JPH04287203A - Disturbance state estimating device - Google Patents

Abstract

PURPOSE:To estimate return type disturbance and non-return type disturbance with a simple constitution. CONSTITUTION:This disturbance estimating device is constituted of a rate-of- change calculating section 13 which calculates the rate of change H1 in the output amount of a controlling object 1 when disturbance occurs in the controlling operations for bringing the output amount of the controlling object 1 to a target value and the rate of change H2 when the output amount is returned after the change and a disturbance state estimating section 14 which estimates the state of the disturbance from the rates of change H1 and H2.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disturbance state estimation device used in temperature control systems and the like.

0002

2. Description of the Related Art For example, when controlling the temperature of a furnace, if there is a disturbance in a settled state, the temperature (control amount) inside the furnace changes. Then, a control action based on the deviation between the target value and the controlled amount operates to correct the manipulated variable and change the heating state, so that the controlled variable is set to the target value again.

As mentioned above, the current control action is basically performed simply based on the deviation, and the control action at the time of the above-mentioned disturbance is also performed regardless of the disturbance state. Therefore, if the control characteristics in the system are set so that the control effect during disturbances is large, the settling time will be shortened but overshoot will occur, whereas if the control characteristics are set so that the control effect is small, no overshoot will occur but the settling time will be shortened. will become longer.

The above-mentioned disturbances can be roughly divided into return (pulse, electric cut) type disturbances and non-return (step) type disturbances.
For example, a reset type disturbance is when the temperature inside the furnace changes temporarily due to the opening and closing of the furnace door or the power outage of the heater, and the temperature inside the furnace changes continuously when the heated object in the furnace is replaced. In cases where this occurs, there is a non-recoverable disturbance; overshoot is likely to occur in a non-recoverable disturbance, and settling time tends to be longer in a non-recoverable disturbance.

[0005]

[Problem to be solved by the invention] In view of the above circumstances,
Disturbance state estimation devices have been developed, but conventional disturbance state estimation devices require a model of the controlled object and an inverse model, making the configuration extremely complex, high cost, and impractical. It was something.

Furthermore, the content of the estimation does not estimate the above-mentioned returnable disturbance or non-returnable disturbance, and disturbance estimation has not been performed in accordance with the actual control situation.

The present invention has been made in view of the above problems, and it is an object of the present invention to enable estimation of reversible disturbances and non-recoverable disturbances with a simple configuration.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the disturbance state estimating device of the present invention provides a disturbance state estimating device that detects a change in the output amount when a disturbance occurs in a control operation that is performed to set the output amount of a controlled object to a target value. a change rate calculation unit that calculates a rate of change H1 and a rate of change H2 at the time of a return change after the change, and a disturbance state estimation unit that estimates a disturbance state based on the respective change rates H1 and H2. The structure is as follows.

[0009]

[Operation] According to the configuration of the present invention, the rate of change H1 when the output amount changes when a disturbance occurs in the control operation performed to set the output amount of the controlled object to the target value, and the change rate when returning after the change. A disturbance state is estimated based on H2.

0010

[Example] Fig. 1 is an overall control system diagram of the temperature control system, where 1 is the controlled object such as a furnace, and 2 is the target value r and the controlled object 1.
3 is a temperature compensator that outputs a manipulated variable U based on a deviation e from an output temperature y as a controlled variable; 3 is a disturbance state estimation device that estimates a disturbance state based on the output temperature y from the controlled object 1; 4 is a disturbance state adaptation device that outputs a correction signal to the temperature compensator 2 based on the estimated signal from the disturbance state estimation device 3.

The temperature compensator 2 includes a proportional operation amount output section 7 that outputs a proportional operation amount based on the deviation e, a differentiator 8 that differentiates the deviation e, and a differential operation amount based on the differential value of the differentiator 8. It is composed of a differential operation amount output section 9 that outputs the differential operation amount, an integrator 10 that integrates the deviation e, and an integral operation amount output section 11 that outputs the integral operation amount based on the integral value of the integrator 10. The sum of the outputs from 7, 9, and 11 is the manipulated variable U
Output as .

The disturbance state estimating device 3 includes a change rate calculation unit 13 that calculates a change rate H1 when the output temperature y changes when a disturbance occurs and a change rate H2 when the output temperature y returns after the change; a disturbance state estimator 14 that estimates a disturbance state based on the rate of change of the disturbance state;
It is configured to output an estimated signal when there is a return type disturbance.

The disturbance state adaptation device 4 adjusts the integrator 1 of the temperature compensator 2 based on the estimated signal from the disturbance state estimation device 3.
It is configured to output a correction signal that resets the integral amount after disturbance to zero.

[0014] In this embodiment, the temperature control system described above is configured by software except for the controlled object 1.
The temperature control operation is performed by a microcomputer according to a predetermined program.

Next, the operation of the temperature control system will be described with reference to the flowchart in FIG. 2 and the disturbance state graph in FIG.

Normally, target value response control is performed, and in this case, the disturbance state adaptation function is turned off (step 1).
, 2: Operation in the part indicated by A in FIG. 3).

When some kind of disturbance occurs and the output temperature y changes, the disturbance state adaptation function is turned on, and when the change in the output temperature y exceeds the set temperature range x, the integral amount U at that time is changed.
I, the temperature y0 at that time, and the time ta at that time are respectively stored (steps 3, 4, 5: operation in the part shown by B in FIG. 3).

When the sign of the rate of change of the output temperature y changes from negative to positive, the time tb at that time is stored, and the elapsed time tb from the time when the output temperature y reaches y0 is stored.
-ta=t1, time tc when data is taken next after adding t2 which is t1/n time to time tb, rate of change in output temperature y from time ta to tb H1=(y1-y0)/t
1 is calculated and stored (steps 6 and 7: operation in the portion shown by C in FIG. 3). The above n is, for example, [3]
, and t2 is set to 1/3 of t1. This is because t2 is sufficient time to calculate the appropriate rate of change H2, and tc is set to 1/3 of t1, and tc is set to 1/3 of t1. The timing is set so that it is not too late to start the operation amount reduction operation.

Then, when it comes to the time tc at which data is to be taken next, the rate of change in the output temperature y from time tb to tc is calculated as H2=(y2-y1)/t2. Furthermore, |H
2/H1| is calculated, and as shown in the graph of FIG. 3, |
If H2/H1|>1, it is determined that the disturbance is a return type disturbance (steps 8, 9, 10, 11: operations in the portion shown by D in FIG. 3).

In the case of a return type disturbance, since the disturbance is temporary, the control effect is significant, and the rate of change H2 is larger than the rate of change H1 in absolute value. On the other hand, in the case of non-returnable disturbances, the disturbance continues, so the control effect is gradual, and the disturbance control characteristics are usually shown in the graph of FIG.
H2/H1|≦1. Note that |H2/H1|>1.
4, it can be determined that it is a power interruption disturbance that exhibits the control characteristics of the disturbance as shown in the graph of FIG. 5, and in the control system,
Furthermore, it is also possible to use this determination content.

When it is determined that the disturbance is a return type disturbance, the integral amount of the integrator 10 is changed to the integral amount U when the output temperature exceeds y0.
I (step 12: operation in the part indicated by D in FIG. 3). This reset reduces the integral manipulated variable and the overall manipulated variable U, so the rate of change becomes gradual, and as a result, the output temperature is stabilized with almost no overshoot, as shown by the solid line in Figure 3. . Integral amount UI
If is not reset, the manipulated variable U is not reduced, so overshoot occurs as shown by the dotted line.

In this temperature control system, as mentioned above, in the case of a resettable disturbance, the integral operation amount is reduced and overshoot is eliminated. The setting should be made so that the control characteristics are good in the case of .

FIG. 6 shows another embodiment of the reset operation part of the integral control amount. After the reset operation, it is determined whether the deviation ry has become smaller than the set value z, and the set value z is determined.
If it does not become smaller, the configuration is such that the reset operation is repeated, thereby more precisely preventing the occurrence of overshoot.

FIG. 7 shows another embodiment of the reset operation portion of the integral control amount. In this embodiment, after the reset operation, it is determined whether the rate of change H3 has become smaller than the set value H0, and the set value is determined. If the value does not become smaller than the value H0, the configuration is such that the reset operation is repeated as in the embodiment shown in FIG.

[0025]

[Effects of the Invention] Since the present invention is configured as described above, it is possible to easily estimate reversible disturbances and non-recoverable disturbances with a simple and low-cost configuration, and the contents of this estimation can be By utilizing this, it becomes possible to perform control operations such as temperature control that are more in line with actual conditions.

[Brief explanation of the drawing]

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

FIG. 2 is a flowchart showing an operational example of the control system.

FIG. 3 is a disturbance state graph diagram corresponding to a control example.

FIG. 4 is a step disturbance state graph diagram.

FIG. 5 is a graph diagram of a power interruption disturbance state.

FIG. 6 is a partial flowchart illustrating another operational embodiment of the control system.

FIG. 7 is a partial flowchart showing yet another operational example of the control system.

[Explanation of symbols]

1. Controlled object 13 Change rate calculation section 14 Disturbance state estimation unit

Claims (1)

[Claims] 1. A rate of change H1 when the output amount changes when a disturbance occurs in a control operation performed to make the output amount of the controlled object (1) a target value, and a change rate H2 when the output amount returns after the change. and a change rate calculation unit (
13); and a disturbance state estimation unit (14) that estimates a disturbance state based on the respective change rates H1 and H2.