JP6708720B2 - Servo control device, servo control method, and servo control program - Google Patents

Description

The present invention relates to a servo control device, a servo control method and a servo control program, and more particularly to a servo control device for a servo motor, a servo control method and a servo control program.

A servo control device for a servo motor is described in Patent Document 1, for example. In Patent Document 1, in the servo control device, when adjusting the speed control gain, the sampling value of the torque command or the current command is converted into the strength of the torque of the servo motor at the frequency, and the strength of the torque of the servo motor becomes a peak. It is described that such a frequency band is determined as the oscillation band and the band stop filter is set so as to attenuate the torque intensity of the servo motor in the oscillation band.

JP, 2013-126266, A (abstract, paragraph 0008, FIG. 2 etc.)

However, in Patent Document 1, when the influence of the control gain is exerted not only on the resonance peak amplitude but also on the resonance frequency, it is not possible to perform the filter adjustment in consideration of the frequency variation.

The present invention provides a servo control device, a servo control method, and a servo control method capable of performing filter adjustment in consideration of the frequency variation when the influence of the control gain is exerted not only on the resonance peak amplitude but also on the resonance frequency. The purpose is to provide a servo control program.

A servo control device (for example, a servo control device 10 described later) according to the present invention is a speed command creation unit (for example, a speed command creation unit described below) that creates a speed command value for a servo motor (for example, a servo motor 20 described below). 100), a speed detection unit (for example, a speed detection unit 107 described below) that detects the speed of the servo motor, a speed control gain (for example, a speed control gain 101 described below) that is a control gain of a speed control loop, A torque command generation unit (for example, a torque command generation unit 102 described below) that generates a torque command value for the servo motor, and at least one filter that attenuates a specific frequency band component included in the torque command value (for example, A filter 103 described later, a sine wave sweep input unit that performs a sine wave sweep in a predetermined frequency range (for example, a sine wave sweep input unit 104 described below), and a frequency characteristic calculation that calculates the frequency characteristic of a sine wave to be swept. And a filter adjusting unit (for example, a filter adjusting unit 106 described later) that adjusts the filter so as to attenuate a specific frequency band component included in the torque command value. ,,
The speed control gain, the torque command creating unit, the filter, and the speed detecting unit form the speed control loop, and the speed control gain includes the sine of the difference between the speed command value and the detected speed. A signal to which a sine wave output from the wave sweep input unit is added is input, and the filter adjustment unit changes the value of the speed control gain, and the resonance frequency included in the frequency characteristic calculated by the frequency characteristic calculation unit. And adjusting the filter by measuring the effect of the speed control gain on the resonance frequency and the resonance peak amplitude, and the filter adjusting unit is obtained from the value of the speed control gain and the frequency characteristic calculating unit. By fitting a quantitative relationship with the resonance frequency of the frequency characteristic, the shift of the frequency that causes the resonance peak amplitude with respect to the fluctuation of the value of the speed control gain is evaluated, and the filter is used at the frequency that causes the resonance peak amplitude. This is the applied servo control device.

A servo control method according to the present invention creates a speed command value for a servo motor, detects the speed of the servo motor, and sweeps a difference between the speed command value and the detected speed in a predetermined frequency range. A signal to which a sine wave is added is input to the speed control gain, a torque command value to the servo motor is created based on the output from the speed control gain, and a specific frequency band component included in the torque command value. Is attenuated by at least one filter, the specific frequency band component is driven by the torque command value is attenuated, the servo control method of the servo control device,
The frequency characteristic of the sine wave swept in the predetermined frequency range is calculated, the resonance frequency included in the calculated frequency characteristic is detected while changing the value of the speed control gain, and the value of the speed control gain is calculated. Is measured on the resonance frequency and the resonance peak amplitude, the filter is adjusted so as to attenuate a specific frequency band component included in the torque command value, and the value of the speed control gain and the calculated value are calculated. By fitting a quantitative relationship with the resonance frequency of the frequency characteristic, the shift of the frequency that causes the resonance peak amplitude with respect to the fluctuation of the value of the speed control gain is evaluated, and the filter is used at the frequency that causes the resonance peak amplitude. It is a servo control method of a servo control device to be applied.

The servo control program according to the present invention is stored in a computer as a servo control device for a servo motor,
A process of creating a speed command value of the servo motor, a process of detecting the speed of the servo motor, and a difference between the speed command value and the detected speed are added with a sine wave swept in a predetermined frequency range. A process of inputting the obtained signal to the speed control gain, a process of creating a torque command value for the servomotor based on the output from the speed control gain, and a specific frequency band component included in the torque command value. A process of attenuating with at least one filter and a process of driving the servo motor by the torque command value in which the specific frequency band component is attenuated are executed,
The frequency characteristic of the sine wave swept in the predetermined frequency range is calculated, the resonance frequency included in the calculated frequency characteristic is detected while changing the value of the speed control gain, and the value of the speed control gain is calculated. Is measured on the resonance frequency and the resonance peak amplitude, the filter is adjusted so as to attenuate a specific frequency band component included in the torque command value, and the value of the speed control gain and the calculated value are calculated. By fitting a quantitative relationship with the resonance frequency of the frequency characteristic, the shift of the frequency that causes the resonance peak amplitude with respect to the fluctuation of the value of the speed control gain is evaluated, and the filter is used at the frequency that causes the resonance peak amplitude. This is the servo control program to be applied.

According to the present invention, when the influence of the control gain is exerted not only on the resonance peak amplitude but also on the resonance frequency, the filter adjustment can be performed in consideration of the frequency variation.

1 is a block diagram showing a system including a servo control device, a servo motor, and a transmission mechanism according to an embodiment of the present invention. FIG. 9 is a characteristic diagram showing a relationship between frequency and gain (amplitude) when the speed control gain varies in the servo control device according to the embodiment of the present invention. In the servo control device according to the embodiment of the present invention, the speed control gain is shown in decibels on the horizontal axis (x axis), and the resonance peak gain (resonance peak amplitude) is shown in decibels on the vertical axis (y axis). Is. 3 is a flowchart showing an operation of the servo control device according to the embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a system including a servo control device, a servo motor, and a transmission mechanism according to an embodiment of the present invention.

As shown in FIG. 1, the servo control device 10 includes a speed command creation unit 100 that creates a speed command value for the servo motor 20, a speed control gain 101 that is a control gain of a speed control loop, and a torque command for the servo motor 20. A torque command creating unit 102 that creates a value and a filter 103 that attenuates a specific frequency band component included in the torque command value are provided.
Further, the servo control device 10 includes a speed detection unit 107 that detects the speed of the servo motor 20, a sine wave sweep input unit (sine wave disturbance input unit) 104 that performs a sine wave sweep to a speed control loop in a predetermined frequency range, and a sine wave. A frequency characteristic calculation unit 105 that calculates the frequency characteristic of the sine wave swept by the wave sweep input unit 104, and a filter adjustment unit 106 that adjusts the filter 103 so as to attenuate a specific frequency band component included in the torque command value. I have it.
The speed control gain 101, the torque command creation unit 102, the filter 103, and the speed detection unit 107 form a speed control loop that controls the rotation speed of the servo motor 20. Although one filter 13 is shown in FIG. 1, a plurality of filters 13 may be provided.

The transmission mechanism 30 is a feed shaft of a machine tool, a speed reducer for reducing the rotation speed of the servo motor 20, a conversion mechanism for converting the rotational motion of the servo motor 20 into a linear motion, and the like.

The filter adjustment unit 106 refers to the output value of the speed control gain 101 while changing the value of the speed control gain 101, detects the resonance frequency included in the frequency characteristic calculated by the frequency characteristic calculation unit 105, and detects the speed control gain 101. The frequency band to be attenuated by the filter 103 is adjusted by measuring the effect of the filter on its resonance frequency and resonance peak amplitude. For example, as shown in FIG. 2, the filter adjusting unit 106 changes the output value of the speed control gain 101 while changing the value ω of the speed control gain of the speed control gain 101 to 200, 400, 800, 1600 (%). The resonance frequency included in the frequency characteristic calculated by the frequency characteristic calculation unit 105 is detected by referring to the reference frequency. Then, the filter adjusting unit 106 adjusts the filter 103 so as to attenuate the specific frequency band component included in the torque command by measuring the influence of the speed control gain 101 on the resonance frequency and the resonance peak amplitude.

As described above, FIG. 2 is a characteristic diagram showing the relationship between the frequency and the gain (amplitude) when the speed control gain changes. As shown in FIG. 2, it can be seen that when the value ω of the speed control gain is changed to 200, 400, 800, 1600 (%), the resonance peak increases corresponding to the increase of the speed control gain. When the value ω of the speed control gain is changed to 200, 400, 800, 1600 (%), the magnitude relationship between the two resonance peak gain values in the frequency region near 860 Hz corresponds to the increase of the speed control gain. It can be seen that the resonance frequency shifts to the low frequency side when the resonance peak gain is obtained in the frequency region near 1150 Hz and 1310 Hz (the resonance frequency at which the maximum resonance peak gain is obtained shifts to the high frequency side). ..

Note that the shift of the resonance frequency is caused by other factors as well, for example, in Non-Patent Document 1 (H.-C. Mo ¨ hring (2) et al. CIRP Annals-Manufacturing Technology 64 (2015) 725-748), It has been reported that the resonance of the mechanical structure has a larger deviation of the resonance frequency in bending vibration than in torsional vibration, and that the resonance frequency of the resonance mode caused by bending is likely to change. In the present embodiment, attention is paid to such characteristics, and when the influence of the speed control gain 101 is significant with respect to the resonance frequency, the frequency variation is also taken into consideration and the specific value included in the torque command is specified. The filter 103 is adjusted so as to attenuate the frequency band component.

The filter adjustment unit 106 describes the quantitative relationship between the value of the speed control gain 101 and the resonance peak amplitude of the frequency characteristic obtained from the frequency characteristic calculation unit 105 in a mathematical expression to evaluate the resonance characteristic and determine the applicability of the filter. You can FIG. 3 is a characteristic diagram in which the speed control gain is shown in decibels on the horizontal axis (x axis), and the resonance peak gain (resonance peak amplitude) is shown in decibels on the vertical axis (y axis). FIG. 3 shows the resonance peak gain in the frequency range near 860 Hz, the resonance peak gain in the frequency range near 1150 Hz, and the resonance peak gain in the frequency range near 1310 Hz. Each of these frequency ranges is indicated by a dotted line in FIG.

The quantitative relationship between the speed control gain and the resonance peak gain is a straight line shown by the following three formulas (Equation 1-Equation 3) shown in FIG. 3 when the speed control gain is 200, 400, 800, 1600, respectively. Can be represented. y represents the resonance peak gain, and x represents the speed control gain. In FIG. 3, R ² is a coefficient of determination and represents a measure of how well the straight line represented by the equations 1 to 3 fits.

Here, if the quantitative relationship between the speed control gain and the resonance peak gain is a linear system (spring mass damper system), the slope of the straight line should be 1. However, the slope is larger than 1 as shown in the equations 1 to 3. Increasing tilt resonance greater than 1 represents the "speed" of nonlinear resonance growth. If the priority of the filter application is determined in the order of "speed", the filter can be preferentially adjusted as the nonlinear resonance growth is faster. As is clear from Equations 1 to 3, since the slope is 1.3368>1.2633>1.1812, the priority order is from the top of the priority order: the frequency range near 1150HZ and the frequency range near 860HZ. The range is a frequency range near 1310HZ. Therefore, it is possible to check the growth method of each gain peak (resonance mode) with respect to the speed control gain and clearly determine the priority by the quantified parameter value. As a result, it is possible to realize the quantitative evaluation of the resonance mode by measuring the frequency response a plurality of times under different control gains, the filter strength adjustment and the determination of the priority based on the quantitative evaluation.

Further, the filter adjustment unit 106 can evaluate the resonance characteristic and determine applicability of the filter based on a quantitative relationship between the value of the speed control gain 101 and the resonance frequency of the frequency characteristic obtained from the frequency characteristic calculation unit 105. As described above, from FIG. 2, when the value ω of the speed control gain is changed to 200, 400, 800, 1600 (%), the resonance frequency at the resonance peak amplitude shifts to the high frequency side or the low frequency side. I know I'm going. Therefore, it is possible to evaluate at which frequency the resonance peak occurs in accordance with the value of the speed control gain, and to determine in which frequency band the filter should be applied.

Next, the operation of the servo control device will be described with reference to the flowchart of FIG.

First, the speed command creating unit 100 outputs a speed command value (target value of speed), and the sine wave sweep input unit 104 outputs a sine wave (sine wave disturbance) in a predetermined frequency range (step S201). For example, the sine wave sweep input unit 104 performs sine wave sweep in the 500 Hz to 2000 Hz frequency range, for example. The speed detection unit 107 detects the actual speed value of the servo motor 20 (step S202) and outputs the speed detection value.

Next, a sine wave (α) is added to the speed error (Vsub) between the speed command value and the actual speed detection value, and the result is input to the speed control gain 101. The value ω of the speed control gain of the speed control gain 101 is set by the filter adjustment unit 106. The torque command generator 102 generates a torque command value based on the output value (ω·(Vsub+α)) of the speed control gain 101 (step S203) and outputs it to the filter 103. The frequency characteristic calculation unit 105 calculates the frequency characteristic of the sine wave swept by the sine wave sweep input unit 104 (step S204).

Based on the output value (ω·(Vsub+α)) of the speed control gain 101 and the frequency characteristic calculated by the frequency characteristic calculating section 105, the filter adjusting section 106 sets the resonance included in the frequency characteristic calculated by the frequency characteristic calculating section 105. The frequency and the resonance peak amplitude are detected (step S205).

Next, the filter adjusting unit 106 changes the speed control gain and determines again whether to calculate the frequency characteristic (S206). When the speed control gain is changed and the frequency characteristic is calculated again (yes in S206), the filter adjustment unit 106 adjusts the speed control gain (step S207), and the process returns to step S201.

On the other hand, when the speed control gain is not changed (No in S206), the filter adjustment unit 106 fits the quantitative relationship between the speed control gain and each resonance peak amplitude and resonance frequency (step S208), and the filter is applied. The resonance to be performed is determined (step S209), and the filter characteristic for the resonance to be filtered is specified for the filter 103 (S210).

All or part of the servo control device according to the embodiments described above can be realized by hardware, software, or a combination thereof. Here, “realized by software” means realized by the computer reading and executing the program. When it is configured by hardware, a part or all of the servo control device shown in FIG. 1 is, for example, an LSI (Large Scale Integrated circuit), an ASIC (Application Specific Integrated Circuit), a gate array, an FPGA (Field Programmable Gate Array). It can be configured by an integrated circuit (IC) such as.

When software is used to configure all or part of the servo control device, a storage unit such as a hard disk or a ROM that stores a program describing all or part of the operation of the servo control device shown in the flowchart of FIG. In a computer including a DRAM that stores necessary data, a CPU, and a bus that connects the respective units, information necessary for calculation can be stored in the DRAM, and the program can be operated by the CPU.

The program can be stored using various types of computer readable media and supplied to the computer. The computer readable medium includes various types of tangible storage medium. Examples of the computer readable medium include a magnetic recording medium (for example, flexible disk, magnetic tape, hard disk drive), magneto-optical recording medium (for example, magneto-optical disk), CD-ROM (Read Only Memory), CD-R, CD-. R/W, semiconductor memory (for example, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (random access memory)) are included.

According to the servo control device and the servo control method of the present embodiment described above, the gain and the filter are integrated to grasp the behavior and analyze the resonance characteristic, so that adjustment without relying on the sense can be automatically performed. , It is possible to maximize the use of a limited number of filters.

Further, according to the servo control apparatus and the servo control method of the present embodiment, by quantifying the nonlinear behavior of the resonance mode, it is possible to easily realize a more robust control system while improving the accuracy of adjustment.

10 Servo Control Device 20 Servo Motor 30 Transmission Mechanism 100 Speed Command Creation Unit 101 Speed Control Gain 102 Torque Command Creation Unit 103 Filter 104 Sine Wave Sweep Input Unit 105 Frequency Characteristic Calculation Unit 106 Filter Adjustment Unit 107 Speed Detection Unit

Claims (3)

A speed command creation unit that creates a speed command value for the servo motor,
A speed detection unit for detecting the speed of the servo motor,
The speed control gain, which is the control gain of the speed control loop,
A torque command creating unit that creates a torque command value for the servo motor,
At least one filter that attenuates a specific frequency band component included in the torque command value,
A sine wave sweep input section that performs a sine wave sweep in a predetermined frequency range,
A frequency characteristic calculation unit for calculating the frequency characteristic of the swept sine wave,
A filter adjusting unit that adjusts the filter so as to attenuate a specific frequency band component included in the torque command value,
The speed control gain, the torque command creation unit, the filter and the speed detection unit constitute the speed control loop,
A signal obtained by adding a sine wave output from the sine wave sweep input unit to a difference between the speed command value and the detected speed is input to the speed control gain,
The filter adjusting unit detects the resonance frequency included in the frequency characteristic calculated by the frequency characteristic calculating unit while changing the value of the speed control gain, and the influence of the speed control gain on the resonance frequency and the resonance peak amplitude. Adjust the filter by measuring,
The filter adjustment unit, by fitting a quantitative relationship between the value of the speed control gain and the resonance frequency of the frequency characteristic obtained from the frequency characteristic calculation unit, the resonance peak amplitude with respect to the fluctuation of the value of the speed control gain. A servo controller that evaluates the frequency shift that is produced and applies the filter at a frequency that produces the resonant peak amplitude. Create a speed command value for the servo motor,
Detecting the speed of the servo motor,
In the difference between the speed command value and the detected speed, a signal to which a sine wave swept in a predetermined frequency range is added is input to the speed control gain,
Create a torque command value to the servo motor based on the output from the speed control gain,
Attenuating a specific frequency band component contained in the torque command value with at least one filter,
A servo control method of a servo control device, which drives the servo motor by the torque command value in which the specific frequency band component is attenuated,
The frequency characteristic of the sine wave swept in the predetermined frequency range is calculated, the resonance frequency included in the calculated frequency characteristic is detected while changing the value of the speed control gain, and the value of the speed control gain is calculated. Adjusts the filter so as to attenuate a specific frequency band component included in the torque command value by measuring the effect of the resonance frequency and the resonance peak amplitude.
By fitting the quantitative relationship between the value of the speed control gain and the resonance frequency of the calculated frequency characteristic, the shift of the frequency that causes the resonance peak amplitude with respect to the variation of the value of the speed control gain is evaluated, and A servo control method for a servo control device, wherein the filter is applied at a frequency that causes a resonance peak amplitude. In the computer as the servo control device of the servo motor,
The process of creating the speed command value of the servo motor,
A process of detecting the speed of the servo motor,
In the difference between the speed command value and the detected speed, a process of inputting a signal to which a sine wave swept in a predetermined frequency range is added to the speed control gain,
A process of creating a torque command value for the servomotor based on the output from the speed control gain;
A process of attenuating a specific frequency band component included in the torque command value with at least one filter,
A process of driving the servo motor by the torque command value in which the specific frequency band component is attenuated,
The frequency characteristic of the sine wave swept in the predetermined frequency range is calculated, the resonance frequency included in the calculated frequency characteristic is detected while changing the value of the speed control gain, and the value of the speed control gain is calculated. Adjusts the filter so as to attenuate a specific frequency band component included in the torque command value by measuring the effect of the resonance frequency and the resonance peak amplitude.
By fitting a quantitative relationship between the value of the speed control gain and the resonance frequency of the calculated frequency characteristic, the shift of the frequency that causes the resonance peak amplitude with respect to the fluctuation of the value of the speed control gain is evaluated, and A servo control program that applies the filter at a frequency that produces a resonant peak amplitude.

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