JP4367185B2 - How to set damping parameters - Google Patents

Description

  The present invention relates to an electric motor control system that analyzes and suppresses vibration generated due to low mechanical rigidity of a control target of the electric motor itself or a connecting shaft that connects the electric motor and the control target.

Conventionally, in a positioning control using an electric motor, a digital servo control using a microcomputer has been performed, and an electric motor damping device for the purpose of vibration suppression has been disclosed (for example, Patent Document 1).

In FIG. 4, by inserting a pre-filter 8, the vibration of the controlled object 3 is changed to a command pattern that does not excite, and the vibration of the controlled object is suppressed. The pre-filter 8 performs second-order differentiation of the position command θ * and calculates a vibration suppression compensation value obtained by multiplying by a predetermined coefficient 1 / (ωa ² ). Here, ωa is calculated from ωa = 2π · fa where the vibration frequency to be controlled is fa.

  As can be seen from the frequency characteristic diagram of the transfer function from the position command θ * to the control target position θL (FIG. 3), the pre-filter 8 lowers the gain of the frequency near the vibration frequency fa of the control target 3 from the command pattern. It has become a thing.

  In order to obtain the vibration frequency of the control target, it is necessary to attach a vibration detection sensor to the control target or use a laser displacement meter. In Patent Document 1, the output of the vibration detection sensor is input to the control device, and the control device detects the vibration. The vibration frequency to be controlled can be automatically determined based on the data obtained from the sensor.

Also, in recent years, positioning control devices using electric motors, so-called servo motors, have been set using a personal computer to set parameters such as servo gain due to the increase in functions and the spread of personal computers, and sent to servo amplifiers using communication means such as RS232C and USB It is supposed to be.
JP 2004-5469 A

  The problem to be solved is that a vibration detection sensor and a laser displacement meter for obtaining a vibration frequency to be controlled are difficult to obtain and expensive.

  In addition, since the data obtained by the vibration detection sensor and the laser displacement meter is vibration amplitude and time data, in order to obtain the vibration frequency, calculation is performed from the vibration period or FFT (Fast Fourier) is performed from the time data of the amplitude. (Transform) must be applied. To apply the FFT, it is necessary to import the vibration detection sensor and laser displacement meter data into a personal computer or use the FFT function of a high-function oscilloscope, but the vibration detection sensor and laser with the function to capture the data into the personal computer Displacement meters and high-function oscilloscopes are difficult to obtain and expensive. In addition, the vibration detection sensor and the laser displacement meter are time-consuming to set, and are difficult for beginners to use.

  Further, in the case where the output of the vibration detection sensor is input to the control device as in Patent Document 1, a circuit for capturing the output of the vibration detection sensor is required for the control device, and a circuit for analyzing the captured data or There are problems that a program is required, the capacity of ROM and RAM is increased, a high-speed microcomputer is required, and the control device is expensive.

  The present invention solves the above-described conventional problems, and an object thereof is to provide an inexpensive motor control system that analyzes and suppresses vibrations related to the motor and the controlled object.

In order to solve the above-described problem, the present invention inputs a command for the motor and the connected control target from the position command generation unit to the position command input unit of the motor control device, and lowers the gain of a predetermined frequency and a frequency in the vicinity thereof. In the motor control system for controlling the motor or the state quantity of the control target to follow the command value by causing the command to act on a pre-filter having characteristics and outputting a follow command value, Without causing the pre-filter to function, the position command from the position command generation unit is converted into a position command suitable for internal calculation by the position command input unit, and the detected motor position follows the position command that has been converted internally. Steps to control
In step 2, the sound data generated from the bell attached to the control object is collected on a personal computer by the microphone function, the vibration frequency is analyzed by applying FFT to the collected sound data, and the vibration frequency analysis in step 2 A step 3 for setting a vibration suppression parameter in the pre-filter through the communication means from the personal computer, the vibration frequency of the control object obtained by halving the frequency with the highest sound pressure level obtained; Thereafter, the pre-filter is operated to drive the electric motor, and a vibration damping parameter setting method for suppressing vibrations of the connected control objects. The vibration frequency relating to the motor and the control object can be easily obtained and vibration suppression Countermeasures are possible.

  According to the motor control system of the present invention, the sound generated from the controlled object is taken into the personal computer using the microphone function and subjected to FFT, so that the vibration frequency of the controlled object can be easily obtained and the optimal control from the personal computer is achieved. Since vibration parameters can be set in the motor control device, vibrations related to the motor and the controlled object can be suppressed.

A command for the motor and the connected control target is input from the position command creation unit to the position command input unit of the motor control device, and the command is applied to a prefilter having a characteristic of reducing the gain of a predetermined frequency and a frequency in the vicinity thereof. It is allowed to output the tracking command value, the electric motive control system that controls so that the motor or state quantity of the controlled object to the follow-up command value to follow, without function the prefilter of the motor control device Converting the position command from the position command generating unit into a position command suitable for internal calculation at a position command input unit, and controlling the detected motor position so as to follow the internally converted position command; and Sound data generated from the bell attached to the controlled object is collected on a personal computer by the microphone function, and the collected sound data is subjected to FFT to analyze the vibration frequency. Step 2 and the vibration frequency of the control object obtained by halving the frequency with the highest sound pressure level obtained in the vibration frequency analysis in Step 2 are applied to the pre-filter through the communication means from the personal computer. Step 3 is set, and after Step 3, the pre-filter is operated to drive the electric motor to suppress vibrations of the connected controlled objects .

  In FIG. 1, 1 is a position command generating unit, 2 is an electric motor, 3 is a controlled object (load), 4 is a position detecting unit, 5 is a sound generator, and 6 is a servo controller as an electric motor control device. The servo controller 6 includes a position command input unit 7, a pre-filter 8, a command tracking control unit 9, and communication means 10. The command follow-up control unit 9 includes a position deviation calculation unit (subtractor) 11, a position control unit 12, a speed calculation unit 13, a speed deviation calculation unit (subtracter) 14, a speed control unit 15, and a current control unit 16. Reference numeral 17 denotes a microphone as a microphone function, and 18 denotes a personal computer. The servo controller 6 and the pre-filter 8 are configured by a program using a microcomputer.

The pre-filter 8 receives the pattern of the position command θ * and changes the pattern to a pattern θM * (motor position command) that does not excite the vibration of the control target position θL. The pre-filter 8 performs second-order differentiation on the position command θ * and calculates a vibration suppression compensation value obtained by multiplying by a predetermined coefficient 1 / (ωa ² ). Where ω
a is calculated from ωa = 2π · fa, where fa is the vibration frequency of the controlled object. FIG. 3 shows a frequency characteristic diagram of a transfer function from the position command θ * to the control target position θL.

  The position command creation unit 1 is configured by, for example, a PLC (Programmable LogiC Controller). The communication means 10 is, for example, RS232C, and parameters can be exchanged between the personal computer 18 and the servo controller 6.

  The motor control system controls the motor 2 so that the position of the control target (load) 3 connected to the motor 2 (hereinafter referred to as “control target position θL”) matches the position command θ *.

  In FIG. 1, the control target position θL cannot be detected. The position detector 4 detects the position of the electric motor 2 (hereinafter referred to as “motor position θM”). The servo controller 6 performs control so that the motor position θM follows the position command θ *. Since the controlled object 3 is connected to the electric motor 2, the controlled object position θL also follows the position command.

  The position command creating unit 1 creates a position command pattern and outputs a position command according to the pattern. The output of the position command generator 1 is input to the position command input unit 7. The position command input unit 7 inputs a position command, converts it into a unit suitable for internal calculation, and outputs it as a position command θ *. Since the pre-filter does not know the vibration frequency of the controlled object 3 at first, the function as a filter is not performed, and the output θ * of the position command input unit is directly passed through to output θM *.

  Therefore, when the rigidity of the connecting shaft connecting the control object 3 or the electric motor 2 and the control object 3 is low, the control object position θL vibrates.

The position deviation calculation unit (subtractor) 11 receives the motor position command θM * and the motor position θM, and calculates the motor position deviation ΔθM (= θM * −θM). The position control unit 12 outputs a speed command ωM * (= Kpp · ΔθM) using the position proportional gain Kpp. Speed calculator 1
3 differentiates the motor position θM to calculate the motor speed ωM (= θM · s). The speed deviation calculation unit (subtractor) 14 receives the speed command ωM * and the motor speed ωM, and calculates a speed deviation ΔωM (= ωM * −ωM). The speed control unit 15 performs a proportional integration calculation based on the speed deviation ΔωM and outputs a torque command T *. The current control unit 16 controls the current value I flowing through the electric motor 2 so that the torque TM output from the electric motor 2 becomes T *.

  Thus, since the pre-filter 8 does not operate at first, sound is generated from the sound generator 5 attached to the controlled object 3 according to the vibration frequency of the controlled object 3. The sound generator 5 may be a bell, for example, and it is desirable that the sound generator 5 is sufficiently light compared to the control target.

  The microphone 17 connected to the microphone terminal of the personal computer 18 is installed near the sound generator 5 and takes sound data into the personal computer 18. The microphone function may be provided in the main body of the personal computer.

  The personal computer 18 converts the sound of the sound generator 5 into a frequency spectrum by FFT. The highest frequency of the sound pressure level is a frequency generated from the sound generator 5 and is a vibration frequency related to the controlled object.

  The frequency spectrum obtained by the experiment is shown in FIG. The frequency indicated by the arrow A is the highest level and is 26 Hz.

  However, the vibration frequency of the controlled object 3 used in the experiment is 13 Hz. This is because when a bell is used as the sound generator 5, the bell of the bell hits the main body of the bell at a frequency twice that of the controlled object every time the controlled object 3 vibrates, and the frequency of the bell is twice that of the controlled object 3. It becomes frequency.

  Therefore, the vibration frequency of the controlled object 3 is calculated by halving the frequency with the highest sound pressure level. The vibration frequency fa of the control target 3 obtained here is transmitted from the personal computer 18 to the servo controller 6 via the communication means 10 and set in the pre-filter 8.

  The pre-filter 8 receives the pattern of the position command θ * and changes the pattern θM * (motor position command) that does not excite the vibration of the control target position θL, and the vibration of the control target 3 is suppressed.

  The electric motor control system of the present invention is suitable for suppressing vibrations generated due to low mechanical rigidity related to the electric motor and the controlled object.

FIG. 1 is a control block diagram of an electric motor control system in Embodiment 1 of the present invention. The figure which shows the frequency spectrum of the sound data in Example 1 of this invention Frequency characteristic diagram of transfer function Control block diagram of conventional motor control method

DESCRIPTION OF SYMBOLS 1 Position command preparation part 2 Electric motor 3 Control object 4 Position detection part 5 Sound generator (bell)
6 Motor controller (servo controller)
DESCRIPTION OF SYMBOLS 7 Position command input part 8 Pre-filter 9 Command follow-up control part 10 Communication means 11 Position deviation calculation part 12 Position control part 13 Speed calculation part 14 Speed deviation calculation part 15 Speed control part 16 Current control part 17 Microphone function (microphone)
18 PC

Claims (1)

A pre- filter having a characteristic of reducing a gain of a predetermined frequency and a frequency in the vicinity thereof by inputting a command for an electric motor having a position detection unit and a connected control target from a position command generation unit to a position command input unit of the motor control device the instruction was allowed to act outputs a tracking command value, the electric motive control system that controls so that the motor or state quantity of the controlled object to the follow-up command value to follow, the pre-filter of the motor control device The position command from the position command generation unit is converted into a position command suitable for internal calculation by the position command input unit, and control is performed so that the detected motor position follows the internally converted position command. Sound data generated from step 1 and the bell attached to the control target is collected on a personal computer by the microphone function, and the collected sound data is subjected to FFT to be applied. Step 2 for analyzing the frequency, and the vibration frequency of the control target obtained by halving the frequency with the highest sound pressure level obtained by the vibration frequency analysis of Step 2 from the personal computer via the communication means. A step 3 for setting vibration damping parameters, and after step 3, the pre-filter is operated to drive the electric motor to suppress vibrations of the connected controlled objects .

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