JPS58207103A - Non-interference control system of plural control systems - Google Patents

Abstract

PURPOSE:To improve reliability of a control system, by adding the result of addition to the preceding operation output at an operation terminal to obtain a new operation output and eliminating the disturbance among plural control systems. CONSTITUTION:The 1st control system includes a deviation arithmetic part 15A, a speed type PID control arithmetic part 16A and an integrator 17A. While the 2nd control system comprises a deviation arithmetic part 16B and an integrator 17B. Outputs DELTAv1 and DELTAv2 of parts 16A and 16B are equal to corrected values and therefore very small compared with the output of each control meter. Therefore the value alphaDELTAv1 obtained by multiplying the output DELTAv1 by a non- interference coefficient alpha is also very small compared with a manipulated variable u2. In the same way, the value betaDELTAv2 obtained by multiplying the output DELTAv2 by a non-interference coefficient beta is very small compared with a manipulated variable u1. Thus, a manual operation at a rise time, a manual operation of just one control system and a switch to a backup control system are facilitated respectively and the breakdown of a control system does not affect so much other control systems.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a non-interference control method that eliminates interference and enables optimal control by using a precompensator in a plurality of control systems that interfere with each other. .

FIG. 1 is a system diagram showing an example of a plurality of control systems that interfere with each other. In the figure, 1 is a pressure regulator, 2 is a calorie regulator, 3 and 4 are flow rate regulators, 5 and 6 are flow rate control valves, and 7° and 8 are flow rate transmitters. , A gas flows in pipe A, B gas flows in pipe B, and mixed gas M of A gas and B gas flows in pipe M.
It is assumed that the calorie of the zero mixed gas M is determined by the mixing ratio of A gas and B gas. Pipe M
In order to stably supply the mixed gas M to the demand side (not shown) via the pipe line M, the pressure P in the pipe line M is detected and the pressure is controlled. That is, the pressure regulator 1 compares the detected pressure P in the conduit M with the internal pressure setting value S and outputs a control output so that the difference becomes zero, but this output is equal to the flow rate. It is given to the controller 3 as its flow rate set value. The flow rate controller 3 compares the A gas flow rate given from the flow rate transmitter 7 with the flow rate set value, sends a control output to the control valve 5 so that the difference becomes zero, adjusts the valve opening, and Gas flow rate control and, in turn, pressure control in the pipe line M are performed.

On the other hand, calorie control of the mixed gas M is performed. That is, the calorie controller 2 compares the calorie detected for the mixed gas M with the internal calorie set value Sv, and outputs a control output so that the difference becomes zero.
This output is given to the flow rate controller 4 as a flow rate setting value. In the flow rate controller 4, B given from the flow rate transmitter 8
The gas flow rate and the flow rate set value are compared, and the control output is sent to the control valve 6 so that the difference becomes zero, and the valve opening is adjusted.
The gas flow rate control and, in turn, the calorie control of the mixed gas M is performed.

The pressure control system and calorie control system described above are control systems that interfere with each other. For example, if the pressure P decreases, the opening of the control valve 5 will increase to restore it and the flow rate of gas A will increase, but this will change the ratio of gas A and gas B in the mixed gas M, causing the calorific value to increase. also changes. Similarly, changes in calories will also affect the pressure control system.

In such a control system of Ii numbers that interfere with each other,
A conventional example of a non-interference control method that eliminates interference and enables optimal control by using a predistorter will be explained with reference to FIG. 2. In FIG. 2, 11 and 12 are position type 13 is a precompensator, and 14 is a process. It is assumed that the first feedback control system including the controller 11 and passing through the process 14 and the second feedback control system including the controller 12 and passing through the process 14 interfere with each other.

The operation will now be described assuming that the predistorter 13 does not exist.

In this case, the output v1 of the position controller 11 directly becomes the manipulated variable u1 for the operating end, and acts on the process 14 to obtain the controlled variable y1. The transfer function between the manipulated variable u1 and the controlled variable y1 is gll. Note that the position type controller 11 is
A calculation (for example, PID calculation) is performed to produce a deviation signal that is the difference between the control amount y1 and an internal set value Sv, and the controller output v1, which is the calculation result, is the position of the operating end (
For example, it is a position type controller that gives the valve opening degree.

Similarly, the output v2 of the controller 12 directly becomes the manipulated variable u2 for the operating end, and acts on the process 14 to obtain the controlled variable y2. The transfer function between the manipulated variable u2 and the controlled variable y2 is g22.

In process 14, the transfer function between the manipulated variable u1 and the controlled variable y2 is g21, and the transfer function between the manipulated variable u2 and the controlled variable y1 is g12. Then, the manipulated variable u1 in the first feedback loose including the controller 11 is
Due to the influence of the transfer function g21, the control fi y2 in the second feedback loop including the controller 12 fluctuates and causes interference.

Therefore, a precompensator 13 is provided, in which the controller 1
The signal (α
×v1) and add it to the output v2 of the controller 12 to obtain u2, the previous 1!2 × g2
2 (=y2) can be changed to cancel out the above-mentioned interference.

Similarly, interference caused by fluctuations in the controlled variable y1 in the first feedback loop caused by the manipulated variable u2 in the feedback loop of jI2 due to the influence of the transmitted variable 'I&g12 is caused by the interference of the controller 12 in the precompensator 13. Output ■ Signal (β x v
2) and add it to the output v1 of the controller 11, and add this to the output v1 of the controller 11.
By setting uIXgo (=y1) up to that point to l, the previous uIXgo (=y1) changes and is canceled out to 0. Now, when starting up 0 control, the conventional non-interference control method as explained above had the following drawbacks. That is, when starting automatic control, it is usual to first bring the amount of operation to the operating end to an appropriate value through manual operation, and then shift from manual operation to automatic operation. When operating manually, use controller 1.
1.12 from automatic to manual and manually operate the operation button attached to the controller, the controller output v1. Adjust v2.

Now, the actual manipulated variables for the operating end are given by ul and u2 - Therefore, even if the values of the manipulated variables u1, p, and u2 are selected to appropriate values, the controller output v1 necessary to obtain those values
If p V2 is not calculated backward according to the following simultaneous linear equations,
Manual operation will not be possible.

■1+β·V2””ul ■2+α·Vl: u2 In order to perform such back calculation without human intervention, a separate arithmetic unit is required, which has the disadvantage of making the configuration complicated and expensive.

Also, if one of the multiple control systems goes down, even if you want to manually operate only that control system, the effect will affect all other control systems via the precompensator. Therefore, it has the disadvantage that it is not easy to perform.

The present invention has been made in order to eliminate the drawbacks of the conventional system as described above, and therefore, an object of the present invention is to eliminate the need to back-calculate the controller output from the manipulated variable during manual operation at the start-up of control. It is an object of the present invention to provide a non-interfering control system for multiple control systems, which allows manual operation of only the control system that is down.

The main point of the configuration of the present invention is that in a non-interfering control method for multiple control systems using a precompensator, the control calculator in each control system is controlled so that the operation output, which is the operation result, is given by the amount of correction of the position of the operation end. The present invention is comprised of a speed-type computing unit that allows for the correction of the position, and performs pre-compensation for the amount of correction of the position based on the computed result.

Next, one embodiment of the present invention will be described with reference to the drawings, but before that, a velocity type arithmetic unit will be explained to facilitate understanding.

In general, a regulator for process control is a type of computing device that performs a calculation to produce a deviation signal (difference between a target value and a measured value) and outputs the result as an operation signal.
A PID calculation is performed in a regulator that uses a control method. As mentioned earlier, there are two types of PID calculations: a position type in which the operation output that is the calculation result gives the position of the operating end (for example, the valve opening), and a speed type in which the operation output provides the amount of correction of the position of the operating end. explained.

Here, the positional form Pjp,, the calculation formula is the following formula (
1) is given by

However, P is the proportional band, Ti is the integral time, TD is the differential time,
τ is the sampling interval, M■ is the manipulated variable (II node high force)
, Dv represents the deviation, P■ represents the measured value, and the suffix represents the sampling time point.

On the other hand, the speed-type PID calculation formula is also expressed by the following equation (2), as is well known.

ΔMVk=Mvk-MVk1...
(2) Here, ΔMV represents the amount of correction to the previous operation output. In other words, the previous operation output is MVk-
If it is 1, then the current operation output MVk can be obtained by adding to this the correction amount ΔMVk obtained by performing velocity type PID calculation.

Transforming equation (2) using equation (1) above, we get the following (3):
The formula is obtained.

FIG. 3 shows a block diagram of a configuration example of a speed type PID control system.

In the figure, 15 is a deviation calculation section for calculating the deviation between the measured value P■ and the target value S■, 16 is a PID control calculation section, 17 is an integrator, and Sl is an automatic/manual switching valve.

Explain the operation. The deviation signal DV calculated in the deviation calculation section 15 is input to the PID control calculation section 16, where the calculation according to the above equation (3), that is, in block P, (
3) A proportional calculation is performed on the first term of the equation, block (3) performs an integral calculation on the second term, and block D performs a differential calculation on the third term. Then, the sum of the calculation results is output as ΔMV, and this ΔMV is input to the integrator 17.

In the integrator 17, the correction amount ΔMY from the calculation unit 16
The previous operation output MY is added to the previous operation output MY to form a new current operation output. Therefore, the integrator 17 can also be said to be a velocity type/position type conversion calculation unit that converts the velocity type calculation result supplied from the calculation unit 16 into a position type operation output and outputs the result.

The output of the integrator 17 is outputted to an operating end (not shown) as an operating output MV via an automatic/manual switching valve Sl.

When the automatic/manual switching valve S1 is switched from the automatic side A to the manual side M, the operation output MV is then manually transferred by means not shown, but even in this case, the manual operation output is integrated. The present invention is configured so that when the switching valve S1 is returned to the automatic side A, the integrator 17 obtains an operation output that follows the previous manual operation. Speed type PID control calculation unit 1
A precompensator is connected to the output side of 6.

FIG. 4 is a block diagram showing one embodiment of the present invention.

In the figure, a first control system is constituted by a deviation calculation section 15A, a speed-type PID control calculation section 16A, and an integrator 17A, and a first control system is configured by a deviation calculation section 15B, a speed-type PID control calculation section 16B, and an integrator 17B. A second control system is configured. The precompensator 13 includes multipliers 18A, 18B and an adder 19A.

19B, and its structure and operation are the same as those of the conventional precompensator shown in FIG.

Output Δ■isΔV2 of PID control calculation units 16A and 16B
(corresponding to ΔMV in FIG. 3) is the correction amount, so the controller output v1. in FIG. This is an extremely small value compared to v2. Therefore, the value (α·Δv1) obtained by multiplying Δv1 by the non-interference coefficient α is also sufficiently smaller than the manipulated variable U2 (corresponding to MV in FIG. 3). Similarly, Δ
The value obtained by multiplying v2 by the non-interference coefficient β (β・ΔV2
) is also sufficiently small compared to the manipulated variable u1.

Therefore, at the time of starting up the control, in the first control system,
Manual operation is performed by ignoring the compensation amounts β and Δv2 supplied from the second control system, and by ignoring the paddle compensation amounts α and Δv1 supplied from the first control system in the second control system. becomes possible. Furthermore, if there is a control system that is down for the same reason, it becomes possible to manually operate only that control system.

As explained above: Therefore, according to the present invention, in a non-interfering control system for a plurality of control systems using a predistorter,
Manual operation at start-up, manual operation of only one control system, switching to a backup control system, etc. are easily possible, and even if one control system goes down, the impact on other control systems is small. Reliability has also been improved. In the description of the embodiment, a two-manpower, two-output control system has been described as an example, but it goes without saying that the present invention can also be applied to a multi-input, multi-output control system.

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing an example of multiple control systems that interfere with each other, Fig. 2 is a block diagram showing a conventional non-interfering control method for multiple control systems using a predistorter, and Fig. 3 is a block diagram showing an example of multiple control systems that interfere with each other. The figure is a block 11 diagram showing an example of the configuration of a speed type PID control method.
The figure is a block diagram showing one embodiment of the present invention. Code explanation

Claims (1)

[Claims] 1) In a plurality of control systems that interfere with each other, the control computing unit in each control system is configured with a velocity type computing unit in which the operation output, which is the calculation result, is given by the amount of correction of the position of the operating end. , comprising means for multiplying the position correction amount as a calculation result in each control system by a non-interference coefficient and mutually adding the result to the calculation results in other systems, and adding the addition result to the previous operation output at the operation end. A non-interference control method for multiple control systems, characterized in that interference between multiple control systems is eliminated by adding the current operation output.