Motor control device

Abstract

A target-motor-torque-command-value-setting unit includes a basic-torque-command-value-setting unit for setting a basic torque command value, a correction unit for correcting basic target torque set by a basic-target-torque-setting unit according to resonance control torque, and a motor torque command value computation unit for computing a motor torque command value on the basis of the basic target torque after correction by the correction unit. The resonance control torque is the sum of first torque obtained by multiplying a prescribed first gain by a differential value of steering torque, and second torque obtained by multiplying a prescribed second gain by the steering torque.

Description

[Technical Field]

[0001] The present invention relates to a motor control device that controls an electric motor that applies a steering force to an output shaft connected to a steering wheel via a torsion bar. [Background technology]

[0002] Patent Document 1 discloses a method for calculating a torque command value for an output shaft by subtracting a disturbance torque, which is a torque other than the motor torque acting on a motor-driven object, from a basic torque command value, and adding a vibration-damping torque obtained by multiplying the steering torque (torsion bar torque) by a predetermined vibration-damping gain to the result of the subtraction. The basic torque command value includes a feedback torque obtained by performing a PD (proportional differential) calculation on the deviation between the automatic steering angle command value and the steering angle detection value or steering angle estimation value.

[0003] In the invention described in Patent Document 1, vibrations are suppressed by setting the vibration suppression gain, the proportional gain used in the PD calculation, and the differential gain used in the PD calculation to predetermined values. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-183046 Summary of the Invention [Problem to be solved by the invention]

[0005] The invention described in Patent Document 1 can suppress vibration, but the resonant frequency of the system is fixed to the mechanical natural frequency (resonant frequency) of the steering wheel, so the resonant frequency of the system cannot be set arbitrarily.

[0006] An object of the present invention is to provide a motor control device that makes it possible to arbitrarily set the resonant frequency of the system. [Means for solving the problem]

[0007] One embodiment of the present invention provides a motor control device that controls an electric motor that applies a steering force to an output shaft connected to a steering wheel via a torsion bar, the motor control device comprising: a steering torque detection unit that detects steering torque applied to the steering wheel; and a motor torque command value setting unit that sets a motor torque command value that is a target value for motor torque of the electric motor, wherein the motor torque command value setting unit includes: a base torque command value setting unit that sets a base torque command value; a correction unit that corrects the base torque command value set by the base torque command value setting unit using a resonance control torque; and a motor torque command value calculation unit that calculates the motor torque command value based on the base torque command value corrected by the correction unit, and the resonance control torque is set using a first torque obtained by multiplying a derivative value of the steering torque by a predetermined first gain, and a second torque obtained by multiplying the steering torque by a predetermined second gain.

[0008] In this configuration, the resonant frequency of the system can be set arbitrarily.

[0009] The above and other objects, features and advantages of the present invention will become apparent from the following description of the embodiments with reference to the accompanying drawings. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing the general configuration of an electric power steering system to which a motor control device according to a first embodiment of the present invention is applied. [Figure 2] FIG. 2 is a block diagram illustrating the electrical configuration of the motor control ECU. [Figure 3] FIG. 3 is a graph showing an example of setting the assist torque command value Tas relative to the steering torque Ttb. [Figure 4] FIG. 4 is a schematic diagram showing an example of a reference EPS model used in the manual steering command value generating unit. [Figure 5] FIG. 5 is a block diagram showing the configuration of the angle control unit. [Figure 6] FIG. 6 is a schematic diagram showing an example of the configuration of a physical model of an electric power steering system. [Figure 7] FIG. 7 is a block diagram showing the configuration of the disturbance torque estimating unit. [Figure 8] FIG. 8 is a block diagram showing the configuration of the torque control unit. [Figure 9] FIG. 9 is a graph showing an example of setting the first weight W1 when each mode setting signal S1, S2, S3 is input. [Figure 10] FIG. 10 is a graph showing an example of setting the second weight W2 when each of the mode setting signals S1, S2, and S3 is input. [Figure 11] FIG. 11 is a graph showing an example of setting the third weight W2 when each mode setting signal S1, S2, S3 is input. [Figure 12] FIG. 12 is a schematic diagram showing a two-inertia model corresponding to the electric power steering system in the automatic steering mode or the cooperative steering mode. [Figure 13] FIG. 13 is a control block diagram of a feedback control system of an electric power steering system in automatic steering mode or cooperative steering mode, in which the column and steering wheel, which are the objects of control, are modeled and expressed. [Figure 14] FIG. 14 is a schematic diagram showing a two-inertia model corresponding to the conventional example. [Figure 15] FIG. 15 is a block diagram showing the configuration of a motor control ECU used in the electric power steering system of the second embodiment. [Figure 16] FIG. 16 is a schematic diagram showing a two-inertia model corresponding to the electric power steering system equipped with the motor control ECU of FIG. [Figure 17]FIG. 17 is a block diagram showing the configuration of an angle control unit used in a motor control ECU in an electric power steering system of the third embodiment. [Figure 18] FIG. 18 is a schematic diagram showing a two-inertia model corresponding to the electric power steering system of the third embodiment in the automatic steering mode or the cooperative steering mode. [Figure 19] FIG. 19 is a control block diagram of a feedback control system of the electric power steering system of the third embodiment in the automatic steering mode or the cooperative steering mode, and is a block diagram in which the column and steering wheel, which are the objects of control, are modeled and expressed. [Figure 20] FIG. 20 is a block diagram showing an example in which a dead band processing unit is provided in the preceding stage of the second torque calculation unit. [Figure 21] FIG. 21 is a graph showing an example of input / output characteristics of the dead-zone processing unit. [Figure 22] FIG. 22 is a graph showing another example of the input / output characteristics of the dead band processing unit. [Figure 23] FIG. 23 is a block diagram showing an example in which a dead-band processing unit is provided in front of both the first torque calculation unit and the second torque calculation unit. [Figure 24] FIG. 24 is a block diagram showing an example in which a dead-band processing unit is provided in the preceding stage of the first torque calculation unit. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Description of the embodiment of the present invention] One embodiment of the present invention provides a motor control device that controls an electric motor that applies a steering force to an output shaft connected to a steering wheel via a torsion bar, the motor control device comprising: a steering torque detection unit that detects steering torque applied to the steering wheel; and a motor torque command value setting unit that sets a motor torque command value that is a target value for motor torque of the electric motor, wherein the motor torque command value setting unit includes: a base torque command value setting unit that sets a base torque command value; a correction unit that corrects the base torque command value set by the base torque command value setting unit using a resonance control torque; and a motor torque command value calculation unit that calculates the motor torque command value based on the base torque command value corrected by the correction unit, and the resonance control torque is set using a first torque obtained by multiplying a derivative value of the steering torque by a predetermined first gain, and a second torque obtained by multiplying the steering torque by a predetermined second gain.

[0012] In this configuration, the resonant frequency of the system can be set arbitrarily.

[0013] In one embodiment of the present invention, there is provided a rotation angle detection unit that detects a rotation angle of the electric motor, and the base torque command value setting unit includes an angle deviation calculation unit that calculates a difference between a rotation angle command value that is a target value for the rotation angle of the output shaft and the rotation angle of the output shaft calculated from the rotation angle detected by the rotation angle detection unit, and a base torque command value calculation unit that calculates the target torque command value by performing a predetermined feedback calculation on the angle deviation calculated by the angle deviation calculation unit.

[0014] In one embodiment of the present invention, there is provided a rotation angle detection unit that detects a rotation angle of the electric motor, and the base torque command value setting unit includes a target torque calculation unit that calculates a target torque based on a rotation angle command value that is a target value for the rotation angle of the output shaft, a feedback torque calculation unit that calculates a feedback torque based on the rotation angle detected by the rotation angle detection unit, and a base torque command value calculation unit that calculates the target torque command value by calculating a deviation between the target torque and the feedback torque, and a gain used in calculating the target torque is different from a gain used in calculating the feedback torque.

[0015] One embodiment of the present invention includes a manual steering command value calculation unit that generates a manual steering command value, and an integrated angle command value calculation unit that adds the manual steering command value to an automatic steering angle command value to calculate an integrated angle command value, and the rotation angle command value is the integrated angle command value.

[0016] In one embodiment of the present invention, the apparatus includes a disturbance torque estimating unit that estimates disturbance torque other than the motor torque of the electric motor acting on the output shaft based on the motor torque command value or the motor torque generated by the electric motor and the rotation angle of the output shaft, and the correction unit is configured to correct the basic torque command value using the resonance control torque and the disturbance torque.

[0017] In one embodiment of the present invention, a dead zone is set for at least one of the steering torque, which is an input value for calculating the first torque, and the steering torque, which is an input value for calculating the second torque.

[0018] Detailed Description of the Embodiments of the Invention Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0019] [First embodiment] FIG. 1 is a schematic diagram showing the general configuration of an electric power steering system to which a motor control device according to a first embodiment of the present invention is applied.

[0020] The electric power steering system 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.

[0021] 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.

[0022] A torque sensor 12 is disposed near the torsion bar 10. The torque sensor 12 detects 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. tb That is, the torque sensor 12 detects the steering torque T based on the amount of twist of the torsion bar 10. tb In this embodiment, the steering torque T tb For example, the torque for steering left is detected as a positive value, and the torque for steering right is detected as a negative value. The larger the absolute value of the torque, the greater the steering torque T tb The magnitude of is assumed to be large.

[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 rotatable integrally therewith.

[0029] 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. 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.

[0030] 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 The steering torque T tb , road load torque (road reaction torque) T rl , friction torque T f etc. are included.

[0031] Steering torque T tb is the torque applied to the output shaft 9 from the steering wheel 2 side by the force applied to the steering wheel 2 by the driver (driver torque), the force generated by steering inertia, etc.

[0032] Road load torque T rl is the 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.

[0033] The vehicle is equipped with a CCD (Charge Coupled Device) camera 25 that captures images of the road ahead in the direction of travel of the vehicle, a GPS (Global Positioning System) 26 for detecting the vehicle's position, a radar 27 for detecting road shapes and obstacles, and a map information memory 28 that stores map information. The vehicle is also equipped with three mode switches 31, 32, and 33 for manually switching steering modes.

[0034] As will be described later, there are three steering modes: a manual steering mode in which steering is performed by manual driving, an automatic steering mode in which steering is performed by automatic driving, and a cooperative steering mode in which steering based on both manual driving and automatic driving is possible. More specific definitions of these steering modes will be described later.

[0035] The CCD camera 25, GPS 26, radar 27, and map information memory 28 are connected to a host ECU (Electronic Control Unit) 201 for performing driving assistance control and automatic driving control. Based on the information obtained by the CCD camera 25, GPS 26, and radar 27 and the map information, the host ECU 201 performs surrounding environment recognition, vehicle position estimation, route planning, etc., and determines control target values ​​for steering and drive actuators.

[0036] In this embodiment, the host ECU 201 controls the automatic steering command value θ adac In this embodiment, the automatic steering control is, for example, a control for making the vehicle travel along a target trajectory. adac is the target value of the steering angle for automatically driving the vehicle along the target trajectory. adac Since the process of setting the target position is well known, detailed description thereof will be omitted here. Note that the automatic steering control (driving assistance control) may be, for example, lane keeping assist (LKA) control for keeping the vehicle within the lane.

[0037] Furthermore, the host ECU 201 generates mode setting signals S1, S2, and S3 in response to the operation of the mode switches 31, 32, and 33. Specifically, when the first mode switch 31 is turned on by the driver, the host ECU 201 outputs a manual steering setting signal S1 for setting the steering mode to the manual steering mode. When the second mode switch 32 is turned on by the driver, the host ECU 201 outputs an automatic steering mode setting signal S2 for setting the steering mode to the automatic steering mode. When the third mode switch 33 is turned on by the driver, the host ECU 201 outputs a cooperative steering mode setting signal S3 for setting the steering mode to the cooperative steering mode.

[0038] The automatic steering command value θ set by the host ECU 201 adac The mode setting signals S1, S2, and S3 are sent to the motor control ECU 202 via the in-vehicle network. tb The output signal of the rotation angle sensor 23 is input to the motor control ECU 202. The motor control ECU 202 controls the electric motor 18 based on these input signals and information provided by the host ECU 201.

[0039] FIG. 2 is a block diagram for explaining the electrical configuration of motor control ECU 202. As shown in FIG.

[0040] The motor control ECU 202 includes a microcomputer 50, a drive circuit (inverter circuit) 41 controlled by the microcomputer 50 and supplying power to the electric motor 18, and a current detection circuit 42 for detecting the current flowing through the electric motor 18 (hereinafter referred to as "motor current I").

[0041] The microcomputer 50 includes a CPU and memory (ROM, RAM, non-volatile memory, etc.), and functions as a plurality of functional processing sections by executing a predetermined program. The plurality of functional processing sections include an assist torque command value setting section 51, a manual steering command value generating section 52, an integrated angle command value calculating section 53, an angle control section 54, a torque control section (current control section) 55, a first weighting section 56, a second weighting section 57, a third weighting section 58, and an adder 59. In this embodiment, the adder 59 is an example of the "motor torque command value calculating section" of the present invention.

[0042] The assist torque command value setting unit 51 sets the assist torque command value T as The assist torque command value setting unit 51 sets the steering torque T tb Based on this, the assist torque command value T as Set the steering torque T tb Assist torque command value T as An example of the configuration is shown in Figure 3.

[0043] Assist torque command value T as 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. as is the steering torque T tb The steering torque T tb The assist torque command value T as is the steering torque T tb The larger the absolute value of the assist torque command value T as is set so that the absolute value of

[0044] The assist torque command value setting unit 51 also takes into consideration the vehicle speed detected by a vehicle speed sensor (not shown) and sets the assist torque command value T asIn this case, the assist torque command value T as is the steering torque T tb The larger the absolute value of the assist torque command value T as The larger the absolute value of the assist torque command value T as is set so that the absolute value of

[0045] The assist torque command value setting unit 51 is configured to set the steering torque T tb is multiplied by a preset constant to obtain the assist torque command value T as may be calculated.

[0046] The first weighting unit 56 adjusts the assist torque command value T set by the assist torque command value setting unit 51 in accordance with the input mode setting signal. as Specifically, when one of the mode setting signals S1, S2, and S3 is input, the first weighting unit 56 first sets a first weight W1 in accordance with the current steering mode and the input mode setting signal. Next, the first weighting unit 56 calculates the assist torque command value T as Then, the first weighting unit 56 multiplies the multiplied value W1·T as is the assist torque command value T as ' is given to the addition unit 59.

[0047] When the driver operates the steering wheel 2, the manual steering command value generating unit 52 generates a steering angle (more precisely, a rotation angle θ of the output shaft 9) corresponding to the steering wheel operation as a manual steering command value θ mdac The manual steering command value generating unit 52 is provided to set the steering torque T tb and the assist torque command value T set by the assist torque command value setting unit 51. as and the manual steering command value θ mdac The manual steering command value generating unit 52 will be described in detail later.

[0048] The third weighting unit 58 adjusts the manual steering command value θ generated by the manual steering command value generating unit 52 in accordance with the input mode setting signal. mdac Specifically, when any of the mode setting signals S1, S2, and S3 is input, the third weighting unit 58 first sets a third weight W3 in accordance with the current steering mode and the input mode setting signal. Next, the third weighting unit 58 performs a third weighting process on the manual steering command value θ mdac The third weighting unit 58 then multiplies the multiplied value W3·θ mdac The manual steering command value θ after the third weighting process mdac ' is given to the integrated angle command value calculation unit 53.

[0049] The integrated angle command value calculation unit 53 calculates the automatic steering command value θ set by the host ECU 201. adac , the manual steering command value θ after the third weighting process mdac ' to obtain the integrated angle command value θ sint Calculate the following.

[0050] The angle control unit 54 calculates the integrated angle command value θ sint Based on this, the integrated angle command value θ sint The integrated motor torque command value T mint The angle control unit 54 will be described in detail later.

[0051] The second weighting unit 57 calculates the integrated motor torque command value T mint Specifically, when one of the mode setting signals S1, S2, and S3 is input, the second weighting unit 57 first sets a second weight W2 in accordance with the current steering mode and the input mode setting signal. Next, the second weighting unit 57 applies a second weight W3 to the integrated motor torque command value T mint The second weighting unit 57 multiplies the multiplied value W2·T mint is the integrated motor torque command value T mint ' is given to the addition unit 59.

[0052] The adder 59 calculates the assist torque command value T after the first weighting process. as ' and the integrated motor torque command value T mint ' and the motor torque command value T m Calculate the following.

[0053] The torque control unit 55 controls the motor torque of the electric motor 18 to be equal to the motor torque command value T m The torque control unit 55 drives the drive circuit 41 so that the torque approaches the torque. Details of the torque control unit 55 will be described later.

[0054] In this embodiment, the manual steering command value generating unit 52 uses the reference EPS model to calculate the manual steering command value θ mdac Set.

[0055] FIG. 4 is a schematic diagram showing an example of a reference EPS model used in the manual steering command value generating unit 52. As shown in FIG.

[0056] This reference EPS model is a single-inertia model including a lower column. The lower column corresponds to the output shaft 9 and the worm wheel 21. In FIG. 4, J c is the inertia of the lower column, and θ c is the rotation angle of the lower column, and T tb is the steering torque. The lower column has a steering torque T tb , torque N·T acting on the output shaft 9 from the electric motor 18 m and road load torque T rl is given. Road load torque T rl is expressed by the following equation (1) using the spring constant k and the viscous damping coefficient c.

[0057]

number

[0058] In this embodiment, predetermined values ​​obtained in advance through experiments, analysis, etc. are set as the spring constant k and the viscous damping coefficient c.

[0059] The equation of motion of the reference EPS model is expressed by the following equation (2).

[0060]

number

[0061] The manual steering command value generating unit 52 is T tb The steering torque T detected by the torque sensor 12 is tb Substituting, T m The assist torque command value T set by the assist torque command value setting unit 51 is as By substituting and solving the differential equation (2), the rotation angle θ of the lower column is c Then, the manual steering command value generating unit 52 calculates the obtained rotation angle θ of the lower column. c The manual steering command value θ mdac Generate it as:

[0062] FIG. 5 is a block diagram showing the configuration of the angle control unit 54.

[0063] The angle control unit 54 calculates the integrated angle command value θ sint , steering torque T tb and the output signal of the rotation angle sensor 23, the integrated motor torque command value T mint The angle control unit 54 includes a low-pass filter (LPF) 61, a feedback control unit 62, a first torque calculation unit 63, a second torque calculation unit 64, a first torque addition unit 65, a disturbance torque estimation unit 66, a second torque addition unit 67, a first reduction ratio division unit 68, a reduction ratio multiplication unit 69, a rotation angle calculation unit 70, and a second reduction ratio division unit 71.

[0064] The reduction ratio multiplication unit 69 multiplies the motor torque command value T m is multiplied by the reduction ratio N of the reducer 19 to obtain the motor torque command value Tm is the output shaft torque command value N·T acting on the output shaft 9. m Convert to.

[0065] The rotation angle calculation unit 70 calculates the rotor rotation angle θ of the electric motor 18 based on the output signal of the rotation angle sensor 23. m The second reduction ratio division unit 71 calculates the rotor rotation angle θ calculated by the rotation angle calculation unit 70. m By dividing by the reduction ratio N, the rotor rotation angle θ m is converted into the rotation angle (actual steering angle) θ of the output shaft 9.

[0066] The low-pass filter 61 calculates the integrated angle command value θ sint The integrated angle command value θ after low-pass filtering is sin is provided to the feedback control section 62.

[0067] The feedback control unit 62 divides the actual steering angle θ calculated by the second reduction ratio division unit 71 into an integrated angle command value θ after low-pass filtering. sin The feedback control unit 62 includes an angle deviation calculation unit 62A and a PD control unit 62B. The angle deviation calculation unit 62A calculates an integrated angle command value θ sin and the deviation Δθ(=θ sin The angle deviation calculation unit 62A calculates the integrated angle command value θ sin and the deviation (θ sin -^θ) may be calculated as the angle deviation Δθ.

[0068] The PD control unit 62B includes a proportional gain multiplication unit 101, a differential calculation unit 102, a differential gain multiplication unit 103, and an addition unit 104. The proportional gain multiplication unit 101 multiplies the angle deviation Δθ calculated by the angle deviation calculation unit 62A by a proportional gain K p Multiply by.

[0069] The differential calculation unit 102 calculates a time differential value dΔθ / dt of the angle deviation Δθ. The differential gain multiplication unit 103 multiplies the differential value dΔθ / dt calculated by the differential calculation unit 102 by a differential gain K d The adder 104 multiplies the multiplication result K p Δθ and the multiplication result K of the differential gain multiplication unit 103 d By adding dΔθ / dt, the feedback control torque T fb In this embodiment, the feedback control torque T fb is an example of the "basic torque command value" of the present invention.

[0070] The first torque calculation unit 63 includes a differential calculation unit 63A and a first gain multiplication unit 63B. tb The time derivative dT of tb The first gain multiplication unit 63B calculates the differential value dT tb / dt with first gain G d By multiplying the first torque G d dT tb Calculates / dt.

[0071] The second torque calculation unit 64 calculates the steering torque T tb Second gain G p By multiplying the second torque G p T tb Calculate the following.

[0072] The first torque addition unit 65 calculates the first torque G d dT tb / dt and second torque G p T tb By adding the above, the resonance control torque T res (=G d dT tb / dt+G p T tb ) is calculated.

[0073] The disturbance torque estimating unit 66 is provided to estimate a nonlinear torque (disturbance torque: torque other than motor torque) that occurs as a disturbance in the output shaft 9 (an example of an object to be controlled by the electric motor 18). The disturbance torque estimating unit 66 estimates the output shaft torque command value N·T m and the actual steering angle θ, the disturbance torque (disturbance load) T lc , steering angle θ and steering angle differential value (angular velocity) dθ / dt are estimated. lc , the estimated values ​​of the steering angle θ and the steering angle differential (angular velocity) dθ / dt are respectively ^T lc , ^θ and d^θ / dt. The disturbance torque estimating unit 66 will be described in detail later.

[0074] The disturbance torque estimated value ^T calculated by the disturbance torque estimator 66 lc is given to the second torque adder 67 as a disturbance torque compensation value.

[0075] The second torque adder 67 calculates the feedback control torque (basic torque command value) T fb The resonance control torque T res The disturbance torque estimate ^T lc By subtracting sint (=T fb +G d dT tb / dt+G p T tb -^T lc ) is calculated.

[0076] Integrated steering torque command value T sint is given to the first reduction ratio division unit 68. The first reduction ratio division unit 68 calculates the integrated steering torque command value T sint By dividing by the reduction ratio N, the integrated motor torque command value T mint This integrated motor torque command value T mint is given to the second weighting unit 57 (see FIG. 2).

[0077] The disturbance torque estimation unit 66 will be described in detail. The disturbance torque estimation unit 66 uses, for example, a physical model 211 of the electric power steering system 1 shown in FIG. 6 to estimate the disturbance torque T lc , and a disturbance observer that estimates the steering angle θ and the angular velocity dθ / dt.

[0078] This physical model 211 includes a steering column (an example of a plant, a motor-driven object) 212 including an output shaft 9 and a worm wheel 21 fixed to the output shaft 9. The steering column 212 has inertia J. This inertia J includes the inertia of the worm wheel 21 (worm wheel inertia), the inertia of the worm gear 20 (worm gear inertia), the inertia of the shaft of the electric motor 18 (motor shaft inertia), the inertia of the pinion shaft 13 (pinion shaft inertia), etc. A steering torque T is transmitted to the steering column 212 from the steering wheel 2 via the torsion bar 10. tb is applied, and a road load torque T rl is given.

[0079] Furthermore, the steering column 212 receives an output shaft torque command value N·T from the electric motor 18 via the worm gear 20. m The driving torque N·T corresponds to m is given, and friction torque T f is given.

[0080] The equation of motion for the inertia of the physical model 211 is expressed by the following equation (3).

[0081]

number

[0082] d 2 θ / dt 2 is the angular acceleration of the steering column 212. N is the reduction ratio of the reducer 19. T lcindicates a disturbance torque other than the motor torque applied to the steering column 212. In this embodiment, the disturbance torque T lc is the steering torque T tb and road load torque T rl and friction torque T f However, in reality, the disturbance torque T lc includes torques other than these.

[0083] The state equation for the physical model 211 in FIG. 6 is expressed by the following equation (4).

[0084]

number

[0085] In the above formula (4), x is a state variable vector, u1 is a known input vector, u2 is an unknown input vector, and y is an output vector (measured value). Also, in the above formula (4), A is a system matrix, B1 is a first input matrix, B2 is a second input matrix, C is an output matrix, and D is a direct feedthrough matrix.

[0086] The state equation is expanded to a system including the unknown input vector u2 as one of the states. The state equation of the expanded system (expanded state equation) is expressed by the following equation (5).

[0087]

number

[0088] In the formula (5), x e is the state variable vector of the extended system and is expressed by the following equation (6).

[0089]

number

[0090] In the formula (5), A e is the system matrix of the extended system, Be is the known input matrix of the extended system, and Ce is the output matrix of the extended system.

[0091] From the extended state equation of the above formula (5), a disturbance observer (extended state observer) expressed by the following formula (7) is constructed.

[0092]

number

[0093] In equation (7), ^x e x e represents the estimated value of . Also, L is the observer gain. Also, ^y represents the estimated value of y. ^x e is expressed by the following equation (8).

[0094]

number

[0095] In equation (8), ^θ is the estimated value of θ, and ^T lc is T lc is an estimate of

[0096] The disturbance torque estimation unit 66 calculates the state variable vector ^x based on the equation (7). e Calculate the following.

[0097] FIG. 7 is a block diagram showing the configuration of the disturbance torque estimating unit 66.

[0098] The disturbance torque estimation unit 66 includes an input vector input unit 81, an output matrix multiplication unit 82, a first addition unit 83, a gain multiplication unit 84, an input matrix multiplication unit 85, a system matrix multiplication unit 86, a second addition unit 87, an integration unit 88, and a state variable vector output unit 89.

[0099] The output shaft torque command value N·T calculated by the reduction ratio multiplication unit 69 (see FIG. 5) mis given to the input vector input unit 81. The input vector input unit 81 outputs the input vector u1.

[0100] The output of the integrator 88 is the state variable vector ^x e (See equation (8) above.) At the start of calculation, the state variable vector ^x e The initial value is given as the state variable vector ^x e The initial value of is, for example, 0.

[0101] The system matrix multiplication unit 86 multiplies the state variable vector ^x e In the system matrix A e The output matrix multiplication unit 82 multiplies the state variable vector ^x e into the output matrix C e Multiply by.

[0102] The first adder 83 calculates the output (C e ^x e ) is subtracted from the output vector y. That is, the first adder 83 subtracts the output vector estimate ^y(=C e ^x e The gain multiplication unit 84 multiplies the output (y-^y) of the first addition unit 83 by the observer gain L (see equation (7) above).

[0103] The input matrix multiplication unit 85 multiplies the input vector u1 output from the input vector input unit 81 by the input matrix B e The second adder 87 multiplies the output (B e u1) and the output of the system matrix multiplication unit 86 (A e ^x e ) and the output (L(y-^y)) of the gain multiplication unit 84, the differential value d^x of the state variable vector is obtained. e The integrator 88 calculates the output (d^x e / dt), the state variable vector ^x eThe state variable vector output unit 89 calculates the state variable vector ^x e Based on this, the disturbance torque estimate ^T lc , the steering angle estimated value ^θ and the angular velocity estimated value d^θ / dt are calculated.

[0104] Unlike the extended state observer described above, a typical disturbance observer consists of an inverse model of the plant and a low-pass filter. The equation of motion of the steering column is expressed by equation (3) as described above. Therefore, the inverse model of the steering column is given by the following equation (9).

[0105]

number

[0106] The input to a typical disturbance observer is J d 2 θ / dt 2 and N.T. m and uses the second-order differential value of the actual steering angle θ, so it is significantly affected by noise from the rotation angle sensor 23. In contrast, the extended state observer of the above-described embodiment estimates the disturbance torque in an integral manner, so it is possible to reduce the influence of noise due to differentiation.

[0107] The disturbance torque estimating section 66 may be a general disturbance observer that is configured from an inverse model of the steering column and a low-pass filter.

[0108] FIG. 8 is a schematic diagram showing the configuration of the torque control unit 55.

[0109] The torque control unit 55 (see FIG. 2) includes a motor current command value calculation unit 91, a current deviation calculation unit 92, a PI control unit 93, and a PWM (Pulse Width Modulation) control unit 94.

[0110] The motor current command value calculation unit 91 calculates the motor torque command value T m The torque constant K of the electric motor 18 tBy dividing by, the motor current command value I cmd Calculate the following.

[0111] The current deviation calculation unit 92 calculates the motor current command value I obtained by the motor current command value calculation unit 91. cmd and the deviation ΔI (=I cmd -I).

[0112] The PI control unit 93 performs a PI calculation (proportional integral calculation) on the current deviation ΔI calculated by the current deviation calculation unit 92, thereby controlling the motor current I flowing through the electric motor 18 to a motor current command value I cmd The PWM control unit 94 generates a PWM control signal with a duty ratio corresponding to the drive command value and supplies it to the drive circuit 41. As a result, power corresponding to the drive command value is supplied to the electric motor 18.

[0113] The operation of this embodiment will be described below.

[0114] In automatic steering mode, the automatic steering command value θ adac The manual steering mode is a steering mode in which the electric motor 18 is controlled based only on the assist torque command value T as The cooperative steering mode is a steering mode in which the electric motor 18 is controlled based only on the automatic steering command value θ adac and manual steering command value θ mdac The integrated angle command value θ sint This refers to a steering mode in which the electric motor 18 is controlled based on the steering angle.

[0115] When the steering mode is set to the cooperative steering mode, the first weight W1 is set to 0, and the second weight W2 and the third weight W3 are set to 1.0.

[0116] When the steering mode is set to the automatic steering mode, the first weight W1 and the third weight W3 are set to zero, and the second weight W2 is set to 1.0.

[0117] When the steering mode is set to the manual steering mode, the first weight W1 is 1.0, the second weight W2 is zero, and the third weight W3 is 0 or 1.0.

[0118] That is, the motor control ECU 202 can switch the steering mode among the normal steering mode, the automatic steering mode, and the manual steering mode by the driver operating the mode switches 31, 32, and 33.

[0119] Examples of setting the first weight W1, the second weight W2, and the third weight W3 in response to switching of the steering mode are shown in FIGS. 9, 10, and 11, respectively.

[0120] In FIG. 9, the state in which the first weight W1 gradually increases from zero to 1.0 from the time when each mode setting signal S1, S2, S3 is input (time t1) until time t2 when a predetermined time T has elapsed is shown by broken line L1, and the state in which it gradually decreases from 1.0 to zero is shown by broken line L2.

[0121] In FIG. 10, the state in which the second weight W2 gradually increases from zero to 1.0 from time t1 to time t2 is shown by a broken line L3, and the state in which the second weight W2 gradually decreases from 1.0 to zero is shown by a broken line L4.

[0122] In FIG. 11, the state in which the third weight W3 gradually increases from zero to 1.0 from time t1 to time t2 is shown by a broken line L5, and the state in which it gradually decreases from 1.0 to zero is shown by a broken line L6.

[0123] As a result, the assist torque command value T as ', the integrated motor torque command value T after the second weighting process mint ' and the manual steering command value θ after the third weighting process mdac Since the absolute values ​​of each of the ' are gradually increased or decreased, switching between the steering modes is performed smoothly.

[0124] The time T required to switch the first weight W1, the second weight W2, and the third weight W3 between zero and 1.0 is set to a predetermined value determined in advance by experiment, analysis, etc. ad The time T required for switching between zero and 1.0 may be set to be different for the second weight W1, the second weight W2, and the third weight W3. Also, the first weight W1, the second weight W2, and the third weight W3 may be set to gradually increase or decrease nonlinearly, rather than linearly.

[0125] In this embodiment, even if the mode switches 31, 32, 33 are operated without changing the steering mode, the operation is invalid. Also, in this embodiment, even if any of the mode switches 31, 32, 33 is operated before a predetermined time T has elapsed since the mode switch 31, 32, 33 was operated, the operation is invalid.

[0126] Although the steering mode is switched by mode switches 31, 32, and 33, host ECU 201 may switch the steering mode in response to an ON / OFF signal for the driving assistance function or the automatic driving function, obstacles, the driver's state, driver operations such as the accelerator and brake, and the vehicle's running state. In this case, host ECU 201 generates a mode setting signal in response to an ON / OFF signal for the driving assistance function or the automatic driving function, obstacles, the driver's state, driver operations such as the accelerator and brake, and the vehicle's running state, and provides the signal to motor control ECU 202.

[0127] FIG. 12 is a schematic diagram showing a two-inertia model 301 corresponding to the electric power steering system 1 in the automatic steering mode or the cooperative steering mode.

[0128] The two-inertia model 301 includes a steering wheel 2 , a torsion bar 10 and a steering column 310 .

[0129] The steering wheel 2 is driven by the inertia of the steering wheel 2 (hereinafter referred to as steering wheel inertia J swThe steering column 310 has a column inertia J p Column inertia J p includes the inertia of the worm wheel 21 (worm wheel inertia), the inertia of the worm gear 20 (worm gear inertia), the inertia of the shaft of the electric motor 18 (motor shaft inertia), the inertia of the pinion shaft 13 (pinion shaft inertia), etc.

[0130] In FIG. 12, θ sw is the rotation angle of the steering wheel 2 (hereinafter referred to as the wheel angle θ sw ) and dθ sw / dt is the angular velocity of the steering wheel 2 (hereinafter referred to as the wheel angular velocity dθ sw / dt.)

[0131] Also, θ p is the rotation angle of the steering column 310 (hereinafter referred to as the column angle θ p ) and dθ p / dt is the angular velocity of the steering column 310 (hereinafter referred to as the column angular velocity dθ p / dt.)

[0132] Also, T d is the driver torque applied to the steering wheel 2 by the driver, and k tb is the stiffness of the torsion bar 10 (hereinafter referred to as the torsion bar stiffness k tb ) and T tb is the steering torque (torsion bar torque), N is the reduction ratio of the reducer 19, and N·T m is the output shaft torque command value N·T m The driving torque N·T corresponds to m Steering torque T tb is T tb =k tb (θ sw -θ p )

[0133] In this two-inertia model 301, the driver applies a driver torque T to the steering wheel 2. dis applied, and a steering torque T tb -T, which is the sign-negated value of tb The steering column 310 is supplied with a driving torque N·T from the electric motor 18. m However, the integrated angle command value θ after low-pass filtering is sin If we set the angle to 0 degrees, then N·T m =(-K p θ p -K d dθ p / dt+G p T tb +G d dT tb / dt).

[0134] If load compensation is not performed, the steering column 310 is subjected to a driving torque N·T m In addition, steering torque T tb and road load torque T rl is given.

[0135] Fig. 13 is a control block diagram of the feedback control system of the electric power steering system 1 in the automatic steering mode or the cooperative steering mode, and is a block diagram in which the column and steering wheel, which are the objects of control, are modeled. Here, Fig. 13 is a block diagram corresponding to Fig. 12 and equations (10a) and (10b) described later.

[0136] Integrated angle command value θ after low-pass filtering sin and column angle θ p The feedback control torque T fb In this embodiment, as will be described later, a proportional gain K p and the differential gain K d are the column inertia J p Contains:

[0137] Feedback control torque T fb The resonance control torque T res (=G d dTtb / dt+G p T tb ) is added. This added value (T fb +G d dT tb / dt+G p T tb ) is the column angle θ p Angular acceleration of (hereinafter referred to as column angular acceleration d 2 θ p / dt 2 ) and the column inertia J p Output shaft torque command value N·T corresponding to the value multiplied by m This corresponds to the output torque command value N·T m A driving torque corresponding to the inertia J is applied from the electric motor 18 to the steering column 310. p The driving torque N·T is applied to the steering column 310. m The steering column 310 rotates by the input of the p ) is measured based on the rotation angle sensor 23 and fed back.

[0138] Here, the steering torque T tb is the column angle θ p and wheel angle θ sw The difference between (θ sw -θ p ) torsion bar stiffness k tb is equivalent to the value multiplied by T tb =k tb (θ sw -θ p ) This steering torque T tb The first gain G d The value G multiplied by d dT tb / dt and this steering torque T tb Second gain G p The value G multiplied by p T tb The sum of these is the resonance control torque T res In addition, the inertia is J sw The steering torque T is applied to the steering wheel 2. tb and driver torque Td When this signal is input, the steering wheel 2 rotates.

[0139] In the two-inertia model 301 of FIG. 12, the equation of motion on the steering column side is expressed by the following equation (10a), and the equation of motion on the steering wheel side is expressed by the following equation (10b).

[0140]

number

[0141] In the two-inertia model 301 of FIG. 12, the proportional gain K p , differential gain K d , the second gain Gp and the first gain G d When the values ​​shown in the following equations (11a), (11b), (11c), and (11d) are set, the driving torque N·T m From column angle θ p Transfer function G(N T m →θ p ) is expressed by the following equation (12a), and the driving torque N·T m from wheel angle θ sw Transfer function G(N T m →θ sw ) is expressed by the following equation (12b).

[0142]

number

[0143]

number

[0144] In the formulas (11a) to (11d) and (12a) and (12b), ω sw is the natural frequency (resonant frequency) of the steering wheel 2 determined by the mechanical characteristics of the steering wheel 2. Also, ω is a variable that represents the resonant frequency of the system.

[0145] In the two-inertia model 301 of FIG. 12, that is, in the first embodiment, the proportional gain K p , differential gain K d , the second gain Gp and the first gain G d are set to the values ​​shown in the above expressions (11a), (11b), (11c), and (11d), respectively, it becomes possible to arbitrarily set the resonance frequency ω and the damping ratio ζ.

[0146] In the first embodiment, the resonant frequency ω and the damping characteristics can be set arbitrarily, and therefore the responsiveness can be changed. Specifically, the higher the resonant frequency ω is set to, the faster the responsiveness becomes.

[0147] In the first embodiment, load compensation is performed, but load compensation may not be performed. In this case, the feedback control torque (basic torque command value) T fb The resonance control torque T res (=G d dT tb / dt+G p T tb ) is added to the value (T fb +G d dT tb / dt+G p T tb ) is the integrated steering torque command value T sint This becomes:

[0148] In the absence of load compensation, the steering torque T tb can be considered to be fed back to the steering column 310 in advance, so the second gain in the case without load compensation is G p ', and the second gain when load compensation is used is G p Then, G p '=(G p -1).

[0149] In the first embodiment, the integrated angle command value θ sint and a cooperative steering mode in which the electric motor 18 can be controlled based on the assist torque command value T asa manual steering mode in which the electric motor 18 can be controlled based only on the automatic steering command value θ adac This allows switching between an automatic steering mode in which the electric motor 18 can be controlled based only on the steering angle.

[0150] That is, the integrated angle command value θ sint In the electric power steering system 1, the electric motor 18 can be controlled based on the assist torque command value T as Therefore, it becomes possible to control the electric motor 18 based only on the above.

[0151] In the first embodiment described above, in the manual steering mode, the assist torque command value T as Since the electric motor 18 is controlled based only on the road load torque (road reaction torque), the driver can receive the actual road load torque (road reaction torque).

[0152] In the first embodiment, the integrated angle command value θ sint Based on the basic torque command value (T fb ) is calculated, and the disturbance torque estimated value ^T lc The basic torque command value (T fb ) is corrected. That is, in the first embodiment described above, nonlinear disturbance torque (torque other than motor torque) that occurs as a disturbance on the output shaft 9 is compensated (load compensated). This makes it possible to suppress the influence of the disturbance torque on the angle control performance. This makes it possible to achieve highly accurate angle control.

[0153] As described in Patent Document 1, the following describes a load compensation function and a R T tb An electric power steering system equipped with an angle control unit to which K is fed back is referred to as a conventional example. R is the damping gain, and K R T tbis the damping torque. In the conventional example, the angle control section is provided with a feedback control section and a feedforward control section, but for simplicity of explanation, it is assumed that the feedforward control section is not provided.

[0154] In the conventional example, the angle control unit uses a feedback control torque T fb Damping torque K R T tb The disturbance torque estimate ^T lc The value obtained by subtracting (=T fb +K R T tb -^T lc ) is the output shaft torque command value N·T m This becomes:

[0155] FIG. 14 is a schematic diagram showing a two-inertia model 302 corresponding to a conventional example.

[0156] In the two-inertia model 302 of FIG. 14, the equation of motion on the steering column side is expressed by the following equation (13a), and the equation of motion on the steering wheel side is expressed by the following equation (13b).

[0157]

number

[0158] In this two-inertia model 302, the steering wheel 2 is subjected to a driver torque T d is applied, and a steering torque T tb -T, which is the sign-negated value of tb The steering column 310 is supplied with a driving torque N·T from the electric motor 18. m However, if the angle command value given to the feedback control unit is 0 degrees, then N·T m =(-K p θ p -K d dθ p / dt+K R T tb ) is Kp is the proportional gain in the conventional example, and K d is the differential gain in the conventional example.

[0159] In the two-inertia model 302 of FIG. 14, the proportional gain K p , differential gain K d and vibration suppression gain K R When the values ​​shown in the following equations (14a), (14b), and (14c) are set, the driving torque N·T m From column angle θ p Transfer function G(N T m →θ p ) is expressed by the following equation (15a), and the driving torque N·T m N.T. m from wheel angle θ sw Transfer function G(N T m →θ sw ) is expressed by the following equation (15b).

[0160]

number

[0161]

number

[0162] In the two-inertia model 302 of FIG. 14, the proportional gain K p , differential gain K d and vibration suppression gain K R are set as shown in the above equations (14a), (14b), and (14c), respectively, the column angle θ p , wheel angle θ sw In both cases, the vibration is suppressed by the critical damping (ζ=1). However, in the two-inertia model 302 of FIG. 14, the resonant frequency is ω sw In other words, in the conventional example, the resonant frequency and the damping characteristics cannot be set arbitrarily.

[0163] [Second embodiment] Next, an electric power steering system to which a motor control device according to a second embodiment of the present invention is applied (hereinafter referred to as "electric power steering system according to the second embodiment") will be described.

[0164] In the electric power steering system of the second embodiment, the configuration of the motor control ECU 202A is different from the configuration of the motor control ECU 202 in Fig. 2. In the electric power steering system of the second embodiment, the automatic steering command value θ adac Furthermore, the mode setting signals S1, S2, and S3 are not provided from the host ECU 201 (see FIG. 1) to the motor control ECU 202A.

[0165] FIG. 15 is a block diagram showing the configuration of a motor control ECU 202A used in the electric power steering system of the second embodiment.

[0166] The motor control ECU 202A includes a microcomputer 50A, a drive circuit (inverter circuit) 41 controlled by the microcomputer 50A and supplying power to the electric motor 18, and a current detection circuit 42 for detecting the current flowing through the electric motor 18 (hereinafter referred to as "motor current I").

[0167] The microcomputer 50A includes a CPU and memory (ROM, RAM, non-volatile memory, etc.), and functions as a plurality of functional processing sections by executing predetermined programs. The plurality of functional processing sections include an assist torque command value setting section 151, a first reduction gear ratio multiplication section 152, a first torque calculation section 153, a second torque calculation section 154, a first torque addition section 155, a disturbance torque calculation section 156, a second torque addition section 157, a first reduction gear ratio division section 158, a torque control section 159, a second reduction gear ratio multiplication section 160, a rotation angle calculation section 161, and a second reduction gear ratio division section 162.

[0168] The second reduction ratio multiplication unit 160 multiplies the motor torque command value T mis multiplied by the reduction ratio N of the reducer 19 to obtain the motor torque command value T m is the output shaft torque command value N·T acting on the output shaft 9. m Convert to.

[0169] The rotation angle calculation unit 161 calculates the rotor rotation angle θ of the electric motor 18 based on the output signal of the rotation angle sensor 23. m The second reduction ratio division unit 162 calculates the rotor rotation angle θ calculated by the rotation angle calculation unit 161. m By dividing by the reduction ratio N, the rotor rotation angle θ m is converted into the rotation angle (actual steering angle) θ of the output shaft 9.

[0170] The assist torque command value setting unit 151 sets the assist torque command value T as The operation of the assist torque command value setting unit 151 is similar to that of the assist torque command value setting unit 51 in FIG.

[0171] The first reduction ratio multiplication unit 152 multiplies the assist torque command value T as is multiplied by the reduction ratio N to obtain the assist torque command value T as is the assist torque command value N·T for output shaft 9. as Converted into assist torque command value T as is given to the second torque adder 157.

[0172] The first torque calculation unit 153 includes a differential calculation unit 153A and a first gain multiplication unit 153B. tb The time derivative dT of tb The first gain multiplication unit 153B calculates the differential value dT tb / dt with first gain G d By multiplying the first torque G d dT tb Calculates / dt.

[0173] The second torque calculation unit 154 calculates the steering torque T tb Second gain G p By multiplying the second torque G p T tb Calculate the following.

[0174] The first torque addition unit 155 calculates the first torque G d dT tb / dt and second torque G p T tb By adding the above, the resonance control torque T res (=G d dT tb / dt+G p T tb ) is calculated. res is given to the second torque adder 157.

[0175] The disturbance torque estimation unit 156 calculates the output shaft torque command value N·T m and the actual steering angle θ, the disturbance torque (disturbance load) T lc , steering angle θ and steering angle differential value (angular velocity) dθ / dt are estimated. lc , the estimated values ​​of the steering angle θ and the steering angle differential (angular velocity) dθ / dt are respectively ^T lc , ^θ and d^θ / dt. The configuration and operation of the disturbance torque estimating section 156 are similar to those of the disturbance torque estimating section 66 in Fig. 5, and therefore detailed description thereof will be omitted.

[0176] The disturbance torque estimated value ^T calculated by the disturbance torque estimator 156 lc is given to the second torque adder 157 as a disturbance torque compensation value.

[0177] The second torque adder 157 calculates the assist torque command value N·T as The resonance control torque T res The disturbance torque estimate ^T lc By subtracting from the output torque command value N·T m (=N·T as +G d dT tb / dt+G p T tb -^T lc ) is calculated.

[0178] Output shaft torque command value N·T m is given to a first reduction ratio division unit 158. The first reduction ratio division unit 158 ​​calculates the output shaft torque command value N·T m is divided by the reduction ratio N to obtain the motor torque command value T m This motor torque command value T m is given to the torque control section 159.

[0179] The torque control unit 159 controls the motor torque of the electric motor 18 to be equal to the motor torque command value T m The drive circuit 41 is driven so that the torque control section 159 approaches the torque control section 55 shown in FIG.

[0180] FIG. 16 is a schematic diagram showing a two-inertia model 303 corresponding to the electric power steering system equipped with the motor control ECU 202A of FIG.

[0181] In this two-inertia model 303, the steering wheel 2 is subjected to a driver torque T d is applied, and a steering torque T tb -T, which is the sign-negated value of tb The steering column 310 is supplied with an output shaft torque command value N·T m The driving torque N·T corresponds to m is given, where N T m =(N T as +G d dT tb / dt+G p T tb )

[0182] In the two-inertia model 303 of FIG. 16, the equation of motion on the steering column side is expressed by the following equation (16a), and the equation of motion on the steering column side is expressed by the following equation (16b).

[0183]

number

[0184] In the two-inertia model 303 of FIG. 16, the second gain G p and the first gain G d When the values ​​shown in the following equations (17a) and (17b) are set, the driving torque N·T m From column angle θ p Transfer function G(N T m →θ p ) is expressed by the following equation (18a), and the driving torque N·T m from wheel angle θ sw Transfer function G(N T m →θ sw ) is expressed by the following equation (18b).

[0185]

number

[0186]

number

[0187] In the two-inertia model 303 of FIG. 16, that is, in this modified example, the second gain G p and the first gain G d are set as shown in the above expressions (17a) and (17b), respectively, the resonance frequency ω and the damping ratio ζ can be set arbitrarily.

[0188] In the second embodiment, the resonant frequency ω and the damping characteristics can be set arbitrarily, so that the responsiveness can be changed. Specifically, the responsiveness becomes faster as the resonant frequency ω is set to a larger value.

[0189] In the second embodiment, load compensation is performed, but load compensation may not be performed. In this case, the second torque adder 157 calculates the assist torque command value N·T as The resonance control torque T res By adding m (=N·T as +G d dT tb / dt+G p T tb ) is calculated.

[0190] In the absence of load compensation, the steering torque T tb can be considered to be fed back to the steering column 310 in advance, so the second gain in the case without load compensation is G p ', and the second gain when load compensation is used is G p Then, G p '=(G p -1).

[0191] [Third embodiment] Next, an electric power steering system to which a motor control device according to a third embodiment of the present invention is applied (hereinafter referred to as "electric power steering system according to the third embodiment") will be described.

[0192] The overall configuration of the electric power steering system of the third embodiment is the same as the configuration in Fig. 1. In the electric power steering system of the third embodiment, the configuration of the motor control ECU 202 is the same as the configuration of the motor control ECU 202 in Fig. 2, but the configuration of the angle control unit 54 in the motor control ECU 202 in Fig. 2 is different. Components 51 to 53 and 55 to 59 other than the angle control unit 54 in Fig. 2 are also the same in the electric power steering system of the third embodiment.

[0193] Fig. 17 is a block diagram showing the configuration of an angle control unit 54A used in the motor control ECU 202 in the electric power steering system of the third embodiment. In Fig. 17, parts corresponding to those in Fig. 5 are denoted by the same reference numerals as in Fig. 5.

[0194] The angle control unit 54A in FIG. 17 calculates an integrated angle command value θ sint , steering torque T tb and the output signal of the rotation angle sensor 23, the integrated motor torque command value T mint Angle control unit 54A in Fig. 17 differs from angle control unit 54 in Fig. 5 in that it does not include low-pass filter (LPF) 61 in Fig. 5 and in that the configuration of feedback control unit 400 is different from the configuration of feedback control unit 62 in Fig. 5.

[0195] The operations of the first torque calculation unit 63, the second torque calculation unit 64, the first torque addition unit 65, the disturbance torque estimation unit 66, the first reduction ratio division unit 68, the reduction ratio multiplication unit 69, the rotation angle calculation unit 70 and the second reduction ratio division unit 71 in FIG. 17 are the same as the operations of the corresponding units in FIG. 5, and therefore will not be described again.

[0196] The feedback control unit 400 includes a target torque calculation unit 401 , a feedback torque calculation unit 402 , and a torque deviation calculation unit 403 .

[0197] The target torque calculation unit 401 calculates the integrated angle command value θ sint By performing a predetermined calculation on the target torque T ta Calculate the following.

[0198] The target torque calculation unit 401 includes a proportional gain multiplication unit 411, a first-order differential calculation unit 412, a first-order differential gain multiplication unit 413, a second-order differential calculation unit 414, a second-order differential gain multiplication unit 415, a third-order differential calculation unit 416, a third-order differential gain multiplication unit 417, a fourth-order differential calculation unit 418, a fourth-order differential gain multiplication unit 419, and first to fourth addition units 420 to 423.

[0199] The proportional gain multiplication unit 411 multiplies the integrated angle command value θ sint Proportional gain K 0dot Multiply by.

[0200] The first-order differential calculation unit 412 calculates the integrated angle command value θ sint The first derivative dθ sint The first-order differential gain multiplication unit 413 calculates the first-order differential value dθ / dt calculated by the first-order differential calculation unit 412. sint / dt with first-order differential gain K 1dot Multiply by.

[0201] The second-order differential calculation unit 414 calculates the integrated angle command value θ sint The second derivative d 2 θ sint / dt 2 The second-order differential gain multiplication unit 415 multiplies the second-order differential value d 2 θ sint / dt 2 Second-order differential gain K 2dot Multiply by.

[0202] The third-order differential calculation unit 416 calculates the integrated angle command value θ sint The third derivative d 3 θ sint / dt 3 The third-order differential gain multiplication unit 417 multiplies the third-order differential value d 3 θ sint / dt 3 The third derivative gain K 3dot Multiply by.

[0203] The fourth-order differential calculation unit 418 calculates the integrated angle command value θ sint The fourth derivative d 4 θ sint / dt 4 The fourth-order differential gain multiplication unit 419 multiplies the fourth-order differential value d 4 θ sint / dt 4 The fourth-order differential gain K 4dot Multiply by.

[0204] The first adder 420 adds the multiplication result K 4dot ·d 4 θ sint / dt 4and the multiplication result K of the third-order differential gain multiplication unit 417 3dot ·d 3 θ sint / dt 3 Add and.

[0205] The second adder 421 adds the sum (K 3dot ·d 3 θ sint / dt 3 +K 4dot ·d 4 θ sint / dt 4 ) and the multiplication result K of the second-order differential gain multiplication unit 415 2dot ·d 2 θ sint / dt 2 Add and.

[0206] The third adder 422 adds the sum (K 2dot ·d 2 θ sint / dt 2 +K 3dot ·d 3 θ sint / dt 3 +K 4dot ·d 4 θ sint / dt 4 ) and the multiplication result K of the first-order differential gain multiplication unit 413 1dot dθ sint Add / dt.

[0207] The fourth adder 423 adds the sum (K 1dot dθ sint / dt+K 2dot ·d 2 θ sint / dt 2 +K 3dot ·d 3 θ sint / dt 3 +K 4dot ·d 4 θ sint / dt 4 ) and the multiplication result K of the proportional gain multiplication unit 411 0dot θ sint By adding these, the target torque Tta Calculate the target torque T ta is (K 0dot θ sint +K 1dot dθ sint / dt+K 2dot ·d 2 θ sint / dt 2 +K 3dot ·d 3 θ sint / dt 3 +K 4dot ·d 4 θ sint / dt 4 )

[0208] The feedback torque calculation unit 402 performs a predetermined calculation on the actual steering angle θ to calculate the feedback torque T fe Calculate the following.

[0209] The feedback torque calculation unit 402 includes a proportional gain multiplication unit 431, a differential calculation unit 432, a differential gain multiplication unit 433, and an addition unit 434. The proportional gain multiplication unit 431 multiplies the actual steering angle θ calculated by the second reduction ratio division unit 71 by a proportional gain K p Multiply by.

[0210] The differential calculation unit 432 calculates a time differential value dθ / dt of the actual steering angle θ. The differential gain multiplication unit 433 multiplies the differential value dθ / dt calculated by the differential calculation unit 432 by a differential gain K d The adder 434 multiplies the multiplication result K p θ and the multiplication result K of the differential gain multiplication unit 433 d By adding dθ / dt, the feedback torque T fe Calculate the feedback torque T fe is (K p θ+K d ·dθ / dt).

[0211] In FIG. 17, the actual steering angle θ calculated by the second reduction ratio division unit 71 is input to the feedback torque calculation unit 402. However, instead of the actual steering angle θ, the steering angle estimation value ^θ calculated by the disturbance torque estimation unit 66 may be input to the feedback torque calculation unit 402. In that case, the feedback torque T fe is (K p ·^θ+K d ·d^θ / dt).

[0212] The torque deviation calculation unit 403 calculates the target torque T ta to feedback torque T fe By subtracting the feedback control torque T fb Calculate the feedback control torque T fb is the actual steering angle θ and the integrated angle command value θ sint In this embodiment, the feedback control torque T fb is an example of the "basic torque command value" of the present invention.

[0213] The second torque adder 67 calculates the feedback control torque (basic torque command value) T fb The resonance control torque T res The disturbance torque estimate ^T lc By subtracting sint (=T fb +G d dT tb / dt+G p T tb -^T lc ) is calculated.

[0214] Integrated steering torque command value T sint is given to the first reduction ratio division unit 68. The first reduction ratio division unit 68 calculates the integrated steering torque command value T sint By dividing by the reduction ratio N, the integrated motor torque command value T mint This integrated motor torque command value T mint is given to the second weighting unit 57 (see FIG. 2).

[0215] FIG. 18 is a schematic diagram showing a two-inertia model 304 corresponding to the electric power steering system of the third embodiment in the automatic steering mode or the cooperative steering mode.

[0216] In this two-inertia model 304, the steering wheel 2 is subjected to a driver torque T d is applied, and a steering torque T tb -T, which is the sign-negated value of tb The steering column 310 is supplied with a driving torque N·T from the electric motor 18. m is given. Driving torque N T m is N.T. m =(K 0dot θ sint +K 1dot dθ sint / dt+K 2dot ·d 2 θ sint / dt 2 +K 3dot ·d 3 θ sint / dt 3 +K 4dot ·d 4 θ sint / dt 4 -K p θ p -K d dθ p / dt+G p T tb +G d dT tb / dt).

[0217] If load compensation is not performed, the steering column 310 is subjected to a driving torque N·T m In addition, steering torque T tb and road load torque T rl is given.

[0218] Fig. 19 is a control block diagram of a feedback control system of the electric power steering system of the third embodiment in the automatic steering mode or the cooperative steering mode, in which the column and the steering wheel, which are the controlled objects, are modeled. Here, Fig. 19 is a block diagram corresponding to Fig. 18 and equations (19a) and (19b) described later.

[0219] Integrated angle command value θ sint The target torque T is calculated by the target torque calculation unit 401 based on ta From the above, the first column angle θ p The feedback torque T calculated by the feedback torque calculation unit 402 based on the actual steering angle θ fe is subtracted, the feedback control torque T fb (=T ta -T fe ) is generated. In this embodiment, as will be described later, the proportional gain K p and the differential gain K d are the column inertia J p It also includes the proportional gain K 0dot , first-order differential gain K 1dot , second-order differential gain K 2dot , third-order differential gain K 3dot and the fourth-order differential gain K 4dot If is set to a significant value other than zero, the column inertia J p Contains:

[0220] Feedback control torque T fb The resonance control torque T res (=G d dT tb / dt+G p T tb ) is added. This added value (T fb +G d dT tb / dt+G p T tb ) is the column angle θ p Angular acceleration of (hereinafter referred to as column angular acceleration d 2 θ p / dt 2) and the column inertia J p Output shaft torque command value N·T corresponding to the value multiplied by m This corresponds to the output torque command value N·T m A driving torque corresponding to the inertia J is applied from the electric motor 18 to the steering column 310. p The driving torque N·T is applied to the steering column 310. m The steering column 310 rotates by the input of the p ) is measured based on the rotation angle sensor 23 and fed back.

[0221] Here, the steering torque T tb is the column angle θ p and wheel angle θ sw The difference between (θ sw -θ p ) torsion bar stiffness k tb is equivalent to the value multiplied by T tb =k tb (θ sw -θ p ) This steering torque T tb The first gain G d The value G multiplied by d dT tb / dt and this steering torque T tb Second gain G p The value G multiplied by p T tb The sum of these is the resonance control torque T res In addition, the inertia is J sw The steering torque T is applied to the steering wheel 2. tb and driver torque T d When this signal is input, the steering wheel 2 rotates.

[0222] In the two-inertia model 304 of FIG. 18, the equation of motion on the steering column side is expressed by the following equation (19a), and the equation of motion on the steering wheel side is expressed by the following equation (19b).

[0223]

number

[0224] In the two-inertia model 304 of FIG. 18, the proportional gain K p , differential gain K d , the second gain Gp and the first gain G d When the values ​​shown in the above expressions (11a), (11b), (11c), and (11d) are respectively set, the integrated angle command value θ sint From column angle θ p Transfer function G(θ sint →θ p ) is expressed by the following equation (20a), and the integrated angle command value θ sint from wheel angle θ sw Transfer function G(θ sint →θ sw ) is expressed by the following equation (20b).

[0225]

number

[0226] Proportional Gain K 0dot , first-order differential gain K 1dot , second-order differential gain K 2dot , third-order differential gain K 3dot and the fourth-order differential gain K 4dot For example, when the angle command value θ is set to a value as shown in the following equation (21), the configuration of the feedback control unit 400 in FIG. 17 becomes equivalent to the feedback control unit 62 in FIG. 5. However, when the angle command value θ is input to the feedback control unit 400 in FIG. sint and the angle command value θ input to the feedback control unit 62 in FIG. sin is different.

[0227]

number

[0228] In this case, the command value angle θ sint (In Fig. 5, θ sin ) gain K pand angular velocity dθ sint / dt (dθ in Figure 5) sin / dt) vs. gain K d are the gains K for the feedback angle θ, respectively. p and gain K for angular velocity dθ / dt d In other words, a common gain is set on the command value side and the feedback side.

[0229] In the third embodiment, it is possible to set different gains on the command value side and the feedback side. In the third embodiment, it is preferable to set different gains on the command value side and the feedback side. In other words, the target torque T ta The gain used in the calculation of the feedback torque T fe It is preferable that the gain used in the calculation of the gain is different from the gain used in the calculation of the gain.

[0230] Hereafter, proportional gain K 0dot , first-order differential gain K 1dot , second-order differential gain K 2dot , third-order differential gain K 3dot and the fourth-order differential gain K 4dot A specific example of the setting of the proportional gain K p , differential gain K d , second gain G p and the first gain G d are set to the values ​​shown in the above expressions (11a), (11b), (11c), and (11d).

[0231] [First setting example] In the first setting example, the proportional gain K 0dot , first-order differential gain K 1dot , second-order differential gain K 2dot , third-order differential gain K 3dot and the fourth-order differential gain K 4dot is set to a value as shown in the following equation (22).

[0232]

number

[0233] In this case, the integrated angle command value θ sint From column angle θ p Transfer function G(θ sint →θ p ) is expressed by the following equation (23a), and the integrated angle command value θ sint from wheel angle θ sw Transfer function G(θ sint →θ sw ) is expressed by the following equation (23b).

[0234]

number

[0235] In this case, the wheel angle θ sw In this case, similar to the first embodiment, the resonance frequency ω and the damping ratio ζ can be set arbitrarily.

[0236] [Second setting example] In the second example, the proportional gain K 0dot , first-order differential gain K 1dot , second-order differential gain K 2dot , third-order differential gain K 3dot and the fourth-order differential gain K 4dot is set to a value as shown in the following equation (24).

[0237]

number

[0238] In this case, the integrated angle command value θ sint From column angle θ p Transfer function G(θ sint →θ p ) is expressed by the following equation (25a), and the integrated angle command value θ sint from wheel angle θ sw Transfer function G(θ sint →θ sw ) is expressed by the following equation (25b).

[0239]

number

[0240] In this case, the wheel angle θ sw responds with a third-order delay. In this case, similar to the first embodiment, the resonance frequency ω can be set arbitrarily.

[0241] [Third setting example] In the third example, the proportional gain K 0dot , first-order differential gain K 1dot , second-order differential gain K 2dot , third-order differential gain K 3dot and the fourth-order differential gain K 4dot is set as shown in the following equation (26).

[0242]

number

[0243] In this case, the integrated angle command value θ sint From column angle θ p Transfer function G(θ sint →θ p ) is expressed by the following equation (27a), and the integrated angle command value θ sint from wheel angle θ sw Transfer function G(θ sint →θ sw ) is expressed by the following equation (27b).

[0244]

number

[0245] In this case, the wheel angle θ sw responds with a second-order delay. In the third setting example, similarly to the first embodiment, it becomes possible to arbitrarily set the resonance frequency ω and the damping ratio ζ.

[0246] [Fourth setting example] In the fourth setting example, the proportional gain K 0dot , first-order differential gain K 1dot , second-order differential gain K 2dot , third-order differential gain K 3dot and the fourth-order differential gain K 4dot is set as shown in the following equation (28).

[0247]

number

[0248] In this case, the integrated angle command value θ sint From column angle θ p Transfer function G(θ sint →θ p ) is expressed by the following equation (29a), and the integrated angle command value θ sint from wheel angle θ sw Transfer function G(θ sint →θ sw ) is expressed by the following equation (29b).

[0249]

number

[0250] In this case, the wheel angle θ sw responds with a first-order delay. In this case, similar to the first embodiment, it is possible to arbitrarily set the resonance frequency ω.

[0251] In this case, it is preferable to provide a low-pass filter (LPF) of first or higher order having a cutoff frequency equal to or lower than ω between integrated angle command value calculation unit 53 (see FIG. 2) and angle control unit 54A (see FIG. 17).

[0252] [Fifth setting example] In the fifth setting example, the proportional gain K 0dot , first-order differential gain K 1dot , second-order differential gain K 2dot , third-order differential gain K 3dot and the fourth-order differential gain K 4dotis set as shown in the following equation (30).

[0253]

number

[0254] In this case, the integrated angle command value θ sint From column angle θ p Transfer function G(θ sint →θ p ) is expressed by the following equation (31a), and the integrated angle command value θ sint from wheel angle θ sw Transfer function G(θ sint →θ sw ) is expressed by the following equation (31b).

[0255]

number

[0256] In this case, the wheel angle θ sw responds without delay.

[0257] In this case, it is preferable to provide a low-pass filter (LPF) of second order or higher, with a cutoff frequency equal to or lower than ω, between integrated angle command value calculation unit 53 (see FIG. 2) and angle control unit 54A (see FIG. 17).

[0258] In the third embodiment, load compensation is performed, but load compensation may not be performed. In this case, the feedback control torque (basic torque command value) T fb The resonance control torque T res (=G d dT tb / dt+G p T tb ) is added to the value (T fb +G d dT tb / dt+G p T tb ) is the integrated steering torque command value T sint This becomes:

[0259] In the absence of load compensation, the steering torque T tb can be considered to be fed back to the steering column 310 in advance, so the second gain in the case without load compensation is G p ', and the second gain when load compensation is used is G p Then, G p '=(G p -1).

[0260] In the third embodiment, the proportional gain K p , differential gain K d , second gain Gp, first gain G d , proportional gain K 0dot , first-order differential gain K 1dot , second-order differential gain K 2dot , third-order differential gain K 3dot and the fourth-order differential gain K 4dot By setting these to the values ​​as described above, it becomes possible to arbitrarily set the response characteristics (such as n-th order delay) in addition to the resonance frequency ω and damping ratio ζ.

[0261] In the third embodiment, the integrated angle command value θ sint and a cooperative steering mode in which the electric motor 18 can be controlled based on the assist torque command value T as a manual steering mode in which the electric motor 18 can be controlled based only on the automatic steering command value θ adac This allows switching between an automatic steering mode in which the electric motor 18 can be controlled based only on the steering angle.

[0262] That is, the integrated angle command value θ sint In the electric power steering system, the electric motor 18 can be controlled based on the assist torque command value T as Therefore, it becomes possible to control the electric motor 18 based only on the above.

[0263] Although the first, second and third embodiments of the present invention have been described above, the present invention can also be embodied in other forms.

[0264] For example, in the first, second, and third embodiments, the steering torque T tb and the steering torque T input to the second torque calculation unit 64, 154 tb A dead-zone processing unit may be provided in at least one of the above. The reason for providing the dead-zone processing unit will be described later.

[0265] Hereinafter, with reference to FIGS. 20, 23, and 24, the steering torque T input to the first torque calculation unit 63 (see FIGS. 5 and 17) of the first embodiment (third embodiment) will be described. tb and the steering torque T input to the second torque calculation unit 64 (see FIGS. 5 and 17). tb 20, 23, and 24, the angle control unit 54, 54A includes a dead band processor. res Only the part related to the calculation of is shown.

[0266] FIG. 20 is a block diagram showing an example in which a dead zone processing unit 501 is provided in front of the second torque calculation unit 64.

[0267] The dead zone processing unit 501 receives the steering torque T tb 21 shows an example of the input / output characteristics of the dead zone processing unit 501.

[0268] The dead zone processing unit 501 calculates the steering torque T tb is within the range of -W / 2 or more and W / 2 or less (dead band area), zero is set, and the steering torque T tb,de Output as

[0269] Steering torque T tb In the region where is smaller than −W / 2, the dead zone processing unit 501 tb +(W / 2)] is the steering torque T after dead zone processing tb,de The steering torque T tb In the region where is greater than W / 2, the dead zone processing unit 501tb -(W / 2)] is the steering torque T after dead zone processing tb,de The dead band width W is set in advance.

[0270] In this case, the second torque calculation unit 64 calculates the steering torque T after the dead zone processing. tb,de Second gain G p By multiplying the second torque G p· T tb,de Therefore, in this case, the resonance control torque T ress is G d· dT tb / dt+G p· T tb,de This becomes:

[0271] The dead zone processing unit 501 is configured to process the steering torque T tb When the absolute value of is within a small dead zone, a value close to zero is set as the steering torque T tb,de For example, the input / output characteristics of the dead zone processing unit 501 may be as shown in FIG.

[0272] That is, the input / output characteristics of the dead zone processing unit 501 are tb In the dead zone where the absolute value of is small (the range between -W / 2 and W / 2), the steering torque T tb,de The absolute value of the steering torque T tb As the absolute value of increases, the steering torque T tb In the range where the absolute value of is larger than the dead band area, the steering torque T tb,de The absolute value of the steering torque T tb The characteristic may be such that it increases linearly as the absolute value of

[0273] As shown in FIG. 23, the dead band processing unit 501 may be provided in front of both the first torque calculation unit 63 and the second torque calculation unit 64.

[0274] In this case, the first torque calculation unit 63 calculates the steering torque T after the dead zone processing.tb,de The time derivative dT of tb,de / dt with first gain G d By multiplying the first torque G d dT tb,de The second torque calculation unit 64 calculates the steering torque T after the dead zone processing. tb,de Second gain G p Therefore, in this case, the second torque is calculated by multiplying the resonance control torque T ress is G d dT tb,de / dt+G p· T tb,de This becomes:

[0275] The dead zone processing unit 501 may be provided in the preceding stage of the first torque calculation unit 63, as shown in FIG.

[0276] In this case, the first torque calculation unit 63 calculates the steering torque T after the dead zone processing. tb,de The time derivative dT of tb,de / dt with first gain G d By multiplying the first torque G d dT tb,de Therefore, in this case, the resonance control torque T ress is G d dT tb,de / dt+G p· T tb This becomes:

[0277] The reason for providing the dead zone processing unit 501 will be explained. tb (The driver torque T applied to the steering wheel 2 mainly by the driver d and the sum of the force generated by steering inertia) may be offset by friction, etc. Therefore, the actual steering torque T tb Even if the absolute value of is zero or close to zero, the steering torque T detected by the torque sensor 12 tb The absolute value of the actual steering torque T tb In this case, the absolute value of the actual steering torque T tbWhen the absolute value of is zero or close to zero, the resonance control torque T res (=G d dT tb / dt+G p T tb ) is output, and the steering angle command value (integrated angle command value θ sint ) deviation (steering angle deviation) occurs.

[0278] As shown in FIG. 20, FIG. 23 or FIG. 24, the steering torque T tb If the dead zone processing unit 501 is provided in at least one of the first torque calculation unit 64 and the second torque calculation unit 64, the following effect can be obtained. tb In the range where the absolute value of is large, the resonance control torque T res On the other hand, in the range where the resonance of the steering wheel 2 is small and resonance control is not necessary (steering torque T tb In the range where the absolute value of the steering torque T tb Therefore, it is possible to prevent the steering angle deviation due to the offset.

[0279] Although not shown, the dead band processing unit 501 may be provided only upstream of the second torque calculation unit 154 (FIG. 15) of the second embodiment, or the dead band processing unit 501 may be provided only upstream of the first torque calculation unit 153 (FIG. 15) of the second embodiment. Furthermore, the dead band processing unit 501 may be provided upstream of both the first torque calculation unit 153 (FIG. 15) and the second torque calculation unit 154 (FIG. 15) of the second embodiment.

[0280] In the first, second and third embodiments described above, the first weighting unit 56, the second weighting unit 57 and the third weighting unit 58 are provided, but the third weighting unit 58 may be omitted. In this case, there are two types of steering modes: a manual steering mode and a cooperative steering mode.

[0281] In the first, second and third embodiments described above, the steering torque (torsion bar torque) T tbT tb =k tb (θ sw -θ p ) and this T tb Although feedback is given, tb =k tb (θ sw -θ p ) is equivalent to feeding back the relative angle between the steering wheel 2 and the steering column 310. Therefore, if an angle sensor is provided to detect the rotation angle of the steering wheel 2, the steering torque T tb Similar control can be achieved without using the above, by feeding back the relative angle between the steering wheel 2 and the steering column 310 and the relative speed between the steering wheel 2 and the steering column 310 (which may be detected by a speed sensor or the differential value of the relative angle).

[0282] In this case, the resonance control torque T res is T res =[{G p '×(relative angle)}+{G d '×(relative velocity)}], where G p '=G p ·k tb , G d ' =G d ·k tb is.

[0283] Although the embodiments of the present invention have been described in detail, these are merely examples used to clarify the technical contents of the present invention, and the present invention should not be construed as being limited to these examples, and the scope of the present invention is limited only by the appended claims.

[0284] This application corresponds to Patent Application No. 2022-6684 filed with the Japan Patent Office on January 19, 2022, the entire disclosure of which is incorporated herein by reference. [Explanation of symbols]

[0285] 1...electric power steering device, 3...steered wheel, 4...steering mechanism, 18...electric motor, 51,151...assist torque command value setting unit, 52...manual steering command value generation unit, 53...integrated angle command value calculation unit, 54...angle control unit, 55...torque control unit, 59...adder, 61...low-pass filter, 62,400...feedback control unit, 63,153...first torque calculation unit, 63A,153A...differential calculation unit, 63B,153B...first gain multiplication unit, 64,154...second torque calculation unit, 65,155...first torque addition unit, 66,156...disturbance torque estimator, 67,157...second torque addition unit, 401...target torque calculation unit, 402...feedback torque calculation unit, 403...torque deviation calculation unit, 501...dead band processing unit

Claims

1. A motor control device that controls an electric motor that applies a steering force to an output shaft that is connected to a steering wheel via a torsion bar, a steering torque detection unit that detects a steering torque applied to the steering wheel; a motor torque command value setting unit that sets a motor torque command value that is a target value of the motor torque of the electric motor; a rotation angle detection unit that detects a rotation angle of the electric motor, The motor torque command value setting unit a basic torque command value setting unit that sets a basic torque command value; a correction unit that corrects the basic torque command value set by the basic torque command value setting unit using a resonance control torque; a motor torque command value calculation unit that calculates the motor torque command value based on the basic torque command value corrected by the correction unit, the resonance control torque is set using a first torque obtained by multiplying a differential value of the steering torque by a predetermined first gain, and a second torque obtained by multiplying the steering torque by a predetermined second gain, The basic torque command value setting unit a target torque calculation unit that calculates a target torque based on a rotation angle command value that is a target value of the rotation angle of the output shaft; a feedback torque calculation unit that calculates a feedback torque based on the rotation angle detected by the rotation angle detection unit; a basic torque command value calculation unit that calculates the basic torque command value by calculating a deviation between the target torque and the feedback torque, A motor control device, wherein a gain used to calculate the target torque is different from a gain used to calculate the feedback torque.

2. a manual steering command value calculation unit that generates a manual steering command value; an integrated angle command value calculation unit that calculates an integrated angle command value by adding the manual steering command value to an automatic steering angle command value, The motor control device according to claim 1 , wherein the rotation angle command value is the integrated angle command value.

3. a disturbance torque estimating unit that estimates disturbance torque other than the motor torque of the electric motor acting on the output shaft based on the motor torque command value or the motor torque generated by the electric motor and a rotation angle of the output shaft, 3. The motor control device according to claim 1, wherein the correction unit is configured to correct the basic torque command value using the resonance control torque and the disturbance torque.

4. 4. The motor control device according to claim 1, wherein a dead zone is set for at least one of the steering torque, which is an input value for calculating the first torque, and the steering torque, which is an input value for calculating the second torque.

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