JP5483074B2 - Electric motor control device - Google Patents

Description

  The present invention relates to an electric motor control device used in, for example, a robot, a machine tool, and the like, and more particularly to an electric motor control device improved in a control parameter tuning method for performing position control, speed control, and the like.

  The servo system is a control device that can perform high-speed and high-accuracy position control of a load machine by driving an electric motor. To achieve high-speed and high-accuracy position control performance, it is necessary to adjust multiple control parameters to appropriate values, but if there are many control parameters that need to be adjusted, the target performance will be achieved. In addition, the parameter adjustment method for enabling stable operation is very complicated.

Patent Document 1 discloses a technique for solving the above-described problems and easily adjusting control parameters.
FIG. 3 is a block diagram showing a configuration of the prior art disclosed in Patent Document 1. In FIG. In FIG. 3, the command generation unit 11 creates a position command to the mechanical unit 18 that is a load of the electric motor 16. The position control unit 12 compares the above position command with the position detection value obtained by the detector 17 and outputs a speed command for the electric motor 16 so that they match.

The speed control unit 13 outputs a torque command such that the speed command and the speed detection value of the electric motor 16 created by the speed signal creation unit 19 coincide with each other. This torque command is filtered by the torque filter unit 14 and converted into a current command for obtaining a torque according to the command. The current control unit 15 calculates a voltage command such that the current command matches the detected current value of the electric motor 16, and applies a voltage according to the voltage command to the electric motor 16.
By configuring the control system in this way, the position of the mechanical unit 18 can be controlled in accordance with the position command from the command generating unit 11.

Here, the feature of the above prior art is a method for determining the control parameter of each unit.
First, the user sets a control parameter selection signal before driving. This control parameter selection signal includes information such as the target response frequency, load inertia, load resonance frequency, and the like.

  The one parameter tuning unit 10 automatically calculates control parameters used in each unit using a predetermined calculation algorithm based on the control parameter selection signal, and gives these control parameters to each unit. The calculation algorithm installed in the one-parameter tuning unit 10 is determined in consideration of the stability condition analysis using mathematical formulas and the operation confirmation result in the actual machine.

  As described above, in the related art according to Patent Document 1, only by setting simple information on the target response frequency and load, the control parameters of each part of the control system that realizes the target performance and enables stable operation are automatically set. Therefore, the adjustment of control parameters can be simplified.

JP 2002-27772 A (paragraphs [0005] to [0011], FIG. 1 etc.)

However, in the prior art according to Patent Document 1, basically, control parameters of each part are obtained from a set target response frequency using a predetermined calculation algorithm, and information such as load inertia and resonance frequency is set. If so, the control parameter is corrected according to the setting information.
In other words, this conventional technique does not consider the type of load machine (hereinafter simply referred to as a load machine), and determines the control parameters of each part using the same arithmetic algorithm even if the type of the load machine is different. It will be.

  However, various types of load machines, such as ball screws and belt loads, are assumed. For this reason, depending on the load machine, there may be a problem such as occurrence of a unique vibration phenomenon, and depending on the application of the load machine, a specific required specification may be imposed in addition to the response frequency.

  In the prior art according to Patent Document 1, since the control parameter is determined by an arithmetic algorithm common to all the load machines without particularly considering the type of the load machine, the control parameter is not appropriate depending on the type of the load machine. In some cases, sufficient control performance cannot be obtained.

  Accordingly, the problem to be solved by the present invention is to provide an electric motor control device that can obtain appropriate control parameters according to the type of the load machine by simple adjustment, and can operate a wide variety of load machines with high accuracy and stability. It is to provide.

In order to solve the above-mentioned problem, the invention according to claim 1 is a control device that controls the electric motor so that the position of a load machine driven by the electric motor matches a position command, and includes a position control unit and a speed control unit. And a control device having a current control unit,
Control parameter setting that automatically calculates control parameters used in the position control unit, speed control unit, and current control unit based on the response setting signal indicating the speed of response to be realized and the load machine type determination signal Means ,
Filter means for suppressing vibrations when starting and stopping the load machine by performing a filtering process on the position command;
First feedforward command calculating means for calculating a speed feedforward command from the position command, and second feedforward command calculating means for calculating a current feedforward command from the speed command of the electric motor ,
The calculation algorithm of the control parameter in the control parameter setting means, and change in response to the load machine type determination signal, and,
In accordance with the load machine type determination signal, the control parameter setting means can switch between valid / invalid operation of the filter means and the first and second feedforward command calculation means at once .

According to the present invention, it is possible to always control an electric motor using an appropriate control parameter by setting a control parameter by an arithmetic algorithm according to the type of the load machine.
As a result, it is possible to obtain highly accurate control performance without requiring complicated parameter adjustments, regardless of what kind of load machine is driven by the electric motor.

It is a block diagram which shows embodiment of this invention. It is a block diagram which shows the structure of the control parameter setting means in FIG. It is a block diagram which shows the prior art described in patent document 1. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The basic configuration of the control device according to this embodiment is the same as that of the prior art shown in FIG. 3, and parts having the same functions are denoted by the same reference numerals as those in FIG. The difference from 3 will be mainly described.

  In FIG. 1, the command filter unit 24 performs a filter process on the position command created by the command generation unit 11 and suppresses vibration when starting and stopping the load machine 20. The position control feedforward unit 25 calculates a speed feedforward command from the filtered position command and adds it to the speed command from the position control unit 12 in the adding means 26. Further, the speed control feedforward unit 27 calculates a current feedforward command from the speed command which is the output of the adding means 26, adds this to the output of the speed control unit 13 in the adding means 28 and inputs it to the current control unit 15. To do.

In the position control feedforward unit 25 and the speed control feedforward unit 27 described above, each command is obtained by feedforward calculation without using the detection value, and functions so as to improve responsiveness.
Reference numeral 21 denotes a position detection circuit that detects the position of the load machine 20 (position of the output shaft or the like of the electric motor 16), and reference numeral 22 denotes a speed detection circuit that detects the speed of the electric motor 16.

The control parameter setting means 23 is a control parameter used in the command filter unit 24, the feedforward units 25 and 27, and the control units 12, 13, and 15 according to the contents of a response setting signal and a load machine type determination signal described later. And a control function valid / invalid switching signal for switching the validity / invalidity of the operation of each unit.
The characteristic part of the present invention is the internal configuration of the control parameter setting means 23.

FIG. 2 shows the internal configuration of the control parameter setting means 23.
The responsiveness setting signal and the load machine type determination signal input to the control parameter setting unit 23 are signals set manually by the user.
The responsiveness setting signal is a signal indicating the speed of response to be realized. For example, the target response frequency may be set directly, or a simple integer value may be set, and the response may be changed stepwise depending on the magnitude of the numerical value. In any case, a control parameter is set such that the higher the value is set as the responsiveness setting signal, the higher the responsiveness is obtained.

  The control parameter setting calculation unit 231 calculates control parameters used in each part of the control system from the input response setting signal. However, even if the same level of responsiveness is realized, the optimum value of the control parameter of each part differs depending on the type of the load machine 20.

  Therefore, in addition to the responsiveness setting signal, a load machine type determination signal is also input to the control parameter setting calculation unit 231. The control parameter setting calculation unit 231 uses the load parameter according to the type of the load machine 20 indicated by the determination signal. The control parameter calculation algorithm can be changed. Therefore, according to the present embodiment, an appropriate control parameter calculated according to the type of the load machine 20 is always obtained.

  On the other hand, the control function switching unit 232 outputs a control function valid / invalid switching signal in order to switch the validity / invalidity of the operation of each part of the control system in accordance with the load machine type determination signal. The control function valid / invalid switching signal is transferred to each part of the control system, and the validity / invalidity of the operation of each part is switched according to the content of the signal.

  Various methods are conceivable for the operation of the control function switching unit 232. For example, for the load machine 20 that wants to operate the machine according to the position command, such as a machine tool, the operation of the command filter unit 24 and the feedforward A method of invalidating the operations of the units 25 and 27 is effective. Since the command filter unit 24 is a delay element, it causes a deviation from the original position command, and each command value by the feedforward units 25 and 27 causes a large deviation due to an overshoot when the command suddenly changes. Therefore, the deviation with respect to the position command becomes smaller when these functions are switched to invalid.

On the other hand, in applications where the load machine 20 is a machine that transports an object and it is only necessary to accurately control even the position where the machine stops, the command filter unit 24 is effective to suppress vibration when the machine stops. Is desirable.
As described above, the control function switching unit 232 can realize highly accurate control performance without performing complicated adjustment by automatically selecting a necessary control function according to the type of the load machine 20. it can.

  As described above, according to the present embodiment, appropriate control parameters are set according to the type of the load machine 20, and only the necessary control functions are automatically switched by enabling / disabling the operation of each part of the control system. By using, high control performance can be realized by simple adjustments regardless of the load machine.

DESCRIPTION OF SYMBOLS 11: Command generation part 12: Position control part 13: Speed control part 15: Current control part 16: Electric motor 20: Load machine 21: Position detection circuit 22: Speed detection circuit 23: Control parameter setting means 231: Control parameter setting calculation part 232: Control function switching unit 24: Command filter unit 25: Position control feedforward unit 26, 28: Adding means 27: Speed control feedforward unit

Claims (1)

A control device that controls the electric motor so that a position of a load machine driven by the electric motor matches a position command, and includes a position control unit, a speed control unit, and a current control unit.
Control parameter setting that automatically calculates control parameters used in the position control unit, speed control unit, and current control unit based on the response setting signal indicating the speed of response to be realized and the load machine type determination signal Means ,
Filter means for suppressing vibrations when starting and stopping the load machine by performing a filtering process on the position command;
First feedforward command calculating means for calculating a speed feedforward command from the position command, and second feedforward command calculating means for calculating a current feedforward command from the speed command of the electric motor ,
The calculation algorithm of the control parameter in the control parameter setting means, and change in response to the load machine type determination signal, and,
According to the load machine type determination signal, the control parameter setting means can switch between valid / invalid operation of the filter means and the first and second feedforward command calculating means at once. The motor control device.

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