JPS62108305A - Pid control device - Google Patents

Abstract

PURPOSE:To improve the PID controllability by calculating a control parameter of optimum proportional gain, integral time, differential time, etc. from an hourly variation of a deviation quantity,and setting it automatically. CONSTITUTION:First of all, control parameters Kc, Ti, and Td are initialized to a manipulated variable arithmetic part 3, and also a changeover switch 4 is switched to a noise vibration monitor part 5 side. The monitor part 5 monitors a derivation e(t), and when its absolute value exceeds a prescribed value, the changeover switch 4 is switched to a peak monitor part 6 side. The monitor part 6 monitors an hourly variation of the deviation e(t) which is varied like a sine wave, calculates Kc, Ti, and Td being optimum parameters through a parameter changing part 7 from the first and the second peak values, and the peak time, and sets them to the manipulated variable arithmetic part 3. In this way, an optimum PID control parameter is set automatically, and a good controllability having no hunting is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a PID control device having a function of automatically setting parameters in PID control, such as proportional gain Kc, integral time Ti, and differential time Td, to optimum values. It is something.

Conventional technology In the past, parameters in PID control were determined by performing experiments on step response characteristics, etc. after the equipment and control device were delivered to the site, and by examining the characteristics of the controlled object, the optimal values were selected and fixed at constant values. It has been done.

Ta.

Problems to be Solved by the Invention However, in the above conventional method, the characteristics of the controlled object are
Since parameters change depending on various conditions, if the parameters are fixed to a constant value, the control operation will become unstable due to changes in the characteristics of the controlled object, hunting will occur, controllability will deteriorate, and the durability of the control equipment will be affected. There was a problem that it deteriorated.

The present invention solves the above-mentioned conventional problems.

PI that can automatically adjust PID control parameters to prevent hunting without operator intervention
The purpose of the present invention is to provide a D control device.

Means for Solving the Problems In order to solve the above problems, the PID control device of the present invention includes a deviation amount calculation section that calculates the deviation amount between the process output and the process setting value, and this deviation amount calculation section. a manipulated variable calculation section that calculates a manipulated variable from the deviation amount calculated by proportional action, integral action, and differential action, and a determination as to whether or not the vibration is due to noise based on the magnitude of the deviation amount calculated by the deviation amount calculation section. a vibration monitoring unit that calculates a first peak value, a first peak time, a second peak value, and a second peak time from a time change in the deviation amount calculated by the deviation amount calculation unit; A vibration damping rate is calculated using a changeover switch that switches between a noise vibration monitoring section and the vibration monitoring section, a first peak value, a first peak time, a second peak value, and a second peak time obtained by the vibration monitoring section. The controller is configured to include a parameter changing section that determines a proportional gain KC, an integral time Ti, and a differential time Td, which are PID control parameters, and changes the operation parameters of the operation amount calculation section.

Effects According to the above configuration, the time change in the amount of deviation between the process output and the set value of the process is monitored, and the control is repeated while changing the PID control parameters according to the vibration damping rate of the deviation amount.

EXAMPLE Hereinafter, an example of the present invention will be described based on FIGS. 1 to 3.

FIG. 1 is a circuit block diagram of a PID control device in an embodiment of the present invention, in which 1 is a deviation amount calculating section, 2 is a controlled object, and 3 is a block diagram of a PID control device according to an embodiment of the present invention.
4 is a changeover switch, 5 is a noise vibration monitoring unit, 6 is a vibration monitoring unit, and 7 is a parameter changing unit.

The deviation amount calculation unit 1 calculates the deviation amount e (x) between the process output y (t) at time t output from the controlled object 2 and the process setting value ``. , from the deviation e (t) calculated by the deviation amount calculation unit 1, the manipulated variable v is calculated by proportional action, integral action, and differential action.
(t) is calculated. The process output y (t) output from the controlled object 2 based on this v (t) usually has a fluctuation caused by the disturbance 8 added thereto. The changeover switch 4 switches between the noise vibration monitoring section 5 and the vibration monitoring section 6. The noise vibration monitoring unit 5 determines whether or not there is noise vibration. The vibration monitoring unit 6 obtains a first peak value, a first peak time, and a second peak value and second peak time of vibration. The parameter changing unit 7 calculates a vibration damping rate based on the first peak value, first peak time, second peak value, and second peak time obtained by the vibration monitoring unit 6, and changes the vibration damping rate to the p I D product:; The parameters proportional gain Kc, integral time T1, and differential time Td are changed.

Next, the operation will be explained. FIG. 2 is a flowchart showing the operations of the deviation amount calculation section 1 and the manipulated variable calculation section 3, and FIG. 3 shows the deviation amount calculation section 1, the changeover switch 4, the noise vibration monitoring section 5, the vibration monitoring section 6, and the parameter changing section 7. These two flows proceed simultaneously. Second
In the figure, when the initial setting of each constant and variable is completed, the deviation amount calculation unit 1 calculates the set value r and the time t using the following formula 0.
The deviation e (t) from the process output y (t) at is calculated.

e (t) = r −y (t) ...0
Next, in the manipulated variable calculating section 3, the deviation e(
), the manipulated variable v (t) is calculated by proportional action, integral action, and differential action as shown in the following equation (2).

Note that Kc is a proportional gain, Ti is an integral time, and Td is a differential time. The values of Kc, Ti, and Td are given initial values by manual operations by the operator, but are changed by the parameter changing section 7 as described later.

The above operations constitute one cycle, and the manipulated variable v (t
), the process returns to the deviation amount calculating section 1 again and repeats the same operation.

In FIG. 3, when the initial settings of each constant and variable and the initialization of the changeover switch 4 are completed, the changeover switch 4 is connected to the noise vibration monitoring section 5.
Then, the deviation e (t) calculated by the deviation amount calculation unit 1
Therefore, when the condition shown in the following equation 0 is satisfied, the changeover switch 4 is switched to the vibration monitoring unit 6 side.

1e(t)l≧DEF ・・・・・・■In addition, DEF
is a constant determined by the operator within a permissible range. In the vibration monitoring unit 6, the deviation e (t
), and since the deviation e (t) shows a sine waveform, the first peak value P1, first peak time T1, second peak value P2, and second peak time T2 of the sine wave are measured. Then, a signal is sent to the parameter changing section 7, and the parameter changing section 7 is activated. Here, the peak time refers to the time when the peak occurs.The parameter changing unit 7 takes the ratio of the first peak value P1 and the second peak value P2, as shown in the following equation 0, and calculates the amplitude attenuation. Calculate the rate α.

And when α≧1, −K e , T i , T
Change d as shown in the following formulas 0 to 0.

Kc4-0.6Kc =--■ Ti=0.5X2X(T2-Tl)...■Td
=0.125X2X(T2-TI)・-
----■ Also, when 0.25≦α<1, Kc is changed as shown in the following equation 0, and TiyTd is changed as shown in the above equation 00.

Further, when α<0.25, the values of Kc, Ti, and Td are not changed. Once the parameters are determined in this way,
Switch the changeover switch 4 to the noise vibration monitoring unit 5 side.

The above operation constitutes one cycle, and after determining the parameters and switching the changeover switch 4 to the noise vibration monitoring unit 5 side, the same operation is repeated.

Effects of the Invention As described above, according to the present invention, based on the vibration of the deviation amount between the process output and the set value, the proportional gain and the integral, which are PID control parameters, are determined according to the magnitude of the vibration damping rate. Since the values of time and differential time are changed, the possibility of hunting occurring can be significantly reduced and controllability can be improved compared to when the PID control parameters are constant.

[Brief explanation of drawings]

FIG. 1 is a circuit block diagram of a PID control device according to an embodiment of the present invention, and FIGS. 2 and 3 are flowcharts each showing a control procedure of the PID control device. 1... Deviation amount calculation unit, 3... Manipulated amount calculation unit, 4...
・Selector switch, ...Noise and vibration monitoring section, 6.Vibration monitoring section, 7.Parameter change section Representative Yoshihiro MorimotoFigure 1Figure 2

Claims (1)

[Claims] 1. A deviation amount calculation unit that calculates the deviation amount between the process output and the process set value, and a manipulated variable is calculated from the deviation amount calculated by this deviation amount calculation unit by proportional action, integral action, and differential action. a noise vibration monitoring unit that determines whether the vibration is due to noise based on the magnitude of the deviation amount calculated by the deviation amount calculation unit; and a noise vibration monitoring unit that determines whether the vibration is due to noise based on the magnitude of the deviation amount calculated by the deviation amount calculation unit; a vibration monitoring section that obtains a first peak value and a first peak time, a second peak value and a second peak time; a changeover switch that switches between the noise vibration monitoring section and the vibration monitoring section; The vibration damping rate is calculated from the first peak value, first peak time, second peak value, and second peak time, and the proportional gain Kc, integral time Ti, and differential time Td, which are PID control parameters, are determined. A PID control device comprising: a parameter changing section that changes an operating parameter of the operation amount calculating section.