JPS59104562A - Device and method for trouble detection of control system - Google Patents

Abstract

PURPOSE:To detect troubles in the idle time of a controlling computer without requiring a long operation time, by detecting the deviation between a target value of a control system and a feedback value with a detection level corresponding to the changing speed of the target value. CONSTITUTION:An oil pressure servo system 3 is driven in accordance with the deviation between a target value X and a feedback value X' to obtain an output Y, and the output Y is detected by a position detector 4 to attain the feedback value X'. Meanwhile, a differentiator 6 of a trouble diagnostic device 2 operates an allowable level correcting value DELTAL on a basis of the changing speed of the target value X, and an adder 7 adds an allowable level initial value L0 and the correcting value DELTAL to set an allowable level L of a level detector 5. A deviation epsilon is inputted to this level detector 5, and an abnormality signal F is outputted if the deviation epsilon is higher than the allowable level set value L, and a duration detector 8 displays a trouble on a display device 9 if the duration of the abnormality signal F is longer than an allowable duration set value T.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control system failure detection apparatus and method. Detection of failures in control systems using conventional methods will be explained with reference to Figure 1.

FIG. 1 is a block diagram showing a conventional failure detection device, where 1° is a control system and 2' is a failure detection device. The failure detection device 2° inputs the target value X of the control system 1", calculates the predicted output value Y° using the control system model 3°, and calculates the deviation ε=Y"-Y from Yl and the output Y of the control system. After the calculation, it is determined whether the deviation ε is within the allowable range using the 1-grass judgment device 4°, and if it is not within the allowable range, it is determined that there is a 1-degree failure.
This is displayed on the display device 51. Note that these speeches and judgments are usually processed by a digital computer dedicated to fault diagnosis.

In fault detection using the method described above, it is necessary to improve the accuracy of the control system model 3'.In other words, if the return difference between the control system model 3° and the actual characteristics of the seed control system 11 is large, at Masatomi Also, the deviation ε becomes large, and there is a risk of misdiagnosis. Control systems are generally modeled using differential equations, but in order to improve the accuracy of the model, it is necessary to increase the order of the differential equations. On the other hand, when the order of the battle equation is increased, the calculation becomes complicated, and when it is calculated by a digital computer, the calculation time becomes longer and a control system model 3 with a quick response cannot be obtained. On the other hand, in recent control systems, control by digital computers is becoming widespread, and there is a strong desire to use the free time of the control computer to detect faults in diagonal threads. However, as mentioned above, it is difficult to implement failure diagnosis using the conventional method because the calculation speed of the control system model 31 becomes a bottleneck. Therefore, it is necessary to install a computer dedicated to failure detection, which has the disadvantage of increasing costs.

The present invention was proposed in view of the above situation, and its purpose is to detect faults in the control system without requiring long calculation time and by utilizing the free time of the control computer. An object of the present invention is to provide a failure detection device and a failure detection method for a control system.

The control system failure detection device according to the present invention inputs the deviation between the target value and the feedback value of the closed loop control system, detects whether the value of the deviation exceeds the allowable level, and outputs a signal 1. =t, a device that inputs signal 1, detects whether the duration of the signal exceeds the allowable duration time, and outputs signal 2, and a device that inputs signal 2 and displays whether or not there is a failure. and a device for inputting a target value of the control system, determining the change in speed of the target value, and correcting the set value of the tolerance level by 1 in accordance with the change, and the present invention. The control system failure detection method inputs the deviation between the target value and feedback 11 of the closed-loop control system, and detects a failure when the value of the deviation exceeds the allowable level continuously for a duration of time or more. , characterized in that the tolerance level is set to =J-variant depending on the rate of change of the target value, and the deviation between the target value and the feedback value of the RI control system is detected at a detection level according to the rate of change of the target value. Additionally, if the detection level is exceeded, a failure can be detected based on the duration.

An embodiment of the present invention will be explained in detail below based on the drawings. Fig. 2 is a block diagram when the present invention is applied to the city 11 system using a hydraulic servo. is a control device, 2 is a failure diagnosis M position, 3 is an oil field servo system, 4 is a position detector, 5 is a level detector, 6 is a differentiator, 7 is an adder, 5
1. 8 is a 1'+fi detector during continuation, and 9 is a display. The position control system is composed of a control device 1, a hydraulic servo system 3, and a position detector 4. The hydraulic servo system 3 is driven by the deviation between the target 4 direct X and the feedback value X+, and the output Y is obtain. Further, the output Y is detected by the position detector 4 to obtain a feedback value X''.

The failure detection device 2 includes a level detector 5, a differentiator 6, and an adder 7.
, Duration detection j4:1 B, 1゛1~ from display 9
The target value XΔX of the control system is input to the differentiator 6, and a differential operation Δt of ΔL=□・K is performed. Here, ΔL is the allowable level correction value, and K is a constant.
AX is a minute value of Δ, which represents the rate of change of the target value X. The adder 7 calculates the tolerance level initial value Lo and the Δ
From L, the calculation L=Lo+ΔL is performed, and the allowable level L of the level detector 5 is set. The level detector 5 is input with the deviation ε between the target value X of the control system and the feedback value X1, and outputs an abnormality signal F when the deviation ε is larger than the above-mentioned allowable level setting value. The duration detector 8 detects the duration of the abnormal signal F and determines whether the error signal is acceptable +fil! If the time is greater than the set value T, "Failure 1" is displayed on the display 49.

Next, a method according to an embodiment of the present invention will be explained in detail. When detecting a failure in the control system using vehicle equipment 6, set the following values in advance as the initial tolerance level LO and tolerance level set value T1 constant.LO is the control system target value X =
The value is 114, which is slightly larger than the deviation ε that exists in the 00 state, T is a value slightly larger than the time constant of the control system, and K is the gain of the control system. These values can be determined by experiment or calculation.

Consider the case where the target value of the control system is changed in this state. As a target value for the 1 system (ii system), it is sufficient to use a combination of 3 types of communication step type, curved type, and sine wave type, so let's consider these three types of target values. The waveform of the deflection ε when the type of target value X is input is shown in FIG. 3 (') + (B) + tC). In the case of a servo system, the system always includes an integral element, so as shown in the figure, the deviation ε increases as the speed of change of the target 111X increases, and if the speed of change is 0, the deviation ε increases. =eε
is also O. Therefore, if the control system is a royal palace, the inner value is X.
The deviation ε input to the level detection 45 when given is the permissible level setting value L = determined from the eye and the LO.
Since it is smaller than L・)+ΔL, the abnormal signal F is not output. Eyes again! Even if +i&X becomes step-like, ε
11j approaches 0 in terms of index and tide due to the time constant of the control system, so a signal F just before a certain time is output. However, if the allowable duration T set in the duration detector 8 is Since it is set to be slightly larger than that, it is not judged as 'Failure 1'.

- If the force control system is abnormal, for example, if a servo valve in the hydraulic servo system breaks down, the hydraulic servo system 3 will not operate even if the target value X is given, or the operating speed will be different compared to the normal value. , the deviation ε becomes larger than the permissible level set value determined by the method described above, and an abnormal signal F is output, and the duration of F becomes permissible 1! It is longer than the sequel T,
°Fault 1 is detected.

As explained above, according to the present invention, failure detection can be performed using E'J
It is 62. Further, the above calculations and determinations can be easily performed by a digital computer, and the processing time is short because no complicated presets are required.

Therefore, an excellent effect can be obtained in that failure detection can be performed during the idle time of the control computer.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional failure detection device, Fig. 2 is a block diagram of an embodiment in which the present invention is applied to a position control system using an oil field servo, and Fig. 3 is a block diagram of a conventional failure detection device.
(Q is a diagram showing the waveforms of each deviation when step-like, ramp-like, positive/wave-like target values are given to the control system of the second cause. 1...Side tilting device, 2...・Failure detection device, 3... Oil field servo system, 4... Position detector, 5... Level detection 4.6... Differentiator, 7... Adder, 8... Continuation time detection Container, 9...Display honor, X...Target value, Y...
1lfll # output of system, e...Is difference, Xl...
Feedback value, ΔL... Differential value representing tolerance, L
O...Tolerance level initial value, L...Tolerance level, F.
... Abnormality signal, T ... 114 setting value when permissible continues, 1°
...Control system, 2°...Fault detection device, 3°...
Control system model, 4゛...failure determination device, 51...display device yl...predicted output value Applicant 1 Summer Attorney Patent Attorney Takehiko Suzue Figure 1

Claims (1)

[Claims] (1) Target value and feedback value of closed loop control system
iii) A device d that manually detects whether the value of the difference exceeds the allowable level and outputs signal 1; and a device d that inputs signal 1 and determines whether the duration of the signal exceeds the duration. There is a device that detects the failure and outputs signal 2, a device that inputs one word 2 and displays whether or not there is a failure, and a device that inputs the target value of the control system and calculates the rate of change of the target value and responds accordingly. A control system failure production device d7゜゛(2) is characterized in that it comprises a device for modifying the set value of the allowable level by inputting the deviation between the target value and the feedback value of the closed loop control system, and adjusting the set value of the tolerance level. A failure is detected when the value of exceeds the permissible level continuously for more than the permissible duration, and
A method for detecting a failure in a control system, characterized in that the four levels are made variable according to the rate of change of the target value.