JPH06309007A - Automatic controller - Google Patents

Abstract

PURPOSE:To optimize the tuning of a PID control constant by providing both functions for following up a set value and suppressing disturbance in simple constitution. CONSTITUTION:The automatic controller is equipped with a set value pattern storage output means 21 which outputs the set value of one set value pattern on the basis of external pattern specification, a control arithmetic part 23 which outputs a 1st manipulated variable for disturbance suppression characteristics to disturbance variation by performing PIPID control arithmetic on the basis of the outputted set value, a manipulated variable pattern storage output means 22 which selects one of plural manipulated variable patterns in correspondence relation with respective set value patterns and outputs a 2nd manipulated variable in synchronism with the output of said set value, and a correcting process means 26 which obtains a final manipulated variable by adding the 2nd manipulated variable outputted from the manipulated variable pattern storage output means to the 1st manipulated variable outputted from the control arithmetic part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic adjusting device used in a plant instrumentation system for steel, petrochemicals, foods, etc., and particularly to a change of a set value when a PI or PID adjusting arithmetic unit is used. The present invention relates to an automatic adjustment device having an improved operation amount output means.

[0002]

2. Description of the Related Art Conventionally, there are adjusting devices for various purposes,
One example is an automatic temperature control device.
This automatic temperature control device needs to improve both the set value tracking characteristic associated with the change of the set value and the disturbance suppression characteristic against the change of the disturbance due to the change of the set value. For this reason, as shown in FIG. An adjusting device adopting the PID control method is used.

FIG. 2 is a diagram showing the structure of such an automatic temperature control device. In the automatic temperature controller, for example, when executing the program control as shown in FIG. 3, when the operator specifies a pattern based on the program to be executed, the specified pattern is set from the set value pattern table 1 serving as the set value changing unit. The set value SV based on the above is output and introduced into the PID adjustment calculation unit 2.

The PID adjustment calculation unit 2 obtains a deviation between the set value SV and the detected temperature PV from the temperature detection end 4 installed in the furnace 3 or the like, and then performs a PID calculation such that the deviation becomes zero. Execution amount change amount for each sampling cycle ΔMV
Is introduced into the manipulated variable integrating section 5. The operation amount integrating unit 5 adds the operation amount up to the previous sampling time point and the current operation amount change amount ΔMV to obtain the final operation amount MV, and then, the fuel flow rate adjusting unit 6 and the air flow rate adjusting unit. It is used for the flow rate target value of 7.

The fuel flow rate adjusting section 6 is provided with an operation amount integrating section 5
The adjustment calculation is executed using the target value as the manipulated variable MV that is the output of the fuel flow rate and the fuel flow rate detected by the fuel flow rate detector 8, and the operation signal MVf of the obtained adjustment calculation result is applied to the fuel control valve 9. Then, the fuel flow rate to be supplied to the burner 10 is adjusted and controlled.

On the other hand, the air flow rate adjusting unit 7 takes in the operation amount MV which is the output of the operation amount integrating unit 5 and obtains a multiplication value of the operation amount MV obtained by the multiplying unit 11 and the air excess ratio μ. The adjustment calculation is executed using the target flow rate value SV and the air flow rate detected by the air flow rate detector 12, and the operation signal MVa of the obtained adjustment calculation result is applied to the air control valve 13 and supplied to the burner 10. Controls the flow rate of the air to be performed.

Therefore, in this automatic temperature control apparatus, the temperature setting pattern table 1 which is a set value changing section and the PID adjustment calculating section 2 are independent from each other, and the set value SV is output from the pattern table 1 according to the designated pattern. , Again P
The ID adjustment calculator 2 is configured to calculate and output the operation amount based on the set value SV from the table 1.

[0008]

By the way, in the adjusting device as described above, not only is it necessary to set the PID control constant used in the PID adjustment calculating section 2, but also the change of the set value and the disturbance caused by the change of the set value. Optimal P according to changes
It is necessary to tune the ID control constant. At this time, it is necessary to compromise the PID control constant depending on whether the setting value tracking characteristic with respect to the setting value change is emphasized or the disturbance suppressing characteristic with respect to the disturbance change is emphasized.
Complete optimization of control constants is very difficult.

Therefore, in recent years, a two-degree-of-freedom PID control system has been proposed. In this case, a target value filter means is newly provided on the set value output end side, or the target value filter means and a feedback control system. It is necessary to properly set various constants such as, and there is a problem that it is complicated and it is difficult to adjust the constants.

The present invention has been made in view of the above circumstances, and makes it possible to satisfy both the set value tracking characteristic and the disturbance suppression characteristic by using a very simple structure, and thus the tuning of the PID control constant is optimized. It is an object of the present invention to provide an automatic adjusting device which improves the controllability and controllability.

[0011]

In order to solve the above-mentioned problems, the invention according to the claims sets a plurality of setting value patterns in advance, and sets values of a certain setting value pattern based on pattern designation from the outside. And a first manipulated variable for the disturbance suppression characteristic with respect to the disturbance change by performing PI or PID adjustment calculation based on the set value output from the set value pattern storage and output means. An operation amount pattern that is obtained and output and a plurality of operation amount patterns having a correspondence relationship with each of the set value patterns is selected, and the operation amount pattern is selected in synchronization with the output of the set value. A manipulated variable pattern storage / output means for outputting a second manipulated variable from one manipulated variable pattern, and a set value addition for changing the set value in the first manipulated variable output from the adjustment calculation section. An automatic adjusting device which is provided with a correcting means for obtaining an operation amount of the required by adding a second operation amount from the operation amount pattern memory output means for characterization.

[0012]

Therefore, according to the invention corresponding to the claims, when the pattern designation is performed from the outside by taking the above means, the set value pattern storing and outputting means receives a certain set value pattern in response to the pattern designation. Along with the selection, the set value is output according to the time from the selected set value pattern. Here, the adjustment calculation unit performs the PI or PID adjustment calculation based on the set value and outputs the first operation amount for the disturbance suppression characteristic with respect to the disturbance change.

On the other hand, in the manipulated variable pattern storage / output means,
When the pattern designation is received, it has a corresponding relationship with the selected set value pattern among a plurality of manipulated variable patterns.
One operation amount pattern is selected, and the second operation amount is output according to the time in synchronization with the set value. And
The desired operation amount is obtained by adding the second operation amount to the first operation amount output from the adjustment calculation unit.

Therefore, if the second manipulated variable by the manipulated variable pattern storing / outputting device is solely devoted to the improvement of the set value tracking characteristic with respect to the set value change, the role of the adjustment calculation section is exclusively for the disturbance suppression with respect to the disturbance change. It is possible to focus on the functions for improving the characteristics, and it is possible to satisfy the disturbance suppression characteristics and the set value tracking characteristics at the same time while easily tuning the PID control constants without complicated configuration and adjustment.
The controllability can be improved.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the device of the present invention. In the figure, the same parts as those in FIG. 2 showing the conventional device are designated by the same reference numerals and detailed description thereof will be omitted, and only different parts will be described below.

This adjusting device is provided with a set value pattern table 21 for storing a large number of set value patterns in advance and a manipulated variable pattern table 22 for storing a large number of manipulated variable patterns having a corresponding relationship with these set value patterns. ing.

When receiving a pattern designation from the outside, the set value pattern table 21 outputs the set value SV corresponding to the required time of the designated pattern. On the other hand, the operation amount pattern table 22 stores an operation amount pattern empirically determined from the set value pattern, and the operation amount is extracted from the corresponding operation amount pattern based on the synchronization signal received from the set value pattern table 21 and output. To do.

The reason why the manipulated variable pattern having a correspondence relationship with the set value pattern is used is to set a PID control constant exclusively for improving the disturbance suppression characteristic with respect to the disturbance change, and instead to the set value change. This is because the manipulated variable pattern is used to improve the set value tracking characteristic.

The set value SV and the manipulated variable output from the set value pattern table 21 and the manipulated variable pattern table 22 are respectively the PI or PID adjustment calculator (hereinafter collectively referred to as PID adjustment calculator) 23 and the manipulated variable. It is sent to the selection means 24.

The PID adjustment calculator 23 is provided in the table 2
Setting value SV output from 1 and detection value P from detection end 4
The PID adjustment calculation is performed so that the deviation from V becomes zero, and the manipulated variable variation ΔMV is obtained and output.

On the other hand, the manipulated variable selecting means 24 has a switching means, for example, whether the set value SV from the set value pattern table 21 is being controlled according to the presence / absence of a pattern designation from the outside or according to an operator's instruction. On the basis of the output of the set value control determining means 25 for determining whether or not, when the set value is being controlled, the output ΔMV of the manipulated variable pattern table 22
It has the function of selecting p and selecting 0% input and manipulated variable zero when the set value control is not in progress.

Reference numeral 26 is a correction processing means, which is a PI.
By adding the operation amount change amount ΔMV sent from the operation amount selecting means 24 to the operation amount change amount ΔMV of the D adjustment calculation unit 23, the operation amount change satisfying the disturbance suppression characteristic and the set value tracking characteristic. The minute ΔMVc is output.

The manipulated variable variation ΔMVc obtained by the correction processing means 26 is sent to the manipulated variable integrating section 5, where it is integrated with the manipulated variables up to the previous time to obtain the final manipulated variable MV.

In the above embodiment, the digital PID
Since it is control, the manipulated variable changes ΔMV and ΔMVc are obtained, but in the case of analog PID control, the manipulated variables are directly obtained.

Next, the operation of the configuration of the above embodiment will be described. Each of the controllers 6 and 7 supplies the fuel flow rate and the air flow rate to the burner 10 with an appropriate flow rate ratio while adjusting and controlling each of the control valves 9 and 13 based on the target flow rate, so that the temperature inside the furnace 3 becomes a predetermined temperature. Control so that. Therefore, the temperature inside the furnace fluctuates due to the combustion of the burner 10. Therefore,
The temperature detecting end 4 is installed in the furnace 3, the temperature inside the furnace is detected by the temperature detecting end 4, and the temperature is guided to the PID adjustment calculation unit 23 described later.
A PID adjustment calculation is performed under the set value SV to obtain a manipulated variable, which is directly supplied to the fuel flow rate controller 6 as a target value, and the multiplication unit 11 multiplies the air-fuel ratio to obtain a target value for the air. It is supplied to the flow rate controller 7, and the control valves 9 and 13 are adjusted and controlled as described above.

By the way, regarding temperature control in the furnace, program control is often executed in a predetermined furnace temperature pattern. In this case, a large number of set value patterns are stored in advance in the set value pattern table 21 and external While specifying the furnace temperature pattern, sequentially select the required set value pattern,
The set value according to the time of one set value pattern among them is set in the PID adjustment calculation unit 23.

The PID adjustment calculation unit 23 executes the PID adjustment calculation according to the set value, obtains the manipulated variable change amount ΔMV due to the current sampling, and supplies it to the correction processing means 26. However, since the PID adjustment calculator 23 is set to the PID control constant that can quickly respond to the disturbance suppression with respect to the disturbance change, it does not contribute to the improvement of the set value tracking characteristic with respect to the set value change.

Therefore, in the apparatus of this embodiment, the manipulated variable pattern having a corresponding relationship with each set value pattern in the set value pattern table 21 is stored in the manipulated variable pattern table 22 in advance, and the pattern is designated from the outside. When one of the plurality of manipulated variable patterns is selected, one manipulated variable pattern corresponding to the set value pattern is selected, and the set value pattern and the manipulated variable pattern are synchronized to operate in response to a change in the set value pattern. Output while changing the operation amount of the quantity pattern.

At this time, the set value control determining means 25 is
The manipulated variable selecting means 2 receives a signal indicating whether the set value control is being performed in response to a pattern designation or an operator designation from the outside.
Is given to 4.

Here, the manipulated variable selection means 24 is always 0.
Although the manipulated variable zero is output based on the% designation, the manipulated variable pattern table 22 is generated when a signal during set value control is input.
Is selected, and the operation amount change amount ΔMVp for correcting the set value following characteristic with respect to the set value change is output and supplied to the correction processing means 26.

In the correction processing means 26, the operation amount selection means 2 is added to the operation amount change amount ΔMV from the PID adjustment calculation part 23.
4 is added or subtracted from the operation amount change amount ΔMVp due to the change in the set value, the operation amount change amount ΔMVc considering both characteristics is taken out based on the change in the set value, and the change amount ΔMVc is further calculated. Then, the operation amount up to the previous time is integrated to obtain the operation amount MV at this time, and this operation amount MV is used as the target value of both controllers 6 and 7.

Therefore, according to the configuration of the above-described embodiment, the PID adjustment calculation unit 23 exclusively uses the P for adjusting the disturbance.
It is only necessary to find the ID control constant, and it is relatively easy to obtain the optimum PI.
The D control constant can be tuned. On the other hand, if the amount of change in the manipulated variable that responds quickly to the follow-up characteristic to the change in the set value is set in the manipulated variable pattern table 22, it corresponds to the set value of the set value pattern from the manipulated variable pattern table 22 during the set value control. Take out the manipulated variable
It suffices to add it to the ID adjustment calculation output, and control for improving both characteristics can be executed.

In the above embodiment, the manipulated variable pattern table 22 is provided separately from the set value pattern table 21 and the manipulated variable pattern corresponding to the set value pattern is stored. If the manipulated variable is calculated each time from the change in the set value, or if the manipulated variable is output as a function, the same effect as the manipulated variable pattern table 22 can be obtained. In this way, even if the setting value pattern table 21 is changed,
It is not necessary to change the manipulated variable pattern table 22 each time.

The device of the present invention is not limited to the embodiment shown in the drawings, but can be applied to all control systems involving disturbances, and can be applied not only to temperature control but also to any controlled object. Further, it can be easily applied to things other than furnaces, such as control of reactors and the like. further,
Although the time data is input to the set value pattern table 21 and the operation amount is output from the operation amount pattern in response to the synchronization signal, the time data may be input to each of the tables 21 and 22 separately. In addition, the present invention can be modified in various ways without departing from the scope of the invention.

[0035]

As described above, according to the present invention, the optimum PID control constant can be easily tuned, and at the same time, both the set value tracking characteristic and the disturbance suppressing characteristic can be simultaneously adjusted when the set value is changed. Not only is it satisfactory, controllability is improved, but reproducibility of control under the same operating conditions of the plant can be secured, and product quality can be made uniform and manufacturing cost estimation can be refined.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an automatic adjustment device according to the present invention.

FIG. 2 is a diagram showing a configuration of a conventional automatic adjustment device.

FIG. 3 is a diagram illustrating pattern designation in program control.

[Explanation of symbols]

3 ... Furnace, 4 ... Temperature detecting end, 5 ... Manipulation amount integrating section, 6 ... Fuel flow rate controller, 7 ... Air flow rate controller, 21 ... Set value pattern table, 22 ... Manipulation amount pattern table, 23 ... P
ID adjustment calculation part, 24 ... Manipulation amount selection means, 25 ... Set value control determination means, 26 ... Correction processing means.

Claims (1)

[Claims] 1. A plurality of set value patterns are set in advance,
PI (P: proportional, I: based on the setting value output from the setting value pattern storing and outputting means for outputting the setting value of a certain setting value pattern based on the pattern designation from the outside and the setting value pattern storing and outputting means. Integration) or PID
(D: Derivative) An adjustment calculation unit that performs adjustment calculation to obtain and output a first operation amount for a disturbance suppression characteristic with respect to a disturbance change, and a plurality of operation amount patterns having a correspondence relationship with each of the set value patterns. Select one operation amount pattern from
A manipulated variable pattern storage output unit that outputs a second manipulated variable from the one manipulated variable pattern, and the first manipulated variable output from the adjustment calculation unit for the set value tracking characteristic with respect to the set value change. An automatic adjustment device comprising: a correction processing unit that obtains a required operation amount by adding a second operation amount from an operation amount pattern storage output unit.