JP7194326B2 - motor controller - Google Patents

Description

The present invention, for example, controls an electric motor used for steering system control in an automatic driving system, a driving support system, a steer-by-wire system, a rear-wheel steering system, etc., and also controls an electric motor for controlling the turning angle of these steering systems. Regarding the device.

In an automatic driving system, a driving support system, a steer-by-wire system, a rear-wheel steering system, and the like, an electric motor controls the steering angle of the steered wheels. This type of motor control uses steering angle feedback control that controls the motor torque of the electric motor according to the difference between the target steering angle and the actual steering angle. PID control is generally used as steering angle feedback control. Specifically, the term of the difference between the target turning angle and the actual turning angle, the integral term of the difference, and the differential term of the difference are multiplied by the proportional gain, the integral gain, and the differential gain, respectively. is added to calculate the target torque. Then, the electric motor is controlled so that the motor torque becomes equal to the target torque.

Japanese Patent Application Laid-Open No. 2004-256076

Since the above-mentioned PID control is a linear control algorithm, the steering angle control is affected by fluctuations in nonlinear disturbance torque such as road surface reaction torque (rack shaft side disturbance torque), steering system friction torque, steering side disturbance torque, etc. Accuracy loss and variability occur.
SUMMARY OF THE INVENTION An object of the present invention is to provide a motor control device capable of compensating for disturbance torque and performing highly accurate motor control.

The invention according to claim 1 is a motor control device for controlling an electric motor (18) for driving a plant, comprising rotation angle detection means (23) for detecting the rotation angle of the electric motor; a target motor torque setting means (42; 153) for setting a target motor torque which is a target value of the motor torque of the motor; and a motor torque of the electric motor based on the target motor torque set by the target motor torque setting means. Control means (45, 46) for feedback control, wherein the target motor torque setting means is set by basic target torque setting means (62; 62 and 63) for setting a basic target torque and the target motor torque setting means. Disturbance torque other than the motor torque of the electric motor acting on the plant is detected based on the target motor torque generated by the electric motor or the motor torque generated by the electric motor and the rotation angle detected by the rotation angle detection means. an estimating disturbance observer (64); a disturbance torque compensating means (65) for correcting the basic target torque set by the basic target torque setting means with the disturbance torque estimated by the disturbance observer; and the disturbance torque compensating means. a target motor torque calculation means for calculating the target motor torque based on the basic target torque corrected by the means. Note that alphanumeric characters in parentheses represent corresponding components and the like in embodiments described later, but the scope of the present invention is of course not limited to those embodiments.

According to this configuration, disturbance torque can be compensated for, so that highly accurate motor control can be performed.
According to a second aspect of the present invention, the disturbance observer detects the target motor torque set by the target motor torque setting means or the motor torque generated by the electric motor and the rotation detected by the rotation angle detection means. the disturbance torque (^Tld) and the rotation angle (^θ) of the plant based on the angle (θm), and the basic target torque setting means estimates the rotation angle of the plant An angle deviation calculation means (62A) for calculating a difference between a target rotation angle (θcmd), which is a target value, and the rotation angle (^θ) of the plant estimated by the disturbance observer, and calculation by the angle deviation calculation means 2. The motor control device according to claim 1, further comprising basic target torque calculation means (62B) for calculating the basic target torque (Tfb) by performing a predetermined feedback calculation on the angular deviation obtained.

According to a third aspect of the present invention, the disturbance observer detects the target motor torque set by the target motor torque setting means or the motor torque generated by the electric motor and the rotation detected by the rotation angle detection means. the disturbance torque (^Tld) and the rotation angle (^θ) of the plant based on the angle (θm), and the basic target torque setting means estimates the rotation angle of the plant An angle deviation calculation means (62A) for calculating a difference between a target rotation angle (θcmd), which is a target value, and the rotation angle (^θ) of the plant estimated by the disturbance observer, and calculation by the angle deviation calculation means A feedback control torque calculation means (62B) for calculating a feedback control torque (Tfb) by performing a predetermined feedback calculation on the angular deviation obtained; A feedforward control torque calculating means (63) for calculating a feedforward control torque (Tff) by multiplying; and a base for calculating the basic target torque by adding the feedforward control torque to the feedback control torque. 2. A motor control device according to claim 1, further comprising a target torque calculation means (65).

In the fourth aspect of the invention, the basic target torque setting means is calculated from a target rotation angle (θcmd), which is a target value of the rotation angle of the plant, and the rotation angle detected by the rotation angle detection means. The basic target torque is calculated by an angular deviation calculating means for calculating a difference from the rotation angle (θ) of the plant, and by performing a predetermined feedback calculation on the angular deviation calculated by the angular deviation calculating means. 2. The motor control device according to claim 1, further comprising basic target torque calculation means.

According to a fifth aspect of the present invention, the basic target torque setting means calculates a target rotation angle (θcmd), which is a target value of the rotation angle of the plant, and the rotation angle (θ) detected by the rotation angle detection means. an angle deviation calculation means for calculating a difference from the calculated rotation angle of the plant; and feedback for calculating a feedback control torque by performing a predetermined feedback calculation on the angle deviation calculated by the angle deviation calculation means. control torque calculation means; feedforward control torque calculation means for calculating a feedforward control torque by multiplying the moment of inertia of the plant by the second derivative of the target rotation angle; and feedforward control torque to the feedback control torque. 2. The motor control device according to claim 1, further comprising basic target torque calculation means for calculating said basic target torque by adding torque.

The invention according to claim 6 is the motor control device according to any one of claims 1 to 5, wherein the electric motor is an electric motor used for steering system control of a vehicle.
According to a seventh aspect of the invention, there is provided a motor control system for controlling an electric motor (18) that applies steering force to a steering column (9, 21) connected to a steering wheel (2) via a torsion bar (10). A device comprising: rotation angle detection means (23) for detecting the rotation angle of the electric motor; target motor torque setting means (42A) for setting a target motor torque, which is a target value of the motor torque of the electric motor; control means (45, 46) for feedback-controlling the motor torque of the electric motor based on the target motor torque, wherein the target motor torque setting means is basic target torque setting means (62; 62 and 63), the target motor torque or the motor torque generated by the electric motor, and the rotation angle, a disturbance torque other than the motor torque of the electric motor acting on the steering column is estimated. A disturbance observer (64), damping torque calculation means (160, 161) for calculating a damping torque for suppressing vibration of the steering wheel, and the basic target torque set by the basic target torque setting means, A motor control comprising correcting means (65) for correcting by the disturbance torque and the damping torque, and target motor torque calculating means for calculating the target motor torque based on the basic target torque corrected by the correcting means. It is a device.

According to this configuration, disturbance torque can be compensated for, so that highly accurate motor control can be performed. Further, according to this configuration, it is possible to suppress torsional vibration generated by the inertia of the steering wheel and the torsion bar during automatic steering or the like.
According to an eighth aspect of the present invention, steering torque detection means (12) for detecting the steering torque applied to the steering wheel is included, and the damping torque calculation means multiplies the steering torque by a predetermined damping gain. The basic target torque setting means calculates a target rotation angle, which is a target value of the rotation angle of the steering column, and the steering column estimated by the disturbance observer. an angle deviation calculation means (62A) for calculating a difference between the rotation angle of the steering column or the rotation angle of the steering column calculated from the rotation angle detected by the rotation angle detection means; and the angle calculated by the angle deviation calculation means 8. The motor control device according to claim 7, further comprising feedback control torque calculation means (62) for calculating the feedback control torque by performing a proportional differential calculation on the deviation.

In the invention according to claim 9, the proportional gain and the differential gain used for the proportional differential calculation are _KP and _{KD, respectively, the damping gain is KR, the rigidity of the torsion bar is Ktb , and} the _Let J _SW be the inertia of the steering wheel, and the anti-resonance frequency _ωa of the steering wheel and the steering column is represented by the following equation (a ₎ . , which are represented by the following equations (b) to (d).

ωa={K _tb ·(1/J _SW )} ^1/2 (a)
K _P =ωa ² (b)
KD= _4ωa (c)
K _R =4/J _SW (d)

FIG. 1 is a schematic diagram showing a schematic configuration of an electric power steering system to which a motor control device according to an embodiment of the invention is applied. FIG. 2 is a block diagram for explaining the electrical configuration of the ECU. FIG. 3 is a block diagram showing the configuration of the target automatic steering torque setting section. FIG. 4 is a schematic diagram showing a configuration example of a physical model of the electric power steering system. FIG. 5 is a block diagram showing the configuration of the disturbance torque estimator. FIG. 6 is a schematic diagram showing a schematic configuration of a dual pinion type electric power steering system. FIG. 7 is a schematic diagram showing a schematic configuration of the steer-by-wire system. FIG. 8 is a block diagram showing the configuration of a control circuit for the steering motor. 9 is a block diagram showing a modification of the target automatic steering torque setting unit shown in FIG. 3. FIG. FIG. 10A is a schematic diagram showing a two-inertia model that does not depend on the disturbance torque after the introduction of the disturbance torque compensator, and in which damping torque is fed back. FIG. 10B shows a model equivalent to FIG. 10A. It is a schematic diagram showing. FIG. 11 is a control block diagram showing the configuration of the feedback control system of the electric power steering system in the automatic driving mode, and is a control block diagram equivalent to FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Below, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic diagram showing a schematic configuration of an electric power steering system to which a motor control device according to an embodiment of the invention is applied.
This electric power steering system (EPS) 1 is a column-type EPS in which an electric motor and a speed reducer are arranged in a column portion.

An electric power steering system 1 includes a steering wheel (steering wheel) 2 as a steering member for steering a vehicle, a steering mechanism 4 for steering steered wheels 3 in conjunction with the rotation of the steering wheel 2, and a driving mechanism. and a steering assist mechanism 5 for assisting a person's steering. The steering wheel 2 and steering mechanism 4 are mechanically connected via a steering shaft 6 and an intermediate shaft 7 .

Steering shaft 6 includes an input shaft 8 connected to steering wheel 2 and an output shaft 9 connected to intermediate shaft 7 . The input shaft 8 and the output shaft 9 are connected via a torsion bar 10 so as to be relatively rotatable.
A torque sensor 12 is arranged near the torsion bar 10 . The torque sensor 12 detects a steering-side disturbance torque Td applied to the steering wheel 2 based on relative rotational displacement amounts of the input shaft 8 and the output shaft 9 . In this embodiment, the steering-side disturbance torque Td detected by the torque sensor 12 is, for example, detected as a positive value for torque for steering to the left and a negative value for torque for steering to the right. It is assumed that the larger the absolute value is, the larger the magnitude of the steering-side disturbance torque is.

The steering mechanism 4 is 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 steering of the steering wheel 2 . A pinion 16 is connected to the tip of the pinion shaft 13 .

The rack shaft 14 extends linearly along the left-right direction of the vehicle. A rack 17 that meshes with the pinion 16 is formed in the axially intermediate portion of the rack shaft 14 . The pinion 16 and 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 steerable wheels 3 can be steered.

When the steering wheel 2 is steered (rotated), this rotation is transmitted to the pinion shaft 13 via the steering shaft 6 and intermediate shaft 7 . Rotation of the pinion shaft 13 is converted into axial movement of the rack shaft 14 by the pinion 16 and the rack 17 . As a result, the steerable wheels 3 are steered.
The steering assist mechanism 5 includes an electric motor 18 for generating a steering assist force (assist torque) and a speed reducer 19 for amplifying the output torque of the electric motor 18 and transmitting it to the steering mechanism 4 . The speed reducer 19 comprises a worm gear mechanism including a worm gear 20 and a worm wheel 21 meshing with the worm gear 20 . The speed reducer 19 is accommodated in a gear housing 22 as a transmission mechanism housing.

The worm gear 20 is rotationally driven by the electric motor 18 . Also, the worm wheel 21 is connected to the output shaft 9 so as to be rotatable together. The worm wheel 21 is rotationally driven by the worm gear 20 .
When the worm gear 20 is rotationally driven by the electric motor 18, the worm wheel 21 is rotationally driven, motor torque is applied to the steering shaft 6, and the steering shaft 6 (output shaft 9) rotates. Rotation of the steering shaft 6 is transmitted to the pinion shaft 13 via the intermediate shaft 7 . Rotation of the pinion shaft 13 is converted into axial movement of the rack shaft 14 . As a result, the steerable wheels 3 are steered. That is, by rotationally driving the worm gear 20 with the electric motor 18, the steering assistance with the electric motor 18 and the steering of the steerable 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 .

The torque applied to the speed reducer 19 includes motor torque from the electric motor 18 and disturbance torque other than the motor torque. The disturbance torque Tld other than the motor torque includes the steering-side disturbance torque Td, road surface reaction torque (rack shaft-side disturbance torque) Tls, friction torque Tf generated in the speed reducer 19, and the like. The steering-side disturbance torque Td is torque applied to the reduction gear 19 from the steering wheel 2 side due to force applied to the steering wheel 2 by the driver, force generated by steering inertia, or the like. The road surface reaction torque Tls is generated by the self-aligning torque generated in the tire, the force generated by the suspension and tire wheel alignment, the frictional force of the rack and pinion mechanism, etc. is the torque applied to

The vehicle includes a vehicle speed sensor 24 for detecting vehicle speed V, a CCD (Charge Coupled Device) camera 25 for photographing the road in front of the vehicle, a GPS (Global Positioning System) 26 for detecting the position of the vehicle, and A radar 27 is mounted for detecting road shapes and obstacles. The vehicle is further equipped with a map information memory 28 storing map information and an automatic steering mode switch 29 for setting and canceling the automatic steering mode.

The CCD camera 25, GPS 26, radar 27, map information memory 28, and automatic steering mode switch 29 are connected to an automatic driving control ECU (ECU: Electronic Control Unit) 201 for performing automatic support control and automatic driving control. . Based on the information and map information obtained by the CCD camera 25, GPS 26 and radar 27, the automatic driving control ECU 201 performs surrounding environment recognition, vehicle position estimation, route planning, etc., and sets control target values for steering and drive actuators. make a decision. Further, the automatic driving control ECU 201 instructs setting and cancellation of the automatic steering mode based on an input signal from the automatic steering mode switch 29 .

In this embodiment, the automatic driving control ECU 201 sets a target rudder angle θcmda for automatic steering, and a mode switching signal (automatic steering mode setting signal or automatic steering mode cancellation signal) according to the operation of the automatic steering mode switch 29 . signal). In this embodiment, the automatic steering control is, for example, lane keep control (a type of driving support control) for running the vehicle along the target trajectory. The target steering angle θcmda is a target value of the steering angle (steering angle or turning angle) for automatically driving the vehicle along the target track. Since the processing for setting the target steering angle θcmda is well known, detailed description thereof will be omitted here.

A target rudder angle θcmda set by the automatic driving control ECU 201 and a mode switching signal generated by the automatic driving control ECU 201 are provided to a steering control ECU 202, which will be described later, via an in-vehicle network.
The steering-side disturbance torque Td detected by the torque sensor 12, the output signal of the rotation angle sensor 23, and the vehicle speed V detected by the vehicle speed sensor 24 are input to the steering control ECU 202. FIG. The steering control ECU 202 controls the electric motor 18 based on these input signals and information given from the automatic driving control ECU 201 .

The steering control ECU 202 controls the electric motor 18 according to an automatic control mode for performing automatic steering control when the automatic steering mode setting signal is given by the automatic driving control ECU 201 . Further, when an automatic steering mode cancellation signal is given by the automatic driving control ECU 201, the steering control ECU 202 cancels the automatic steering control and performs manual steering control (assist control) according to the manual steering mode (assist control mode). It controls the electric motor 18 . The manual steering mode is a steering assist force (assist torque) for assisting steering by the driver based on the steering-side disturbance torque Td detected by the torque sensor 12 and the vehicle speed V detected by the vehicle speed sensor 24. is generated from the electric motor 18.

The steering control ECU 202 switches the control mode according to a mode switching signal from the automatic driving control ECU 201. In the automatic steering mode, when there is an intervention operation by the driver's steering operation (steering operation), the automatic steering is performed. It has a function (override function) to switch the control mode from mode to manual steering mode.
FIG. 2 is a block diagram for explaining the electrical configuration of the steering control ECU 202. As shown in FIG.

The steering control ECU 202 includes a microcomputer 40, a drive circuit (inverter circuit) 31 that is controlled by the microcomputer 40 and supplies electric power to the electric motor 18, and a current flowing through the electric motor 18 (hereinafter referred to as "motor current I"). ) and a current detection circuit 32 for detecting the current.
The microcomputer 40 has a CPU and memory (ROM, RAM, non-volatile memory, etc.), and functions as a plurality of functional processing units by executing predetermined programs. The plurality of function processing units include a target assist torque setting unit 41, a target automatic steering torque setting unit 42, a mode switching unit (target torque switching unit) 43, a target motor current calculation unit 44, and a current deviation calculation unit. 45 , a PI controller 46 and a PWM (Pulse Width Modulation) controller 47 .

The target assist torque setting unit 41 sets a target assist torque Tm1, which is a target value of the assist torque. Target assist torque setting unit 41 sets target assist torque Tm<b>1 based on steering-side disturbance torque Td detected by torque sensor 12 and vehicle speed V detected by vehicle speed sensor 24 . The target assist torque Tm1 takes a positive value for a positive value of the steering disturbance torque Td, and takes a negative value for a negative value of the steering disturbance torque Td. The target assist torque Tm1 is set such that its absolute value increases as the absolute value of the steering-side disturbance torque Td increases. Target assist torque Tm1 is set such that its absolute value decreases as vehicle speed V detected by vehicle speed sensor 24 increases.

A target automatic steering torque setting unit 42 sets a target automatic steering torque Tm2, which is a target value of the motor torque of the electric motor 18 in the automatic steering mode. The details of the target automatic steering torque setting unit 42 will be described later.
A target assist torque Tm1, a target automatic steering torque Tm2, a mode switching signal from the automatic driving control ECU 201, and a steering disturbance torque Td detected by the torque sensor 12 are input to the mode switching unit 43. The mode switching unit 43 switches the control mode according to a mode switching signal from the ECU 201 for controlling automatic operation. Further, when the control mode is set to the automatic steering mode, for example, when the absolute value |Td| , to switch the control mode to manual steering mode.

When the control mode is set to the manual steering mode, the mode switching unit 43 outputs the target assist torque Tm1 set by the target assist torque setting unit 41 as the target motor torque Tm. When the control mode is set to the automatic steering mode, the mode switching unit 43 outputs the target automatic steering torque Tm2 set by the target automatic steering torque setting unit 42 as the target motor torque Tm.

The target motor current calculation unit 44 calculates the target motor current Icmd by dividing the target motor torque Tm set by the mode switching unit 43 by the torque constant Kt of the electric motor 18 .
A current deviation calculator 45 calculates a deviation ΔI (=Icmd−I) between the target motor current Icmd obtained by the target motor current calculator 44 and the motor current I detected by the current detection circuit 32 .

The PI control unit 46 performs PI calculation (proportional integral calculation) on the current deviation ΔI calculated by the current deviation calculation unit 45, thereby issuing a drive command for guiding the motor current I flowing through the electric motor 18 to the target motor current Icmd. generate a value. The PWM control section 47 generates a PWM control signal having a duty ratio corresponding to the drive command value, and supplies it to the drive circuit 31 . As a result, electric power corresponding to the drive command value is supplied to the electric motor 18 .

When the control mode is set to the manual steering mode, the target assist torque Tm1 is set as the target motor torque Tm. is controlled (manual steering control). On the other hand, when the control mode is set to the automatic steering mode, the target automatic steering torque Tm2 is set as the target motor torque Tm. , the electric motor 18 is controlled (automatic steering control).

FIG. 3 is a block diagram showing the configuration of the target automatic steering torque setting section 42. As shown in FIG.
A target automatic steering torque setting unit 42 calculates a target automatic steering torque Tm2 based on the target steering angle θcmda. The target automatic steering torque setting unit 42 includes a low-pass filter (LPF) 61, a feedback control unit 62, a feedforward control unit 63, a disturbance torque estimation unit 64, a torque addition unit 65, and a first reduction ratio division unit. 66 , a reduction ratio multiplication unit 67 , a rotation angle calculation unit 68 , and a second reduction ratio division unit 69 . Hereinafter, the target automatic steering torque Tm2 calculated by the target automatic steering torque setting unit 42 may be referred to as "target automatic steering torque Tm" for convenience of explanation.

The reduction ratio multiplication unit 67 multiplies the target automatic steering torque Tm (Tm2) calculated by the first reduction ratio division unit 66 by the reduction ratio N of the reduction gear 19, thereby outputting the target automatic steering torque Tm to the output shaft 9. (Worm wheel 21) is converted into torque N·Tm.
The rotation angle calculator 68 calculates the rotor rotation angle θm of the electric motor 18 based on the output signal of the rotation angle sensor 23 . A second reduction ratio division unit 69 divides the rotor rotation angle θm calculated by the rotation angle calculation unit 68 by the reduction ratio N to obtain the rotor rotation angle θm as the rotation angle (actual steering angle) of the output shaft 9 . Convert to θ. In the embodiment of FIG. 1, the rotation angle (steering angle) of the output shaft 9 is called "rudder angle".

The low-pass filter 61 performs low-pass filtering on the target steering angle θcmda given from the automatic driving control ECU 201 . The target rudder angle θcmd after low-pass filtering is applied to feedback control section 62 and feedforward control section 63 .
The feedback control section 62 is provided to bring the estimated steering angle value ̂θ calculated by the disturbance torque estimating section 64 closer to the target steering angle θcmd after the low-pass filter processing. The feedback controller 62 includes an angular deviation calculator 62A and a PD controller 62B. The angular deviation calculator 62A calculates a deviation Δθ (=θcmd−̂θ) between the low-pass filtered target steering angle θcmd and the estimated steering angle ^θ calculated by the disturbance torque estimator 64 . The angle deviation calculation unit 62A calculates the deviation (θcmd−θ) between the target steering angle θcmd after low-pass filtering and the actual steering angle θ calculated by the second reduction ratio division unit 69 as the angle deviation Δθ. You may make it calculate.

The PD control section 62B calculates the feedback control torque Tfb by performing a PD calculation (proportional differential calculation) on the angular deviation Δθ calculated by the angular deviation calculating section 62A. Feedback control torque Tfb is applied to torque addition section 65 .
The feedforward control section 63 is provided to compensate for the response delay due to the inertia of the electric power steering system 1 and improve the control response. Feedforward control section 63 includes an angular acceleration calculation section 63A and an inertia multiplication section 63B. The angular acceleration calculator 63A calculates a target angular acceleration d ² θcmd/dt ² by second-order differentiation of the low-pass filtered target steering angle θcmd. The inertia multiplier 63B multiplies the target angular acceleration d ² θcmd/dt ² calculated by the angular acceleration calculator 63A by the inertia J of the electric power steering system 1 to obtain the feedforward torque Tff (=J·d ² θcmd/dt ² ). The inertia J is obtained, for example, from a physical model (see FIG. 4) of the electric power steering system 1, which will be described later. Feedforward torque Tff is given to torque addition section 65 as an inertia compensation value.

The disturbance torque estimator 64 is provided for estimating and compensating for non-linear torque (disturbance torque: torque other than motor torque) generated as disturbance in the plant (controlled object (motor driven object)). A disturbance torque estimation unit 64 calculates a disturbance torque (disturbance load) Tld, an actual steering angle θ and steering angle differential value (angular velocity) dθ/dt are estimated. Estimated values of disturbance torque Tld, actual steering angle θ, and steering angle differential value (angular velocity) dθ/dt are represented by ̂Tld, ̂θ, and d̂θ/dt, respectively. The disturbance torque estimated value ̂Tld calculated by the disturbance torque estimator 64 is given to the torque adder 65 as a disturbance torque compensation value. The steering angle estimated value ^θ calculated by the disturbance torque estimator 64 is provided to the angle deviation calculator 62A. Details of the disturbance torque estimator 64 will be described later.

Torque adding section 65 calculates target steering torque Tcmd (=Tfb+Tff-^Tld) by subtracting disturbance torque estimated value ̂Tld from a value obtained by adding feedforward torque Tff to feedback control torque Tfb. As a result, the target steering torque (target torque for the output shaft 9) with inertia and disturbance torque compensated is obtained. As a result, highly accurate motor control (steering angle control) can be performed. In this embodiment, the value obtained by adding the feedforward torque Tff to the feedback control torque Tfb is the basic target torque.

Target steering torque Tcmd is provided to first reduction gear ratio division unit 66 . A first speed reduction ratio division unit 66 divides the target steering torque Tcmd by the speed reduction ratio N to calculate a target automatic steering torque Tm (Tm2). This target automatic steering torque Tm (Tm2) is applied to the mode switching section 43 (see FIG. 2).
The disturbance torque estimator 64 will be described in detail. The disturbance torque estimator 64 is composed of a disturbance observer that uses a physical model of the electric power steering system 1 to calculate a disturbance torque estimate ̂Tld, a steering angle estimate ̂θ, and an angular velocity estimate d̂θ/dt. ing.

FIG. 4 is a schematic diagram showing a configuration example of a physical model of the electric power steering system 1. As shown in FIG.
This physical model 71 includes a steering column (plant) 72 including an output shaft 9 and a worm wheel 21 fixed to the output shaft 9 . The steering column 72 is supplied with a steering-side disturbance torque Td from the steering wheel 2 via the torsion bar 10, and is also supplied with a road surface reaction torque Tls from the steered wheel 3 side. Further, the steering column 72 is given a motor torque N·Tm via the worm gear 20 and a friction torque Tf due to friction between the worm wheel 21 and the worm gear 20 .

Assuming that the inertia of the steering column 72 is J, the equation of motion for the inertia of the physical model 71 is expressed by the following equation (1).

d ² θ/dt ² is the acceleration of steering column 72 . N is the speed reduction ratio of the speed reducer 19 . Tld indicates disturbance torque other than the motor torque applied to the steering column 72 . Here, disturbance torque Tld is shown as the sum of steering-side disturbance torque Td, friction torque Tf, and road surface reaction torque Tls, but in reality, disturbance torque Tld includes torques other than these.

A state equation for the physical model 71 of FIG. 4 is represented by the following equation (2).

In the above equation (2), x is a state variable vector. In equation (2) above, u1 is a known input vector. In Equation (2) above, u2 is an unknown input vector. In the above equation (2), y is the output vector (measured value). In equation (2) above, A is a system matrix. In equation (2), B1 is the first input matrix. In equation (2) above, B2 is the second input matrix. In equation (2) above, C is the output matrix. In the above equation (2), D is a feedthrough matrix.

The above state equation is extended to a system including the unknown input vector u2 as one of the states. The state equation of the extended system (extended state equation) is represented by the following equation (3).

In the above equation (3), xe is a state variable vector of the extended system and is represented by the following equation (4).

In the above equation (3), Ae is the extended system matrix. In the above equation (3), Be is the known input matrix of the extended system. In the above equation (3), Ce is the output matrix of the extended system.
A disturbance observer (extended state observer) represented by the following equation (5) is constructed from the extended state equation of equation (3).

In equation (5), ̂xe represents the estimated value of xe. Also, L is an observer gain. Also, ^y represents the estimated value of y. ^xe is represented by the following equation (6).

^θ is an estimate of θ, and ^Tld is an estimate of Tld.
The disturbance torque estimator 64 calculates the state variable vector ̂xe based on the equation (5).
FIG. 5 is a block diagram showing the configuration of the disturbance torque estimator 64. As shown in FIG.
The disturbance torque estimation unit 64 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 It includes an addition section 87 , an integration section 88 and a state variable vector output section 89 .

The target steering torque N·Tm calculated by the reduction ratio multiplication section 67 (see FIG. 3) is given to the input vector input section 81 . The input vector input unit 81 outputs an input vector u1.
The output of the integrator 88 is the state variable vector ̂xe (see equation (6) above). At the start of computation, an initial value is given as the state variable vector ̂xe. The initial value of the state variable vector ̂xe is 0, for example.

A system matrix multiplier 86 multiplies the state variable vector ̂xe by the system matrix Ae. The output matrix multiplier 82 multiplies the state variable vector ̂xe by the output matrix Ce.
The first adder 83 calculates the output (Ce·^ xe). That is, the first adder 83 calculates the difference (y−̂y) between the output vector y and the output vector estimated value ̂y (=Ce·̂xe). The gain multiplier 84 multiplies the output (y−̂y) of the first adder 83 by the observer gain L (see the above equation (5)).

The input matrix multiplication unit 85 multiplies the input vector u1 output from the input vector input unit 81 by the input matrix Be. The second adder 87 outputs the output (Be·u1) of the input matrix multiplier 85, the output (Ae·̂xe) of the system matrix multiplier 86, and the output of the gain multiplier 84 (L(y−̂y) ) to calculate the differential value d^xe/dt of the state variable vector. The integrator 88 calculates the state variable vector ̂xe by integrating the output (d̂xe/dt) of the second adder 87 . A state variable vector output unit 89 calculates an estimated disturbance load value ̂Tld, an estimated steering angle value ̂θ, and an estimated angular velocity value d̂θ/dt based on the state variable vector ̂xe.

A general disturbance observer consists of an inverse model of the plant and a low-pass filter, unlike the extended state observer described above. The equation of motion of the plant is expressed by the following equation (7).

Therefore, the inverse model of the plant is the following equation (8).

Inputs to a general disturbance observer are J·d ² θ/dt ² and Tm. On the other hand, in the extended state observer of the above-described embodiment, in accordance with the difference (y−^y) between the steering angle estimated value ̂θ estimated from the motor torque input and the actual steering angle θ, the disturbance is integrated. Since the torque is estimated, the noise effect due to differentiation can be reduced.

Although one embodiment of the present invention has been described above, the present invention can also be implemented in other forms. For example, in the above-described embodiment, the present invention is applied to automatic steering control of a column-type EPS, but the present invention can also be applied to automatic steering control of EPSs other than column-type EPS.
For example, the motor control device according to the present invention can also be applied to automatic steering control of a dual pinion type electric power steering system as shown in FIG.

In FIG. 6, parts corresponding to those in FIG. 1 are denoted by the same reference numerals as in FIG. The electric power steering system 1A of FIG. 6 is a dual pinion type electric power steering system. In this electric power steering system 1A, a pinion 16 (hereinafter referred to as "first pinion 16") of a pinion shaft 13 (hereinafter referred to as "first pinion shaft 13") is provided on the first end side of the rack shaft 14 in the axial direction. ) is formed (hereinafter referred to as “first rack 17”). When the steering wheel 2 is steered (rotated), this rotation is transmitted to the first pinion shaft 13 via the steering shaft 6 and the intermediate shaft 7 . The rotation of the first pinion shaft 13 is converted into axial movement of the rack shaft 14 by the first pinion 16 and the first rack 17 . As a result, the steerable wheels 3 are steered.

The steering assist mechanism 5 includes an electric motor 18 , a reduction gear 19 , a second pinion shaft 91 , a second pinion 92 and a second rack 93 . The second pinion shaft 91 is arranged separately from the steering shaft 6 . The speed reducer 19 includes a worm gear (not shown) that is integrally rotatably connected to the output shaft of the electric motor 18, and a worm wheel that meshes with the worm gear and is integrally rotatably connected to the second pinion shaft 91. (not shown). The second pinion 92 is connected to the tip of the second pinion shaft 91 . The second rack 93 is formed on the side of the second end opposite to the first end in the axial direction of the rack shaft 14 . The second pinion 92 meshes with the second rack 93 . The electric motor 18 is provided with a rotation angle sensor 23 for detecting the rotation angle of its rotor.

When the electric motor 18 is rotationally driven, the rotation of the electric motor 18 is transmitted to the second pinion shaft 91 via the reduction gear 19 . Rotation of the second pinion shaft 91 is converted into axial movement of the rack shaft 14 by the second pinion 92 and the second rack 93 . As a result, the steerable wheels 3 are steered.
The electrical configuration of the steering control ECU 202 in FIG. 6 is the same as the electrical configuration of the steering control ECU 202 in FIG. 1 (see FIG. 2). However, in the electric power steering system 1</b>A of FIG. 6 , the plant (motor driven object) is composed of the second pinion shaft 91 and the worm wheel fixed to the second pinion shaft 91 . As the speed reduction ratio N, the speed reduction ratio of the speed reducer 19 in FIG. 6 is used.

Further, the motor control device according to the present invention can also be applied to a steering motor control device for a steer-by-wire system as shown in FIG. In FIG. 7, parts corresponding to those in FIG. 1 are denoted by the same reference numerals as in FIG.
The steer-by-wire system 1</b>B includes a steering wheel 2 , a steering mechanism 4 for steering steerable wheels 3 , and a steering shaft 6 connected to the steering wheel 2 . However, the steering shaft 6 is not mechanically connected to the steering mechanism 4 .

The steering shaft 6 includes an input shaft 8 connected to the steering wheel 2 , a torsion bar 10 connected to the input shaft 8 and an output shaft 9 connected to the torsion bar 10 . A reaction motor 122 is connected to the output shaft 9 via a reduction gear 121 . The reaction force motor 122 is an electric motor for applying a steering reaction force (torque in the direction opposite to the steering direction) to the steering wheel 2 . The speed reducer 121 includes a worm shaft (not shown) that is integrally rotatably connected to the output shaft of the reaction motor 122, and a worm that meshes with the worm shaft and is integrally rotatably connected to the output shaft 9. It consists of a worm gear mechanism including a wheel (not shown). The reaction motor 122 is provided with a rotation angle sensor 123 for detecting the rotation angle of the reaction motor 122 .

The steering mechanism 4 includes a rack shaft 14 as a steering shaft and a steering actuator 130 for applying a steering force to the rack shaft 14 . The steered wheels 3 are connected to each end of the rack shaft 14 via tie rods 15 and knuckle arms (not shown).
The steering actuator 130 has a configuration similar to that of the steering assist mechanism 5 of FIG. That is, the steering actuator 130 includes the steering motor 18 , the reduction gear 19 , the pinion shaft 91 , the pinion 92 and the rack 93 . The pinion shaft 91 is arranged separately from the steering shaft 6 . The speed reducer 19 includes a worm shaft (not shown) that is integrally rotatably connected to the output shaft of the steering motor 18, and a worm that meshes with the worm shaft and is integrally rotatably connected to the pinion shaft 91. It consists of a worm gear mechanism including a wheel (not shown).

The pinion 92 is connected to the tip of the pinion shaft 91 . The rack 93 is provided at the end of the rack shaft 14 . The pinion 92 meshes with the rack 93 . The steering motor 18 is provided with a rotation angle sensor 23 for detecting the rotation angle of the steering motor 18 .
The automatic driving control ECU 201 calculates a target steering angle (target steering angle) θcmda for automatic steering, and a mode switching signal (automatic steering mode setting signal or automatic steering mode setting signal) according to the operation of the automatic steering mode switch 29 . release signal). The target steering angle θcmda calculated by the automatic driving control ECU 201 and the mode switching signal generated by the automatic driving control ECU 201 are provided to the steering control ECU 203 . The output signals of the rotation angle sensors 23 and 123 and the vehicle speed V detected by the vehicle speed sensor 24 are input to the steering control ECU 203 . The steering control ECU 203 controls the reaction force motor 122 and the steering motor 18 based on these input signals and the information given from the automatic driving control ECU 201 . That is, the steering control ECU 203 includes a motor control circuit for the reaction force motor 122 and a motor control circuit for the steering motor 18 .

The motor control circuit of the reaction force motor 122 is controlled by a reaction force motor control unit (not shown) configured by a microcomputer and a reaction force motor control unit, and is controlled by a drive circuit (not shown) that supplies power to the reaction force motor 122. ) and a current detector (not shown) for detecting the motor current flowing through the reaction motor 122 . The reaction force motor control unit, for example, determines the target steering angle based on the steering angle θh (rotation angle of the steering wheel 2) calculated based on the output of the rotation angle sensor 123 and the vehicle speed V detected by the vehicle speed sensor 24. set. Then, the drive circuit of the reaction force motor 122 is controlled so that the steering angle θh becomes equal to the target steering angle.

FIG. 8 shows a motor control circuit for the steering motor 18. As shown in FIG.
A motor control circuit of the steering motor 18 is controlled by a steering motor control unit 141 configured by a microcomputer and a driving circuit (inverter circuit) 142 that supplies power to the steering motor 18 . and a current detection circuit 143 for detecting the motor current flowing through the steering motor 18 .

The steering motor control unit 141 includes a target steering angle setting unit 151, a mode switching unit 152, a target motor torque calculation unit 153, a target motor current calculation unit 154, a current deviation calculation unit 155, and a PI control unit 156. , and the PWM control unit 157 .
The target steering angle setting unit 151 calculates the target steering angle for the manual steering mode based on the steering angle θh calculated based on the output of the rotation angle sensor 123 and the vehicle speed V detected by the vehicle speed sensor 24, for example. Then, from this target steering angle, a target steering angle θcmdb, which is a target value of the steering angle of the steerable wheels 3 (for example, the rotation angle of the pinion shaft 91) for the manual steering mode, is set. This target steering angle θcmdb is given to mode switching section 152 .

The mode switching unit 152 is supplied with the target steering angle θcmda calculated by the automatic operation control ECU 201 . The mode switching unit 152 switches the control mode based on a mode switching signal given from the ECU 201 for automatic operation control. When the control mode is set to the manual steering mode, the mode switching unit 152 outputs the target steering angle θcmdb set by the target steering angle setting unit 151 as the target steering angle θcmdc. When the control mode is set to the automatic steering mode, the mode switching unit 152 outputs the target steering angle θcmda set by the automatic driving control ECU 201 as the target steering angle θcmdc.

The target motor torque calculation unit 153 calculates a target motor torque Tm, which is a target value of the motor torque of the steering motor 18, based on the target steering angle θcmdc output from the mode switching unit 152. The configuration of the target motor torque calculation unit 153 is the same as the configuration of the target automatic steering torque setting unit 42 in FIG. As the speed reduction ratio N, the speed reduction ratio of the speed reducer 19 in the steering actuator 130 is used.

The target motor current calculator 154 calculates the target motor current Icmd by dividing the target motor torque Tm set by the target motor torque calculator 153 by the torque constant Kt of the steering motor 18 . A current deviation calculator 155 calculates a deviation ΔI (=Icmd−I) between the target motor current Icmd obtained by the target motor current calculator 154 and the motor current I detected by the current detection circuit 143 .

The PI control unit 156 performs PI calculation (proportional integral calculation) on the current deviation ΔI calculated by the current deviation calculation unit 155, thereby driving the motor current I flowing through the steering motor 18 to the target motor current Icmd. Generate a command value. The PWM control unit 157 generates a PWM control signal having a duty ratio corresponding to the drive command value, and supplies it to the drive circuit 142 . As a result, electric power corresponding to the drive command value is supplied to the steering motor 18 . Thereby, the steering motor 18 is controlled such that the motor torque corresponding to the target motor torque Tm is generated from the steering motor 18 . As a result, in the manual steering mode, the steering angle of the steerable wheels 3 is controlled so as to approach the target steering angle θcmdb set by the target steering angle setting section 151 . On the other hand, in the automatic steering mode, the steering angle of the steered wheels 3 is controlled so as to approach the target steering angle θcmda set by the ECU 201 for controlling automatic driving.

Further, the motor control device according to the present invention can also be applied to steering angle control of a rear wheel steering system. Further, the motor control device according to the present invention can be applied not only to steering angle control, but also to control of an electric motor used for steering system control (for example, angle control of a steering wheel, etc.).
Furthermore, the present invention can also be applied when controlling an electric motor by feedback control other than angle feedback control.

In the above embodiment, the target automatic steering torque setting section 42 and the target motor torque calculating section 153 are provided with the feedforward control section 63, but the feedforward control section 63 may be omitted. In this case, the feedback control torque Tfb calculated by the feedback control section 62 becomes the basic target torque.
In all of the above-described embodiments, the disturbance torque estimator 64 estimates the disturbance torque _Tld based on the target motor torque (target automatic steering torque Tm2) and the actual steering angle θ (plant rotation angle θ). However, a motor torque acquisition unit that acquires the motor torque generated by the electric motor 18 may be provided, and the motor torque acquired by this motor torque acquisition unit may be used instead of the target motor torque Tm2.

FIG. 9 is a block diagram showing a modification of the target automatic steering torque setting section 42 shown in FIG. In FIG. 9, the same reference numerals as in FIG. 3 denote the parts corresponding to the parts in FIG. 3 described above.
The target automatic steering torque setting section 42A differs from the target automatic steering torque setting section 42 shown in FIG. 3 in that a damping torque calculation section 160 is provided. The damping torque calculator 160 calculates a damping torque for suppressing vibration of the steering wheel 2 in the automatic control mode. The damping torque calculation section 160 is composed of a multiplication section 161 in this modification. The multiplication unit 161 multiplies the steering wheel inertia torque (hereinafter referred to as steering torque) during automatic driving (in the hands-free state) detected by the torque sensor 12 by a preset damping gain K _R (K _R >1). , damping torque _KR ·Td.

FIG. 9 more specifically shows the configuration of the PD control unit 62B. s is the differential operator. In FIG. 9, the PD control section 62B includes a proportional gain multiplication section 171, a differential operation section 172, a differential gain multiplication section 173, and an addition section 174. The proportional gain multiplier 171 multiplies the angular deviation Δθ (=θcmd−̂θ) calculated by the angular deviation calculator 62A by the proportional gain _KP .

The differential calculator 172 calculates a time differential value dΔθ/dt of the angular deviation Δθ. The differential gain multiplier 173 multiplies the differential value _dΔθ /dt calculated by the differential calculator 172 by the differential gain KD. Addition unit 174 adds the multiplication result _KP ·Δθ of proportional gain multiplication unit 171 and the multiplication result KD· _dΔθ /dt of differential gain multiplication unit 173 to calculate feedback control torque Tfb.

Torque adding section 65 subtracts estimated disturbance torque Tld from the sum of feedback control torque Tfb, feedforward torque _Tff , and damping torque (KR·Td) to obtain target steering torque Tcmd (= Tfb+ _Tff +KR·Td−̂Tld). In this embodiment, the value obtained by adding the feedforward torque Tff to the feedback control torque Tfb is the basic target torque.

Target steering torque Tcmd is provided to first reduction gear ratio division unit 66 . A first speed reduction ratio division unit 66 divides the target steering torque Tcmd by the speed reduction ratio N to calculate a target automatic steering torque Tm (Tm2). This target automatic steering torque Tm (Tm2) is applied to the mode switching section 43 (see FIG. 2).
In the target automatic steering torque setting section 42A, similarly to the target automatic steering torque setting section 42 described above, non-linear disturbance torque (torque other than motor torque) generated as a disturbance in the steering column is compensated. Therefore, as shown in FIG. 10A, the electric power steering system 1 in the automatic control mode is handled as a two-inertia model (inertia _JSW of the steering wheel 2 and inertia _JC of the steering column 181) that does not depend on disturbance torque. becomes possible. Steering column 181 includes output shaft 9 and worm wheel 21 .

In FIG. 10A, 10 indicates a torsion bar. In FIG. 10A, θ (actual steering angle θ) is the rotation angle of steering column 181 (hereinafter referred to as column angle θ), and θ _SW is the rotation angle of steering wheel 2 (hereinafter referred to as steering angle θ _SW ). be. In FIG. 10A, _Ktb is the rigidity of the torsion bar 10 (hereinafter referred to as torsion bar rigidity _Ktb ), Td is steering torque (torsion bar torque), and _KR ·Td is damping torque. , N is the speed reduction ratio of the speed reducer 19, and Tm is the target motor torque. Hereinafter, the inertia _JSW of the steering wheel 2 may be referred to as steering inertia _JSW , and the inertia _JC of the steering column 181 may be referred to as column inertia _JC .

FIG. 11 is a control block diagram showing the configuration of the feedback control system of the electric power steering system in the automatic driving mode. However, for convenience of explanation, the steering angle fed back to the feedback control section is not the steering angle estimated value ^θ calculated by the disturbance torque estimating section 64, but the actual steering angle calculated by the second reduction ratio division section 69. θ (column angle θ).

A feedback control torque Tfb is generated by PD control for the deviation between the target steering angle θcmd after low-pass filtering and the column angle θ. A damping torque (K _R ·Td) is added to the feedback control torque Tfb. This added value ( _Tfb +KR·Td) represents the angular acceleration of the column angle θ (hereinafter referred to as column angular acceleration d ² θ/dt ² ).
A motor torque N·Tm corresponding to a value obtained by multiplying the column angular acceleration d ² θ/dt ² by the column inertia J _C is applied from the electric motor 18 to the steering column 181 (see FIG. 10A). This motor torque N·Tm is multiplied by the reciprocal of the column inertia _JC , and a value obtained by second-order integration of the multiplication result is fed back as the column angle θ.

The steering torque Td is obtained by multiplying the difference between the column angle θ and the steering angle _θSW by the torsion bar stiffness _Ktb . A value obtained by multiplying this steering torque _Td by a damping gain KR is fed back as a damping torque. The steering torque Td is multiplied by the reciprocal of the steering inertia _JSW , and the result of the multiplication is second-order integrated, which is fed back as the steering angle _θSW .

The target automatic steering torque setting unit 42A in FIG. 9 is provided with the damping torque calculation unit 160, so that the vibration of the steering wheel 2 can be suppressed in the automatic control mode. Specifically, it is possible to suppress the torsional vibration generated by the torsion bar 10 and the steering inertia _JSW in the automatic control mode. This point will be described more specifically.
In the two-inertia model shown in FIG. 10A, if the damping torque K _R ·Td is not fed back, the resonance frequency ωr and the anti-resonance frequency ωa are expressed by the following equations (9) and (10), respectively.

ωr=[K _tb ·{(1/J _SW )+1}] ^1/2 (9)
ωa={K _tb ·(1/J _SW )} ^1/2 (10)
In the target automatic steering torque setting unit 42A of FIG. 9, the damping torque _KR ·Td is fed back, so the column inertia _JC can be virtually reduced to 1/ _KR . That is, the model shown in FIG. 10A is equivalent to the model shown in FIG. 10B. Therefore, the resonance frequency ωr of the two-inertia model shown in FIG. 10A is given by the following equation (11).

ωr=[K _tb ·{(1/J _SW )+K _R }] ^1/2 (11)
As a result, the resonance frequency ωr can be increased, so vibrations during the automatic steering mode can be suppressed.
A method of setting the proportional gain K _P , the differential gain K _D and the damping gain K _R will be described below. These gains are set to values that achieve both stability and responsiveness using the transfer coefficient from the target steering angle _θcmd to the steering angle θSW shown in FIG. Specifically, using the anti-resonance frequency ωa of the formula (10), the proportional gain K _P , the differential gain K _D and the damping gain K _R are set to the values shown by the following formulas (12) to (14). set.

K _P =ωa ² (12)
K _D = 4ωa (13)
_KR = 4/ _JSW (14)
As the damping torque calculation unit 160, any one other than the damping torque calculation unit 160 described in FIG. can be anything.

The feedforward control section 63 may be omitted from the target automatic steering torque setting section 42A of FIG. In that case, the basic target torque consists only of the feedback control torque Tfb.
In addition, the present invention can be modified in various ways within the scope of the claims.

DESCRIPTION OF SYMBOLS 1, 1A... Electric power steering apparatus 1B... Steer-by-wire system 3... Steerable wheel 4... Steering mechanism 18... Electric motor 42, 42A... Target automatic steering torque setting part 61... Low-pass filter (LPF), 62 Feedback control unit 63 Feedforward control unit 64 Disturbance torque estimation unit (disturbance observer) 65 Torque addition unit 151 Target steering angle setting unit 153 Target motor torque calculation unit 160 Damping Torque calculation unit 161 Damping gain multiplication unit 171 Proportional gain multiplication unit 172 Differential calculation unit 173 Differential gain multiplication unit 174 Addition unit 201 Automatic driving control ECU 202, 203 Steering ECU for control

Claims (8)

A motor control device for controlling an electric motor for driving a plant,
rotation angle detection means for detecting the rotation angle of the electric motor;
target motor torque setting means for setting a target motor torque, which is a target value of the motor torque of the electric motor;
control means for feedback-controlling the motor torque of the electric motor based on the target motor torque set by the target motor torque setting means;
The target motor torque setting means includes:
basic target torque setting means for setting a basic target torque;
The electric motor acting on the plant based on the target motor torque set by the target motor torque setting means or the motor torque generated by the electric motor and the rotation angle detected by the rotation angle detection means. a disturbance observer that estimates a disturbance torque other than the motor torque of
disturbance torque compensating means for correcting the basic target torque set by the basic target torque setting means with the disturbance torque estimated by the disturbance observer;
target motor torque calculation means for calculating the target motor torque based on the basic target torque corrected by the disturbance torque compensation means ;
The electric motor is an electric motor used for steering system control of a vehicle,
motor controller. The disturbance observer detects the disturbance torque based on the target motor torque set by the target motor torque setting means or the motor torque generated by the electric motor and the rotation angle detected by the rotation angle detection means. and configured to estimate a rotation angle of the plant,
The basic target torque setting means includes:
angle deviation calculation means for calculating a difference between a target rotation angle, which is a target value of the rotation angle of the plant, and the rotation angle of the plant estimated by the disturbance observer;
2. The motor control device according to claim 1, further comprising basic target torque computing means for computing said basic target torque by performing a predetermined feedback computation on the angular deviation computed by said angular deviation computing means. The disturbance observer detects the disturbance torque based on the target motor torque set by the target motor torque setting means or the motor torque generated by the electric motor and the rotation angle detected by the rotation angle detection means. and configured to estimate a rotation angle of the plant,
The basic target torque setting means includes:
angle deviation calculation means for calculating a difference between a target rotation angle, which is a target value of the rotation angle of the plant, and the rotation angle of the plant estimated by the disturbance observer;
feedback control torque calculation means for calculating a feedback control torque by performing a predetermined feedback calculation on the angular deviation calculated by the angular deviation calculation means;
feedforward control torque calculation means for calculating the feedforward control torque by multiplying the moment of inertia of the plant by the second derivative of the target rotation angle;
2. The motor control device according to claim 1, further comprising basic target torque calculation means for calculating said basic target torque by adding said feedforward control torque to said feedback control torque. The basic target torque setting means includes:
angle deviation calculation means for calculating a difference between a target rotation angle, which is a target value of the rotation angle of the plant, and the rotation angle of the plant calculated from the rotation angle detected by the rotation angle detection means;
2. The motor control device according to claim 1, further comprising basic target torque computing means for computing said basic target torque by performing a predetermined feedback computation on the angular deviation computed by said angular deviation computing means. The basic target torque setting means includes:
angle deviation calculation means for calculating a difference between a target rotation angle, which is a target value of the rotation angle of the plant, and the rotation angle of the plant calculated from the rotation angle detected by the rotation angle detection means;
feedback control torque calculation means for calculating a feedback control torque by performing a predetermined feedback calculation on the angular deviation calculated by the angular deviation calculation means;
feedforward control torque calculation means for calculating the feedforward control torque by multiplying the moment of inertia of the plant by the second derivative of the target rotation angle;
2. The motor control device according to claim 1, further comprising basic target torque calculation means for calculating said basic target torque by adding said feedforward control torque to said feedback control torque. A motor control device that controls an electric motor that applies a steering force to a steering column that is connected to a steering wheel via a torsion bar,
rotation angle detection means for detecting the rotation angle of the electric motor;
target motor torque setting means for setting a target motor torque, which is a target value of the motor torque of the electric motor;
a control means for feedback-controlling the motor torque of the electric motor based on the target motor torque;
The target motor torque setting means includes:
basic target torque setting means for setting a basic target torque;
a disturbance observer for estimating a disturbance torque other than the motor torque of the electric motor acting on the steering column based on the target motor torque or the motor torque generated by the electric motor and the rotation angle;
damping torque computing means for computing a damping torque for suppressing vibration of the steering wheel;
correction means for correcting the basic target torque set by the basic target torque setting means by using the disturbance torque and the damping torque;
a target motor torque calculation means for calculating the target motor torque based on the basic target torque corrected by the correction means. including steering torque detection means for detecting steering torque applied to the steering wheel;
The damping torque calculation means is configured to calculate a damping torque by multiplying the steering torque by a predetermined damping gain,
The basic target torque setting means includes:
Rotation of the steering column calculated from a target rotation angle, which is a target value of the rotation angle of the steering column, and the rotation angle of the steering column estimated by the disturbance observer or the rotation angle detected by the rotation angle detection means. angle deviation calculation means for calculating the difference from the angle;
7. The motor control device according to claim 6 , further comprising feedback control torque calculation means for calculating feedback control torque by performing a proportional differential calculation on the angular deviation calculated by said angular deviation calculation means. Let K _P and K _D be the proportional gain and K D, respectively, the damping gain be K _R , the stiffness of the torsion bar be K _tb , the inertia of the steering wheel be J _SW , and When the anti-resonance frequency ωa of the steering wheel and the steering column is represented by the following equation (a),
8. The motor control device according to claim 7 , wherein said proportional gain K _P , said differential gain K _D and said damping gain K _R are represented by the following equations (b) to (d).
ωa={K _tb ·(1/J _SW )} ^1/2 (a)
K _P =ωa ² (b)
KD= _4ωa (c)
K _R =4/J _SW (d)

Images