JPS629403A - Digital controller - Google Patents

Abstract

PURPOSE:To prevent the runaway of a control system by stopping the working of the control system based on the output of a fault detector which decides the normal or abnormal state of the control system. CONSTITUTION:A fault detector 14 decides the normal or abnormal state of a control system from the position thetan2 of a control subject and the control amount In5 and delivers an error signal 14. Then the signal 14 is supplied to a selector 15 with output of '0' and '1' with the normal and abnormal states of the control system respectively. The selector 15 selects the output 16 of a servo control circuit 12 when the signal 14 is equal to '0'. While the selector 15 switches the controlled valuable 5 to '0' of 17 to stop the controlled system when the signal 14 is equal to '1'. Thus the runaway of the control system is prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a digital control device that can detect abnormalities in a control system due to aging of a controlled object, environmental changes, etc., and can prevent runaway of the control system. It is something.

[Conventional technology]

Generally, a digital control device has a configuration as shown in FIG. In FIG. 4 (11 is target position data X n
, (21 is the controlled object position θn.

(31 is X n (11 and on (deviation En of 21, (
The servo control circuit (4) outputs the control amount In (5) according to the deviation E n (31).

[Problem that the invention seeks to solve]

However, if an abnormality occurs in the controlled object, or due to aging or environmental changes in the controlled object, the predetermined control law is not titrated, and the control amount In (51) is outputted inappropriately, causing the control system to run out of control. There was a problem.

This invention was made in order to solve this problem.The purpose of this invention is to create a control system model from the input to the controlled object and the output from the controlled object, and to control the control system obtained from this model. By comparing the system parameters with the required control system parameters, it is possible to prevent the control system from running out of control when an abnormality occurs in the controlled object, or by detecting aging or environmental changes in the controlled object. This is the purpose.

[Means for solving problems]

The digital control device of the present invention detects abnormalities in the control system by estimating a model of the controlled object during operation and comparing the control system parameters obtained from this model with the required control system parameters. The apparatus is provided with an abnormality detector and a selector that switches the output to the controlled object based on the error signal output by the abnormality detector.

[Effect]

In this invention, the abnormality detector determines whether or not the control system is operating properly, and if the control system is operating properly, the output of the servo control circuit is used as the control amount to prevent the control system from malfunctioning. If appropriate, the control amount is set to #O" and the control system is stopped.

〔Example〕

The present invention will be specifically explained below with reference to an embodiment shown in FIGS. 1 and 2.

FIG. 1 is an overall configuration diagram of a control system including a digital control device according to the present invention.

In FIG. 1, (6) is a digital control device according to the present invention that outputs a control amount Inf51 from target position data Xn (11) and controlled object position θn (21).
I n (51 is converted into an analog quantity by the digital-to-analog converter (7), amplified appropriately by the amplifier (8), and becomes an input to the drive machine (9), which is the controlled object, and is driven according to the controlled quantity. Machine (9) is activated.

When the drive machine (9) operates, the position is detected by the connected synchro oscillator (11), and is fed back as the controlled object position θn(2) via the synchro digital converter (lυ).

FIG. 2 is a diagram specifically showing the digital control device (3), where (11, (21, and 51) are the same as in FIG. 1.

In FIG. 2, (3) is target position data X n (1
1 and the controlled object position θn(2), and (
I3 is a servo control circuit which takes the deviation E n (31) as an input and implements a control law that determines the control amount In (51) that optimizes the system-dependent evaluation function.

(I3 is an abnormality detector, which determines whether the control system is normal or abnormal from the controlled object position θn (2) and the controlled amount In (51),
Outputs I4 error signal.

The error signal α is 10# when the control system is normal.

If the control system is abnormal, #l# is output and a! It is input to the selector 9.

The selector (I!9 selects the output αe of the servo control circuit when the error signal (14 is “0#”), and selects the output αe of the servo control circuit when the error signal (14) is “1”, selects the control 1t (51'k IAH #0 By switching to # and stopping the controlled object, runaway of the control system is prevented.

FIG. 3 is a diagram showing the abnormality detector a1+1,
(2) and (5) are the same as in FIGS. 1 and 2.

Nishiki is a model estimation circuit, and the controlled object position θn(2)
The model of the controlled object is estimated from the control amount In(51).

In other words, the controlled object position θn(2
) and the control amount I n (51), a 9th order model can be considered.

H(z)・θn = G(z) ・I n where n: Sampling time θn; Controlled object position In at sampling time n; Controlled amount G(z-1) at sampling time n: Next in the control system Model Glz 11=At Z + ・・・・・・・・・+Ak−Z−k H(z−1); m-order model of control system H(z−1)=10B,・Z× ......+Bm-Z-1 In the model estimation circuit Qli, the observed controlled object position θ
Using n (21) and control t I n (5), the coefficients of the next model of the control system and the m coefficients of the m-order model of the control system are determined in a 9-order manner.

Qn+1=Qn-Xn+1 ・(Xn+1'-Qn-Q
n) Xn+1=Pn-Xn+1・(1+Xn+1・・P
nXn+1) 'Pn+1=Pn-Pn-Xn+1・(
1+Xn+1l-Pn・Xn+11'-1・Xn+1'
Pn where Po; identity matrix Qn: k+m coefficient matrix = (As, At,...Ak, Bt, B
t,...Bm)
hAm+...Ak, B+, Bt.

...The control parameters can be obtained from Bm as follows.

gain= (At +=-...+Ak) / (1
+Bt +...-+Bm) L=i where gain: gain L of open 1 loop of control system
;Dead time i: The coefficients from Az to Ai are approximately "OIT."

Additionally, the time constant of the control system can be determined as needed.

(a) is the control parameter GK+ required for the control system.
Gv and Ll, which are input to the comparison circuit of r2υ,
Compare with the control parameters obtained by the control parameter estimation circuit.

Gl (gain (Gt and L) If Lt is satisfied, it is determined that the control system is normal and #0# is output as error signal I; otherwise, the control system is abnormal and outputs #1#. Input to selector.

Although the above embodiment is an example of the open 1 loop gain and dead time of the control system, the present invention can be applied even when other control parameters are required. [Effects of the Invention] As described above, the present invention According to this method, an abnormality in a controlled object can be detected from physical parameters necessary for control design, and there is an advantage that runaway of the control system can be suppressed.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of a control system including a digital control device according to the present invention, and FIG.
), FIG. 3 is a diagram specifically showing abnormality detector 0, and FIG. 4 is a diagram showing a conventional digital control device. Data Xn, (2
) is the controlled object position θn, (31 is the deviation E n ,
(41 is the servo control circuit, (5) is the control circuit
n, (61 is a digital control device, (7) is a digital to analog converter, (8) is an amplifier, (9) is a driver, +11 is a synchro oscillator, al is a synchro digital converter, wholesale is a servo control circuit. 0 is an abnormality detector, a4 is an error signal, a!9 is a selector,
H, (Ltl is the output value, α seconds is the model estimation circuit, (I9
is a control parameter estimation circuit, ■ is a parameter, and clυ is a comparison circuit. In addition, the same or corresponding parts in FIG. 1 are given the same reference numerals.

Claims (1)

[Claims] A servo control circuit that takes the error from the target value as input and outputs the controlled amount to the controlled object, and a control system model from the input to the controlled object and the output from the controlled object, and from this control system model. An abnormality detector that detects abnormalities in the controlled object by comparing the obtained control system parameters with the required control system parameters, and an error signal outputted by the abnormality detector to output to the controlled object. What is claimed is: 1. A digital control device comprising: a selector for switching a control object;