JPS63129875A - Controller for motor - Google Patents

Abstract

PURPOSE:To stabilize a servo system, by a method wherein the inertia of a load is estimated and the gain of the servo system is regulated automatically based on the estimation. CONSTITUTION:The controller for a motor M is provided with a digital processing unit A and a hybrid processing unit B while the rotating position of said motor M is detected by an encoder C and is inputted into a F/V converter 11 and a pulse counter 12. The F/V converter 11 converts the position signal into the signal of the rotating speed of the motor while a pulse counter 12 counts the number of pulse and outputs the present position of the motor M. A servo operating unit 12 is provided also in the controller and PID operation is effected by said output to operate the speed commanding value of the motor M. In this case, a regulating means 19 is provided to estimate the inertia moment of a load based on the commanding value of the torque and the rotational speed of the motor M whereby the gain of an amplifier 18 is regulated based on the estimation. According to this method, a servo system may be stabilized and the system may be regulated easily.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a motor control device.

[Prior art] [) [) ([) direct Drtve)
Because it has a structure without a reduction gear, it has high rigidity.
There is little vibration during high-speed operation. Therefore, when a DD motor is used, the position reproducibility is good.

For this reason, the DD motor is suitable for position control of arms and the like.

[Problems to be Solved by the Invention] Fig. 5 does not show a block diagram of the servo system of the DD motor. In a motor like this block diagram, position control and speed control are performed by the position controller (
Hybrid i, II! which uses a rough 1 header (hereinafter referred to as PC) and a servo driver (hereinafter referred to as SD). I am using II.

In the figure, X I N l is the 1st command box, XOU 1 is the current rotational position of the motor, and Tuc disturbance.

The transfer function of such a servo system is as follows.

Here, σ: Rise time, α: Wave constant, η: Feedforward gain, E gain, S: Laplace deductor, KT: DD'E torque constant, KP: Encoder constant, Ko, K3: Constant , becomes.

Such a formula was derived from gain design using the model reference method. Also, as a reference, ``81 methods for establishing a control system based on partial knowledge of the controlled object'' by Toshiyuki Kitamori <Oawa 5
(August 4, Proceedings of the Society of Instrument and Control Engineers, Volume 15, No. 4).

(2) As can be seen from the equation, the moment of inertia J is the parameter that varies in determining the gain of the 1-nervo system. In the case of a DD motor, the motor's own moment of inertia JM
is sufficiently smaller than the moment of inertia JL of the load.
In most cases, L is dominant. For example, J.L.
is 10~/IO times that of JM.

Since the DD motor is directly affected by fluctuations in the inertia of the load, in order to determine the gain so that the servo system does not oscillate,
In addition to the value of the moment of inertia JL, the value of the inertia of the zero load must be known.

Further, even if the inertia of the load does not change, proper tuning cannot be performed unless the value of the inertia V of the load is known at the time of initial tuning of the servo system. Furthermore, modern control i
It is impossible to design a servo system using instant theory unless you know the value of the inertia of the load.

The present invention has been made in view of these points, and it is possible to estimate the inertia value of the load, adjust the gain of the servo system appropriately based on the estimated value, and stabilize the length-bore system. The purpose is to realize a motor control device.

[Means for Solving the Problems] The present invention includes: a constant current amplifier that supplies an excitation current proportional to a motor torque command value to a motor coil, an encoder that detects the rotational position of the motor, and this encoder. a speed detection unit that detects the rotational speed of the motor based on a detection signal of the motor; a test signal generation unit that generates a test signal of the rotational speed of the motor; and a difference between the test signal and the detection signal of the speed detection unit. an amplifier that amplifies the signal, and an inertia value of the load applied to the motor based on the relationship between the output of this amplifier and the detected speed of the speed detection section, jl[,
A motor control device comprising: adjusting means for adjusting the gain of the amplifier so that the difference signal becomes zero using an adaptive algorithm from an estimated value.

[Example〕 The present invention will be explained below.

As can be seen from Fig. 5, in a system including an unknown parameter J, the torque command 1fl u and the motor rotational speed statement OUT
The relationship has a very simple form. Therefore, it becomes easy to convert the 0 expression into a form suitable for microprocessor operation, for example, a recursive form. However, in order to realize the recursible form operation, it is necessary to know the torque command value and speed signal from the SD, and further adjust the gain by the PC.

An example of a reference on recursible forms is ``Theory and Practice of Adaptive Control Systems'' by Landau Waka (Ohm Publishing).

Therefore, the motor control i according to the present invention (for the I device,
SD and PC integrated into one board.

FIG. 1 shows the structure of an embodiment of a motor control device according to the present invention.

In the figure, part A is a digital processing section, and part B is a hybrid processing section.

AI+Δ2 is a constant current amplifier, which supplies a current proportional to the torque command value U to the coil LI+L2 of the DD motor.

C is an encoder that detects the rotational position of the motor M. The encoder detection signal is sent to the F/F via an encoder interface (hereinafter referred to as encoder I/F) 10.
The signal is applied to a V converter 11 and a pulse counter 12.

The F/V converter 11 converts the position signal from the encoder 1/F10 into a signal representing the rotational speed of the motor.

The pulse counter 12 counts the number of pulses of the signal from the encoder 10, and outputs a signal Xour indicating the current position of the motor after the count value.

13 is a robot calculation section which performs PID calculation based on the position command value XIN and the signal of the motor's current position Xout, and calculates and outputs the motor speed command value.

A microprocessor or DS is used for the calculation of the servo calculation unit 13.
P(Di9italSignal Processo
r) etc. are used.

A signal generator 14 generates a known test signal (speed signal).

15 is an adder, which connects the servo calculation section 13 and the signal generator 1.
Add the outputs of 4. The signal generator 14 is a switch SW1
It is connected to the network via nm15.

16 is a D/A converter that converts the output of the adder 15 into a D/A converter.

A subtracter 17 outputs a difference signal between the outputs of the D/A converter 16 and the F/V converter 11. "/V converter 11 is
It is connected to the subtracter 17 via the switch SW2.

18 is an amplifier with a gain of E, which amplifies the difference signal from the subtracter 17; The output of the amplifier 18 becomes the torque command value U of the DD motor.

H+ and H2 are commutation means, and the command value, S1n value and C
Given the OS value, convert it into a current for the commutation switch 11 and convert it into a constant current amplifier △7. Give to A2.

19 is an adjustment means, which adjusts the moment of inertia J of the load based on the command value U of 1 to luke of the DD motor and the rotation speed aXour.
L is estimated, and the gain E of the amplifier 18 is adjusted based on the estimated value.

Next, the operation of such a device will be explained.

In gain adjustment mode, switch SW1 is turned on,
Signal generator 14 generates a random noise signal. Input/output ryJ related to this random noise signal, that is, torque command #nu and current speed X.

The load inertia 17JL is estimated from the IJT relationship, and the gain E of the amplifier 18 is adjusted based on the estimated value. Inertia is estimated by a parameter estimation method using an adaptive algorithm. This estimation method will be described later.

When the estimation is finished, switch SW2 is turned OFF to set the normal servo mode.

Note that the switch SW1 is turned OFF, the input command value XxN is varied, and the load inertia JL is determined from this variation.
You may also ask for

From this, the servo calculation section 13 and the signal generator 14 constitute a test signal generation section.

Here, a parameter estimation method using an adaptive algorithm will be explained.

Adaptive algorithms for control systems are currently being actively researched and applied. Among them, MRAS (ModeI Ref
Adaptive System)
is attracting attention.

FIGS. 2 and 3 are diagrams illustrating the operation of continuous MRAS. FIG. 3 is a qualitative diagram illustrating the operation.

In FIG. 2, Dl is a means for giving an ideal value of the model, D2 is a means for giving an estimated value, D3 is a subtractor, and D4 is a means for determining new parameters. Each code is as follows.

u(t): Control input X: To state variable x (t): Estimated variables a, b: Model control parameters a (t), b (t): Estimated control parameter Aa
+Ieb: The positive constant means D1 performs the calculation of the following equation.

Intersection = a x ten b u
Equation 00 was obtained from the ideal curve of the model created in it i I.

Means D2 performs the calculation of the following equation.

Intersection (t) = 6 (1) (1) - t - b (t) u (t) ■ Subtractor D 3 obtains a difference signal e (t) = x - x (t).

Means D4 obtains a new parameter a(t) from the following equation.

Eight Find b(t).

With such a calculation method, if e(t) is positive and x(t) is positive as shown in Figure 3, then from equation 0, da(t)
/'dt becomes positive, so a(t) increases and e (t
) converges to O.

Also, if e(t) is negative and u(t) is positive, d'b(t)/dt is negative from equation (2), so b (
t > decreases, causing e(t > to converge to O.

In this way, the estimated value is brought closer to the associated value.

When applying MRAS to formula 0, set a = a (t) - 〇, command value U, current speed statement ourKyKP/JS
Control human power u (t), x (t), b (t) respectively
Make it. Further, this performance is performed by the ita adjustment means 19.

FIG. 4 is a diagram showing the configuration of another embodiment of the motor control device according to the present invention. In FIG. 4, the same parts as in FIG. 1 are given the same reference numerals.

The device shown in FIG. 1 uses analog calculations for motor speed control and commutation control, but the device shown in FIG. 4 uses digital control to perform these controls.

In the figure, 20.21 is a D/A converter IIA which converts the output of commutation means 1-1+ and H2 from D/A to analog.

22 is a Δ/D converter that converts the position signal from the encoder I/FIO into Δ/D, and 23 is a Δ/D converter that converts the position signal converted by the A/D converter 22 into a velocity and sends it to the paralysis device 17. It is a speed processing means.

The F/V conversion mechanism 11 shown in FIG. 1 and the speed processing means 2 shown in FIG.
3 corresponds to the speed detection section.

In the embodiment, t--9 is a two-phase motor, but a motor with a different number of phases may be used.

Further, the ff, IIin device according to the present invention may be applied not only to DC motors but also to general DC motors (direct current motors) and the like.

In addition, in the embodiment, the position signal r3XoUv is sent to the servo calculation unit 1.
3, a speed loop may be constructed by setting XIN and Xo UT to the speed command value and the current speed.

However, in this case, it is necessary to turn off the switch SW2.

[Effects] According to the present invention, load inertia is the only unknown parameter when controlling a motor. Since JL is estimated and the gain of the servo system is automatically adjusted based on the estimated value, the servo system can be stabilized and adjustment of the servo system becomes easy.

In addition, since constant current amplifiers A+ and △2 are used as power amplifiers to supply the motor coil with a current proportional to the torque command value, the relationship between the torque command value and the motor rotation speed is simple as shown in equation 0. The moment of inertia Jc of the load can be easily determined as 1ffl.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of a motor control device according to the present invention, FIGS. 2 and 3 are explanatory diagrams of an MRA S algorithm, and FIG. 4 is a diagram of an embodiment of a motor control device according to the present invention. FIG. 5 is a block diagram of the servo system of the DC motor. M...Motor, C...Encoder, △1. A2...
・Constant current amplifier, 11...F/V converter, 13...
Servo calculation section, 14... Signal generator, 18... Amplifier, 19... Adjustment means, 23... Speed Ig, processing means. 2nd cause 3rd mountain 5th figure

Claims (1)

[Claims] A constant current amplifier that supplies an excitation current proportional to a motor torque command value to a motor coil, an encoder that detects the rotational position of the motor, and a motor that rotates based on the detection signal of the encoder. a speed detection section that detects the speed; a test signal generation section that generates a test signal of the rotational speed of the motor; an amplifier that amplifies the difference signal between the test signal and the detection signal of the speed detection section; and an output of the amplifier. Adjustment means for estimating the inertia value of the load applied to the motor based on the speed relationship detected by the speed detection section, and adjusting the gain of the amplifier using an adaptive algorithm from the estimated value so that the difference signal becomes zero. A motor control device equipped with the following.