JPS581205A - Pid controller - Google Patents

Abstract

PURPOSE:To obtain the sufficient control characteristics even with the complicated characteristics of control variable, by obtaining a relation of a linear equation including a term of bias as an optimum proportional gain, an integral time, and a rate time. and calculating the equation. CONSTITUTION:A constant ap stored in a constant set element 11 is multiplied with a limit sensitivity Kc to be inputted with a multiplication element 13. A constant bp stored in a constant set element 12 is added to this signal with an addition element 14 to obtain a proportional gain P. In this case, the P is expressed as P=apKc+bp. Similarly, multiplication and addition are made to a limit period Pc inputted separately to calculate an integral time I and a rate time D, which are given to an element 30. The time I and D are expressed as a linear equation. An element 30 executes a PID control operation by using the values of P, I, D, from inputted control variable and reference, determines a manipulated value and controls the control variable. Thus, even if the characteristics of the control variable is complicated, excellent control can be performed.

Description

[Detailed Description of the Invention] This invention provides proportional, integral,
This relates to a differential operation controller (hereinafter referred to as a PID controller) K.

1' ID controller proportional gain P, integral time! The Ziegler and Nichols limit sensitivity method is widely known as a method for determining the differential time. In other words, when the controller is set to only proportional operation and its proportional gain is set to a large value, and the main control system enters a steady vibration state, the value of the proportional gain is taken as the limit sensitivity, and 0.6 times this value is set as the proportional gain P. , and the vibration period in a steady vibration state is taken as the limit period, and the percentage of this value is the integration time I.

This is a method that uses the differential time.

But in this way? , 1. When controlling a controlled object using a PID controller with a determined D value, the 41 property of the controlled object is
Regardless of the simple case such as the "first-order delay + dead time" characteristic, there is a drawback that sufficient control characteristics cannot be obtained in cases with more complex characteristics.

This release was made to solve the key writing problem.
The purpose is to provide a PID controller that can effectively control a wide range of control objects.

This invention is configured to confirm by Soaki that the appropriate P, I, and D values are given by a linear function of critical sensitivity and critical period, and to add a means for calculating the linear function of .

Hereinafter, embodiments of the present invention will be described in detail with reference to FIG. WVc.

FIG. 7 is a conceptual diagram showing one embodiment of the present invention.

//, /ko, J/, ko, ko, and tame are constant setting elements, proportional gain P, and integral time! and constants hp by at b* an hD necessary for calculating the differential time are set and held, respectively.

/J, u, and koku are multiplication elements, and lda, a, and Jj are addition elements. Jo is a PID control calculation element, and proportional gain P
, integral time! and the differential time signal,
A manipulated variable is output so that the controlled variable matches the target value. The input limit sensitivity Kc is multiplied by the constant a held in the constant setting element // by the multiplication element /J. Next, the constant held in the constant setting element /J is added to this signal by the addition element lda, and PI is set as the proportional gain P.
D Control calculation element Transmit the multiplication and addition to the limit period P, which was input separately in the same way.
The integral time for each! and calculate the differential time,
It is transmitted to the PID control calculation element 30.

Therefore, proportional gain P, integral time! and the differential time are expressed by the following equations (1), (2), and (3).

P wma FKC+ b t ------・-・
−・−(1) ■厘＊P＋b ・・・−・・−・
・・・・・・−・(2) ICI D −a P + b ==−−(3) DO
I PID control calculation element Performs PID control calculation using the above-mentioned P, I, and D values from the controlled quantity and target value, determines the manipulated variable, and controls the controlled quantity.

In this way, the bias ring (
b, b, b, ) can be obtained, so even when the characteristics of the controlled object are complex, the constant at &I'11 by bll)n can be expressed as t liao t − There is an advantage in that sufficient control characteristics can be obtained by selecting RA.

In the above embodiment, the case of PID control was explained, but in the case of PI control, the constant setting element ko for calculating the differential time, the multiplication element n and the addition element X are unnecessary, or the addition This can be done by setting the output signal value of the element to zero. In the case of FD control, the constant setting elements ko/, JJ, multiplication element n, and addition element - for calculating the integral time can be omitted, or the output signal value of the addition element should be made very flexible. Just leave it there.

Similarly, in the case of P control, the above-mentioned P! Control case and F
If you use the D control case and use it as if you are rowing at the same time, it will be a storm.

moreover%? ! D Proportional gain as control calculation element 30?
When using a type that uses proportional bands instead of
As shown in the figure, by adding an inverse function generation element and setting the value 100/p, which is ioo times the reciprocal of the proportional gain P calculated as described above, as a proportional band, the PIDID control calculation element will disappear. . Also.

PIDID control calculation element is integral time not I but □
When using a type that uses a set rate, add an inverse function generating element as shown in Figure 3.

It is possible to transmit the reciprocal number 1A of the integration time l calculated as described above to the PID control calculation element 30 as the reset F rate.

In the embodiments described above, the limit sensitivity and limit cycle are limited to the case where the limit sensitivity and limit cycle are constant, but if the limit sensitivity and/or the limit cycle change due to process variables such as load, the process variables are The function of the limit sensitivity and limit cycle for the main body is calculated, and the process variables are inputted to generate the limit sensitivity and limit cycle at that time, and inputted to the PID controller of the present invention, which enables control by load fluctuations. It is possible to change the PID value in response to changes in the characteristics of the target quantity.

As explained in detail above, the present invention can control the control target with excellent performance even when the characteristics of the controlled object are "first-order delay + dead time". Effective O

[Brief explanation of drawings]

Figure 1 is a conceptual diagram showing an embodiment of this invention, and Figure 1 is a conceptual diagram showing an embodiment of this invention.
Conceptual diagram when using a proportional band as an ID control calculation element, Part 3
The figure is a conceptual diagram when a reset rate is used as a PID control calculation element. //, /ko,ko/, JJ, Jj, 24...constant setting element, /J. JJ, 27-... multiplication element, /41. Jl, J
j-... addition element, J6-... prn control calculation element,
Invasion, nail...inverse function generating element. Applicant's agent Kiyoshi Inomata

Claims (1)

[Scope of Claims] Proportional gain calculation means for calculating a proportional gain that is a linear function of the value representing the limit sensitivity by performing arithmetic operations on a value representing the limit sensitivity of the controlled quantity. At least of an integral time calculating means and a differential time calculating means, each of which calculates an integral time and a differential time, which are linear functions of the value representing the critical period, by performing arithmetic operations on the value representing the critical period of the controlled quantity. It has the proportional gain calculation means, and performs fIj control in response to an output signal from any of the proportional gain calculation means, the integral time calculation means, and the differential time calculation means, including the key proportional gain calculation means. A PID controller characterized by controlling a target quantity to match a target value.