JPH1091211A - Control constant adjusting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the control constant adjusting device which can minimize the frequency of implementation of a system identifying test. SOLUTION: This control constant controller is equipped with an input/output data gathering means 3 which gathers manipulated variables and controlled variables, a control performance decision means 5 which decides the control performance of a feedback system, a control specification indicating means 6 which gives the control specifications of the feedback system, a model generating means 7 which generates a transfer function model, and a control constant determining means 9 which calculates a control constant. The control performance decision means 5 decides whether or not the precision of the transfer function model meets a specific reference value, and indicates the restructuring of the transfer function model to the model generating means 7 when it is judged that the reference value is not met and indicates the variation of the control constant to the control constant determining means 9 when it is judged that the reference value is met.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a repetitive control constant adjusting device for adjusting a control constant of a control device in a feedback system.

[0002]

2. Description of the Related Art FIG. 8 shows a schematic configuration of a feedback system used as a control system of various industrial plants. When controlling the control amount of the control target 1 to the target value r in this feedback system, the control device 2 outputs an operation amount u to the control target 1, and the output of the control device 2 for the operation amount u. The control amount y is measured. Then, the measured control amount y is fed back and compared with the target value r, and the control device 2 outputs a new operation amount u to the control target 1 again.

[0003] The control constants of the control device in the feedback system are determined in advance to optimal values for optimal operation of the plant. However, deviations from the optimal operating conditions may occur due to changes in plant characteristics. Therefore, it is necessary for the operator to constantly monitor the operation state of the plant and to readjust the control constants when the operation state deviates from the optimum operation state. In the readjustment of the control constants, a method in which an operator manually changes the control constants or a method in which the control constants are changed by using an auto-tuning tool is adopted.

A conventional auto-tuning tool changes a control constant according to a processing procedure as shown in FIG. First, the identification condition determination device 90 determines the type of signal necessary for generating an identification signal. Next, an actual identification signal is calculated by the identification signal generation device 91 based on the condition determined by the identification condition determination device 90, and the identification signal is applied to the application position specified by the identification signal application device 92. Then, the identification data collection and processing device 93 collects the time series data y and u of the control amount y and the operation amount u of the control target 1 while the identification signal is being applied. Next, the model structure determining device 94 determines parameters such as the structure of the transfer function model. Using the parameters such as the model structure determined by the model structure determining device 94 and the time series data y, u, the transfer function model estimating device 95 determines a transfer function model. next,
The design parameters are determined by the design parameter determining device 96, and a new control constant is determined by the control constant determining device 97. The conventional auto-tuning technique is to apply a new control constant to the control device, observe the operating state of the plant, and repeat the above procedure until an optimal operating state is obtained.

[0005]

However, the system identification test performed in the above-described conventional auto-tuning tool involves adding a disturbance signal called an identification signal to a control target, and therefore has a bad influence on plant operation. This causes a problem that the quality of the product being manufactured is deteriorated. In addition, in the conventional auto-tuning tool, since the system identification test is performed each time the adjustment is performed, it is necessary to perform the identification test many times before the optimum control constant is obtained. In the conventional method, an optimal control constant is designed based on the obtained transfer function model. However, in practice, there is always a deviation between the transfer function model and the control target. Therefore, the response when the obtained control constant is applied to the control device is significantly different from the response predicted using a transfer function model in advance, and in some cases, the feedback system becomes unstable.

Accordingly, an object of the present invention is to provide a control constant adjusting apparatus which can solve the above-mentioned various problems and can minimize the number of times of performing a system identification test.

[0007]

According to a first aspect of the present invention, there is provided a control constant adjusting device for adjusting a control constant of a control device of a feedback system. Input / output data collecting means for collecting a control amount, a control performance determining means for determining control performance of the feedback system based on the control amount and the operation amount collected by the input / output data collecting means, and the feedback Control specification instruction means for giving a control specification of the system, model creation means for creating a transfer function model of the control target, control constant determination means for calculating a control constant of the control device,
When the control performance of the feedback system does not satisfy the control specification, the control performance determination unit determines whether or not the accuracy of the transfer function model satisfies a predetermined reference value, and satisfies the predetermined reference value. If it is determined that the transfer function model is not reconstructed, it is instructed to reconstruct the transfer function model to the model creation means, while if it is determined that the predetermined reference value is satisfied, the control constant determination means Until the control performance of the feedback system satisfies the control specifications, accuracy evaluation of the transfer function model, reconstruction of the transfer function model or It is characterized in that the change is repeated.

According to a second aspect of the present invention, there is provided a control constant adjusting apparatus, further comprising a control target monitoring means for displaying trend data of the control amount and the operation amount.

According to a third aspect of the present invention, in the control constant adjusting apparatus, the control target monitoring means displays a trend data display section for displaying trend data of the control amount and the operation amount, and a control performance of the feedback system. And a switch unit for starting or stopping the adjustment of the control constant, and an adjustment mode display unit for displaying a current adjustment mode during the adjustment of the control constant. .

According to a fourth aspect of the present invention, in the control constant adjusting apparatus, the control performance determining means determines a control amount calculated by the transfer function model and the control amount obtained as an output of the controlled object. It is characterized by having a model accuracy determining means for comparing and determining the accuracy of the transfer function model.

According to a fifth aspect of the present invention, in the control constant adjusting apparatus, the model creating means determines identification condition of an identification signal to be added to the control target to create the transfer function model; An identification signal generating means for generating the identification signal; an identification signal applying means for applying the identification signal generated by the identification signal generating means to the control object; and adding the identification signal to the control object by the identification signal applying means. Collecting the control amount and the operation amount at the time of performing, performing an appropriate filtering process on the collected control amount and the operation amount to create identification data, Model structure determining means for determining model parameters required to determine the transfer function model of the controlled object based on the Characterized in that it comprises a transfer function model estimating means for determining the transfer function model based on Dell parameter, a.

[0012] The control constant adjusting apparatus according to the present invention further comprises a model database for storing the transfer function model determined by the model creating means, and the control performance judging means includes the latest transfer function. The accuracy of the transfer function model is evaluated using not only the model but also the past transfer function model stored in the model database.

According to a seventh aspect of the present invention, in the control constant adjusting apparatus, the control constant determining means determines a design parameter value required for calculating a new control constant, and the design parameter determining means determines the value of the design parameter. A control constant calculating means for obtaining the control constant using a parameter, calculating a rate of change between the control constant obtained last time and the control constant obtained this time, and determining whether the rate of change is within a predetermined range. Control constant change rate calculating means for determining whether the change rate is outside the predetermined range by the control constant change rate calculating means. Is changed to obtain a predetermined control constant.

The control constant adjusting apparatus according to the present invention further includes a control constant database for storing the control constants applied to the control device in the past, and the new control constant determining means determined by the control constant determining means. When the control performance of the feedback system does not satisfy the control specification even though the control constant is applied to the control device, the past control constant stored in the control constant database is applied to the control device. It is characterized by doing so.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A repetitive control constant adjusting apparatus according to an embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a schematic configuration of a control constant adjusting device according to the present embodiment. A control device 2 for controlling the control target 1 is connected to the control target 1. In FIG. 1, a symbol r indicates a target value of the controlled object 1, a symbol y indicates a control amount which is an output of the controlled object 1,
The symbol u indicates an operation amount that is an output of the control device 2.
The target value r, the control amount y, and the operation amount u are sent to the input / output data collection device 3 via a signal line, and time-series data is input and stored in each observation cycle. The data stored in the input / output data collection device 3 is input to the control target monitoring device 4 and sent to the control performance determination device 5 at each observation cycle.

The control performance judging device 5 determines the control performance of the feedback system based on each observation data (input / output data) sent from the input / output data collecting device 3 and the control specification given from the control specification indicating device 6. It is determined whether the control specifications are satisfied. Furthermore, when the control performance of the feedback system does not satisfy the control specifications, the control performance determination device 5 determines whether or not the accuracy of the transfer function model currently used satisfies a predetermined reference value. If it is determined that the accuracy of the transfer function model does not satisfy the predetermined reference value, it instructs the model creation device 7 to reconstruct the transfer function model. If it is determined that the value satisfies the value, the control parameter determination unit 9 is instructed to change the control parameter without reconstructing the transfer function model.

The transfer function model obtained by the model creation device 7 is stored in a model database 8, and the control constant obtained by the control constant determination device 9 is stored in a control constant database 10.

FIGS. 2A and 2B show an example of a screen of the display monitor 11 of the control target monitoring device 4.
Shows the case where the control state of the control system is good, and (b)
Indicates a case where the control state of the control system is not good. Then, the respective amounts such as the control amount and the operation amount input to the control target monitoring device 4 are displayed in the trend data display window 11d of the display monitor 11. Further, the control target monitoring device 4
The display monitor 11 has a control performance display window 11a,
It has an adjustment start / end button 11b and an adjustment mode display window 11c. Control performance display window 11a
, The current control performance obtained from the control performance determination device 5 shown in FIG. 1 is graphically displayed, and if the control state of the control system is good (see FIG. 2A), adjustment is necessary. A message as to whether or not there is (see FIG. 2B) is displayed. If adjustment is required, a message is displayed blinking and an alarm is sounded to notify the operator that adjustment is required. Then, when the operator determines to adjust the control constant, the adjustment is started by pressing the start button of the adjustment start button / end button 11b. If it is desired to stop the adjustment halfway, the adjustment can be stopped by pressing the end button. Also,
Whether the adjustment mode display window 11c is in the “monitoring mode” in which trend data of the control amount y and the operation amount u is simply displayed (see FIG. 2A), or the control constant is adjusted. "Adjustment mode" (Fig. 2
(Refer to (b)). Further, in the case of the adjustment mode, "Model is being created" is displayed in the adjustment mode display window 11c when the model is being created, and "Control is being determined" when the control constant is being determined.
Is displayed so that the operator can know which stage of the process in the adjustment mode is currently being performed.

FIG. 3 shows a schematic configuration of the control performance judging device 5. The control performance judging device 5 includes a control state judging device 30. The control state determination device 30 includes:
Each observation data (input / output data) sent from the input / output data collection device 3 and the control specification given by the control specification instruction device 6 are input. Here, the control specification is given by, for example, a settling time until the target value of the control amount is changed to reach the target value or a time until the influence of disturbance is removed when the disturbance is applied. Further, the control specification is given as a value having a certain width, and it is determined that the control is being performed well during the time within this width.

The control state determination device 30 determines how much the current feedback loop system satisfies the control specifications based on each observation data (input / output data) and control specifications, and the result is shown in FIG. Is displayed on the display monitor 11 of the control target monitoring device 4. If there is a large departure from the control specifications, the display monitor 1 indicates this fact.
(1) The operator is notified by the display and the alarm on the upper part, and the operator is prompted to start adjusting the control constant. When the operator instructs the adjustment of the control constant, the control constant is adjusted according to the following procedure.

First, the transfer function model (controlled object model) of the controlled object 1 stored in the model database 8 is sent to the model accuracy judging device 31 shown in FIG. It is determined whether the response is sufficiently represented. Specifically, the model accuracy coefficient △ G is calculated by the model accuracy coefficient calculation device 40 using the input / output data of the control object 1, the current control constant of the control device 2, and the transfer function model of the control object 1. For the calculation of ΔG, the difference between the output response of the controlled object 1 when the same input is applied and the transient response of the output response of the transfer function model, the difference between the frequency response obtained from the frequency analysis, and the like are used. be able to. For example, when the output response (control amount calculation value) when the input (operation amount) u of the control target 1 is added to the transfer function model M using the model accuracy determination device 31 illustrated in FIG. , The square norm △ G = | F (y−y ′) | ² of the difference between the output response y ′ and the control amount y is obtained. Where F
Is a suitable data filter, and a low-pass filter is generally used.

[0022] Then, as shown in FIG. 3, when the maximum allowable value of the square norm △ G △ and _{G max, △ G ≦ △ G} max if the accuracy of the transfer function model is determined to be sufficient, the system The control constants are adjusted using this transfer function model without performing an identification test or reconstructing the transfer function model. On the other hand, if △ G> △ _Gmax , it is determined that the accuracy of the transfer function model is insufficient, and the transfer function model satisfying _７G ≦ △ _Gmax is reconstructed by the model creation device 7.

FIG. 5 shows a schematic configuration of the model creating apparatus 7. First, the kind of signal, the magnitude of the signal,
The application time, application location, and the like of the signal are determined. The signal types include a step signal, a rectangular wave signal, an M-sequence signal, a random signal, and the like. The signal application location includes the operation amount u of the control target 1, the target value r, and the like. Next, an actual identification signal is calculated by the identification signal generation device 51 based on the conditions determined by the identification condition determination device 50, and the identification signal is applied to the application point designated by the identification signal application device 52.

Then, the identification data collecting and processing device 53 collects time series data y and u of the control amount y and the operation amount u of the control target 1 while the identification signal is being applied, and performs filtering processing using the preprocessing filter F _d Te. The pre-processing filter F _d is an appropriate data filter, and for example, a low-pass filter having a pass band similar to that of the data filter F used in the model accuracy evaluation can be used. The time series data of the control amount y and the operation amount u after performing the filtering process are defined as y _f and u _f .

Next, the model structure determination device 54
The parameters necessary for model determination, such as the structure of the transfer function model, the order of the model, and the length of the dead time, are determined. Here, an ARX model or an ARMAX model structure can be used as the structure of the transfer function. Using the parameters such as the model structure determined by the model structure determining device 54 and the time series data y _f , _uf , the transfer function model estimating device 55 is used.
To determine the transfer function model.

The determined transfer function model is stored in the model database 8 shown in FIG.
It is determined whether or not △ G ≦ △ _Gmax is satisfied. Then, the determined transfer function model is expressed as △ G ≦ △ G
_{If max} is not satisfied, the model structure determination device 5
By changing each parameter in 4, a transfer function model satisfying the condition is created. If it is not possible to create a transfer function model that satisfies the conditions even if the parameters are changed, the identification conditions in the identification condition determination device 50 are changed,
Start over from the system identification test. Then, the above-described procedure is repeated until a transfer function model satisfying the above conditions is obtained, and the transfer function model is reconstructed. △ G ≦ △ G
_{When a} transfer function model that satisfies _max is obtained, FIG.
A new control constant within a predetermined range that satisfies the control specifications is determined by the control constant determination device 9 shown in FIG.

FIG. 6 shows a schematic configuration of the control constant determining device 9. Hereinafter, a procedure for determining the control constant will be described with reference to FIG. Various control devices such as a PID control device, an optimum regulator, and an H∞ control device can be used as the control device 2 shown in FIG.
The control device will be described as an example. In addition, typical methods for determining the control constants of the PID control device include a limit sensitivity method and a Ziegler method.
and Nichols method, partial model matching method for closed loop response and frequency model matching method. Here, as an example, description will be made using a frequency model matching method using a frequency-weighted optimal regulator as a reference model.

An appropriate transfer function may be given to the frequency weight of the optimal regulator. For example, an inverse system of a transfer function of a second-order lag system having a pass band similar to that of the pre-processing filter used for model reconstruction is used. It can be realized by using. Further, assuming that a weight coefficient of an evaluation function for designing an optimal regulator is Q, this coefficient Q is a design parameter for designing an optimal regulator. The coefficient Q is determined by the design parameter determination device 60 shown in FIG.

Next, using the design parameters determined by the design parameter determination device 60 and the transfer function model of the controlled object, the control constant calculation device 61 determines the control constant of the PID control device. Then, the control constant calculation device 61
Then, the change rate ΔC between the control constant calculated this time and the current control constant is calculated by the control constant change rate calculation device 62, and it is determined whether the change rate ΔC satisfies a predetermined condition. For example, the maximum value of the rate of change of the proportional gain, the integral gain, and the differential gain, which are the control constants of the PID control device, can be used as ΔC. Also, △ C _max is given in advance as the maximum allowable value of the change rate 、 C, and it is determined whether or not the change rate △ C calculated this time is larger than the maximum allowable value △ C _max . When it is determined that △ C> △ C _max , the process returns to the design parameter determination device 60 and △ C ≦
The coefficient Q is changed until a control constant of _{ΔC max} is obtained, and a series of control constant calculation is repeated.

When a control constant _satisfying △ C ≦ △ _Cmax is obtained in this way, a simulation using the control object model and the new control constant is performed by the control response determination device 63 to determine whether the control can be stably performed. Determine whether or not. When it is determined that stable control can be performed, a new control constant is applied to the control device 2. The new control constant is sent to and stored in the control constant database 10 shown in FIG. On the other hand, if the control response determination device 63 determines that the control cannot be performed stably with the control constant calculated this time, the process returns to the design parameter determination device 60 to change the design parameter Q again, and the above-described series of control constants is changed. A new control constant is obtained by calculation.

Next, after applying the new control constant obtained by the control constant determination device 9 to the control device 2, the control performance determination device 5 shown in FIG. It is determined whether or not the control is being performed stably based on the control. If the control is being performed stably, it is determined whether or not the performance given by the control specification indicating device 6 is satisfied.
If the performance given by the control specification indicating device 6 is not satisfied, the above-described series of procedures is repeated until the performance is satisfied. On the other hand, when the response of the control target 1 becomes unstable or shows a response exceeding the control specification when a new control constant is applied, the control constant is read from the control constant database 10 to perform control. Applied to the device 2 to return to the original state.

As described above, according to the control constant adjusting apparatus of the present embodiment, the control state of the feedback system is determined from the input signal (operation amount) u and the output signal (control amount) y of the control target 1, and If the control performance greatly deviates from the control specifications or shows an unstable control response, the transfer function model of the controlled object is repeatedly updated and the control constant is changed until the desired control performance is obtained. In this case, the accuracy of the transfer function model is evaluated every time.If sufficient model accuracy is obtained, update of the transfer function model is omitted and only the control constant is changed. Therefore, the number of system identification tests involved in updating the transfer function model can be minimized.

Further, the change of the control constant per operation is limited to within the upper limit of the rate of change of the control constant.
The difference between the predicted response and the actual control response caused by the difference between the control target 1 and the transfer function model can be suppressed, and the control constant can be adjusted to an optimum value while the feedback system is kept stable.

EXAMPLE Next, an example of the above embodiment will be described with reference to FIG. The present embodiment relates to model creation and control constant determination when an ARX model is used as a transfer function model of a control target 1 and a PID control device is used as a control device 2. Here, the unknown parameters of the ARX model are obtained by using the least squares method so as to minimize the one-step-ahead prediction error, and the control constants of the PID controller are determined by a frequency model matching method using an optimal regulator as a reference model. Calculate using First, using the control amount y (t), the operation amount u (t), and the target value r (t) of the control amount collected by the input / output data collection device 3, the evaluation function J of the following equation (1) is obtained.
Find (k).

[0035]

(Equation 1) Here, N is the number of data, and λ is a weight coefficient given in advance. At this time, the feedback system is shown in FIG.
(A) can be considered. In FIG. 7A, reference numeral 70 denotes a PID control device, and reference numeral 71 denotes a model of a disturbance added to the control amount.

The evaluation function obtained from the data when the newly obtained control constant is applied is represented by J (k +
Assuming 1), a new control constant is determined so that J (k + 1) <J (k). Where J (k + 1) is
Since the control constant cannot be calculated until it is determined and applied to the control device 2, it cannot be directly evaluated when designing the control constant. Therefore, three new evaluation functions that satisfy the triangle inequality of the following equation (2) are indirectly evaluated to obtain a control constant. | J ^LQ −J ^id −J ^PI | ≦ | J | ≦ | J ^LQ + J ^id + J ^PI | (2) In the above equation (2), if J ^id and J ^PI can be made sufficiently small, J ^LQ is ^calculated by the equation (1) ) Is equivalent to the evaluation function
^{You just have} to evaluate the ^LQ . The specific calculation procedure is shown below.

Procedure 1 Control amount y collected by input / output data collection device 3
(T) and the operation amount u (t), the evaluation function J of the following equation (3)
^Find a transfer function model that minimizes ^id .

[0038]

(Equation 2) ^{Here, y p (t), u} p (t) is the controlled variable and the manipulated variable for the transfer function model P hat obtained here. At this time, a feedback system including the PID controller 70 and the model 73 of the control target 1 shown in FIG.

Further, the one-step ahead predicted value _ypr of the control amount is given by the following equation (4).

[0040]

(Equation 3) Here, H is the transfer function model 74 of the disturbance added to the control amount. One step ahead prediction error defined by the difference between y _pr and the actual control amount is e (t). As shown in the following equation (5), when the sum of squares of D (z) e (t) obtained by multiplying e (t) by data filter D (z) is V, the model P hat that minimizes V is It can be easily obtained by the least squares method.

[0041]

(Equation 4) Furthermore, by appropriately selecting the data filter D (z), the evaluation function J ^id of the equation (3) can be made equal to V of the equation (5). It is obtained by equations (6) and (7).

[0042]

(Equation 5) Here, K ^P is a discrete-time transfer function of the PID controller. Since the transfer function model P obtained here is included in the denominator of D (z), D (z) cannot be obtained in advance. Therefore, in order to simplify the calculation, D
As the P hat included in the denominator of (z), the transfer function model obtained last time (defined as P hat _k-1 ) is used.

By selecting D (z) as described above and finding a P hat that minimizes equation (5), a model P hat that minimizes equation (3) can be found.

Procedure 2 Next, an optimal regulator is designed using the model obtained in the above procedure 1. This design is based on the evaluation function J of the following equation (8).
Design to minimize ^LQ .

[0045]

(Equation 6) At this time, design is performed using a system including the optimal regulator 75 and the control target model 73 shown in FIG. However, the model obtained in step 1 contains the true control target 1
Therefore, it is preferable to use an evaluation function including frequency weights F ₁ and F ₂ as shown in the following equation (9).

[0046]

(Equation 7) Here, F ₁ and F ₂ are given in the form of transfer functions and may be given in advance by a designer, or an appropriate filter can be designed using observation data and simulation data. The evaluation function of the above equation (9) can be converted into the form of the equation (8) by extending the transfer function model P hat of the controlled object 1 using the filters F ₁ and F ₂ . Since the evaluation function J ^LQ of Expression (8) is equal to the evaluation function of a normal optimal regulator, the optimal regulator that minimizes J ^LQ can be easily obtained.

Step 3 Using the optimal regulator obtained in step 2 as a reference model,
A control constant of the PID control device is obtained by a frequency model matching method. At this time, a control constant is determined so as to minimize the evaluation function J ^PI given by the following equation (10).

[0048]

(Equation 8) Here, u ^C and y ^C are operation amounts and control amounts when the optimal regulator is used as the control device 2 and the transfer function model obtained in step 2 is used as the control target.

When the evaluation function of the above equation (10) is expressed in the frequency domain, the following equation (11) is obtained.

[0050]

(Equation 9) Further, the frequency band for performing model matching is [w1,
and w2], (defined as K _k-1 ^P.) The transfer function K ^P a transfer function obtained previous PID controller included in the denominator of the J ^PI replacing the J ^PI is as follows (12) Can be transformed.

[0051]

(Equation 10) Control constants for the J ^PI to a minimum, can be easily obtained by the least square method from the method of frequency model matching.

Step 4 The control constant obtained in step 3 is applied to the control device 2 and the response of the control amount y and the operation amount u is observed. If a sufficient response has been obtained, the adjustment ends. On the other hand, if a sufficient response has not been obtained, the procedure returns to procedure 1 to continue the adjustment.

[0053]

As described above, according to the control constant adjusting apparatus of the present invention, the control performance determining means determines whether or not the transfer function model currently used sufficiently represents the characteristics of the controlled object. Since the transfer function model is not updated while the control constants are updated only when the accuracy of the transfer function model is judged to be sufficient, the system required when reconstructing the transfer function model The number of times of performing the identification test can be minimized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing a control constant adjusting device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a display monitor screen of a control target monitoring device of the control constant adjusting device according to the embodiment of the present invention.

FIG. 3 is a configuration diagram schematically showing a control performance determination device of a control constant adjustment device according to an embodiment of the present invention.

FIG. 4 is a configuration diagram schematically showing a model accuracy determination device of a control constant adjustment device according to an embodiment of the present invention.

FIG. 5 is a configuration diagram schematically showing a model creation device of a control constant adjustment device according to an embodiment of the present invention.

FIG. 6 is a configuration diagram schematically showing a control constant determining device of the control constant adjusting device according to the embodiment of the present invention.

FIG. 7 is an explanatory diagram showing a feedback loop used in the control constant adjusting device according to the example of the embodiment of the present invention.

FIG. 8 is a configuration diagram schematically showing a feedback system.

FIG. 9 is an explanatory diagram showing a conventional auto-tuning technique.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 control target 2 control device 3 input / output data collection device 4 control target monitoring device 5 control performance determination device 6 control specification indicating device 7 model creation device 8 model database 9 control constant determination device 10 control constant database 11 display monitor 30 control state determination Apparatus 31 Model accuracy determination apparatus 50 Identification condition determination apparatus 51 Identification signal generation apparatus 52 Identification signal application apparatus 53 Identification data collection / processing apparatus 54 Model structure determination apparatus 55 Transfer function model estimation apparatus 60 Design parameter determination apparatus 61 Control constant calculation apparatus 62 Control constant change rate calculation device 63 Control response judgment device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G05B 23/02 301 G05B 23/02 301W

Claims (8)

[Claims] 1. A control constant adjusting device for adjusting a control constant of a control device of a feedback system, comprising: input / output data collecting means for collecting an operation amount and a control amount which are input / output of a control target; Control performance determination means for determining the control performance of the feedback system based on the control amount and the operation amount collected by the collection means; control specification instruction means for providing control specifications of the feedback system; and transmission of the control target. Model creation means for creating a function model, and control constant determination means for calculating a control constant of the control device, wherein the control performance determination means, when the control performance of the feedback system does not satisfy the control specifications, It is determined whether or not the accuracy of the transfer function model satisfies a predetermined reference value. If it is determined that the value does not satisfy the value, it instructs the model creation means to reconstruct the transfer function model, while if it determines that the value satisfies the predetermined reference value, the control constant is determined. Instructing the means to change the control constant, until the control performance of the feedback system satisfies the control specification, accuracy evaluation of the transfer function model, reconstruction of the transfer function model or A control constant adjusting device characterized by repeatedly changing a control constant. 2. The control constant adjusting device according to claim 1, further comprising control target monitoring means for displaying trend data of said control amount and said operation amount. 3. The control object monitoring means includes: a trend data display unit for displaying trend data of the control amount and the operation amount; a control performance display unit for displaying control performance of the feedback system; The control constant adjusting device according to claim 2, further comprising: a switch unit for starting or stopping the adjustment; and an adjustment mode display unit for displaying a current adjustment mode during the adjustment of the control constant. 4. The control performance judgment means judges the accuracy of the transfer function model by comparing a control amount calculation value calculated by the transfer function model with the control amount obtained as an output of the controlled object. The control constant adjusting device according to claim 1, further comprising a model accuracy determining unit that performs the control. 5. An identification condition determining means for determining an identification condition of an identification signal to be applied to the control object to create the transfer function model, and an identification signal generating means for generating the identification signal. An identification signal application unit that applies the identification signal generated by the identification signal generation unit to the control target; and the control amount and the operation amount when the identification signal is applied to the control target by the identification signal application unit. Collecting, performing an appropriate filtering process on the collected control amount and the operation amount to create identification data, and an identification data collection and processing unit, and the transfer function model of the control target based on the identification data. Model structure determining means for determining model parameters necessary for determination, and the transfer function model based on the model parameters Control constant adjusting device according to any one of claims 1 to 4, characterized in that it comprises a transfer function model estimation means determining, the. 6. A model database for storing the transfer function model determined by the model creating means, wherein the control performance determining means stores not only the latest transfer function model but also the model stored in the model database. The control constant adjusting device according to claim 1, wherein accuracy of the transfer function model is evaluated using the past transfer function model. 7. A control parameter determining means for determining a value of a design parameter required for calculating a new control parameter, a control parameter for obtaining the control parameter using the design parameter. Calculation means, and a control constant change rate calculating means for calculating a change rate between the control constant obtained last time and the control constant obtained this time, and determining whether the change rate is within a predetermined range. When the control constant change rate calculating means determines that the change rate is outside the predetermined range, the design parameter determining means changes the design parameter to obtain a predetermined control constant. The control constant adjusting device according to any one of claims 1 to 6, characterized in that: 8. A control constant database which stores the control constants previously applied to the control device, wherein the control constants determined by the control constant determining means are applied to the control device. Regardless, when the control performance of the feedback system does not satisfy the control specification, the past control constant stored in the control constant database is applied to the control device. The control constant adjusting device according to claim 7.