JPS61184602A - Digital controller - Google Patents

Abstract

PURPOSE:To suppress the out-of-control of a control system by estimating the position of a controlled system from a controlled valuable given to the controlled system so as to detect an abnormality in an outer peripheral environment and switching an output to the controlled system. CONSTITUTION:A servo control circuit 12 inputs a deviation 3 and outputs 16 the controlled valuable to the controlled system. An abnormality detector 13 estimates the position of the current controlled system, which allows the useless time, from the previous position of the controlled system and the controlled valuable 5, compares said position with the inputted current controlled system position 2, decides the normalcy or abnormality of the control system and outputs an error signal 14. The Zero and '1' of the signals 14 are outputted when the control system is normal and when it is abnormal, respectively, and are inputted to a selector 15. When the signal 14 is zero, the selector 15 selects the output 16 of the circuit 12, and when the signal 14 is '1', it switches the controlled valuable 5 to the zero of an output 17. Then the controlled system is stopped, thereby suppressing the out-of-control 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. The present invention relates to a digital control device that can perform the following functions.

[Conventional technology]

Generally, a digital control device has a configuration as shown in FIG. In FIG. 3, +11 is target position data In;
(2+Fi control target position θn, (3nI/'1X
The servo control circuit (4) is the deviation Kn between nfil and θn(2).

The control amount n in (5) is output in accordance with En131.

[Problem that the invention seeks to solve]

However, if an abnormality occurs in the means for measuring the controlled object position θn(2), and L<, if an abnormality occurs in the means for transmitting the measured data, the control amount In(5) becomes abnormal. There was a problem in that if the output was continued for an arbitrary length of time, it would cause the control system to run out of control.

For example, even if an abnormality occurs in the means for measuring the controlled object position θn(2) and the controlled object is activated, the controlled object position θn(2)
becomes a constant value, the target position data In
+11 and the deviation Enf31 between the controlled object position θn(2) becomes constant, and the corresponding control amount n(5) also continues to output a constant value, causing the control system to run out of control in a certain direction.

This invention has been made to solve this problem, and takes into account the wasted time that always exists in a control system.
The purpose of this is to detect abnormalities in the surrounding environment by appropriately estimating the position of the controlled object based on the control amount given to the controlled object, and to prevent the control system from running out of control.

[Means to solve the problem]

The digital control device of the present invention estimates the current position of the controlled object from the previous position of the controlled object and the control amount, taking dead time into account, and compares it with the inputted current position of the controlled object. The apparatus is provided with an abnormality detector that detects an abnormality in the environment, and a selector that switches the output to the controlled object based on the error signal output by the abnormality detector.

[Operation] 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 control the control system. If the operation is inappropriate, the control amount is set to 0'' and the control system is stopped.

〔Example〕

The present invention will be specifically described 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 the first male, (611Ii target position data Xn (
This is a digital control device according to the present invention which outputs a control value n(5) from a control object position θn(2) and a control target position θn(2), and the control value n(511d(71) is converted into an analog quantity by a digital output converter. It is suitably amplified by the amplifier h (81) 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 synchro oscillators of fc members, and the position of the controlled object θn(2) is fed back via all synchro digital converters.

FIG. 2 is a diagram specifically showing the digital control device (31). +21. +31. (51 is the same as in FIG. 1).

In FIG. 2, α2 is a servo control circuit.

Deviation 1! It takes i n (31) as an input and realizes a control law that determines the control value n (51) that optimizes the system-dependent evaluation function.

0 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).

I's construction surface - Outputs a signal.

In other words, the controlled object position θn(2
) and control precious n(5), if the control system is normal, 2
The following relationship holds true.

θn=θn−1+A−In−k −−−−−1−−−
−−−+11 where n; sampling time θn; position of the controlled object at sampling time n; n; constant that depends on the controlled variable A at sampling time n; θn(2)
and the control target position estimated by the control amount In(5) is 8n
Then, sn is Sn = θn-1 + A, engineering n-K
------------- (Given in 21, the error with the actually obtained controlled object position θn(2) and the allowable error range e that depends on the system.

1sn-θn1(e If the following is satisfied, it is determined that the control system is normal.

The error signal aa outputs "0" when the control system is normal, and outputs "1" when the control system is abnormal, and is input to the selector a9.

The selector a selects the output αe of the servo control circuit +13 when the error signal a4 is “ON”, and the error signal α4 is “ON”.
In the case of 1'', the control amount (5) is switched to aη of 0'' and the controlled object is stopped, thereby preventing the control system from running out of control.

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, wasted time can be taken into account even when an abnormality occurs in any one of the position measuring means, synchro-digital converter, and digital-to-analog converter of the controlled object.
It is possible to accurately detect this by checking the control system, and furthermore, it is possible to detect abnormalities in the controlled object, which has the benefit 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.
), and FIG. 3 is an fc diagram showing a conventional digital control device. In the figure, (l) is the target position data In, (21 is the controlled object position θn, f31 is the deviation En, (41 servo control circuit, (5) is the control element n, +61 is the digital control device, (71 is the Digital to analog converter, (8) is amplifier, (9) is driver, α is synchro oscillator, (
Ill is a synchro digital converter, α is a servo control circuit, (13 is an abnormality detector, α4 is an error signal, α is a selector, (I61. aη
is the output value. Note that the same reference numerals are given to the same or corresponding parts in the two figures.

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 estimates the current position of the controlled object based on the previous position of the controlled object and the controlled amount, taking into account dead time. an abnormality detector that detects an abnormality in the surrounding environment of the servo control circuit by comparing it with the current position of the controlled object; and an error signal outputted by the abnormality detector. 1. A digital control device comprising a selector for switching output to a target, and suppressing runaway of a control system due to an abnormality in the surrounding environment.