JPS628203A - Digital controller - Google Patents

Abstract

PURPOSE:To prevent the runaway of a controlled system due to abnormality by determining whether a control system is in proper operation or not by an abnormality detector, and using the output of a servocontrol circuit as a controlled variable when the operation is normal and stopping the control system when abnormal. CONSTITUTION:Deviation pressure En3 is deviation between target position data Xn1 and the position thetan2 of the controlled system. The servocontrol circuit 12 inputs the deviation En3 and realizes a control rule for determining a controlled variable In5 for optimizing an evaluation function depending upon the system. The abnormality detector 13 decides whether the control system is normal or not on the basis of the position thetan2 of the controlled system and controlled variable In5 and outputs an error signal 14. A selector 15 selects the output 16 of the servocontrol circuit 12 as the output of the error signal 14 when the control system is normal or switches the controlled variable 5 and stops the controlled system when abnormal, thereby suppressing the runaway of the control system.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention detects abnormalities in the surrounding environment of a controlled object, such as a measurement environment, a data converter, and a data transmission path, and prevents a control system from running out of control. [Prior Art] A digital control device generally has a configuration as shown in FIG. 4. In FIG. 4, (1) is target position data In,
(21 is the controlled object position θn'''C, +31 is In
With the deviation Kn between +11 and θn(2), the servo control circuit in (4) is.

The control value n of (5) is output according to the deviation Kn (31).

[Problem that the invention seeks to solve]

However, if an abnormality occurs in the means for measuring the controlled object position θn(2), or if an abnormality occurs in the means for transmitting the [ttllll data], the control valuable n(
There was a problem that 5) was outputted inappropriately, causing the control system to run out of control. For example, an abnormality occurred in the means for measuring the controlled object position θn (2), and even if the controlled object was activated, the controlled object Position θn(2)
becomes a constant value, the target position data Xn
tl) and the controlled object position θn(2) deviation In+31
ri becomes constant, and the corresponding control value n(5) also continues to output a constant value, causing the control system to run out of control in a certain direction.

Furthermore, even if the control system is normal, the output of the controlled object changes due to gradual fluctuations in the controlled object, making it difficult to detect true abnormalities with a fixed model.

Furthermore, an abnormality may occur due to accumulation of gradual fluctuations in the controlled object, and it has been a very difficult problem to determine whether the entire control system is abnormal.

This invention was made to solve this problem, and basically, a model of the control system is created from the input to the controlled object and the output from the controlled object, and the model is given to the model and the controlled object. This is achieved by appropriately estimating the position of the controlled object from the controlled variable.

While following gradual fluctuations in the controlled object, it detects abnormalities in the surrounding environment and prevents the control system from running out of control.

Furthermore, the purpose is to determine whether required control parameters are satisfied.

[Means for solving problems]

The digital control device of the present invention estimates a model of a controlled object in operation, and compares the output estimated from this model with the observed output of the controlled object.

and an abnormality detector that detects an abnormality in the surrounding environment by determining whether a control parameter obtained from the model of the controlled object in operation satisfies a necessary value;
A selector is provided for switching 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 system is stopped by setting the control amount to 0''.

〔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 target position data Xn fl)
This is a digital control device according to the present invention which outputs a control value n(5) from a controlled object position θn(2), and the control value n(5) and (7) are converted into an analog quantity by a digital-to-analog converter (8). ) is appropriately amplified by the amplifier (9), and becomes an input to the drive machine (9) which is the controlled object, and the drive machine (9) operates according to the control amount.

When the drive machine (9) operates, the position is detected by the connected OI's ink oscillator, and the position is fed back as the controlled object position θn(2) via the αυ synchronized digital converter.

FIG. 2 is a diagram specifically showing the digital control device (6). 11), +21. [5+Fil O which is the same as in Fig. 1 In Fig. 2, (3) is a deviation of 11 inches between the target position data Xn (11) and the controlled object position θn (2), and a
'zr is a servo control circuit which takes the deviation In +31 as an input and implements a control law that determines a control amount In(5) that optimizes a system-dependent evaluation function.

03 is an abnormality detector, which determines whether the control system is normal or abnormal based on the controlled object position θn(2) and the controlled amount In +51.

Outputs a4 error signal.

The error signal α4 outputs "0" when the control system is normal, and outputs "1" when the control system is abnormal, and is input to the selector.

The selector α9 selects the output αG of the servo control circuit aZ when the error signal α4 is “0”, and selects the output αG of the servo control circuit aZ when the error signal α4 is “1”.
'', the control system can be prevented from running out of control by switching the control amount (5) to aη of ``0'' and stopping the controlled object. In the diagram shown)
, +21. +51 is the same as in FIGS. 1 and 2.

αe is a model estimation circuit, and the controlled object position θn(2
) and the control amount In(5) to estimate the model of the controlled object.

In other words, the controlled object position θn(2
) and the control amount In(5) can be considered a first-order sodel.

H[21aθn-G(zls engineering n where n: sampling time θn; controlled object position engineering n at sampling time n; control amount () (Z-1) at sampling time n; next model G ( z-1)
-A1@Z +-・-+Ak@Z-kH (Z-1);
m-order model of control system H(z-1)-1+B1eZ +
−−−−−−+BmmZ−”The model estimation circuit uses the observed controlled object position θn(2) and the control value n(5) to generate the (k+−)th model of the control system as follows. Find (k+m) coefficients of.

Qn+1mQn-ICn+1#(In+1'5Qn-Q
n) Kn+1-Pn@In+1 #(1+In+1'@
Pn@Xn+1 )-1Pn+1-Pn-Pn*Xn+
1@(1+In+1'*PnsXn+1)sXn-N'
*Pn where Po; degree matrix Qn; (k+m) coefficient matrix -(A1.A2.・-
Ak, B1...-B! n) xn; observed Qn and engineering n
matrix) (n+; The transposed matrix aS of the observed Qn and In is the predicted output an of the model estimation circuit tis, and is given from the next model of the obtained control system as follows.

Qnw (11#z-'+ """+Al(@Z-k
)*Xn-(B1+...song+Bz eZ-” '″'
)-#n-1 ■ The comparison circuit depends on the system to determine the error between the actually obtained output θn(2) of the controlled object and the predicted output an obtained from the next model of the estimated control system. Compared to the tolerance range e.

If fSn-〇nl(e) is satisfied, it is determined that the control system is normal and an error signal is output as '0'; otherwise, it is determined that the control system is abnormal and outputs '1'.

@ is the control parameter estimation circuit, and the model estimation circuit Q
AI+A2+...Ak obtained in 16, B1.
B2. ...The control parameters can be obtained from Bm as follows.

gainw(A1←=-+Ak>/C1+B1 +・,
, , , +Bk) Here, gain ; o of the control system
pen 1oop's gay/L ; wasted time 1 ; coefficients from A1 to A1 are approximately "0" 1 What is ? Bl + control parameter G1 required for control system
゜G2, Ll is input to the comparison circuit of 91 examples,
Compare the parameters with the control parameters obtained using the parameter estimation circuit.

If G2(gain(G1 and L(Ll) is satisfied, it is determined that the control system is normal and outputs "0" as an error signal (c); otherwise, it indicates that the control system is abnormal and outputs "1".

@ is a logic sum circuit which takes the logical homology between the error signal Qυ and the error signal (to) and outputs it to the selector G9.

Although the above embodiment uses a synchro oscillator for measurement, the present invention can also be applied to other means capable of measuring two positions.

〔Effect of the invention〕

As described above, according to the present invention, there is no need for a control system model in advance, and the position measuring means, synchro-digital converter, and digital-to-analog converter of the controlled object can be adjusted while following the gradual fluctuations of the controlled object. It is possible to detect an abnormality if any occurs, and it is also possible to detect an abnormality in the case of steady changes in the controlled object.
This has the advantage of preventing runaway of the control system.

[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 the abnormality detector σ3, and FIG. 4 is a diagram showing a conventional digital control device. In the figure, (1) is the target position data In, +21 is the controlled object position θn, (3) is the deviation Hn, +41 is the servo control circuit, (5) is the control amount In, (61 is the digital control device,
(7) is a digital-to-analog converter, (8) is an amplifier,
(9) is a driver, 01 is a synchro oscillator, aυ is a synchro digital converter, α? is the servo control circuit, G3 is the abnormality detector, I is the error signal, ttst' is the selector,
as, a'n is the output value, (lli model estimation circuit, G
9 is the controlled system parameter Qn actually obtained by the parameter comparison circuit Qυ, ■ is the comparison circuit, C+U is the error signal, and is the control parameter estimation circuit. ! 3ri
Control parameters, @ is comparison circuit. (c) is an error signal, and (4) is an OR estimation circuit. In addition, the same or equivalent parts in the two figures 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 detects abnormalities in the surrounding environment of the servo control circuit and the controlled object from the input to the controlled object and the output from the controlled object. It has an abnormality detector that detects an abnormality, and a selector that switches output to a controlled object based on an error signal output by the abnormality detector, and detects abnormalities in the surrounding environment and runaway of the control system due to the controlled object. A digital control device characterized by suppressing.