JP2001157478A - Controller for motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a mechanical vibration by accurately measuring the vibration generated from a machine resonance system. SOLUTION: An observer in a damping controller 18 multiplies a difference between a motor speed Vfb and an estimated speed mVfb by multiplying a constant α (α>0, α=ωf 2), integrates the product, subtracts the value obtained by multiplying the estimated speed mVfb by multiplying a constant β (β>0, β=ωf/Qf) from the value, and adds it to a torque command Tr used in the observer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device provided with a compensating means for suppressing vibration generated in the entire drive system when a motor drives a control object to perform position control or speed control.

[0002]

2. Description of the Related Art A motor is used in various mechanical devices in the FA field, and the position and speed of the motor are controlled in accordance with the specifications of the mechanical device. Such a mechanical device is often provided with a power transmission mechanism between a motor and a control target to transmit power. Then, a form in which the rotational position of the motor is detected to control the position and speed is general and widely used. The configuration includes a position control unit that inputs a position command and a rotation position of a motor to output a speed command, a speed control unit that inputs the speed command and the rotation speed of the motor to output a current command, and a speed control unit. And a current control unit that supplies a current to the motor in accordance with the above-mentioned command, and has a minor loop for speed control to perform position control.

However, if only such a general configuration is adopted, the movement of the motor or the control target may be oscillating due to resonance of the mechanical structure or the like, which may cause a problem. Various control methods and devices have been developed for such a vibration problem, and one of effective techniques is disclosed in Japanese Patent Application Laid-Open No. 7-337057. The technology shown there separates the mechanical system including the motor into an equivalent rigid system and a mechanical vibration system, configures an observer based on the model of the equivalent rigid system, estimates mechanical vibration at high speed, and controls vibration suppression. That is.

FIG. 3 shows the configuration. 31 is a divider,
A torque command Tr is input, and a value Tr / J obtained by dividing by a total inertia value J = Jm + Jl of the motor and the load is output.
An adder 32 adds the output total value dpi of the above-mentioned Tr / J and an observer compensator described later and outputs an mTr. 34 is an equivalent rigid body model gain 1, 35 is an equivalent rigid body model gain 2, and 33 is an adder. Reference numeral 34 denotes an inertia term, and reference numeral 35 denotes a viscous friction term. An adder 36 adds the estimated speed mVfb generated from the equivalent rigid body models 34 and 35 and the actual motor speed Vfb. Reference numeral 37 denotes an inverter, and the output of the inverter 37 is a mechanical resonance estimation signal Vib. 38 is an observer compensating means 1 and 39 is an observer compensating means 2, 38 is a proportional element, and 39 is an integral element, which means a disturbance estimation signal.
An adder 40 adds the outputs of the observer compensating means 38 and 39, and the output thereof is the total output value dpi of the above-described observer compensating means 38 and 39. Therefore,
By adding the mechanical resonance estimation signal Vib or the disturbance estimation signal to the torque command Tr or the speed command after the phase compensation, the mechanical resonance can be suppressed.

[0005]

However, in the prior art, the transfer function G (s) from the motor speed Vfb to the estimated speed mVfb is G (s) = {(ωf / Q) * S + ωf {2} / ｛S ＾ 2
+ (Ωf / Q) * S + ωf {2}, and the configuration has a zero point of −ωf * Q. When it is desired to increase the estimation accuracy of the mechanical resonance estimation signal and the disturbance estimation signal, there is a problem that the observer itself becomes unstable and oscillates depending on the set values of ωf and Q, which are the compensation means of the observer. Here, S is a Laplace operator.
Originally, a vibration model represented by a two-mass system has a resonance frequency of ω and a damping constant of D, where ω ＾ 2 / ｛S
{2 + 2 * D * ω * S + ω {2}, and the conventional compensation means cannot suppress the target mechanical resonance because the influence of the zero point of the observer itself appears in the mechanical resonance estimation signal and the disturbance estimation signal. There's a problem.

An object of the present invention is to provide a motor control device capable of accurately measuring vibration generated from a mechanical resonance system and suppressing mechanical vibration.

[0007]

In order to solve the above problems, according to the present invention, a command generator for outputting a speed command, a speed controller for inputting a speed command and a motor speed and outputting a torque command, A current control unit that receives and amplifies the torque command and outputs a current to the motor, a detector that detects the rotational position of the motor shaft and outputs the motor position, and receives a signal from the detector to reduce the motor speed. The differential drive to be output, the torque command and the motor speed are input, and the difference speed between the motor speed and the estimated speed estimated by the internal observer is multiplied by γ (γ> 0) and added to the speed command to be driven by the motor. A motor control device that includes a vibration suppression control unit that suppresses vibration induced by a mechanical unit, and a motor speed control function that matches a speed command with the motor speed by feedback control. The observer in the control unit calculates the difference speed between the motor speed and the estimated speed as a constant α (α> 0, α = ωf ＾ 2)
Multiply and integrate, and from that value the estimated speed is multiplied by a constant β (β>
(0, β = ωf / Qf) is subtracted and added to the torque command used in the observer.

In the present invention, the transfer function G (s) ′ from the motor speed Vfb to the estimated speed mVf is given by: G (s) ′ = ωf ｛2 / ｛S ＾ 2 + (ωf / Q) * S +
ωf {2}, which is a configuration having no zero point of −ωf * Q, which is the prior art. Therefore, when it is desired to increase the estimation accuracy of the mechanical resonance estimation signal and the disturbance estimation signal, the observer itself can be stabilized by stably providing the poles of the characteristic equation which is the denominator of the transfer function. The design becomes very simple.

[0009]

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

FIG. 1 is a block diagram of a motor control device according to one embodiment of the present invention. The command generation unit 11 outputs the speed command Vr
Is output. The speed control unit 12 receives the speed command Vr and the detected speed signal Vfb of the motor 14 and
r is output, and the speed of the motor 14 is controlled so that the two input signals match. The current control unit 13 supplies a current to the motor 14 in response to the torque command Tr. Detector 15
Is connected to the rotating shaft of the motor 14 and the rotational position P of the rotating shaft is
fb is detected. The differentiator 16 receives the output signal of the detector 15 and calculates a difference, thereby calculating a speed signal Vfb of the motor 14. The mechanism 17 is driven by a motor 14. The vibration suppression control unit 18 receives the torque command Tr and the motor speed Vfb, and calculates the difference speed between the motor speed Vfb and the estimated speed mVfb by γ.
Times (γ> 0) and adds it to the speed command Vr.

Next, details of the present embodiment will be described. In order to simplify the explanation, the current control unit 13 is assumed to be 1 (the torque command Tr is converted into the motor current without any delay (error)), and the control system including the mechanism unit 17 is as shown in FIG. Is assumed. Here, the mechanism section 17 has a two-inertia vibration system in which the spring constant is Kω, the motor-side load is Jm, and the load-side load is Jl. The adder / subtractor 21 adds a damping control signal γVib output from the damping control unit 18 to the speed command Vr,
The speed deviation Ve is output by subtracting the motor speed signal Vfb. The integrator 22 integrates the speed deviation Ve with a time constant Ti. The multiplier 23 adds a constant P (0 ≦ P ≦
Multiply by 1). The adder / subtractor 24 adds the output of the multiplier 23 and the output of the integrator 22 to reduce the speed Vfb. Multiplier 2
Numeral 5 multiplies the output of the adder / subtractor 24 by the speed loop gain Kv to output a torque command Tr. Reference numeral 26 denotes a motor-side load when a control target is considered using a two-inertia model, reference numeral 27 denotes a spring constant, reference numeral 28 denotes a load-side load, and reference numerals 29 and 2a denote subtracters. The divider 2b receives the torque command Tr, and outputs a value Tr / J obtained by dividing the torque command Tr by a total inertia value J = Jm + Jl of the motor and the load. The adder 2c is connected to the Tr
/ J and the output total value dip of the observer compensating means described later are added to output mTr. 2d is an equivalent rigid model gain 1, 2e is an equivalent rigid model gain 2, 2f is an adder. The adder 2g calculates the estimated speed mVfb generated from the equivalent rigid body models 2d and 2e and the actual motor speed Vfb.
Is added. The output of the adder 2g is the mechanical resonance estimation signal Vib. 2h is an observer compensating means 1 and 2i is an observer compensating means 2; 2h is a constant β;
Is a constant α (claim 1). Reference numeral 2j denotes an adder for adding the outputs of the compensating means 2h and 2i of the observer, and the output thereof is the total output value dip of the observer compensating means.

In the present embodiment, the transfer function G (s) ′ from the motor speed Vfb to the estimated speed mVfb is G (s) ′ = ωf ＾ 2 / ＾ S ＾ 2 + (ωf / Q) * S +
ωf {2}, which is a configuration having no zero point of −ωf * Q, which is the prior art. Therefore, the mechanical resonance estimation signal Vi
If it is desired to improve the estimation accuracy of the disturbance estimation signal and the disturbance estimation signal, the observer itself can be stabilized if the poles of the characteristic equation, which is the denominator of the transfer function, can be stabilized. become.

[0013]

As described above, according to the present invention,
It is possible to provide a motor control device capable of accurately estimating the vibration generated from the mechanical resonance system, making the design of the compensator extremely simple, and suppressing the mechanical vibration.

[Brief description of the drawings]

FIG. 1 is a block diagram of a motor control device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating details of the embodiment of FIG. 1;

FIG. 3 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Command generation part 12 Speed control part 13 Current control part 14 Motor control part 15 Detector 16 Difference machine 17 Mechanical part 18 Vibration suppression control part 21, 29, 2a Subtractor 22 Integrator 23, 25 Multiplier 24 Adder / Subtracter 26 Motor Side load 27 Spring constant 28 Load side load 2b Divider 2c, 2f, 2g Adder 2d Equivalent rigid model gain 1 2e Equivalent rigid model gain 2 2h Observer compensator 1 2i Observer compensator 2 2j Adder 31 Divider 32, 33 , 36, 3a Adder 34 Equivalent rigid body model gain 1 35 Equivalent rigid body model gain 2 37 Inverter 38 Observer compensation means 1 39 Observer compensation means 2 Vr Speed command Tr Torque command Vfb Motor speed Vib Mechanical resonance estimation signal Pfb Rotational position mVfb Estimation speed

Claims (1)

[Claims] 1. A command generator for outputting a speed command, a speed controller for inputting the speed command and a motor speed and outputting a torque command, receiving the torque command, amplifying the torque command, and supplying a current to the motor. A current control unit that outputs, a detector that detects the rotational position of the motor shaft and outputs a motor position, a difference device that receives the signal of the detector and outputs the motor speed, By inputting the motor speed, multiplying the difference between the motor speed and the estimated speed estimated by the internal observer by γ times (γ> 0) and adding the difference to the speed command, the motor speed is induced by a mechanism driven by the motor. A motor control device comprising: a vibration suppression control unit that suppresses vibration caused by the motor; and a speed control function of a motor that matches the speed command with the motor speed by feedback control. The said observer, the difference speed of the motor speed and the estimated rate constant α (α> 0, α = ωf ^
2) multiplying and integrating, subtracting a value obtained by multiplying the estimated speed by a constant β (β> 0, β = ωf / Qf) from the value and adding it to a torque command used in the observer; Motor control device.