JPH0336978A - Motor-speed controller - Google Patents

Abstract

PURPOSE:To obtain a speed control system suppressing the vibration of a motor load and being excellent in speed response by making a speed feedback (FB) value and position FB value variable at the time of feedbacking the estimate of the state (speed, position) of a load connected with a motor so that the present speed of response is equal to a target responding property. CONSTITUTION:The responding property of a system including an observer system 9 is judged by a characteristic value A-KT. A is a part of the indication of variables of a mathematical expression model state and KT is the feedback FB matrix of the block diagram. Then, the characteristic value is alphai, a target system characteristic value betai is stored beforehand in the memory of a computing element 12, and alphai and betai are compared with each other. In case of alphai>betai, the present responding property is larger than a target responding property so that only Komega 15 and Ktheta 16 further shown in the drawing are feedbacked. At the time of alphai<betai, FB is reduced, because the responding property is under the target, and the correction of FB is not performed in case of alphai=betai. Thus, when Komega 15 and Ktheta 16 are variably feedbacked to a position command 1 and speed command 2 according to the responding property, a speed responding property can be made equal to the target response.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a motor speed control device used in NC machine tools, industrial robots, and the like.

Conventional technology In recent years, there has been a remarkable shift towards FA in industry, and NC
Machine tools and industrial robots are growing rapidly, and motor speed control devices are also making remarkable progress.

A conventional motor control device will be described below with reference to the drawings.

FIG. 4 shows a block diagram of a conventional motor speed control device.

Moreover, FIG. 3 is a mathematical model diagram of a motor section connected to a load. In FIG. 3, 11 is an inductor with a motor inductance L, 12 is a resistor with a resistance value R1, and 13 is an inductor with a resistance value R1.
is a motor with rotor inertia JM where the power generation constant is Kh and the l'k constant is □. 16 is a mathematical model of the load connected to the motor 13, 14 is a spring constant Ks, 1
5 is motor friction, and 17 is load inertia JL. Now, the motor rotates at an angular velocity ωM, the load rotates at an angular velocity ωL, the rotor position is θM, and the rotational position of the load is θL. If the motor applied voltage is V, then V a” Rm I a + L a I a + K
b (J) m ”'”' filθ.

=ω, ・・・・・・(2
) K a I a = J M(d M+ K s (
θ□-θL)+BS(ω.-ω,)...(3) Kg(θ-θt)+Bs(ωM-ωL)=JL(II
L...(4) θL:ωL...(5) It becomes.

(1) above.

(2).

(3).

(4).

State variable display from equation (5) if, ・・・・・・(6) becomes.

(6) formula =Ax +b Let's call it U.

however, x=[Imωyθ%lωlθL]' b=[1 0]゛.

u=Va.

This state variable■□ ωL+ θL.

ωM.

When state feedback is performed using 0M, the block diagram shown in FIG. 4 is obtained. 1 is position gain, 2 is velocity system gain, 3 is compensation gain, 4 is current loop gain, 5 is current compensation gain,
6 is the motor transfer function coefficient. Note that the state variable ωL,
Since θL cannot be directly observed, an observer method is used to estimate it.

In the speed control device of FIG. 4, the speed of the load.

The vibration of the load is suppressed by estimating the speed 9 position of the load using the observer 9 and feeding back the position feedback.

Problems to be Solved by the Invention However, although the above configuration can suppress the vibration of the load to some extent, it has the disadvantage that it does not take into account the responsiveness until the load reaches a steady state.

In view of the above drawbacks, the present invention provides a motor speed control device that suppresses load vibration and has good speed response.

Means for Solving the Problems In order to solve the above problems, the motor speed control device of the present invention includes a first means for calculating the state of a load connected to the motor, and a speed command that variably uses the calculated value of the first means. a second means for feeding back to the first position command; a third means for calculating the speed responsiveness; and a third means for comparing the standard speed responsiveness and the speed responsiveness calculated by the third means and outputting the difference value. It is composed of four means.

According to the present invention, with the above-described configuration, it is possible to improve the speed response by setting the desired speed response as the reference response and correcting the load state feedback calculation value so that the current speed response becomes equal to the reference. Become.

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

FIG. 1 shows a block diagram of a motor speed control method in an embodiment of the present invention. In FIG. 1, the same components as in FIG. 4 are designated by the same numbers, and their explanations will be omitted. Reference numeral 12 denotes a computing unit that can compare the standard speed response value and the current speed response and make the feedback calculation value variable. Further, FIG. 2 is a flowchart showing the processing contents of the arithmetic unit 12. First, the angular velocity ωM1 position θM of the motor and the angular velocity ω52 position θ of the load estimated by the observer.

Find the deviation.

Δω=ω□−ω, ・・・・・・(7)
Δθ=θM−θL (8)
becomes.

Next, if the feedback matrix in Fig. 1 is kT, then k"-[K+, K, M, KPM, K, t,
Kst] --(becomes 91.

u = −k”x ・
...11 (If 1 is the state feedback, G1
Substituting the formula into formula (6), x=Ax-kTx= (A-k")x...
(11).

Here, the responsiveness of the system is determined by the eigenvalue of A-kT.

In equation (9), if θL is replaced with an equation that includes the deviation of equation (8) for t, then K-t= k-L(1+Δω)...
・(12) K11L=#t (1+Δθ)
...(13).

By substituting equations (12) and (13) into the feedback matrix of equation (9) and finding the eigenvalue of A−kT in equation (11), the responsiveness including the observer system can be obtained. Let the obtained eigenvalue be αI (i=1...n), and the eigenvalue of the target system be β1 (i=1......n).
・N) is stored in the memory of the arithmetic unit 12 in advance, and α and β values are compared. As a result, 1α1! 〉1β1
If it is 1, the current responsiveness exceeds the target responsiveness, and further feedback is given as ks=b l α11-1 β11 ・
...(15) (a and b are weighting coefficients). If 1α11<1β, the responsiveness is lower than the target,
k,=-a11a+l-lβ-l,ke--b If
Decrease feedback as all lβ.

Also, if 1α11=1β11, then =ks−〇,
No feedback correction is performed. As described above, the arithmetic unit 12 calculates k as shown in FIG.

By variably feeding back β16 to the speed command and the position command, the speed responsiveness can be made equal to the standard response. As described above, according to this embodiment, when feeding back the estimated value of the state g (velocity 1 position) of the load connected to the motor, the current response speed is made equal to the reference (target) response. By making the speed feedback value 1 and the position feedback value variable, it is possible to suppress vibrations of the motor load and configure a speed control system with good coordination.

Effects of the Invention As described above, according to the present invention, vibration of the load can be suppressed and speed responsiveness can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a motor speed control device according to an embodiment of the present invention, FIG. 2 is a flowchart showing the processing contents of the computing unit 12 of the same device, FIG. 3 is a mathematical model diagram of the motor section and load, and FIG. The figure is a circuit diagram of a conventional motor control device. 12... Arithmetic unit.

Claims (1)

[Claims] In a motor speed control device that detects the position and speed of a rotor using an encoder of the motor and causes the position and speed of the rotor to follow a position command and a speed command, a first means for calculating a state of a load connected to the motor; a second means for variably feeding back the calculated value of the first means to a speed command and a position command; a third means for calculating speed responsiveness; and a speed standard responsiveness calculated by the third means. A motor speed control device comprising a fourth means for comparing speed responses and outputting a difference value.