JP2007143224A - Vibration detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect the resonance frequency and the antiresonance frequency silently in a short time only through minute movement without applying a mechanical burden to a motor with a load. <P>SOLUTION: The vibration detector comprises a position amplitude operating unit 101 outputting a position amplitude by receiving a position, a rigidity operating unit 102 outputting rigidity between motor and load by receiving the position amplitude, a load inertia moment operating unit 103 outputting a a load inertia moment by receiving the position amplitude, and a resonance/antiresonance frequency operating unit 104 calculating and outputting a vibration detection value, i.e. the resonance frequency and the antiresonance frequency, of a motor with a load by receiving the rigidity between motor and load and the the load inertia moment. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vibration detection device that detects vibration of an electric motor with a load.

FIG. 3 shows a conventional vibration detector.
In FIG. 3, 301 is a command generator, 302 is a speed controller, 303 is a current controller, 304 is a motor and a mechanical load, 305 is a detector, and 306 is a signal processor.
In FIG.
The command generator 301 outputs a swept sine wave signal.
The speed controller 302 outputs a torque command.
The current controller 303 inputs a current command and a response signal, which is an added value of the sweep sine wave signal and the torque command, and outputs a motor current.
The motor and mechanical load 304 are driven by the motor current, and the response signal is detected and output by the detector 305.
The signal processor 306 inputs the swept sine wave signal and the response signal, and calculates and outputs the frequency of the swept sine wave signal at a time when the response signal takes a maximum value as a resonance frequency. (For example, see Patent Document 1)

As described above, the conventional vibration detection device inputs the swept sine wave signal to the motor and the mechanical load 304, and determines the resonance frequency of the motor and the mechanical load 304 from the frequency of the swept sine wave signal at which the maximum value of the response signal occurs. It detects.
JP 2003-348871 A (3rd page, FIG. 3)

  The conventional vibration detection apparatus is configured to input a swept sine wave signal to the motor and the mechanical load 304, and when the frequency of the swept sine wave signal matches the resonance frequency of the motor and the mechanical load 304, There was a problem that a mechanical load was applied to the load 304 to generate noise. Further, there is a problem that vibration cannot be detected when the movable range of the motor and the mechanical load 304 is limited.

  The present invention has been made in view of such problems, and the resonance frequency and anti-resonance frequency of a motor with a load are applied with a small amount of motion in a short time without placing a mechanical burden on the motor with a load. It is an object of the present invention to provide a vibration detection device that can detect a vibration.

In order to solve the above problems, the present invention is configured as follows.
The invention according to claim 1 is a position command generator that outputs a position command, a position controller that inputs the position command and position and outputs a speed command, and inputs the speed command and speed and outputs a torque command. A speed controller that inputs the torque command and drives the motor with a motor current, a differentiator that inputs the position of the motor detected by a position detector and outputs the speed, and the position A vibration detector comprising: a vibration detector that calculates and outputs a vibration detection value that is a resonance frequency and an anti-resonance frequency of the electric motor that is input and has a load, wherein the vibration detector receives the position and inputs a position A position amplitude calculator that calculates and outputs the amplitude, a rigidity calculator that calculates and outputs the rigidity between the motor loads by inputting the position amplitude, and a load inertia that calculates and outputs the load inertia moment by inputting the position amplitude. A moment calculating unit, those having a resonance-antiresonance frequency calculator that said type motor load between rigidity the load inertia and outputs calculate the vibration detection value.

  According to a second aspect of the present invention, in the vibration detection device according to the first aspect, the position amplitude calculator calculates a fundamental frequency component of the position by Fourier transform and calculates the position amplitude which is the amplitude. Is.

  According to a third aspect of the present invention, in the vibration detection device according to the first aspect, the position amplitude calculator calculates a fundamental frequency component of the position by a band pass filter and calculates the position amplitude which is the amplitude. To do.

  According to a fourth aspect of the present invention, in the vibration detection device according to the first aspect, the position command is a periodic signal whose fundamental frequency is sufficiently smaller than a resonance frequency and an anti-resonance frequency of the motor with a load. The first position command is a second position command that is a sufficiently large periodic signal.

  According to a fifth aspect of the present invention, in the vibration detection device according to the first aspect, the position controller is proportionally controlled and the speed controller is proportionally controlled.

  According to a sixth aspect of the present invention, in the vibration detection device according to the fifth aspect, the proportional control gain of the position controller is set to a plurality of different gains.

  According to a seventh aspect of the present invention, in the vibration detection device according to the sixth aspect, the first position proportional control gain and the second position proportional which are two different gains for the plurality of proportional control gains of the position controller. Control gain.

In the invention according to claim 8, the gain of the position controller is set to two different first position proportional control gain Kp1 and second position proportional control gain Kp2, and the speed proportional control gain of the speed controller is set to Kvj. The position command is a periodic signal that is sufficiently smaller than the resonance frequency and anti-resonance frequency of the motor with a fundamental frequency loaded, the first position command having an amplitude u0 and a frequency ω1, and a sufficiently large periodic signal. Assuming that the second position command of the amplitude u0 and the frequency ω2 is Jm, the motor inertia moment that is the inertia moment of the motor alone is Jm, the load inertia moment is Jl, the effective inertia moment is Je, and the rigidity between the motor loads is k, The vibration detector calculates the resonance frequency ωr and the anti-resonance frequency ωa of the electric motor, which are the vibration detection values, by the equations (1) and (2), respectively. Is shall.

According to the first, fourth, fifth, sixth, seventh and eighth aspects of the invention, the resonance frequency and the anti-resonance frequency can be detected quietly in a short time without applying a mechanical load to the motor with load. can do.
In addition, according to the inventions of the second and third aspects, the influence of noise and nonlinear friction is suppressed, and the resonance frequency and the resonance frequency can be set in only a short time in a short time without imposing a mechanical burden on the loaded motor. An anti-resonance frequency can be detected.

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

FIG. 2 shows a vibration detecting apparatus according to the first embodiment of the present invention.
In FIG. 2, 201 is a position command generator, 202 is a position controller, 203 is a speed controller, 204 is a torque controller, 205 is an electric motor, 206 is a position detector, 207 is a differentiator, and 208 is a vibration detector. is there.
In FIG. 2, a position command generator 201 outputs a position command.
The position controller 202 inputs the position command and the position and outputs a speed command.
The speed controller 203 inputs the speed command and the speed and outputs a torque command.
The torque controller 204 inputs the torque command and outputs a motor current.
The motor 205 is driven by the motor current, and the position is detected and output by the position detector 206.
The differentiator 207 inputs the position and outputs the speed.
The vibration detector 208 inputs the position, calculates and outputs a vibration detection value that is a resonance frequency and an anti-resonance frequency of the motor 205 with a load.

FIG. 1 is a vibration detector showing a first embodiment of the present invention.
In FIG. 1, 101 is a position amplitude calculator, 102 is a stiffness calculator, 103 is a load inertia moment calculator, and 104 is a resonance anti-resonance frequency calculator.
In FIG. 1, a position amplitude calculator 101 receives a position, calculates a fundamental frequency component of the position using a Fourier transform or a band pass filter, and calculates and outputs the amplitude as a position amplitude.
The stiffness calculator 102 inputs the position amplitude, calculates the motor load stiffness, and outputs it.
A load inertia moment calculator 103 receives the position amplitude, calculates and outputs a load inertia moment.
The resonance anti-resonance frequency calculator 104 inputs the rigidity between the motor loads and the load inertia moment, and calculates and outputs a vibration detection value that is a resonance frequency and an anti-resonance frequency of the motor 205 with a load.

  The difference between the present invention and the prior art is that the vibration detector 208 receives a position amplitude and outputs a rigidity between motor loads, and a load inertia moment calculator that inputs a position amplitude and outputs a load inertia moment. 103 and a resonance anti-resonance frequency calculator 104 that inputs a rigidity between the motor loads and a load inertia moment and calculates a vibration detection value.

  Hereinafter, the operation of the vibration detector 208 will be described. However, since the resonance anti-resonance frequency calculator 104 calculates the vibration detection value using the position amplitude which is the fundamental frequency component amplitude of the position calculated using a Fourier transform or a band pass filter, the resonance anti-resonance frequency calculator 104 described below. Only the fundamental frequency component of each signal is considered in the derivation of the resonant frequency equation.

In FIG. 2, the motor 205 is assumed to have a load attached to the motor, the motor inertia moment is Jm, the load inertia moment is J1, the motor viscous friction is D, the load viscous friction is cl, the position of the motor 205 is θm, and the load position is When θl, motor load stiffness is k, motor load viscous friction is c, torque command is Tref, and constant torque disturbance is w, an open-loop system equation of motion including torque controller 204, motor 205, and position detector 206 is shown. Is represented by Formula (3) and Formula (4).
When the position command u is a sine wave having an amplitude u0 and a frequency ω, Expression (5) is obtained.
Assuming that the position command frequency, which is the position command frequency, is a first position command frequency ω = ω1, which is sufficiently lower than the resonance frequency of the motor 205 with a load, θm≈θl is approximately established as Equation (3) And Equation (4) can be rewritten as Equation (6).
When the position controller 202 is set to proportional control with a gain of Kp and the speed controller 203 is set to proportional control with a gain of Kvj, the torque command is expressed by Equation (7).
Substituting equation (7) into equation (6) yields equation (8).
When the gain of the position controller 202 is set to the first position proportional control gain Kp = Kp1, the position amplitude in the steady state detected when the minute position command having the first position command frequency ω = ω1 is given to the vibration detecting device. Is represented by equation (9).
Similarly, when the gain of the position controller 202 is the second position proportional control gain Kp = Kp2, the position amplitude in the steady state is expressed by Expression (10).
When Expressions (9) and (10) are solved for the load moment of inertia Jl, Expression (11) is obtained.
In FIG. 1, the load inertia moment calculator 103 calculates the load inertia moment using the equation (11).

Next, assuming that the position command frequency, which is the frequency of the position command, is a second position command frequency ω = ω2, which is a value sufficiently higher than the resonance frequency of the motor 205 with a load, θl = 0 holds and Equation (3) Is rewritten as equation (12).
When the gain of the position controller 202 is the first position proportional control gain Kp = Kp1, the position amplitude in the steady state detected when the minute position command of the second position command frequency ω = ω2 is given to the vibration detection device. Is represented by equation (13).
Similarly, when the gain of the position controller 202 is set to the second position proportional control gain Kp = Kp2, the position amplitude in the steady state is expressed by Expression (14).
The motor load rigidity k is obtained by the equation (15) using the equations (13) and (14).
In FIG. 1, the stiffness calculator 102 calculates the motor load stiffness using the equation (15).

The effective inertia moment Je of the open loop system is expressed by equation (16) using the motor inertia moment Jm and the load inertia moment Jl.
Using the equations (11), (15), and (16), vibration detection values that are the resonance frequency ωr and the anti-resonance frequency ωa of the open loop system are expressed by equations (17) and (18). .
The resonance anti-resonance frequency calculator 104 calculates the vibration detection value using the equations (11), (15), (16), (17), and (18). Since the position amplitude is used, the influence of constant torque disturbance and noise can be suppressed.

  Since the position amplitude calculator 101 calculates the fundamental frequency component of the position using a Fourier transform or a bandpass filter and calculates the amplitude as the position amplitude, the influence of nonlinear friction, noise, etc. is suppressed, and the steady state of the position is calculated. Vibration can be detected in a short time without waiting for the state. Further, vibration can be detected even if the position command is an arbitrary periodic signal.

Hereinafter, a simulation of the present embodiment will be shown.
Numerical values used in this simulation are shown in Equation (19).
However, the motor 205 is a load applied to the motor, Jm is the motor inertia moment, Jl * is the true value of the load inertia moment, ωr * is the true resonance frequency, D is the motor viscous friction, cl is the load viscous friction, c Is a viscous friction between motor loads, Kp1 is a first position proportional control gain, Kp2 is a second position proportional control gain, Kv is a normalized speed proportional control gain, Kvj is a speed proportional control gain, T is a control cycle, and Trat is a rated torque , U0 is a position command amplitude, ω1 is a first position command frequency, ω2 is a second position command frequency, and w is a constant torque disturbance.

The effective moment of inertia true value Je *, the motor load rigidity true value k *, and the anti-resonance frequency true value ωa * are obtained as Equation (20), Equation (21), and Equation (22) using the numerical value of Equation (19). It is done.

The load inertia moment identification value calculated by Expression (11) is Jl = 0.15883 × 10 ^ −3 kg * m ^ 2, and the load inertia moment identification error eJl is determined as Expression (23).
The motor load stiffness identification value calculated by the equation (15) is k = 4.4560 N * m / rad, and the motor load stiffness identification error ek is obtained by the equation (24).
The resonance frequency identification value calculated by the equation (17) is ωr = 103.46 (2π) rad / s, and the resonance frequency identification error is obtained by the equation (25).
The anti-resonance frequency identification value calculated by equation (18) was ωa = 31.22 (2π) rad / s, and the anti-resonance frequency identification error was obtained as equation (26).
In this simulation, the position amplitude was always 0.15 rad or less, and the vibration part amplitude of the torque command was always 3% or less of the rated torque.

  As described above, the rigidity calculator 102 that inputs the position amplitude and outputs the rigidity between the motor loads, the load inertia moment calculator 103 that inputs the position amplitude and outputs the load inertia moment, and the rigidity between the motor loads and the load inertia moment. Since it is configured to have a resonance anti-resonance frequency calculator 104 that inputs, calculates and outputs a vibration detection value, the resonance frequency can be quietly operated in a short period of time without imposing a mechanical burden on the motor with load. And anti-resonance frequency can be detected.

  By using periodic position commands with different frequencies and multiple position control gains, the resonance frequency and anti-resonance frequency of a motor with a load can be detected, so that the inverse transfer function compensation of general industrial machines such as semiconductor manufacturing equipment It can also be used for the purpose of automatic instrument adjustment.

Vibration detector showing first embodiment of the present invention Vibration detecting apparatus showing a first embodiment of the present invention Conventional vibration detector

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Position amplitude calculator 102 Stiffness calculator 103 Load inertia moment calculator 104 Resonance anti-resonance frequency calculator 201 Position command generator 202 Position controller 203 Speed controller 204 Torque controller 205 Electric motor 206 Position detector 207 Differentiator 208 Vibration Detector 301 Command generator 302 Speed controller 303 Current controller 304 Motor and mechanical load 305 Detector 306 Signal processor

Claims (8)

A position command generator that outputs a position command; a position controller that inputs the position command and position and outputs a speed command; a speed controller that inputs the speed command and speed and outputs a torque command; and the torque command A torque controller that drives the motor by a motor current, a differentiator that inputs the position of the motor detected by a position detector and outputs the speed, and a motor that inputs the position and has a load. In a vibration detector comprising a vibration detector that calculates and outputs a vibration detection value that is a resonance frequency and an anti-resonance frequency,
The vibration detector is
A position amplitude calculator that inputs the position, calculates and outputs a position amplitude; and
A rigidity calculator that inputs the position amplitude and calculates and outputs the rigidity between the motor loads;
A load inertia moment calculator that inputs the position amplitude and calculates and outputs a load inertia moment;
Resonance anti-resonance frequency calculator that inputs the motor load rigidity and the load moment of inertia and calculates and outputs the vibration detection value;
A vibration detection apparatus comprising:   2. The vibration detection apparatus according to claim 1, wherein the position amplitude calculator calculates a fundamental frequency component of the position by Fourier transform and calculates the position amplitude which is an amplitude thereof.   2. The vibration detection apparatus according to claim 1, wherein the position amplitude calculator calculates a fundamental frequency component of the position by a band pass filter and calculates the position amplitude which is an amplitude thereof.   The position command is defined as a first position command that is a periodic signal sufficiently smaller than a resonance frequency and an anti-resonance frequency of the motor with a basic frequency loaded, and a second position command that is a sufficiently large periodic signal. The vibration detection apparatus according to claim 1, wherein   The vibration detection apparatus according to claim 1, wherein the position controller is a proportional control and the speed controller is a proportional control.   6. The vibration detecting apparatus according to claim 5, wherein the proportional control gain of the position controller is set to a plurality of different gains.   The vibration detection apparatus according to claim 6, wherein the plurality of proportional control gains of the position controller are a first position proportional control gain and a second position proportional control gain which are two different gains. The gain of the position controller is two different first position proportional control gain Kp1 and second position proportional control gain Kp2,
The speed proportional control gain of the speed controller is Kvj,
The position command is a periodic signal that is sufficiently smaller than the resonance frequency and anti-resonance frequency of the motor with a fundamental frequency loaded, and is a first position command having an amplitude u0 and a frequency ω1, and a sufficiently large periodic signal. As a second position command with a certain amplitude u0 and frequency ω2,
Assuming that the motor moment of inertia is Jm, the load moment of inertia is Jl, the effective moment of inertia is Je, and the motor load rigidity is k,
The vibration detector according to claim 1, wherein the vibration detector calculates the resonance frequency ωr and the anti-resonance frequency ωa of the electric motor, which are the vibration detection values, by the equations (1) and (2), respectively. .