JP2008048545A - Position control device and position control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position control device and a position control method capable of suppressing vibration even when the vibration frequency changes depending on the position of a machine.
A position provided with a motor speed control unit (13) for matching a speed command and a motor speed signal by feedback control, and a motor position control unit (12) for matching a position command and a motor position signal by feedback control. In the control device, a damping signal calculation unit (18) that calculates a damping signal from the torque command and the motor speed, a proportional compensator, an integral compensator, a high-pass filter, and a low-pass filter of the damping signal calculation unit based on the motor position signal And a gain switching unit (19) for switching the gain of the filter.
[Selection] Figure 1

Description

  The present invention relates to a position control device including a compensation unit that suppresses vibrations generated from a mechanism driven by a motor.

A conventional position control device suppresses vibration by estimating a motor speed with an observer and feeding back a difference signal between the actual motor speed and the estimated speed (see, for example, Patent Document 1).
In FIG. 3, 21 is a subtractor that subtracts the motor position signal Pfbm from the position command Pref and outputs a position deviation signal, 22 is a position controller that receives the position deviation signal and outputs a speed command Vref, and 23 is a speed command Vref. A subtractor that subtracts the motor speed signal Vfbm and outputs a speed deviation signal, 24 is a speed controller that receives the speed deviation signal and outputs a torque command Tref, and 25 is an input of the torque command Tref and the motor speed Vfbm to obtain an estimated speed. An observer that calculates and outputs a difference signal obtained by subtracting the estimated speed from the motor speed. The observer is a proportional compensator 33 that performs proportional compensation, an integral compensator 34 that performs integral compensation, an inertia model 37 that receives a torque command, an estimated acceleration signal that is generated by the inertia model, and a first compensation that is generated by the proportional compensator. An adder 36 for adding the signal and the second compensation signal generated by the integral compensator; an integrator 38 for integrating the addition result to generate an estimated speed signal; and a proportional compensator by subtracting the estimated speed signal from the motor speed signal. And a subtractor 35 for inputting to the integral compensator. 26 is a high-pass filter that receives the observer output signal and advances the phase, and 27 outputs a low-pass filter that cuts and outputs the high-frequency component of the output signal of the high-pass filter. 28 is a coefficient as a damping gain for the output of the low-pass filter. A coefficient unit that multiplies α and outputs a damping signal, and 30 is an adder that adds the damping signal to the speed command and outputs a new speed command Vref.
JP-A-9-56183

The conventional position control device adjusts the gain of the observer's proportional compensator, integral compensator, high-pass filter, and low-pass filter according to the machine's vibration frequency, so the vibration frequency changes depending on the machine position. In this case, there is a problem that vibration cannot be suppressed at a position where the vibration frequency does not match.
The present invention has been made in view of such problems, and an object thereof is to provide a position control device capable of suppressing vibration even when the vibration frequency changes depending on the position of the machine.

In order to solve the above problem, the present invention is configured as follows.
According to the first aspect of the present invention, a position control unit that generates a speed command by controlling a position deviation between the position command and the position signal, and a torque command is generated by controlling the speed deviation between the speed command and the speed signal. A speed control unit that drives the motor based on the torque command, a vibration suppression signal calculation unit that generates a vibration suppression signal from the torque command and the speed signal, and the vibration control signal as the speed command. In the position control device, the damping signal calculation unit includes an observer that generates a first damping signal from the torque command and the speed signal, and a phase of the first damping signal. The high-pass filter for generating the second damping signal, the low-pass filter for removing the high frequency component of the second damping signal and generating the third damping signal, and adjusting the gain of the third damping signal Generate vibration signal The number unit, is characterized in that and a gain switcher for switching the gain of the low-pass filter and the observer and the high-pass filter from said position signal.
According to a second aspect of the present invention, in the position control device according to the first aspect, the observer generates an estimated velocity signal by integrating an inertia model that generates an estimated acceleration signal from the torque command and the estimated acceleration signal. An integrator for generating a first compensation signal by multiplying a difference between the speed signal and the estimated speed signal by a proportionality constant; an integration compensator for generating a second compensation signal by performing integral compensation; An adder that adds the first compensation signal, the second compensation signal, and the estimated acceleration signal to obtain a new estimated acceleration signal is provided.
According to a third aspect of the present invention, in the position control device according to the first aspect, the gain switch measures in advance a gain that minimizes vibration according to the position signal, and stores the gain. A table is provided.
According to a fourth aspect of the present invention, in the position control device according to the first aspect, the position signal is generated from a position detector coupled to a motor.
A fifth aspect of the present invention is the position control apparatus according to the first aspect, wherein the position signal is generated from a position detector coupled to a load.
According to a sixth aspect of the present invention, in the position control apparatus according to the first aspect, the speed signal is generated from a time difference of a position signal of a position detector coupled to a motor.
According to a seventh aspect of the present invention, a position control unit that generates a speed command by controlling a position deviation between a position command and a position signal, and generates a torque command by controlling a speed deviation between the speed command and the speed signal A speed control unit that drives the motor based on the torque command, a vibration suppression signal calculation unit that generates a vibration suppression signal from the torque command and the speed signal, and the vibration control signal as the speed command. In the position control method of the position control device comprising: Accordingly, the step of reading out the gains of the low-pass filter, high-pass filter and observer from the table, and the estimated acceleration signal from the torque command A step of adding and integrating the estimated acceleration signal, the first compensation signal and the second compensation signal to generate an estimated speed signal; and subtracting the speed signal and the estimated speed signal to obtain a first damping Generating a signal, multiplying the first damping signal by an observer proportional gain to generate the first compensation signal, multiplying the first damping signal by a previous observer integral and integrating the second compensation signal Generating a second damping signal by passing the first damping signal through a high-pass filter, and generating a third damping signal by passing the second damping signal through a low-pass filter. And a step of multiplying the third damping signal by a coefficient to generate the damping signal, and a step of adding the torque command and the damping signal to generate a new torque command. It is an.

According to the present invention, since the gain of the proportional compensator, the integral compensator, the high-pass filter, and the low-pass filter is obtained from the motor position and switched, the position control for suppressing the vibration even when the vibration frequency changes depending on the position of the machine A device and a position control method can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a motor control system to which the position control device of the present invention is applied. In the figure, 11 is a command generation unit that outputs a position command Pref, 12 is a position command Pref and a detected motor position Pfbm, and outputs a speed command Vref, so that the two input signals coincide with each other. A position control unit 13 that performs position control, and a speed control unit 13 that inputs the speed command Vref and the calculated motor speed Vfbm, outputs a torque command Tref, and controls the motor speed so that the two input signals coincide with each other. , 14 is a current control unit that receives a torque command Tref and supplies current to the motor 15, 16 is a motor position detector that detects the rotational position of the rotating shaft by connecting to the rotating shaft of the motor 15, and 17 is a motor position. A speed calculation unit 18 that receives the motor position signal Pfbm of the detector and calculates a difference to generate the motor speed Vfbm, 18 is the torque command Tref A vibration suppression signal calculation unit 19 for inputting the motor speed Vfbm and outputting a vibration suppression signal, 19 switches the gains of the proportional compensator, integral compensator, high-pass filter, and low-pass filter of the vibration suppression signal calculation unit based on the motor position. It is a gain changer.
FIG. 2 is a detailed block diagram showing an embodiment of the present invention. In the figure, 21 is a subtractor that generates a position deviation signal by subtracting the motor position signal Pfbm from the position command Pref, 22 is a position controller that receives the position deviation signal and generates a speed command Vref, and 23 is a motor from the speed command Vref. A subtractor that subtracts the speed signal Vfbm to generate a speed deviation signal, 24 is a speed controller that receives the speed deviation signal and generates a torque command Tref, and 25 is a motor that calculates an estimated speed from the torque command Tref and the motor speed Vfbm. It is an observer that generates a difference signal obtained by subtracting the estimated speed from the speed. The observer performs proportional compensation to generate a first compensation signal, a proportional compensator 33, an integral compensator 34 to perform integral compensation, an inertia model 37 to which a torque command is input, an estimated acceleration signal generated by the inertia model, and proportional compensation. An adder 36 for adding the first compensation signal generated by the generator and the second compensation signal generated by the integral compensator; an integrator 38 for integrating the addition result to generate an estimated speed signal; and an estimated speed from the motor speed signal. A subtractor 35 that subtracts the signal and generates a first damping signal. A high-pass filter 26 receives the first damping signal of the observer and advances the phase to generate a second damping signal, and 27 cuts a high-frequency component of the second damping signal to generate a third damping signal. 28 is a coefficient unit that multiplies the output of the low-pass filter by a coefficient α as a damping gain and outputs a damping signal; 30 is an adder that adds the damping signal to the speed command and outputs a new speed command Vref; 19 Is a gain switch for inputting the motor position and switching the gains of the proportional compensator 33, the integral compensator 34, the high-pass filter 26, and the low-pass filter 27 of the vibration suppression signal calculation unit based on the motor position.
The present invention is different from Patent Document 1 in that it includes a switcher that switches the proportional compensator, integral compensator, high-pass filter, and low-pass filter gain of the vibration suppression signal calculation unit based on the motor position signal. The gains of the proportional compensator, integral compensator, high-pass filter, and low-pass filter of the vibration suppression signal calculation unit that switches based on the motor position are measured in advance by measuring the change in vibration frequency depending on the motor position, and the relationship between the motor position and gain. Prepare a table that stores.

  FIG. 4 is a flowchart showing the position control method of the position control apparatus according to the present invention, which is executed at every control time except step 1. In FIG. 1, the gains of the low-pass filter, high-pass filter and observer are previously written from the table according to the position signal in step ST1, and the gains of the low-pass filter, high-pass filter and observer are read from the table according to the position signal in step ST2. In step ST3, an estimated acceleration signal is generated from the torque command. In step ST4, the estimated acceleration signal, the first compensation signal, and the second compensation signal are added and integrated to generate an estimated speed signal. In step ST5, the estimated speed signal is estimated. A first damping signal is generated by subtracting the speed signal, a first compensation signal is generated by multiplying the first damping signal by an observer proportional gain in step ST6, and a first-term observer integration is performed on the first damping signal in step ST7. Is multiplied and integrated to generate a second compensation signal. In step ST8, the first damping signal is A second damping signal is generated by passing through the pass filter, a third damping signal is generated by passing the second damping signal through the low-pass filter in step ST9, and a coefficient is multiplied by the third damping signal in step ST10. Generate a damping signal.

  By switching the gain of the proportional compensator, integral compensator, high-pass filter, and low-pass filter of the vibration suppression signal calculation unit based on the motor position, vibration can be suppressed even when the vibration frequency changes depending on the position of the machine. .

Block diagram of a motor control system to which the present invention is applied The block diagram which shows the Example of this invention Block diagram explaining the conventional method The flowchart which shows the position control method of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Command generation part 12 Position control part 13 Speed control part 14 Current control part 15 Motor 16 Position detector 17 Speed calculation part 18 Vibration suppression signal calculation part 19 Gain switcher 21, 23, 35 Subtractor 22 Position controller 24 Speed control 25 Observer 26 High-pass filter 27 Low-pass filter 28 Coefficient units 30 and 36 Adder 33 Proportional compensator 34 Integration compensator 37 Inertia model 38 Integrator

Claims (7)

A position control unit that generates a speed command by controlling a position deviation of the position command and the position signal, a speed control unit that generates a torque command by controlling a speed deviation of the speed command and the speed signal, and the torque command A motor drive unit that drives a motor based on the torque command, a vibration suppression signal calculation unit that generates a vibration suppression signal from the torque command and the speed signal, and an adder that adds the vibration suppression signal to the speed command. In the position control device
The vibration suppression signal calculation unit includes: an observer that generates a first vibration suppression signal from the torque command and the speed signal; a high-pass filter that generates a second vibration suppression signal by advancing the phase of the first vibration suppression signal; A low-pass filter that generates a third damping signal by removing high-frequency components of the two damping signals, a coefficient unit that adjusts the gain of the third damping signal and generates a damping signal,
A gain switching unit that switches the gain of the observer, the high-pass filter, and the low-pass filter from the position signal;
A position control device comprising:   The observer includes an inertia model that generates an estimated acceleration signal from the torque command, an integrator that integrates the estimated acceleration signal to generate an estimated speed signal, and a difference constant between the speed signal and the estimated speed signal. A proportional compensator that multiplies and generates a first compensation signal; an integral compensator that performs integral compensation to generate a second compensation signal; and adds the first compensation signal, the second compensation signal, and the estimated acceleration signal. The position control device according to claim 1, further comprising: an adder for generating a new estimated acceleration signal. The position control device according to claim 1, wherein the gain switching unit includes a table that measures in advance a gain that minimizes vibration in accordance with the position signal and stores the gain.   The position control device according to claim 1, wherein the position signal is generated from a position detector coupled to a motor.   The position control device according to claim 1, wherein the position signal is generated from a position detector coupled to a load.   The position control device according to claim 1, wherein the speed signal is generated from a time difference of position signals of a position detector coupled to a motor. A position control unit that generates a speed command by controlling a position deviation of the position command and the position signal, a speed control unit that generates a torque command by controlling a speed deviation of the speed command and the speed signal, and the torque command A motor drive unit that drives a motor based on the torque command, a vibration suppression signal calculation unit that generates a vibration suppression signal from the torque command and the speed signal, and an adder that adds the vibration suppression signal to the speed command. In the position control method of the position control device,
Writing a low-pass filter, a high-pass filter, and an observer gain from a table in advance according to the position signal;
Reading the gain of the low-pass filter, high-pass filter, and observer from the table according to the position signal for each control time; and
Generating an estimated acceleration signal from the torque command;
Adding and integrating the estimated acceleration signal, the first compensation signal, and the second compensation signal to generate an estimated speed signal;
Subtracting the speed signal and the estimated speed signal to generate a first damping signal;
Multiplying the first damping signal by an observer proportional gain to generate the first compensation signal;
Multiplying the first damping signal by a previous observer integral to generate a second compensation signal;
Passing the first damping signal through a high-pass filter to generate a second damping signal;
Passing the second damping signal through a low pass filter to generate a third damping signal;
Generating the damping signal by multiplying the third damping signal by a coefficient;
Adding the torque command and the damping signal to generate a new torque command;
A position control method comprising:

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