JPH0328902A - Program pattern controller - Google Patents

Abstract

PURPOSE:To attain the proper estimation control by operating a correcting manipulated variable to the change of the target value from a program pattern and the delay time of a control subject. CONSTITUTION:A deviation (e) is obtained by subtracting a controlled variable PV of a control subject 4 from the target controlled variable SV of a process via a subtraction means 2a. A control means 2b controls a manipulated variable based on the deviation (e). Then a program pattern is outputted via a function generator 1 and a target value signal SVt is obtained from the present target value signal SVO after the delay time of the process. An estimated correcting manipulated variable (b) is decided at a present time point by reference to the target value SVt. That is, a correcting computing element 3 calculates a correction amount a (= SVt - SVO) and a multiplication means 3a multiplies the amount (a) by a correcting gain coefficient K. Then an arithmetic means 2c adds the variable (b), i.e., the output of the means 3a to the manipulated variable of the means 2b. Thus the correcting arithmetic output serves as a manipulated variable which corrects the velocity deviation of the program pattern and the process delay time. As a result, the proper estimation control is attained.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a process control device, and particularly to a program pattern control device. (Prior Art) A conventional general PID control system includes a program pattern that generates a target value for the time from the start of control, a control device comprising a subtraction means and an adjustment means, and a control amount Pv and a control amount of a controlled object. It consists of a subtraction means that calculates the deviation e of the target value (generated from the program pattern) SV, and an adjustment means that performs adjustment calculations based on the deviation e, and the adjustment means performs (proportional + integral) operation (PI operation ), the transfer function Gc(s) of the adjustment means is expressed as follows.

Here, kp is the proportional gain and T2 is the integration time. Furthermore, the transfer function Gc(s) when the adjustment means is set to (proportional + integral-sufficient differential) operation (PID operation) is as follows. Here, kP is the proportional gain, d. is the integral time and TD is the differential time. In this case, the program pattern is often a combination of multiple broken lines. For example, if the adjustment means for lamp input is (
P+I) operation, if the controlled object is considered to be a process that can be approximated by an 11th-order delay, a speed deviation will remain in the response. In order to remove this speed deviation. Adopts an adjustment means with added D action. Also, in the conventional technology. (P1I+D) operation is often adopted as the g-section means.

When the target value Sv changes in slope, a speed deviation remains in response to (P+I') operation, but no speed deviation exists in response to (P+I+D) operation. Then, sometimes an overshoot occurs in the shaded area after the break point. This overshoot is a qualitative movement of the D operation in the control calculation.
This is because the operation amount of the D movement is calculated by predicting that the slope of v (differential coefficient at point P) will continue.

In the present invention, when the target value is determined in advance and the delay time of the process can be estimated, as in program pattern control, a correction calculation formula is provided in place of the manipulated variable of the D operation. (Problem to be Solved by the Invention) The present invention calculates a correction operation amount for a change in the target value from the program pattern and the delay time of the controlled object when the target value is determined in advance as in program pattern control. The purpose is to provide a control device that [Structure of the Invention] (Means for Solving Problem 'llA) The present invention performs control calculations on the process using a signal that feeds back the control amount of the process to be controlled and a target value signal of the control amount of the process. This is a program pattern control device consisting of a control device that generates input operation signals and a function generator that generates target value signals. (Function) Using a function generator, find the target value signal SVt after a certain period of time has elapsed from the current target value signal Sv0, and find the correction value b for the operation signal by b = K (SVt - SVa).
However, K is the correction gain. (Example) Next, an example of the present invention will be explained. FIG. 1 shows a function generator 1 that outputs a target value Sv, a correction calculator 3 that corrects the target value Sv output from the function generator 1, and a correction calculator 3 that subtracts a controlled variable pv from a controlled object 4 from the target value SV. an adjusting means 2b which adjusts by the deviation e from the subtracting means 2a, and a correction amount a from the correction calculator 3.
This figure shows a program pattern control device consisting of a multiplier 3a for multiplying . And the control device [2 is the deviation e (=SV-P
In addition to the subtraction means 2a and the adjustment means 2b for calculating V), there are also a function generator 1 and a correction calculator 3 that calculates the correction amount a using the target value Sv, and a multiplication means 3 that multiplies the correction amount a by a coefficient K.
a, a calculation means 2c which adds the correction operation amount b, which is the output of the multiplication means 3a, to the operation amount of the adjustment means 2b.

The correction calculator 3 is a means for obtaining a predicted operation amount when a change in the target value SV can be predicted as in a program pattern, and will be explained with reference to FIG. Let the current point be the target introduction Sv0 at point A, and the delay time of the process to be controlled is T
Then, the correction operation point b of the prediction added at point A is the delay time T
, that is, at point B. That is, the target value to be considered at point A should be determined by looking at the target value SVt at point B to determine the correction operation amount b for the current prediction. The corrected manipulated variable b is determined by b = K - a = K (SVt SV.) (where K is a coefficient), and the response of the control device to which this corrected manipulated variable is added is considered. There is a constant slope from the corner point P of the program pattern to the point Q before the delay time T, and the correction calculation output a becomes the manipulated variable for correcting the speed deviation. (Region R in Fig. 3) Also, from point Q to corner point P, calculation is performed to obtain a corrected manipulated variable taking into account the process delay time T in the change in target value SV. (Area S in Fig. 3) This is the manipulated variable for speed deviation correction calculations on different slopes after the turning point P (Area T in Fig. 3) [Effects of the Invention] The present invention obtains a target value that predicts a program pattern. This enables more appropriate predictive control.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a pattern control device showing an embodiment of the present invention, and FIGS. 2 and 3 are explanatory diagrams of the operation of FIG. 1.

Claims (1)

[Claims] a function generator that outputs a target value; a correction calculator that corrects the target value output from the function generator; a subtractor that subtracts a controlled variable from a controlled object from the target value; A program pattern control device comprising an adjusting means for adjusting according to an output, a multiplier for multiplying the output from the correction calculator by a constant, and an adding means for adding the output of the multiplier and the output of the adjusting means.