completion detection unit 34 detects that the initial diagnostic of the first system 1000 is completed, the second output limiting unit 35 limits the instruction value A1' to a predetermined upper limit value U2 or lower to set the target current command value Ir. On the other hand, when the diagnostic completion detection unit 34 does not detect that the initial diagnostic of the first system 1000 is completed, the second output limiting unit 35 limits the instruction value A2 to an upper limit value U2 or lower to set the target current command value Ir. For example, instruction values ​​A1' or A2 exceeding "U2" are replaced with "U2", and instruction values ​​A1' or A2 below "-U2" are replaced with "-U2". In addition, when the second initial diagnostic unit 32 completes the initial diagnostic of the second system 2000, the second output limiting unit 35 first sets the absolute value of the upper limit value U2 to "0", and then gradually increases it from "0" to a predetermined set value.

[0066] Therefore, the target current command value Ir of the second system 2000 immediately becomes "0" immediately after the initial diagnosis of the second system 2000 is completed, and then gradually changes from "0" to the command value A1'. Thus, for example, when switching from the first mode to the second mode, the steering assist force of the second system 2000 immediately after the switch can be set to "0", and the target current command value Ir is gradually increased, thereby suppressing abrupt changes in motor output. Furthermore, the amount of change in the upper limit value U2 during each change is set constant so that the time required to reach the "set value" is constant (e.g., 1 second). Additionally, the second output limiting unit 35 can set a lower set value when the temperature of the electric motor 12 or the second motor drive unit 37 detected by the second temperature detection unit 40 is higher than a predetermined temperature, compared to when the temperature is lower than a predetermined temperature. The target current command value Ir is output to the second current control unit 36.

[0067] The second current control unit 36 ​​generates a voltage control command value Vref based on the deviation between the current value Im of the second system coil 14 (received from feedback) and the target current command value Ir, using feedback control such as PI (proportional-integral) control. For example, the current value Im can be the q-axis current iq and d-axis current id obtained by converting the phase currents of each phase A, B, and C of the second system coil 14. Similarly, the voltage control command value Vref can be the voltage command values ​​of each phase A, B, and C. Furthermore, based on the generated voltage control command value Vref, the second current control unit 36 ​​generates a gate signal (PWM signal) for driving the second motor drive unit 37 (e.g., an inverter). In other words, the second current control unit 36 ​​generates a PWM signal (control signal) to drive the second motor drive unit 37 based on the target current command value Ir (the limited command value A2).

[0068] With this structure, in the case where no instruction value A1 is sent from the first microprocessor 18 when the initial diagnosis of the second system 2000 is completed (hereinafter also referred to as the "third state"), it becomes the third mode, and the second microprocessor 19 drives the second motor drive unit 37 based on the instruction value A2 (the substitute value of the second instruction value) calculated by the second instruction value generation unit 33. Additionally, the second microprocessor 19 sends the calculated instruction value A2 (the substitute value of the second instruction value) to the first microprocessor 18. Then, when the initial diagnosis of the first system 1000 is completed and the initial diagnosis of the first system 1000 is detected by the diagnosis completion detection unit 34, it switches to the fourth mode, receives the instruction value A1' (the corrected second instruction value) sent from the first microprocessor 18, and drives the second motor drive unit 37 of the second system 2000 based on the received instruction value A1'. On the other hand, when the initial diagnosis of the second system 2000 has been completed and the instruction value A1 from the first microprocessor 18 has been sent (hereinafter also referred to as the "fourth state"), the second microprocessor 19 switches from the first mode to the second mode, receives the instruction value A1' (corrected second instruction value) sent from the first microprocessor 18, and drives the second motor drive unit 37 of the second system 2000 based on the received instruction value A1'.

[0069] The second motor drive unit 37 is a drive circuit that supplies power to the second system coil 14. Driven by a PWM signal output from the second microprocessor 19, the second motor drive unit 37 supplies current (electricity) to the second system coil 14 of the electric motor 12 such that the deviation between the current value Im of the second system coil 14 and the target current command value Ir is "0". That is, the second motor drive unit 37 is driven based on the PWM signal (a signal based on the limited command value A2). For example, an inverter can be used as the second motor drive unit 37.

[0070] The second voltage detection unit 38 detects the voltage of the second motor drive unit 37. The second current detection unit 39 detects the phase current of each phase of the second system coil 14. The second temperature detection unit 40 detects the temperature of the electric motor 12 or the second motor drive unit 37. The second rotation angle detection unit 41 detects the rotation angle θm of the electric motor 12. The detected voltage, phase current, temperature, and rotation angle θm are output to the second microprocessor 19.

[0071] The second power supply unit 42 is located between the battery 15, the second microprocessor 19, and the second motor drive unit 37. It connects or disconnects the battery 15 from the second microprocessor 19 and the second motor drive unit 37 based on a control signal output from the second microprocessor 19. This starts or stops the power supply from the battery 15 to the second microprocessor 19 and the second motor drive unit 37. For example, a relay can be used as the second power supply unit 42.

[0072] 2. Operation of the electric power steering system

[0073] Next, the operation of the electric power steering system 100 will be explained.

[0074] First, when the vehicle is started, and the driver operates the ignition switch 16, initial diagnostics begin in both the first system 1000 and the second system 2000. Here, as... Figure 5 As shown, the first system 1000 completes its initial diagnosis first, while the second system 2000 has not completed its initial diagnosis. In this first state, the first mode begins. Figure 5 This diagram illustrates the operation of the electric power steering system 100 in the first mode. In this mode, since it is the first mode, the cross-attenuation unit 23 sets the first gain G1 to "1", sets the second gain G2 to "0", and outputs the command value A1 as the command value A1' (A1'=A1). Therefore, in the first system 1000, the current control of the first system coil 13 begins based on the command value A1 (first command value) calculated sequentially by the first command value generation unit 22. On the other hand, in the second system 2000, since the initial diagnosis of the second system 2000 has not been completed, the second microprocessor 19 does not perform any operations other than the initial diagnosis, and does not begin the current control of the second system coil 14. That is, in the first mode, the electric motor 12 is not driven based on the second system 2000, and the electric motor 12 is driven and controlled only by the first system 1000 using the command value A1 calculated by the first system 1000 (single system control). Therefore, for example, compared to the method of waiting for the initial diagnosis of the second system 2000 to also be completed and for both the first system 1000 and the second system 2000 to begin applying steering assistance force, although the steering assistance force is reduced, the application of steering assistance force can begin earlier.

[0075] In addition, such as Figure 6 As shown, after the initial diagnosis of the first system 1000 is completed, the initial diagnosis of the second system 2000 is completed and it enters the fourth state, switching from the first mode to the second mode. Figure 6 This diagram illustrates the operation of the electric power steering system 100 in either the second or fourth mode. In this mode, the current control of the first system coil 13 based on the command value A1, which is performed in the first mode, continues in the first system 1000. Furthermore, in the second system 2000, the current control of the second system coil 14 begins based on the command value A1' (=A1, the second command value) sequentially sent from the first microprocessor 18. That is, in the second mode, the drive control (coordinated control) of the electric motor 12 is performed in both the first system 1000 and the second system 2000 using the command value A1 calculated by the first system 1000. Therefore, compared to the first mode, the steering assist force can be increased. Additionally, the generation of noise and vibration caused by interference between the steering assist force provided by the first system 1000 and the steering assist force provided by the second system 2000 can be suppressed.

[0076] On the other hand, after the initial diagnosis begins in the first system 1000 and the second system 2000 respectively, such as Figure 7 As shown, the initial diagnosis of the second system 2000 is completed first, and the third state, in which the initial diagnosis of the first system 1000 is not completed, begins, starting the third mode. Figure 7 This diagram illustrates the operation of the electric power steering system 100 in the third mode. In this mode, since the initial diagnosis of the first system 1000 is not yet complete, the first microprocessor 18 does not perform any actions other than the initial diagnosis, and the current control of the first system coil 13 is not initiated. On the other hand, in the second system 2000, the current control of the second system coil 14 is initiated based on the instruction value A2 (alternate value) calculated sequentially by the second instruction value generation unit 33. That is, in the third mode, the electric motor 12 based on the first system 1000 is not driven, and the electric motor 12 is driven and controlled solely by the second system 2000 using the instruction value A2 calculated by the second system 2000 (single system control). Therefore, for example, compared to the method of waiting for the initial diagnosis of the first system 1000 to also be completed and then having both the first system 1000 and the second system 2000 initiate the application of steering assist force, although the steering assist force is reduced, the application of steering assist force can be initiated earlier.

[0077] In addition, such as Figure 8 As shown, after the initial diagnosis of the second system 2000 is completed, the initial diagnosis of the first system 1000 is completed and it enters the second state, switching from the third mode to the fourth mode. Figure 8 This diagram illustrates the operation of the electric power steering system 100 in the fourth mode. In this mode, since it is the fourth mode, the cross-attenuation unit 23 gradually changes the first gain G1 from "0" to "1" and the second gain G2 from "1" to "0". As a result, the cross-attenuation unit 23 receives the instruction value A2 (specific substitution value A2') sent from the first microprocessor 18, corrects the instruction value A1 by gradually approaching the instruction value A1 (first instruction value, second instruction value) sequentially calculated by the first instruction value generation unit 22 from the received specific substitution value A2', and outputs the corrected instruction value A1 as instruction value A1'. Furthermore, the first output limiting unit 24 gradually changes the target current instruction value Ir from "0" to instruction value A1' based on the output instruction value A1'. Therefore, in the first system 1000, the current control of the first system coil 13 is performed based on the target current instruction value Ir of the first output limiting unit 24, which gradually changes from "0" to instruction value A1'. In addition, in the second system 2000, the current control of the second system coil 14 is started based on the instruction value A1' sent from the first microprocessor 18, which is a value that gradually changes from a specific alternative value A2' to the instruction value A1 (second instruction value).

[0078] Specifically, after operating the ignition switch 16, if the initial diagnostics of the first system 1000 are not completed but only the initial diagnostics of the second system 2000 are completed, and the third mode is started, as follows: Figure 7 As shown, the first system 1000 does not initially drive the electric motor 12; instead, it uses the command value A2 calculated by the second system 2000, and only the second system 2000 performs drive control of the electric motor 12. Later, when the first system 1000 completes its initial diagnostics and switches from the third mode to the fourth mode, as... Figure 8 As shown, immediately after the switch, the first microprocessor 18 outputs / sends a specific substitution value A2' (i.e., the instruction value A2 before the switch) as instruction value A1'. Therefore, in the second system 2000, the drive control of the electric motor 12 is performed based on the specific substitution value A2', and the drive control of the electric motor 12 is the same as before the switch. Furthermore, in the first system 1000, the target current instruction value Ir is set to "0" in the first output limiting unit 24, so no drive control of the electric motor 12 is performed. Therefore, the total amount of steering assist force provided by the first system 1000 and the second system 2000 is the same as the total amount before the switch.

[0079] Next, the first microprocessor 18 outputs the instruction value A1' as a value that makes a specific substitution value A2' (a fixed value) slightly closer to the instruction value A1. Therefore, as... Figure 6As shown, in the second system 2000, the drive control of the electric motor 12 is performed based on the new command value A1' (=A2'+Δ), and the drive control of the electric motor 12 is slightly different from the control before the switch. Meanwhile, in the first system 1000, since the absolute value of the target current command value Ir is made slightly greater than "0" in the first output limiting unit 24, the drive control of the electric motor 12 is slightly executed. Therefore, the total amount of steering assist force provided by the first system 1000 and the second system 2000 is slightly different from the total amount before the switch. Therefore, when switching to the fourth mode, the total amount of steering assist force gradually changes from the total amount before the switch, suppressing abrupt changes.

[0080] Furthermore, by repeatedly performing the above-described calculations and controls, the command value A1' gradually approaches the command value A1 (latest value) from a specific alternative value A2' (fixed value), becoming the same value as the command value A1. Additionally, the first output limiting unit 24 outputs the command value A1' (=A1) as the target current command value Ir. Therefore, the first system 1000 and the second system 2000 respectively perform drive control of the electric motor 12 according to the same target current command value Ir (i.e., the target current command value Ir based on command value A1). That is, using the command value A1 (command value A1') set by the first system 1000, drive control (coordinated control) of the electric motor 12 is performed in both the first system 1000 and the second system 2000. Therefore, compared to the third mode, the steering assist force can be increased. Furthermore, the generation of noise and vibration caused by interference between the steering assist force provided by the first system 1000 and the steering assist force provided by the second system 2000 can be suppressed.

[0081] [3. Variations]

[0082] (1) In addition, in the first embodiment, an example is shown where the cross-attenuation section 23 of the first microprocessor 18 adds the instruction value A1 to a specific substitution value A2' at a predetermined ratio G1:G2 to set the instruction value A1', but other structures can also be adopted. For example, it can also be configured such that, when switching from the third mode to the fourth mode, ... Figure 9 As shown, the cross-attenuation unit 23 calculates a difference value (A1”-A2’), which is obtained by subtracting the specific substitution value A2’ from the instruction value A1 (second instruction value, hereinafter also referred to as “acquisition instruction value A1”) calculated when the specific substitution value A2’ is received. The cross-attenuation unit 23 sets the subtraction value to the instruction value A1’ (generally referred to as “corrected second instruction value”). This subtraction value is obtained by subtracting the decrease value (G3) obtained by subtracting the calculated difference value (A1”-A2’) from the instruction value A1 (second instruction value) calculated sequentially by the first instruction value generation unit 22. The value obtained by (A1”-A2')). The third gain G3 is a value set in the range of 0 to 1. In addition, as a method for setting the command value A1” when it is acquired, for example, the command value A2 can be received and the command value A1 can be calculated from before switching to the fourth mode, and the command value A2 and the command value A1 at the time of switching can be set as a specific substitute value A2' and the command value A1” when acquired. Here, the value of the third gain G3 gradually changes from "1" to "0" over time after switching to the fourth mode.

[0083] Figure 9 This diagram illustrates an example of the structure of the cross-attenuation unit 23 that performs the aforementioned actions. For example, in the case of switching from the third mode to the fourth mode, Figure 9 The cross-attenuation unit 23 sets the third gain G3 to "1" and gradually changes the third gain G3 from "1" to "0", causing the output of the third gain G3 (the output of the cross-attenuation unit 23) to gradually change from "-(A1"-A2')" to "0", making the command value A1' gradually approach the command value A1. Thus, as shown... Figure 10 as well as Figure 11 As shown, it can make the rate of change of instruction value A1' uniform and can suppress the rapid change of instruction value A1'. Figure 10 This is a diagram illustrating the operation of the electronic control unit 200. Figure 10 (a) is a graph showing the relationship between instruction value and time. Figure 10 (b) is a diagram showing the case where the instruction value is immediately switched from A2 to A1. Figure 11 This is a diagram illustrating the operation of the electronic control unit 200. Figure 11 (a) is a graph showing the relationship between the target current command value Ir, the upper limit value U1 and time for the first system 1000. Figure 11 (b) is a graph showing the relationship between the target current command value Ir, the upper limit value U2, and time for the second system 2000. Additionally, in the third mode, as... Figure 7 As shown, since the first microprocessor 18 is in the initial diagnostic stage, the operation of the first instruction value generation unit 22 to the first current control unit 25 is stopped, and the cross-attenuation unit 23 does not perform the calculation of instruction value A1'.

[0084] Furthermore, for example, the following processing is performed when in the first mode and when switching from the first mode to the second mode. In the first mode, since the second microprocessor 19 has not completed the initial diagnosis, the cross-attenuation unit 23 cannot receive the instruction value A2. Therefore, the cross-attenuation unit 23 determines whether the instruction value A2 can be received from the second microprocessor 19. If it determines that it cannot be received, it determines that it is in the first mode, sets the third gain G3 to "0" and holds it thereafter. As a result, the instruction value A1 is output from the third gain G3 (cross-attenuation unit 23) as the instruction value A1'. In addition, since the third gain G3 is held to "0" in the first mode, even if it is subsequently switched from the first mode to the second mode, the third gain G3 (cross-attenuation unit 23) will still output the instruction value A1 as the instruction value A1'.

[0085] (2) Furthermore, in the first embodiment, an example was shown where the initial diagnosis of the second system 2000 was completed before the initial diagnosis of the first system 1000, in which the second instruction value generation unit 33 performed the calculation of instruction value A2. However, other structures can also be adopted. For example, such as Figure 12 As shown, it can be configured such that the second instruction value generation unit 33 continues the operation of instruction value A2 (substitution value) (step S202). See Figure 7 Until the diagnostic completion detection unit 34 detects that the initial diagnostic of the first system 1000 is complete (step S201 is "No"), when the diagnostic completion of the first system 1000 is detected (step S201 is "Yes"), the operation of the instruction value A2 is stopped (step S203). See Figure 13 This avoids unnecessary calculations and reduces power consumption.

[0086] (3) Furthermore, in the first embodiment, an example is shown where the time required for instruction value A1' to reach instruction value A1 from a specific alternative value A2' (hereinafter also referred to as "time required to reach") is set to a constant value after switching to the fourth mode, but other structures can also be adopted. For example, such as Figure 14 As shown, it can also be configured to vary the arrival time. Figure 14In the example below, when the steering torque Th detected by the first torque sensor 9 is above a predetermined value (step S301 is "Yes"), compared to the case where it is below the predetermined value, the first microprocessor 18 (cross-attenuation unit 23) corrects the command value A1 (second command value) to shorten the time required to reach the target value, and sets it to command value A1' (generally "corrected second command value") (step S302). As a method to shorten the time required to reach the target value, for example, the following method can be used: when the first gain G1 gradually changes from "0" to "1", the change in the first gain G1 at each change is increased, shortening the time until the first gain G1 changes from "0" to "1", and shortening the time until the second gain G2 changes from "1" to "0". Thus, for example, when the driver's steering torque Th is large, the proportion of the specific substitution value A2' can be reduced, and the proportion of the command value A1 reflecting the large steering torque Th can be increased, thus providing appropriate steering assistance. Furthermore, for the third gain G3 (see reference...), Figure 9 Similarly, the change in the third gain G3 can be increased with each change to shorten the time to reach the required value.

[0087] (4) In addition, in the first embodiment, an example is shown in which the allocation ratio of the current command value Ir0 allocated by the first command value generation unit 22 and the second command value generation unit 33 for the first command value and the second command value is set to 50:50, but it is not limited to this, for example, it can also be set to other ratios such as 60:40.

[0088] Label Explanation

[0089] 1…Steering wheel, 2…Steering shaft, 3…Reduction gear, 4a, 4b…Universal joint, 5…Pinary rack mechanism, 5a…Pinary gear, 5b…Rack, 6a, 6b…Tie rod, 7a, 7b…Wheel hub unit, 8L, 8R…Steering wheel, 9…First torque sensor, 10…Second torque sensor, 11…Steering angle sensor, 12…Electric motor, 13…First system coil, 14…Second system coil, 15…Battery, 16…Ignition switch, 18…First microprocessor, 19…Second microprocessor, 20…Storage unit, 21…First initial diagnostic unit, 22…First instruction value generation unit, 23…Cross-attenuation unit, 24…First output limiting unit, 25…First current control unit, 26…First motor drive unit, 27… …First voltage detection unit, 28…First current detection unit, 29…First temperature detection unit, 30…First rotation angle detection unit, 31…First power supply unit, 32…Second initial diagnosis unit, 33…Second command value generation unit, 34…Diagnosis completion detection unit, 35…Second output limiting unit, 36…Second current control unit, 37…Second motor drive unit, 38…Second voltage detection unit, 39…Second current detection unit, 40…Second temperature detection unit, 41…Second rotation angle detection unit, 42…Second power supply unit, 43…Bus, 44…First multiplier, 45…Second multiplier, 46…Adder, 100…Electric power steering device, 200…Electronic control unit, 1000…First system, 2000…Second system.

Claims

1. A motor control device, wherein the motor control device controls the driving of an electric motor having multiple winding groups, wherein, The motor control device includes: Multiple drive circuits supply power to the winding assembly; and Multiple control units generate control signals to drive the drive circuit based on command values. When a set of constituent elements, including the winding group, the drive circuit, and the control unit that are formed correspondingly to each other, is defined as a first system, and the other set of constituent elements is defined as a second system, A first control unit, acting as the control unit of the first system, calculates the instruction value of the first control unit and the instruction value of the second control unit, acting as the control unit of the second system. Based on the calculated first instruction value (which is the instruction value of the first control unit), it drives the drive circuit of the first system and sends the calculated second instruction value (which is the instruction value of the second control unit) to the second control unit. The second control unit receives the second instruction value sent from the first control unit, and drives the drive circuit of the second system based on the received second instruction value. Furthermore, the second control unit includes: The diagnostic completion detection unit detects the completion of the initial diagnosis of the first system; and The substitution value calculation unit calculates the substitution value for the second instruction value. If the diagnosis completion detection unit does not detect the initial diagnosis completion of the first system when the initial diagnosis of the second system is completed, the second control unit drives the drive circuit of the second system based on the substitution value calculated by the substitution value calculation unit, and sends the substitution value to the first control unit. Then, when the diagnosis completion detection unit detects the initial diagnosis completion of the first system, it drives the drive circuit of the second system based on the second instruction value sent from the first control unit. First control unit If the substitution value from the second control unit has been sent when the initial diagnosis of the first system is completed, the substitution value sent from the second control unit is received, and the second command value calculated by the first control unit is corrected in such a way that a specific substitution value, which is the received substitution value, gradually approaches the second command value calculated by the first control unit. The corrected second command value is sent to the second control unit, and the first command value calculated by the first control unit is corrected in such a way that the specific substitution value gradually approaches the first command value calculated by the first control unit. The absolute value of the corrected first command value is limited to gradually increasing from "0" to below the upper limit of a predetermined set value, and the drive circuit of the first system is driven based on the limited first command value.

2. The motor control device according to claim 1, wherein, The first control unit sequentially sends the following addition value as the corrected second instruction value to the second control unit. The addition value is the value obtained by adding the second instruction value calculated by the first control unit to the specific substitution value at a predetermined ratio. Furthermore, the first control unit changes the predetermined ratio so that the ratio of the second instruction value is "0" at the beginning of the addition and then gradually increases from "0".

3. The motor control device according to claim 1, wherein, The first control unit calculates the difference value obtained by subtracting the specific substitution value from the second instruction value calculated when the specific substitution value is received, and sends the subtraction value obtained by subtracting the decrease value obtained by decreasing the calculated difference value from the second instruction value calculated sequentially by the first control unit as the corrected second instruction value to the second control unit.

4. The motor control device according to claim 1, wherein, When the diagnostic completion detection unit detects that the initial diagnosis of the first system is complete, the substitution value calculation unit stops the calculation of the substitution value.

5. The motor control device according to claim 1, wherein, The motor control device includes a torque sensor that detects the driver's steering torque. When the steering torque detected by the torque sensor is above a predetermined value, the first control unit corrects the second command value in a way that shortens the time required to reach the second command value from the specific alternative value compared to when it is below the predetermined value. The corrected second command value is then sent sequentially to the second control unit as the corrected second command value.

6. The motor control device according to claim 1, wherein, The first instruction value and the second instruction value are the same instruction values.

7. An electric power steering system, wherein, The electric power steering system includes: The motor control device according to any one of claims 1 to 6; and An electric motor, which is controlled by the motor control device, The electric power steering device provides steering assistance to the vehicle's steering system through the electric motor.

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