JPH05108110A - Feedback loop compensator - Google Patents

Abstract

PURPOSE:To improve the response characteristic to the fluctuation of a target value when a feedback loop compensator and a process are serially arranged, to minimize the influence to the controlled variable even for the unknown disturbance and to prevent the deterioration of the control performance even when the change in the elapse of time is performed for the process. CONSTITUTION:In a feedback loop compensator 10 arranged serially to a process 1, the system to feed back the communication characteristic of the K(constant)/S (Laplace operator) is made into a rule model part 11, an output y* of the rule model part 11 and a controlled variable (y) fed back from the process 1 are compared by a comparator 22, and a deviation value delta is obtained. Based on the deviation value delta, the unknown parameter is searched by the integration function, and the transfer characteristic matched with the process 1 is constituted to become the K/S.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a feedback loop compensator applied to process steam temperature control and the like.

[0002]

2. Description of the Related Art FIG. 2 shows a typical example of a conventional feedback loop compensator (generally called a PID controller). The controlled variable y, which is the output of the process 1, is calculated by comparing the target value r with the comparator 2
And the value is called the control deviation ε. The control deviation ε is input to the PID controller 3, the output of which is the manipulated variable u, and the input of the process 1.

[0003]

The above-mentioned conventional feedback loop compensator is a feedback loop compensator (P
The parameters of the ID controller 3) are fixed. If the parameters of the compensator are fixed in this way, there is a problem that when the process changes with time, it deviates from the optimum adjustment state and the control performance deteriorates.

The present invention has been made in view of the above circumstances, has a good response characteristic to a change in a target value, can reduce an influence on a control amount even for an unknown disturbance, and even when a process changes with time. An object of the present invention is to provide a feedback loop compensator capable of keeping control performance in an optimum state.

[0005]

According to the present invention, a feedback loop compensator arranged in series to a process uses a system in which a transfer characteristic of K (constant) / S (Laplace operator) is fed back as a reference model. , The deviation value is obtained by comparing the output of this reference model with the feedback signal from the above process, an unknown parameter is searched for by the integration function based on this deviation value, and the transfer characteristic combined with the above process becomes K / S. It is characterized in that the parameters are learned as described above.

[0006]

The system in which the transfer characteristic of K / S is fed back is used as a reference model, the parameters of the compensator connected to the process are searched, and the transfer characteristic of the compensator and the process is K / S.
The output (control amount) of the process and the output of the reference model are matched so that S becomes S. Here, the structure of the compensator is predetermined, and only the parameters are unknown, and the parameters are searched by the integration function in order to gradually bring the deviation between the process output and the reference model output closer to zero.

By learning the para-parameters of the feedback loop compensator so that the transfer characteristic combined with the process becomes K / S as described above, the response characteristic can be improved and the reference is always maintained even if the process changes with time. Can follow the model.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a feedback loop compensator with a learning function according to an embodiment of the present invention. In the figure, 10 is a feedback loop compensator, which comprises a reference model unit 11 and other circuit elements. The reference model unit 11 includes a K / S transfer characteristic element 12 and a comparator 13. S in this transfer characteristic element 12
Is a Laplace operator and K is a constant. The comparator 13
Is the output y ^* of the transfer characteristic element 12 of the target value r and K / S. And the output ε ^* Is input to the K / S transfer characteristic element 12.

Further, the feedback loop compensator 10 is provided with a coefficient unit 14. The coefficient unit 14 receives the control deviation ε from the comparator 2, and its output 15 is input to the multiplier 16 and is also supplied to the multiplier 23 via the differentiator 17.

On the other hand, the output y ^* of the transfer characteristic element 12 in the reference model section 9 Is sent to the comparator 22 for process 1
The deviation value δ from the controlled variable y is calculated. This deviation value δ
Is input to the multipliers 20 and 26 together with the output of the comparator 13. The output of the multiplier 20 is input to the multiplier 16 via the coefficient unit (α1) 19 and the integrator 18. Similarly, the output of the multiplier 26 is input to the multiplier 23 via the coefficient unit (α 2) 25 and the integrator 24.

Further, the output y ^* of the transfer characteristic element 12 in the reference model section 11 Is input to the multiplier 29. In addition, the deviation value δ output from the comparator 22 is input to the multiplier 29.
Is input, and the multiplication output is added to the output of the multiplier 23 by the adder 30. The output of the adder 30 is the adder 3
When it is 1, it is added to the output of the multiplier 16 to form a manipulated variable 7 (u), which is sent to the process 1.

Next, the operation of the above embodiment will be described. K / S
It is well known that the feedback characteristic of the transfer characteristic becomes the first-order delay characteristic. In this case, the time constant becomes 1 / K, and the larger the constant K, the smaller the time constant. That is, if the constant K is increased, the response characteristic is improved.

In the present invention, attention is paid to this point, and the transfer characteristic element 1
The K / S transfer characteristic in 2 is fed back to form the reference model unit 11, and the parameters of the feedback loop compensator 10 connected to the process 1 are searched for to obtain the compensator 1
The output of the process 1 (control amount y) and the reference model unit 11 are set so that the combined transfer characteristic of 0 and process 1 becomes K / S.
Output of y ^* Match. Here, the structure of the compensator 10 is predetermined, only the parameters are unknown, and the output y of the process 1 and the output y ^{* of the reference} model unit 11 are set ^.
The deviation value δ between and is obtained by the comparator 22, and the parameter is searched by the integration function in order to gradually bring the deviation value δ close to zero.

That is, in the system of the multiplier 20, the coefficient unit 19, and the integrator 18, “ε ^* .alpha.1 .delta. / S "is calculated, and is multiplied by K.epsilon. Further, in the multiplier 26, the coefficient unit 25, and the integrator 24, “ε ^* [alpha] 2 [delta] / S "is calculated and multiplied by K [epsilon] S output from the differentiator 17 in the multiplier 23. The multiplication outputs of the multipliers 16 and 23 are added by the adders 30 and 31, and are fed back to the comparator 22 through the process 1 to try to set the deviation value δ to zero.

Further, a coefficient unit (α 3) 27, an integrator 28,
In the system of the multiplier 29, "y ^* .alpha.3.delta. / S "is calculated, and the comparator 2 is passed through the process 1 in the same manner as the above-mentioned other systems.
It is fed back to 2 and tries to make the deviation value δ zero.

As a result of the above, if the deviation value δ becomes zero, y ^*
And y are the same, the output y of the process 1 is the output y ^{* of the reference} model unit 11 ^. And similarly the control deviation ε output from the comparator 2 and the output ε ^{* of the} comparator 13
Also matches. That is, the characteristic becomes K / S, and the control performance is improved. In addition, the above "y ^* The system that performs the processing of α 3 δ / S has a function equivalent to that of the PID integrator.

As the feedback control performance is improved as described above, the control performance against unknown disturbance is also necessarily improved. Further, even if the process 1 changes with time, it can always follow the reference model, so that the characteristic of the output y when the control deviation ε is input is K / S, which is not affected by the change with time and the control performance is deteriorated. To be prevented.

[0019]

As described above in detail, according to the present invention, when the feedback loop compensator and the process are arranged in series, the transfer characteristic obtained by combining them is K / S. The response characteristics to fluctuations can be improved, and the influence on the controlled variable can be reduced even for unknown disturbances.
Moreover, even if the process changes over time, it is possible to maintain the optimum adjustment state and prevent deterioration of the control performance.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a feedback loop compensator according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional feedback loop compensator.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Process, 2, 13, 22 ... Comparator, 3 ... PID regulator, 11 ... Reference | standard model part, 12 ... Transfer characteristic element, 13
... Comparator, 14, 19, 25, 27 ... Coefficient unit, 16, 2
3, 29 ... Multiplier, 17 ... Differentiator, 18, 24, 28 ...
Integrator, 30, 31 ... Adder, r ... Target value, ε ... Control deviation, y ... Control amount, u ... Manipulation amount.

Claims (1)

[Claims] 1. A feedback loop compensator arranged in series with respect to a process uses a system in which a transfer characteristic of K (constant) / S (Laplace operator) is fed back as a reference model, and the output of this reference model and the above Calculate the deviation value by comparison with the feedback signal from the process,
A feedback loop compensator characterized in that an unknown parameter is searched by an integration function based on this deviation value, and a transfer characteristic combined with the above process is K / S.