JP3015553B2 - Complementary feedback control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a complementary feedback control device.

[0002]

2. Description of the Related Art Conventionally, a complementary feedback control device is known as one of controllers used in a process automatic control system or the like. FIG. 7 shows an example of such a conventional complementary feedback control device. I have. This conventional complementary feedback control device is of a position type and includes a subtraction circuit 101, a static characteristic circuit 102 for performing static characteristic compensation, an adding circuit 103, and a dynamic characteristic circuit 104 for performing dynamic characteristic compensation. The subtraction circuit 101 subtracts a target value SV set by a setting device or the like from a control amount PV output from the process 105, and obtains an operation amount MV based on the obtained deviation by a method described later. By supplying the operation amount MV to the process 105, the process 105 is controlled such that the control amount PV of the process 105 matches the target value SV.

A subtraction circuit 101 calculates a difference (deviation) between a target value SV set by a setting device or the like and a control amount PV output from a process 105, and supplies the deviation to a static characteristic circuit 102, in the characteristic circuit 102 gives the static characteristic compensation of 1 / K _p relative deviation, and supplies to the adder circuit 103 a signal thus obtained.

The dynamic characteristic circuit 104 feeds back a signal output from the adding circuit 103, that is, the manipulated variable MV, performs dynamic characteristic compensation _Gp , and outputs the output to the adding circuit 103.

In the addition circuit 103, the static characteristic circuit 1
02 and the signal output from the dynamic characteristic circuit 104 are synthesized and output to the process 105 as the final manipulated variable MV, and the process feedback control is performed.

[0006]

[SUMMARY OF THE INVENTION However, in the conventional position type complementary feedback controller, the static characteristic simulating the transfer function K _p and dynamic characteristics circuit 10 of the static characteristic circuit 102
Dynamics simulated transfer function G _p is the static properties of the real process 4, it is possible to perform the best complementary feedback control when matching the dynamic characteristic, only an unnecessary control that amount when the deviation between the two resulting In this case, extra time is required until the control system is stabilized.

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and provides a complementary feedback control capable of reducing the influence of a simulated transfer function being different from an actual transfer function and improving control stability. It is intended to provide a device.

[0008]

According to a first aspect of the present invention, there is provided a method for simulating static characteristics of a process with respect to a deviation between a target value and a control amount.
A static characteristic portion for performing static characteristic compensation using the inverse of the function, before
Using dynamic characteristic simulated transfer function
A dynamic characteristic section for performing dynamic characteristic compensation by means of the static characteristic section.
Adding the output and the output of the dynamic characteristic unit by adding means,
A supplementary feedback control device that outputs this as a manipulated variable to the process , further comprising: a target value monitoring unit that detects a change in the target value and outputs a manipulated variable output command; , A manipulated variable monitoring unit that outputs a manipulated variable output command when the manipulated variable exceeds a predetermined range, a target value monitoring unit, a time management unit, or a manipulated variable monitoring unit. And a control unit that outputs the manipulated variable to the process only when receiving a manipulated variable output command from any of the above.

A complementary feedback control according to the second aspect of the present invention.
The device is able to process statically against the deviation between the target value and the control amount.
Perform static characteristic compensation using the inverse of the characteristic simulation transfer function ,
A static characteristic section that outputs a static characteristic compensation signal, a dynamic characteristic section that performs dynamic characteristic compensation using a dynamic characteristic simulated transfer function for the operation amount of the process, and outputs the internal control amount, First addition means for calculating a deviation between the manipulated variable and the internal control quantity; and second addition for calculating a deviation between the static characteristic compensation signal and the output of the first addition means and outputting the difference as a manipulated variable differential value. Means, an integration means for outputting the integration result of the manipulated variable differential value output from the second addition means to the process as the operation amount, and an operation amount output finger for detecting a change in the target value.
Target value monitoring unit for outputting a decree, output operation amount for each predetermined cycle
A time management unit that outputs a force command, and outputs a manipulated variable output command when the manipulated variable differential value exceeds a predetermined value .
Operation amount monitoring unit, target value monitoring unit, time management unit
Or, output the manipulated variable output command from
A compensating circuit including a control unit that changes the manipulated variable by accumulating the manipulated variable differential value output from the second adding means in the accumulating means only when received .

[0010]

In the position-type complementary feedback control device according to the present invention, when the static characteristics are compensated in the static characteristics section, the dynamic characteristics are compensated in the dynamic characteristic section, and when these combined outputs are outputted as the manipulated variables, the target value is monitored. The unit detects a change in the target value and outputs a manipulated variable output command.The time management unit outputs a manipulated variable output command when a predetermined cycle has arrived. When any one of the operation amount output commands is output upon detecting that the output has become larger than the above, the combined output is output to the process and feedback control is performed.

In this way, when the manipulated variable is smaller than the predetermined range, the manipulated variable is not output so that the process control variable does not needlessly fluctuate, and the control stability is improved. Realize.

In the supplementary feedback control device according to the second aspect of the present invention, unless the manipulated variable differential value exceeds a predetermined range and increases, the target value does not change or a predetermined period does not arrive. An operation amount differential value is integrated so as not to be input to the process, thereby preventing the process from becoming unstable due to a minute change in the operation amount.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 and 2 show a circuit configuration of an embodiment of the present invention. As a conventional example, a compensating circuit 106 is further inserted between the adding circuit 103 and the process 105 in the circuit configuration shown in FIG. This is the configuration. As shown in FIG. 2, the compensation circuit 106 detects a change in the target value SV and outputs a manipulated variable output command.
7, a time management unit 108 that outputs a manipulated variable output command every predetermined cycle T, a manipulated variable monitoring unit 109 that outputs a manipulated variable output command when the manipulated variable MV exceeds a predetermined range, These target value monitoring unit 107 and time management unit 1
08, a control unit 110 that outputs the operation amount MV from the adding circuit 103 to the process 105 in response to an operation amount output command from any of the operation amount monitoring units 109.

Next, the operation of the position type complementary feedback control device of the above embodiment will be described.

Similar to the conventional example shown in FIG. 7, a target value SV is given from a setting device or the like, and a deviation from a control amount PV from a process 105 is calculated in a subtraction circuit 101. To perform static characteristic compensation, and this signal is output to the addition circuit 103.

The manipulated variable M output from the addition circuit 103
V is subjected to dynamic characteristic compensation by the dynamic characteristic circuit 104, and its signal is also fed back to the adding circuit 103. The combined output is output to the actual process 105 as the final manipulated variable MV, and the position form complementary feedback control is executed.

When outputting the manipulated variable MV,
If the process control is performed for a small change in the manipulated variable MV, the stability of the process is impaired.
At 6, the following operation is performed.

(1) When the change in the operation amount MV is within a certain set value range, the operation amount MV is not changed.

(2) For a change in the manipulated variable MV exceeding a certain set value determined in (1), the MV corresponding to the change
Make changes.

(3) The manipulated variable MV is changed every fixed period T determined from the process time constant of the plant, regardless of the above (1) and (2).

In order to realize this operation, the target value monitoring unit 107 monitors a change in the target value SV, and if a change is given to the target value, gives a manipulated variable output command to the control unit 110, and also performs time management. The unit 108 gives an operation amount output command to the control unit 110 every time the fixed period T arrives, and the operation amount monitoring unit 109 outputs an operation amount output command when the operation amount MV exceeds a range of a preset set value. Control unit 11
0, and the control unit 110 controls the operation from the adding circuit 103 only when an operation amount output command is input from any of the target value monitoring unit 107, the time management unit 108, and the operation amount monitoring unit 109. Process MV quantity 1
05 directly.

Thus, as shown in the response example of the real process and the simulated transfer function shown in FIG.
The operation amount is not changed with respect to the difference between the expected error between the estimated error and the simulated transfer function B of the control device, and when the estimated error is exceeded, the manipulated variable MV is output to the process 105 and fed back. The control is performed so that the control system does not unnecessarily fluctuate due to a minute change and loses stability.

However, when the target value SV changes, it is necessary to make the control amount of the actual process 105 coincide with the change. Therefore, the change of the target value SV is small and the operation amount MV is also small. Even in the case of a minute amount, feedback control is performed to control the control amount PV of the process 105 to be equal to the target value SV.

Further, the deviation between the characteristics of the actual process and the characteristics of the simulated transfer function is large in the case of a transient state.
If it has been a while since the target value SV is given, the control amount PV
Becomes stable, so as shown in FIG. 4 (a), after the target value SV changes, every fixed period T (this period T is a time determined by the characteristics of the target control system). The operation amount is output even if the change is minute, so that strict feedback control of the process 105 can be performed.

It should be noted that the present invention is not limited to the above-described embodiment, and may have, for example, a circuit configuration shown in FIG. That is, the operation amount MV is immediately changed in response to the change in the target value SV, and in order to speed up the control response, a static characteristic circuit 111 for providing static characteristic compensation for the target value SV, an addition circuit 112, an operation amount A dynamic characteristic circuit 113 that performs dynamic characteristic compensation on the MV, a static characteristic circuit 114 that performs static characteristic compensation on the control amount PV with respect to the feedback amount, and a subtraction that subtracts the output of the dynamic characteristic circuit 113 from the output of the static characteristic circuit 114 It comprises a circuit 115 and a compensation circuit 116.

In the apparatus of this embodiment, the target value S
The static characteristic compensation for V is performed in the static characteristic circuit 111, the result is output to the adding circuit 112, and the control amount PV is fed back to another static characteristic circuit 114 to compensate for the static characteristic. The dynamic characteristic compensation amount from the circuit 113 is subtracted, and in this compensation circuit 116, as in the first embodiment shown in FIG. 1, when the target value changes, when the fixed period T arrives, or when the operation amount MV is And outputs the manipulated variable MV to the adder circuit 112 only in any case where there is a large fluctuation beyond the range.

Therefore, when the target value SV is changed, the manipulated variable MV immediately rises in the adding circuit 112 based on the target value SV input to the static characteristic circuit 111, and this is given to the process 105 to process control. Will be performed promptly.

In a normal state, the operation amount MV is not changed unless the operation amount exceeds a predetermined range or a predetermined period T arrives, thereby preventing the process 105 from fluctuating unnecessarily. Thus, the stability of the control system is improved.

In each of the above embodiments, the operation amount MV is given to the process 105 every time a predetermined period T arrives, and the operation amount MV is changed as a whole. In this case, since the process fluctuates with a constant time constant, a slight margin time t ₀ is set before and after the constant period T as shown in FIG. By doing so, the stability can be further improved.

FIG. 6 shows a circuit configuration of still another embodiment of the complementary feedback control device of the present invention.

The complementary feedback control device of this embodiment includes a subtraction circuit 201 and a static characteristic circuit 20 for performing static characteristic compensation.
2, a subtraction circuit 203, an accumulation circuit 204, a dynamic characteristic circuit 205 for performing dynamic characteristic compensation, and a subtraction circuit 206.
3 and an integrating circuit 204.

In the complementary feedback control device of this embodiment, a target value SV is set by a setting device or the like, and is provided to the subtraction circuit 201.
Asking, this was subject to static characteristic compensation using simulated transfer function 1 / K _p in static characteristic circuit 202, and outputs the output e ₁ to the adder circuit 203.

The manipulated variable MV is calculated by the dynamic characteristic circuit 205.
Is performed using the simulated transfer function _Gp for
The resulting internal control variable PV by subtracting the subtracting circuit 206 from the operation amount MV as an internal target value SV, giving a signal _{e 2} which is obtained to the subtraction circuit 203.

Therefore, in the subtraction circuit 203, the static characteristic circuit 2
Subtracted from the 02 output e ₁ and dynamics circuit 205 circuit 206
Subtracts the signal e ₂ which is output via, applied to the integrated circuit 204 and the output signal e ₃ as a differential value of the manipulated variable MV, where integrated with previous value, the final manipulated variable MV an integration circuit Output from 204 to process 208.

Here, the compensation circuit 207 is a subtraction circuit 203
The output e ₃ of the performs the following determination processing.

(1) When the difference between the deviations e ₁ and e ₂ is smaller than a predetermined value, that is, when e ₃ is smaller than a predetermined value, the compensating circuit 207 is used.
Is set to 0, and the manipulated variable MV is not changed.

(2) If a certain period T determined from the process time constant of the plant has passed, regardless of (1),
as it is adopted e _3, to change the manipulated variable MV.

[0039] (3) Check the target value SV, this when the target value SV there is a change is adopted as it is the e ₃ regardless of the (1), to change the manipulated variable MV.

As described above, also in the speed-type complementary feedback control device, the simulated transfer function of the process has a large deviation from the actual characteristic of the process, for example, immediately after the change of the target value SV, but thereafter becomes stable. In such a situation, unnecessary control is not performed in an area where fluctuations are large, and a change in the operation amount is performed only when the control amount exceeds a predetermined value range so that the control system is quickly stabilized. Improve the sex.

[0041]

As described above, according to the present invention, when the change in the operation amount is within a certain set range, the change in the operation amount is not performed.
If the MV is changed and the target value is changed,
Because it has performed the changes of the manipulated variables further every predetermined period when determined from constant corresponding process, in particular the control response
At times such as the rise of the answer, the operation amount is changed only for changes that exceed the expected error, and unnecessary control is frequently performed by constantly changing the operation amount as in the past, It is possible to solve the problem that extra time is required for the system to stabilize, to reduce the influence of the simulated transfer function deviating from the actual process, and to increase the control stability.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of one embodiment of the present invention.

FIG. 2 is a block diagram showing a detailed internal configuration of a compensation circuit in the embodiment.

FIG. 3 is a graph showing an actual process showing dynamic characteristics of the embodiment and a response example of a simulated transfer function.

FIG. 4 is a timing chart showing the timing of changing the manipulated variable in the embodiment.

FIG. 5 is a circuit block diagram of another embodiment of the present invention.

FIG. 6 is a circuit block diagram showing still another embodiment of the present invention;
FIG.

FIG. 7 is a circuit block diagram of a conventional example.

[Explanation of symbols]

 Reference Signs List 101 subtraction circuit 102 static characteristic circuit 103 addition circuit 104 dynamic characteristic circuit 106 compensation circuit 107 target value monitoring unit 108 time management unit 109 operation amount monitoring unit 110 control unit 201 subtraction circuit 202 static characteristic circuit 203 subtraction circuit 204 integration circuit 205 dynamic characteristic Circuit 206 Subtraction circuit 207 Compensation circuit 208 Process SV Target value MV Operation amount PV Control amount

────────────────────────────────────────────────── ─── Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) G05B 11/36 505-507 G05B 13/00-13/04 JICST file (JOIS)

Claims (2)

(57) [Claims] 1. A process for a deviation between a target value and a control amount.
Line static characteristic compensation using the inverse of the static characteristic simulating the transfer function of the scan
The static characteristic part and the dynamic characteristic with respect to the operation amount of the process
A dynamic characteristic unit that performs dynamic characteristic compensation using a simulated transfer function, and adds an output of the static characteristic unit and an output of the dynamic characteristic unit
Means, and use this as the manipulated variable for the process.
A supplementary feedback control device that outputs a manipulated variable output command by detecting a change in the target value, and a time management unit that outputs a manipulated variable output command at predetermined intervals. An operation amount monitoring unit that outputs an operation amount output command when the operation amount exceeds a predetermined range, and an operation amount output from any of the target value monitoring unit, the time management unit, and the operation amount monitoring unit. And a control unit that outputs the manipulated variable to the process only when a command is received. 2. A process for a deviation between a target value and a control amount.
A static characteristic unit that performs static characteristic compensation using the reciprocal of the static characteristic simulated transfer function and outputs a static characteristic compensation signal, and uses the dynamic characteristic simulated transfer function for the operation amount of the process .
A dynamic characteristic section for performing dynamic characteristic compensation and outputting the result as an internal control amount; first adding means for obtaining a deviation between the operation amount and the internal control amount; and a static characteristic compensation signal and the first adding means. A second adding means for calculating a deviation from the output of the second processing means and outputting the result as a manipulated variable differential value; and an integrating means for outputting the integrated result of the manipulated variable differential value output from the second adding means to the process as the manipulated variable. Detecting a change in the target value and outputting a manipulated variable output command
Target value monitor, outputs manipulated variable output command at predetermined intervals
Time management unit, the differential value of the manipulated variable exceeds a predetermined value and becomes large.
MV monitoring that outputs a MV output command when it becomes necessary
Units and their target value monitoring units, time management units or manipulated variables
When a manipulated variable output command is received from any of the monitoring units
Control for changing the manipulated variable by integrating only the manipulated variable differential value output from the second adding means to the integrating means.
A complementary feedback control device comprising: a compensating circuit comprising a unit.