JP2008259271A - Servo controller and automatic constant adjustment method - Google Patents

Abstract

Provided are a servo control device and a constant automatic adjustment method capable of performing automatic adjustment without vibration even at a machine having a low resonance frequency.
In a servo control device, a command filter (19B) for filtering a speed command to generate a new speed command and a torque feedforward command, and a new speed by performing a vibration suppression type filter process on the speed command. A vibration suppression filter (19A) for generating a command and a torque feedforward command, an inertia moment identification unit (16) for identifying the total moment of inertia from the torque command and the motor speed, and detecting motor vibration from the torque command and the motor speed. A vibration detection unit (17) for analyzing a motor vibration frequency, adjusting a speed control gain of the speed control unit, a command filter, and constants of a vibration suppression filter so that the motor speed has no vibration and a high-speed response; And a constant adjustment unit (18) for selecting whether the filter is a vibration suppression filter.
[Selection] Figure 1

Description

The present invention relates to a servo control device capable of automatically adjusting a control constant.

Conventionally, the automatic adjustment of the constants of the servo control device is performed so that the settling time is shortened according to the flowchart of FIG. First, adjust the speed control gain of the speed control system so that high-frequency components such as speed deviation and torque command waveform do not increase (S31), and then adjust the command filter constant so that no overshoot occurs and no vibration occurs Was. (S32)
A conventional vibration suppression filter is disclosed in Patent Document 1. Patent Document 1 processes a command to be input to a servo control unit into an optimal command so that a control target having a vibration element does not vibrate and the delay with respect to the command is as small as possible. An Nth order filter process is performed and a feedforward command is generated by the four arithmetic operation units. FIG. 5 is a configuration diagram of the prior art disclosed in Patent Document 1. In FIG. Reference numeral 101 denotes an Nth order filter processing unit, and reference numeral 102 denotes an arithmetic operation unit.
Japanese Patent Laid-Open No. 2002-241802

However, with the conventional constant automatic adjustment, in a machine with low frequency mechanical resonance, the vibration may not be suppressed due to the influence of the mechanical resonance, and the positioning completion signal generated when the position deviation falls within the predetermined value Cracking occurs and positioning completion is not determined. For this reason, there has been a problem that the control gain must be lowered and it takes a long time to settle.
Further, there is a problem that even if there is mechanical resonance in the low frequency band, the settling time may be shortened by using the torque feed forward and the speed feed forward, and the constant cannot be automatically adjusted.

  The present invention has been made in view of such problems, and it is an object of the present invention to provide a servo control device and an automatic constant adjustment method capable of performing automatic adjustment without a crack in a positioning completion signal even in a machine having a low resonance frequency. It is said.

In order to solve the above problems, the following configuration is adopted.
The invention according to claim 1 is a speed control unit that generates a torque command from a speed command and a motor speed, and controls a current based on the torque command to cause a motor and a load driven by the motor to follow the speed command. A command filter that filters the speed command to generate a new speed command and a torque feedforward command;
A vibration suppression filter that generates a new speed command and a torque feedforward command by performing a vibration suppression filter process on the speed command; an inertia moment identification unit that identifies a total moment of inertia from the torque command and the motor speed; A vibration detection unit that detects motor vibration from a torque command and the motor speed and analyzes a motor vibration frequency, a speed control gain of the speed control unit, a command filter, And a constant adjustment unit that adjusts a constant of the vibration suppression filter and selects whether the command filter is the vibration suppression filter.
According to a second aspect of the present invention, in the servo control device according to the first aspect of the present invention, a torque command filter that filters the torque command to generate a new torque command is provided.
According to a third aspect of the present invention, in the servo control device according to the second aspect, the torque command filter includes at least one of a low-pass filter and a notch filter.
According to a fourth aspect of the present invention, in the servo control device according to the third aspect, the constant adjustment unit changes the constant of the low-pass filter in accordance with the motor vibration frequency and the speed control gain. is there.
The invention according to claim 5 is the servo control device according to claim 43, wherein the constant adjustment unit changes the frequency of the notch filter in accordance with the motor vibration frequency and the speed control gain. is there.
According to a sixth aspect of the present invention, in the servo control device according to the first aspect, the vibration suppression filter includes a high-order filter and a feedforward command generation unit using an inverse transfer function of a mechanical system. It is.
According to a seventh aspect of the present invention, in the servo control device according to the first aspect, the constant adjustment unit generates a constant of a feedforward command generation unit from the motor vibration frequency and the total moment of inertia. Is.
The invention according to claim 8 is based on a position control unit that generates a speed command from the position command and the motor position, a speed control unit that generates a torque command from the speed command and the motor speed, and the torque command. And a current control unit that controls the current and causes the motor to follow the speed command, and filters the speed command to generate a new position command, speed feed forward command, and torque feed forward command. A command filter to be generated; a vibration suppression filter that generates a new position command, a speed feedforward command, and a torque feedforward command by subjecting the speed command to a damping filter process; and a total inertia based on the torque command and the motor speed. A moment of inertia identifying unit for identifying a moment, and motor vibration from the torque command and the motor speed. A vibration detection unit that analyzes the motor vibration frequency, a position control gain of the position control unit, a speed control gain of the speed control unit, the command filter, and the vibration suppression so that the motor speed has no vibration and a high-speed response. And a constant adjusting unit that adjusts a constant of the filter and selects whether the command filter is the vibration suppression filter.
According to a ninth aspect of the present invention, in the servo control device according to the eighth aspect of the present invention, a torque command filter that filters the torque command to generate a new torque command is provided.
According to a tenth aspect of the present invention, in the servo control device according to the ninth aspect, the torque command filter includes at least one of a low-pass filter and a notch filter.
According to an eleventh aspect of the present invention, in the servo control device according to the tenth aspect, the constant adjustment unit adjusts the constant of the low-pass filter in accordance with the motor vibration frequency, the position control gain, and the speed control gain. To do.
According to a twelfth aspect of the present invention, in the servo control device according to the tenth aspect, the constant adjustment unit adjusts the frequency of the notch filter corresponding to the motor vibration frequency, the position control gain, and the speed control gain. To do.
A thirteenth aspect of the present invention is the servo control device according to the eighth aspect, wherein the vibration suppression filter includes a high-order filter and a feedforward command generation unit using an inverse transfer function of a mechanical system. is there.
According to a fourteenth aspect of the present invention, in the servo control device according to the thirteenth aspect, the constant adjustment unit generates a constant of the feedforward command generation unit from the motor vibration frequency and the total moment of inertia.
According to a fifteenth aspect of the present invention, in the servo control device according to the eighth aspect, the constant adjustment unit has a predetermined value that is a position deviation that is a difference between the position command and the motor position after the dispensing of the position command is completed. A settling time measurement unit that measures the settling time until the following is provided, and the settling time when the vibration suppression filter is used is compared with the settling time when the command filter is used, and the filter with the shorter settling time is selected. It is characterized by this.
According to a sixteenth aspect of the present invention, a position control unit that generates a speed command from the position command and the motor position, a speed control unit that generates a torque command from the speed command and the motor speed, and a current based on the torque command And adjusting the control gains of the position control unit and the speed control unit, and a motor vibration in the constant automatic adjustment method of the servo control device including the current control unit that controls the motor to follow the speed command A step of detecting whether there is vibration, a step of setting a constant of the vibration suppression filter and returning to the adjustment of the control gain again, a step of adjusting the constant of the command filter if there is no vibration, a motor vibration A step of detecting whether there is vibration, a step of returning to the adjustment of the command filter again if there is vibration, and a first settling time when there is no vibration. A step of determining whether or not the vibration suppression filter has been adjusted; a step of releasing the vibration suppression filter if adjusted; a step of adjusting the command filter; and a step of measuring the second settling time at this time And a step of selecting the shorter adjustment value of the first settling time and the second settling time.

  According to the present invention, the settling time when adjusted using the vibration suppression control type vibration suppression filter is compared with the settling time when adjusted using the normal command filter, and the filter with the shorter settling time is used. Therefore, it is possible to provide a servo control device and a constant automatic adjustment method that can perform automatic adjustment without vibration with high-speed response.

  Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of a speed control type servo control apparatus according to a first embodiment of the present invention.
In FIG. 1, 11 is a speed control unit, 12 is a current control unit, 13 is a motor, 14 is a detector, 15 is a load, 16 is a moment of inertia identification unit, 17 is a motor vibration detection unit, 18 is a constant adjustment unit, 19A. Is a vibration suppression command filter, 19B is a command filter, and 20 is a switch.

Next, the operation will be described. The vibration suppression command filter 19A generates a new speed command and a torque feedforward command by subjecting the speed command to a vibration suppression control type filter process. A vibration suppression control type filter is a speed command that is first subjected to high-order filter processing, and then multiple-order differentiation is performed. A torque feedforward command and a differential term of the reverse transfer function of the machine speed / torque are used as coefficients. A new speed command is generated. The command filter 19B filters the speed command without using damping control, differentiates the new speed command and the speed command, and multiplies the constant α to generate a torque feedforward command. The constant α is determined from the moment of inertia of the motor 14 and the load 16, the speed command, the motor speed overshoot amount, and the like. The switch 20 selects a vibration suppression command filter or a command filter based on a selection signal from the constant adjustment unit 18. The speed control unit 11 performs a control process for a speed deviation of a difference between the speed command and the motor speed, and performs a filter process to generate a torque command. The control process at this time executes at least one of proportional control, integral control, and differential control.
Further, the speed control unit adds a torque command and a torque feedforward command to generate a new torque command. The torque feed forward command may be added before or after the filtering process. The current control unit 13 converts the torque command into a current command, generates a voltage command by controlling the current deviation of the difference from the motor current, converts the torque command into a PWM signal, and amplifies the power to power the motor. To drive.

Next, features of the present invention will be described. The inertia moment identification unit 16 identifies the total inertia moment of the mechanical system from the torque command and the motor speed, and the vibration detection unit 17 detects the motor vibration from the torque command and the motor speed and analyzes the vibration frequency. The constant adjustment unit 18 generates a transfer function of the machine from the motor vibration frequency and the total moment of inertia, and obtains a reverse transfer function to generate a torque feed forward coefficient. The constant adjustment unit 18 sets a control gain of the speed control unit 11 to obtain a control gain that does not cause the motor to vibrate, and sets a filter constant and a torque feedforward coefficient of the command filter 19B based on the motor vibration frequency and the control gain. Calculate. Furthermore, when the speed control unit 11 includes a torque command filter, the constant adjustment unit 18 adjusts the filter constant of the torque command filter of the speed control unit 11 based on the motor vibration frequency and the control gain.
The constant adjustment unit 20 includes a settling time measurement unit, measures the settling time when the speed deviation after the speed command is issued is equal to or less than a predetermined value, and uses the vibration suppression command filter as a first settling. The time is compared with the second settling time when the command filter is used, and the filter with the shorter settling time is selected.

FIG. 2 is a block diagram of a position control type servo control apparatus according to the second embodiment of the present invention.
The second embodiment is different from the first embodiment in that a position control unit is added. In FIG. 2, 21 is a position control unit, 11 is a speed control unit, 12 is a current control unit, 13 is a motor, 14 is a detector, 15 is a load, 16 is an inertia moment identification unit, 17 is a motor vibration detection unit, 18 Is a constant adjustment unit, 19A is a vibration suppression command filter, 19B is a command filter, and 20 is a switch.

Next, the characteristic part of Example 2 is demonstrated. The position control unit 21 controls the position deviation of the difference between the position command and the motor position to generate a speed command. Here, the control process executes at least one of proportional control, integral control, and differential control. The vibration suppression command filter 19A performs a vibration suppression control type filter process on the position command to generate a new position command, a speed feedforward command, and a torque feedforward command.
A vibration suppression control type filter is a position command, which is first subjected to high-order filter processing, then multiple-order differentiation is performed, and the velocity forward for each differential term of the machine position / torque inverse transfer function as a coefficient. A command is generated, and a torque feedforward command is generated using each differential term of the reverse transfer function of the machine position / torque as a coefficient. The filter command filter 22B filters the position command without using vibration suppression control, differentiates a new position command and position command, multiplies the constant β, generates a speed feedforward command, and performs second-order differentiation on the position command to obtain a constant. Multiply α to generate a torque feed forward command.
The constant α is determined from the moment of inertia of the motor 14 and the load 16, the speed command, the motor speed overshoot amount, and the like. The constant β is determined from the position command and the amount of overshoot obtained from the motor position.
The constant adjustment unit 18 generates a machine transfer function from the position control gain, the speed control gain, the motor vibration frequency, and the total moment of inertia, obtains the inverse transfer function, and calculates the coefficient of the speed feedforward command and the coefficient of the torque feedforward command. Is generated. The constant adjustment unit 18 generates a filter constant of the command filter 19B, a coefficient of the speed feedforward command, and a coefficient of the torque feedforward command based on the motor vibration frequency. Further, when the speed control unit 11 includes a torque command filter, the constant adjustment unit 18 adjusts the filter constant of the torque command filter of the speed control unit 11 based on the position control gain, the speed control gain, and the motor vibration frequency. To do. The constant adjustment unit 18 includes a settling time measuring unit, measures the settling time when the position deviation after the position command is paid out is equal to or less than a predetermined value, and uses the vibration suppression command filter and the command filter. Compare the settling time when using and select the filter with the shorter settling time.

  FIG. 3 is a flowchart showing the constant adjustment method of the present invention. In step S11, the control gain is adjusted. In step S12, it is detected whether there is motor vibration. If there is motor vibration, a vibration suppression filter is set in step S13, and the control gain is readjusted in step S11. In step S14, the command filter is adjusted. In step S15, it is detected whether there is motor vibration. If there is vibration, the process returns to step S14 to readjust the command filter. Next, in step S16, the first settling time is measured. In step S17, it is determined whether or not the vibration suppression filter has been adjusted. If it has been completed, the vibration suppression filter is released in step S18, and the command filter is adjusted in step S19. In step S20, the second settling time is set. Next, in step S21, the first settling time and the second settling time are compared, and the shorter settling time is selected.

It is a block diagram which shows the structure of Example 1 of this invention. It is a block diagram which shows the structure of Example 2 of this invention. It is a flowchart which shows the constant adjustment method of Example 3 of this invention. It is a flowchart which shows the conventional constant adjustment method. It is a block diagram of the conventional servo control apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Speed control part 12 Current control part 13 Motor 14 Detector 15 Load 16 Inertia moment identification part 17 Vibration detection part 18 Constant adjustment part 19A Vibration suppression command filter 19B Command filter 20 Switch 21 Position control part

Claims (16)

A servo comprising: a speed control unit that generates a torque command from the speed command and the motor speed; and a current control unit that controls a current based on the torque command and causes a motor and a load driven by the motor to follow the speed command. In the control device,
A command filter that filters the speed command to generate a new speed command and a torque feedforward command;
A vibration suppression filter that performs a vibration suppression filter process on the speed command to generate a new speed command and a torque feedforward command;
An inertia moment identifying unit for identifying a total inertia moment from the torque command and the motor speed;
A vibration detector that detects motor vibration from the torque command and the motor speed and analyzes a motor vibration frequency;
A constant for adjusting the speed control gain of the speed control unit, the command filter, and the constant of the vibration suppression filter so that the motor speed has no vibration and a high-speed response, and selects whether the command filter is the vibration suppression filter. An adjustment unit;
A servo control device comprising:   The servo control device according to claim 1, further comprising a torque command filter that filters the torque command to generate a new torque command.   The servo control device according to claim 2, wherein the torque command filter includes at least one of a low-pass filter and a notch filter.   4. The servo control device according to claim 3, wherein the constant adjusting unit changes the constant of the low-pass filter in accordance with a motor vibration frequency and a speed control gain.   4. The servo control device according to claim 3, wherein the constant adjustment unit changes the frequency of the notch filter in accordance with a motor vibration frequency and a speed control gain.   The servo control device according to claim 1, wherein the vibration suppression filter includes a high-order filter and a feedforward command generation unit using an inverse transfer function of a mechanical system.   The servo control device according to claim 1, wherein the constant adjustment unit generates a constant of a feedforward command generation unit from the motor vibration frequency and the total moment of inertia. A position control unit for generating a speed command from the position command and the motor position; a speed control unit for generating a torque command from the speed command and the motor speed; and a current control based on the torque command to In a servo control device including a current control unit that follows a command,
A command filter that filters the speed command to generate a new position command, a speed feedforward command, and a torque feedforward command;
A vibration suppression filter that generates a new position command, a speed feedforward command, and a torque feedforward command by subjecting the speed command to a damping filter process;
An inertia moment identifying unit for identifying a total inertia moment from the torque command and the motor speed;
A vibration detector that detects motor vibration from the torque command and the motor speed and analyzes a motor vibration frequency;
Adjusting the position control gain of the position control unit, the speed control gain of the speed control unit, the constants of the command filter and the vibration suppression filter so that the motor speed has no vibration and has a high-speed response, and the command filter A constant adjustment unit for selecting the vibration suppression filter;
A servo control device comprising:   The servo control device according to claim 8, further comprising a torque command filter that filters the torque command to generate a new torque command.   The servo control device according to claim 9, wherein the torque command filter includes at least one of a low-pass filter and a notch filter.   The servo control device according to claim 10, wherein the constant adjustment unit adjusts a constant of the low-pass filter corresponding to a motor vibration frequency, a position control gain, and a speed control gain.   11. The servo control device according to claim 10, wherein the constant adjustment unit adjusts the frequency of the notch filter in accordance with a motor vibration frequency, a position control gain, and a speed control gain.   The servo control device according to claim 8, wherein the vibration suppression filter includes a high-order filter and a feedforward command generation unit based on a reverse transfer function of a mechanical system.   14. The servo control device according to claim 13, wherein the constant adjustment unit generates a constant of the feedforward command generation unit from the motor vibration frequency and the total moment of inertia.   The constant adjustment unit includes a settling time measurement unit that measures a settling time until a position deviation that is a difference between the position command and the motor position is equal to or less than a predetermined value after the dispensing of the position command is completed, 9. The servo control apparatus according to claim 8, wherein a settling time is compared between a case where a vibration suppression filter is used and a case where the command filter is used, and a filter having a shorter settling time is selected. A position control unit for generating a speed command from the position command and the motor position; a speed control unit for generating a torque command from the speed command and the motor speed; and a current control based on the torque command to In a constant automatic adjustment method of a servo control device including a current control unit that follows a command,
Adjusting the control gain of the position control unit and the speed control unit;
Detecting whether there is motor vibration;
If there is vibration, set the vibration suppression filter constant and return to the control gain adjustment again.
A step of adjusting the constant of the command filter when there is no vibration;
Detecting whether there is motor vibration;
If there is vibration, return to the adjustment of the command filter again,
Measuring a first settling time when there is no vibration;
Determining whether the vibration suppression filter has been adjusted;
If already adjusted, release the vibration suppression filter;
Adjusting the command filter;
Measuring the second settling time at this time;
Selecting the shorter adjustment value of the first settling time and the second settling time;
A constant automatic adjustment method for a servo control device, comprising:

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