JPS58165105A - Process controller - Google Patents

Abstract

PURPOSE:To suppress the control quantity due to a disturbance and to stabilize the operation, by separating a disturbance compensation transfer function of feedforward components to a proportional part and an incomplete differentiating part and using the feedforward mainly in a region where a disturbance signal passing through the incomplete differentiating part exceeds a prescribed range. CONSTITUTION:A disturbance signal 11 is inputted to a coefficient equipment 12 and is multiplied by a delay/advance transfer function K, and the disturbance transfer function is separated to the proportional part and the incomplete differentiating part inputted to a differential operating part 13 and an incomplete differentiating part 14. The difference between a set value 1 and a control quantity 2 is taken out by an adder 3, and this difference 4 is applied to an control operating part 5 where an integration I and a differentiation D are combined. The speed output from the operating part 5 is applied to a speed position signal converting part 7 through a switch 16 and is converted to a position signal, and this position signal is applied to an adder 8 to which the feedforward signal of the differentiating part 14 is inputted. The feedback control output from a high/low setting part 15 is set to zero in the region where the signal passing through the differentiating part 14 exceeds a prescribed range, thus suppressing the control quantity due to the disturbance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to zero combination control of feedback control and feedforward control in a process control device in which feedforward control is added to a feedback control system.

[Technical background of the invention]

FIG. 1 shows a conventional feedforward control device.

The difference between the set value l and the control amount 2 is taken by an adder 3, and a deviation 4 is taken out. This deviation signal is input to the adjustment calculation section 6, and the PI
The adjustment signal obtained by the D calculation is outputted to the adder 21K.

After the disturbance signal 11 is multiplied by the coefficient K in the coefficient unit 12,
After passing through a lead/deviate function 22, it is added to the adder 21 for disturbance compensation.

The adjustment signal to which the external power compensation signal obtained from the adder 21 is added is applied to the process 10 as the operation signal 9 to control the process and obtain the control amount 2. In this way, the external power compensation signal is fed to the feedback control system. This is to forward and suppress the effects of external disturbances.

[Problems with background contact]

The transfer function of outer 1 compensation in the control V-stem is the manipulated variable→
The transfer function between the controlled variables is Kp/1+6-b1, and the transfer function between the disturbance and the controlled variable is /1+TD-8, where nigain, T: time constant, and 8nira plus operator.

Conventionally, when this feedforward control and feedback control are combined, the tweed forward control signal is simply added to the feedback control system.

Feedforward control signal directly to the feedback control system! Regarding process control equipment that adds, this is strange even from a theoretical and logical point of view. Feedforward l control is a feedback control system, and if a disturbance suddenly changes during steady control □, feedback! By catching changes in the disturbance before the control system responds, and anticipating the influence of the disturbance, the control amount can be adjusted to
Therefore, it is suppressed so that it does not fluctuate.

Therefore, the feedback control system P(
(proportional), (integral), and D (differential) adjustment calculation amounts are added, and the optimum correction of the long-awaited feedforward control is disturbed.

In other words, a conventional process control device that simply adds feedforward control to a feedback control loop has the disadvantage that the effect of the long-awaited feedforward control is greatly diminished.

[Purpose of the invention]

The present invention provides a process control device that combines a feedback control loop and a tweed forward control loop that eliminates the drawbacks of the conventional method.

!・.

[Summary of the invention] - This invention separates the feedforward O lead/lag transfer function into a proportional part and an imperfect differentiation part that corrects the response speed, and each section signal passes through this imperfect differentiation part. In a region where the magnitude of the signal exceeds a predetermined range, feedback control is stopped and control is performed using only feedforward control, thereby eliminating all of the conventional defects. The purpose is

Embodiments of the invention described below and 4 will be described in detail based on the drawings. .

[Embodiments of the invention]

FIG. 3 is a configuration diagram showing an embodiment of the present invention.

Note that in FIG. 0 i1 below, the same components as shown in FIG. 1 are indicated using the same reference numerals.

1pJKJI for a detailed explanation of the invention! Let's prove it with a diagram.

In order for Figure 2 (a) and 's2 Figure 佽) to be equivalent, Tx
In order for both the left and right sides to be equal, TP=TD+T1,°, -Tx = (TP, -TD) That is: Considering that the proportional part and speed correction can be incomplete, the embodiment of the present invention is as shown in FIG. The configuration is as follows.

The difference between the set value 1 and the control amount 2 is taken out by the adder 3, and this difference, that is, the deviation 4, is calculated as P (proportional).

Adjustment calculation unit l based on combination K of I (integral) and D (differentiation)
Introduce sK and take out the velocity type output. The speed type output of the adjustment calculation unit 5 passes through the switch 16 and the adder 6, and then is converted into a position type signal by the gear conversion unit 7, and then is output from the incomplete differentiator 14. , that is, an adder 8 which inputs a feedforward signal for speed correction.
added to. The output of this adder 8 is the operation signal 9
Then, in addition to the process lO, adjust the limit am.

On the other hand, the disturbance signal 11 is multiplied by a coefficient K in a coefficient multiplier 12, and then the difference calculation unit 13 converts the signal into a proportional part and an incomplete differential part of the error/delay transfer function. After converting the input signal into a velocity shadow signal, an adder 6 outputs the output of the adjustment calculation section 5 to an adder 6 which receives the input signal.・Output to calculator 8. Further, the output of the incomplete differentiator 14 is given to a high/low setting section 15.

This high/low setting section 15 makes the switch 16 non-conductive in a region exceeding the upper limit (high) and lower @ (low) values.
The output of the adjustment calculation section 5 is set to zero, and only feedforward control (hereinafter referred to as F-P) is performed, and when the upper and lower limits are within the range, the switch 16 is turned on to make use of the output of the adjustment calculation section 5. , feedback control (hereinafter referred to as F
-Referred to as B. ) and feedforward control (F-1i'
) is controlled by a combination of

Next, the operation of the process control apparatus of the present invention shown in FIG. 3 will be explained with reference to FIG.

The response waveform of the output signal En of the incomplete divider 140 when the disturbance signal 11 changes by a unit amount, and the open/close state table feedback control system and feedforward control of the switch f16 for the upper and lower limit levels of the output signal EzenO The operation of the system is as indicated by each of the 1114allK's.

□As shown in FIG. 4, the waveform of the unit quantity Kn of the disturbance signal 11 is centered around zero, as shown in the fourth figure.

This signal En is guided to the high/low setting section 15, and En
is larger than h (high) or smaller than -1<low), the switch 16 is made non-conductive (Fig. 4), the feedback control FB is stopped, and the feedforward control F
When En is −j≦En (h, the switch 16 is turned on as shown in FIG. 4, and control is performed by utilizing both FB and FF.

That is, when speed compensation is effective, only feedforward control is performed, and in areas where speed compensation is not effective, feedback control and feedforward control are used together.

Next, an embodiment of another process control apparatus according to the present invention will be described with reference to FIG.

The difference between the process control device of other embodiments and the process control device of FIG. and the adder 8 on the output side of the position shadow signal converter 70.
The output signals of No. 4 may be switched on and off by additional contacts. In this case, the output signal En of the incomplete differentiator 14
When the magnitude falls within a predetermined range, the switch 16 is made conductive to take advantage of feedback control, and the switch 17 is made non-conductive to make the signal for feedforward speed compensation zero.

Another advantage of the process control device according to the embodiment of the present application is that when the disturbance fluctuation is small, sufficient controllability can be obtained with only the proportional section of feedback control and feedforward control, and the incomplete differential section is unnecessary. It has the characteristic that it does not give any effect to the process.

Note that the switch 11 may be replaced with a function generator having a dead band. The characteristics of this function generator are such that when the switch 17 is in a non-conducting state, a zero output signal is produced, and when the switch 17 is in a conducting state, an output of the incomplete differentiator is produced.

〔Effect of the invention〕

This invention is decomposed into feedforward control O transmission, completely separated into a proportional part and a fast longitudinal compensation part by incomplete differentiation, and the qualitative and fixed meaning is clarified, and 1siI! In addition to making it easier to control the feedforward control, it also makes it easier to provide dead zones and directionality to the feedforward control, making it a versatile control device.

Also, among the separated signals, the magnitude of the signal that passed through the incomplete differentiation section exceeded the predetermined range! In the field, we expanded the tsuku control with fx and made it possible to control by making use of only the feedforward gusset, and our beliefs suddenly changed, and we were able to achieve the optimum fx by controlling the feed forward pitch.
+@jrfa*tnfz°z,,y+,,,,b n
s <・7(-IF′<Tsuku control, P (proportional), I(
It is possible to provide a process control device with high controllability that completely eliminates the need for optimum correction of the feedforward control due to the addition of the adjustment calculation amount due to the combination of the integral) and the D@min.

[Brief explanation of the drawing]

ns1 diagram is a block diagram showing the configuration of a conventional feedforward control device, FIG. 2 is an explanatory diagram for separating the feedforward component into a proportional part and an incomplete differential part, and FIG. 3 is a diagram showing the process of the present invention. FIG. 49 is a diagram for explaining the operation of FIG. 3, and FIG. 95 is a diagram showing the configuration of the O process control device according to the present invention in a block configuration. Ai 0 5...Adjustment calculation unit 7...Ex II →Position signal conversion unit 10...Pu a umbrella, 1 12...Coefficient port 13...Difference control unit 14... Incomplete differentiation section 15...Hi/Low setting section 16...Switch Fig. 1 Fig. 2 □ Fig. 3 Fig. 4

Claims (1)

[Claims] The deviation value between the set value and the control amount is adjusted and calculated by the speed type adjustment calculation unit, and the result is converted into a position type signal, and the disturbance compensation signal is added and fed to the feedback node which outputs this position type signal as an operation signal. In a process control device with forward control, the disturbance compensation transfer function of the feedforward component is separated into a proportional part and an incomplete mold part,
The i-deformation adjustment output signal of the feedback adjustment device is set to zero in a region where the outside signal passing through the copying part exceeds a predetermined range due to incompleteness, and the main body is tweed fow control. Process control equipment.