JPH0744206A - Preceding function controller - Google Patents

Abstract

PURPOSE:To provide the preceding function controller which can stabilize control based on internal model control(IMC) structure even when error is contained in the model specification of a controlled system process. CONSTITUTION:A preceding function storage part 6a stores the parameter of a preceding function part to output a preceding followup amount yf to follow up a target value (r) easilier than a controlled variable (y) of the controlled system process. Based on the parameter for which the model specification of the controlled system process is performed, the parameter of the preceding function part is calculated by a preceding function parameter calculation part 10, and the preceding function part is decided. Next, a feedback amount (e) is subtracted from the output of a target value filter part 2 by a first subtraction processing part 3 and a manipulated variable (u) is operated from the output of the first subtraction processing part 3 by a manipulated variable calculation part 4 and outputted to the controlled system process. Thus, a feedback control system is constituted so that the preceding followup amount yf can be subtracted from the controlled variable (y) by a second subtraction processing part 8 and fed back to the first subtraction processing part 3 as the feedback amount (e).

Description

Detailed Description of the Invention

[0001]

The present invention relates to an IMC (Internal Model)
Control) structure-based controller, and more particularly to a controller using an antecedent function part whose output follows a target value prior to a controlled variable of a controlled object process instead of an internal model which is a characteristic of IMC.

[0002]

2. Description of the Related Art Conventionally, there has been proposed a controller using an IMC structure control algorithm for performing control by incorporating an internal model in which a control target process is expressed by a mathematical expression.
If this IMC controller is used, a large dead time (time from when hot air comes out of the air conditioner to when the indoor temperature rises) in the process to be controlled (e.g., if this controller is an indoor air conditioner corresponds to the indoor environment) It has an excellent advantage that it can be dealt with even if it exists.

FIG. 10 is a block diagram of a control system using a conventional IMC controller. Reference numeral 13 denotes a first subtraction processing unit that subtracts a feedback amount, which will be described later, from a target value (indoor temperature setting value), and reference numeral 12 denotes a filter unit that prevents a change in the output of the first subtraction processing unit 13 from being transmitted abruptly. ,
Reference numeral 14 is an operation unit for calculating an operation amount (temperature of hot air or cold air from the indoor air conditioner), which is the output of the controller, based on the output of the filter unit 12, and 16 is a mathematical expression approximating the control target process. The second subtraction process of outputting a feedback amount by subtracting the reference control amount from the internal model 16 from the control amount and outputting the reference control amount corresponding to the control amount (indoor temperature) which is the control result. Part 20 is a process to be controlled.

Further, F, Gc, Gm and Gp are the transfer function of the filter unit 12, the operating unit 14, the internal model 16 and the controlled process 20, respectively, r is the target value, u is the manipulated variable and d.
Is, for example, a disturbance corresponding to the outdoor environment with respect to the indoor environment,
y is a control amount, ym is a reference control amount, and e is a feedback amount.

Next, the operation of such an IMC controller will be described. First, the first subtraction processing unit 13 subtracts the feedback amount e from the target value r, and the result is output to the filter unit 12. Next, the operation amount u is calculated by the operation unit 14 from the output of the filter unit 12, and is output to the control target process 20 and the internal model 16 of the controller. Then, the second subtraction processing unit 18 subtracts the reference control amount ym from the internal model 16 that approximates the control target process 20 from the control amount y of the control target process 20, and the result is the feedback amount e. A feedback control system that is fed back to the first subtraction processing unit 13 is configured as.

Ideally, the internal model 16 of such an IMC controller is expressed by a mathematical expression so as to be exactly the same as the process 20 to be controlled.
Is ideally the inverse characteristic (1 / Gm) of the transfer function of the internal model 16, but since the reciprocal of the dead time element of the internal model 16 is not possible, normally the dead time element is ignore. Therefore, the control amount y can be obtained by the following equation from the target value r and the disturbance d with such a configuration. y = F * Gp * Gc * r / {1 + F * Gc * (Gp-Gm)} + (1-F * Gm * Gc) * d / {1 + F * Gc * (Gp-Gm)} ... (1 )

Here, the transfer function Gm of the internal model 16 is equal to the transfer function Gp of the controlled process 20, and the transfer function Gc of the operating unit 14 is the reciprocal of the transfer function of the internal model 16 (1 / Gm = 1 / Gp). Assuming an ideal state equal to, equation (1) becomes y = F × r + (1-F) × d (2)

Further, under ideal conditions in which the target value r does not change suddenly, the filter unit 12 is unnecessary and F = 1 can be set, so that the control amount y becomes equal to the target value r (y =
r), it is possible to realize the control without any influence of the disturbance d. Further, focusing on the disturbance d, the controlled process 2
0 and the internal model 16 have the same dead time with respect to the manipulated variable u even if the internal model 16 has a large dead time, the feedback amount e output from the second subtraction processing unit 18 is equal to the disturbance d.
It is understood that the disturbance d can be suppressed.

Such an IMC controller is usually
It is designed based on a design condition for robust stability showing stability when the error between the controlled process 20 and the internal model 16 becomes large, and similarly robust performance showing performance when the error becomes large. Further, when the internal model 16 is determined by such a model identification technique, a model identification error of the internal model 16 with respect to the process 20 to be controlled is unavoidable to some extent, but the control when the estimation of the model identification error is erroneous is performed. Since it does not operate as expected, countermeasures in that case are performed by an expert having knowledge of control.

[0010]

Since the conventional IMC controller is configured as described above, if there is an error in the internal model identification and the estimation is improper, the controller does not operate as expected and fails. There is a problem in that the operator becomes stable and an operator other than an expert having control knowledge has to give up the use of the IMC controller. In addition, it is particularly effective to correct the gain of the internal model when there is an error in the identification of the internal model, but there is no specific index for correcting the gain and there is the problem that trial and error must be used. It was In order to solve the above problems, an object of the present invention is to provide a preceding function controller that is based on the IMC structure and can stabilize the control even when an error is included in the model identification of the process to be controlled. .

[0011]

According to the present invention, there is provided a target value filter section for outputting an input target value for control with a characteristic of a time delay of a transfer function, and subtracting a feedback amount from the output of the target value filter section. The target value / disturbance filter unit that outputs the output of the first subtraction processing unit and the output of the first subtraction processing unit with the characteristic of the time delay of the transfer function, and the operation amount that is output to the control target process based on the preceding function parameter. An operation amount calculation unit including an operation unit that calculates from the output of the disturbance filter unit,
A preceding function storage unit that stores the preceding function parameter and updates it when a new preceding function parameter is input,
The control function of the control target process, which is the control result, changes the control value of the control target process from the control variable of the control target process. A second that outputs a feedback amount by subtracting the preceding following amount output from the calculation unit
And a preceding function parameter calculation unit that calculates a preceding function parameter based on a parameter obtained by model-identifying the control target process and outputs the preceding function parameter to the preceding function storage unit.

Further, the preceding function parameter calculation unit sets a value obtained by multiplying the gain in the parameter obtained by model-identifying the process to be controlled by a number larger than 1 as the gain in the preceding function parameter.

Further, the preceding function parameter calculation unit sets a value obtained by multiplying the time constant in the parameter obtained by model-identifying the controlled object process by a number smaller than 1 as the time constant in the preceding function parameter.

[0014]

According to the present invention, the target value is input to the target value filter unit, the feedback amount is subtracted from the output of the target value filter unit in the first subtraction processing unit, and the operation amount calculation unit outputs the first feedback value. The operation amount is calculated from the output of the subtraction processing unit and output to the controlled process and the preceding function calculation unit. Then
In the second subtraction processing unit, the preceding follow-up amount from the preceding function calculation unit is subtracted from the control amount of the controlled process, and the result is output as the feedback amount to the first subtraction processing unit. ing. Then, the preceding function parameter is calculated by the preceding function parameter calculation unit based on the parameter obtained by identifying the controlled process, and the preceding function parameter is changed by outputting this parameter to the preceding function storage unit. . The gain in the preceding function parameter is calculated by multiplying the gain in the parameter obtained by model-identifying the process to be controlled by a number larger than 1. The time constant in the parameter of the preceding function is calculated by multiplying the time constant in the parameter obtained by model-identifying the process to be controlled by a number smaller than 1.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of a preceding function controller showing an embodiment of the present invention, FIG. 2 is a block diagram of a control system using this preceding function controller, and FIG. It is a figure which shows an example. In FIG. 1, reference numeral 1 is a target value input section for inputting a target value r set by an operator (not shown) to this controller, and 2 is a target value r from the target value input section 1 for which the transfer function has a first-order lag characteristic. The target value filter unit 3 and 3 are first subtraction processing units that subtract the feedback amount e from the output of the target value filter unit 2.

Reference numeral 4 denotes a manipulated variable calculation unit for computing a manipulated variable u from the output of the first subtraction processing unit 3 based on a parameter from a preceding function storage unit described later, and 5 denotes an output from the manipulated variable calculation unit 4. 1 is a signal output unit that outputs the manipulated variable u to a control target process not shown in FIG. 1, 6a is a preceding function storage unit that stores a preceding function parameter described later, and 6b is based on the parameter output from the preceding function storage unit 6a. A preceding function calculation unit that outputs a preceding follow-up amount yf that follows and changes to the target value r before the control amount y of the control target process, 7 is a control amount input that inputs the control amount y from the control target process to this controller It is a department.

A second reference numeral 8 outputs a feedback amount e by subtracting the preceding follow-up amount yf output from the preceding function computing unit 6b from the control amount y output from the control amount input unit 7.
Subtraction processing unit, 9 is a process parameter input unit to which a parameter obtained by model-identifying the process to be controlled is input, and 10 is a pre-function parameter calculated based on the parameter output from the process parameter input unit 9. It is a preceding function parameter calculation unit that changes the preceding function parameter by outputting the parameter to the preceding function storage unit 6a.

In FIG. 2, reference numeral 4a indicates the inside of the manipulated variable calculation unit 4, and the transfer function of the output of the first subtraction processing unit 3 is 1
Target value / disturbance filter unit that outputs with the characteristics of the next delay, 4b
Is also inside the target value / disturbance filter unit 4a.
An operation unit for calculating the manipulated variable u from the output of, a reference function unit 6 including a preceding function storage unit 6a and a preceding function calculation unit 6b,
F1, F2, and Gf are transfer functions of the target value filter unit 2, the target value / disturbance filter unit 4a, and the preceding function unit 6, respectively.

FIG. 2 shows the target value filter unit 2, the first subtraction processing unit 3, the manipulated variable calculation unit 4, the preceding function storage unit 6a of FIG.
The control target process 2 is added to the basic configuration of this controller including the preceding function calculation unit 6b and the second subtraction processing unit 8.
It is rewritten as a control system including 0 and the disturbance d. Further, in FIG. 3, at time 0, the target value r, which is a step input, is input, and the manipulated variable calculator 4 outputs the manipulated variable u to the control target process 20. As a result, the controlled variable y changes following the target value r. The state is finally shown in which the target value r and the settling state are reached.

The controller of this embodiment is shown in FIG.
As shown in FIG. 10, the target value filter unit 2 is added to the IMC controller of FIG. 10 and the internal model 16 is replaced with the preceding function unit 6, which can be said to be based on the IMC structure. However, the internal model 16 of the conventional IMC is The result of model identification of the controlled process 20 is used as it is. Therefore, the internal model 16 of the IMC is
Of the reference control amount y corresponding to the control amount y
Output m.

On the other hand, the advance function unit 6 having the characteristic of the transfer function Gf, which will be described later, as shown in FIG. 3, follows the control value y of the controlled process 20 so as to follow the target value r. Output the quantity yf. Therefore, a controller having a control structure using such a preceding function unit 6 is called a preceding function controller.

Next, regarding the operation of such a preceding function controller, the operation as a feedback control system will be described first. The target value r is set by the operator of this controller or the like, and is input to the target value filter unit 2 via the target value input unit 1. Target value filter unit 2
Outputs the target value r with the characteristic of the transfer function F1 as shown in the following equation in which the time constant is T1. F1 = 1 / (1 + T1 × s) (3)

Next, the first subtraction processing unit 3 subtracts the feedback amount e output from the second subtraction processing unit 8 from the output of the target value filter unit 2. The target value / disturbance filter unit 4a in the manipulated variable calculation unit 4 includes the first subtraction processing unit 3
Of the transfer function F2 with the time constant T2. F2 = 1 / (1 + T2 × s) (4)

Similarly, the operation unit 4 in the operation amount calculation unit 4
b is the manipulated variable u from the output of the target value / disturbance filter unit 4a.
Is calculated, the transfer function Gc of which is calculated by the preceding function storage unit 6a.
Preceding function part 6 which is the preceding function parameter output from
The following equation is obtained according to the gain and the time constant. Gc = (1 + Tf × s) / Kf (5) Here, Kf and Tf are gains of the preceding function unit 6, respectively.
It is a time constant.

Therefore, the transfer function of the operation amount computing section 4 as a whole is given by the following equation. F2 × Gc = (1 + Tf × s) / {Kf × (1 + T2 × s)} (6) In this way, the operation amount u is calculated from the output of the first subtraction processing unit 3 and the signal output unit is calculated. It is output to the control target process 20 via 5 and is also output to the preceding function calculation unit 6b.

Then, the preceding function unit 6 uses the preceding function parameter consisting of the gain Kf, the time constant Tf, and the dead time Lf stored in the preceding function storage unit 6a to determine the output of the preceding tracking amount yf as the controlled object process. The control value y of 20 is set to follow the target value r, and the preceding function calculating unit 6b calculates the preceding following amount yf from the operation amount u output from the operation amount calculating unit 4. The preceding follow-up transfer function Gf of the preceding function unit 6 is given by the following equation. Gf = Kf × exp (−Lf × s) / (1 + Tf × s) (7)

Next, the second subtraction processing unit 8 subtracts the preceding follow-up amount yf from the preceding function computing unit 6b from the controlled variable y from the controlled process 20 input via the controlled variable input unit 7. And outputs the feedback amount e. Then, this feedback amount e is determined by the first subtraction processing unit 3 as described above.
Entered in. This establishes the feedback control system of the preceding function controller.

In the control system of the preceding function controller of this embodiment, in the control system of the example of FIG. 10, the filter unit 12 is set to the target value / disturbance filter unit 4a, and the target value filter unit 2 for the target value r. Since it corresponds to the control system to which is added, the control amount y is given by the following equation from the equation (1). y = F1 * F2 * Gp * Gc * r / {1 + F2 * Gc * (Gp-Gf)} + (1-F2 * Gf * Gc) * d / {1 + F2 * Gc * (Gp-Gf)} ... (8)

In such a control system, the process parameter input unit 9 and the preceding function parameter calculating unit 10 perform the gain Kf and the time constant Tf of the preceding function unit 6 as follows.
And the dead time Lf is determined.

First, the control target process 20 assumes that it has the elements of the first-order delay and the dead time, and its transfer function Gp.
Can be expressed by an approximate transfer function as follows. Gp = Kp × exp (−Lp × s) / (1 + Tp × s) (9) Here, Kp, Lp, and Tp are gains of the control target process 20 obtained as a result of model identification of the control target process 20. , Dead time and time constant.

The gain Kp, the time constant Tp, and the dead time Lp obtained by model-identifying the controlled object process 20 are externally input to the process parameter input unit 9. Next, the preceding function parameter calculation unit 10 determines the preceding function parameter according to the following equation based on the gain Kp, the time constant Tp, and the dead time Lp output from the process parameter input unit 9.

Kf = α × Kp (10) Tf = β × Tp (11) Lf = Lp (12) α and β are proportional constants, α> 1 and β <1 Is.

Here, the robust stability condition of the preceding function controller can be expressed by the following equation. {1 / (1 + ω ² × T2 ² ) ^1/2 } × | (Kp / Kf) × (1 + ω ² × Tf × Tp) / (1 + ω ² × Tp ² ) −1 + i × (Kp / Kf) × ω × (Tf-Tp) / (1 + ω ² × Tp ² ) | <1 ... (13) ω is the frequency of the input target value r, and i is an imaginary unit.

From equation (13), it can be seen that it is sufficient to increase the time constant T2 of the target value / disturbance filter unit 4a in order to ensure the control stability, but the rise of the control amount y will be delayed. Therefore, the true parameter of the controlled process 20 and the parameter Kp obtained by model-identifying the true parameter,
If Tp and Lp are within a range that is not extremely different, equation (1
From 3), it is preferable that Kf ≧ Kp and Tf ≦ Tp.

Therefore, the preceding function parameter calculation unit 10
Means that the parameters are set by the equations (10) to (12), which means that the preceding follow-up amount yf of the preceding function unit 6 precedes the control amount y of the control target process 20 and the target value as described above. This means that the parameter is set so as to change following r.

Then, the gain Kf, the time constant Tf, and the dead time Lf of the preceding function unit 6 thus determined are output from the preceding function parameter calculation unit 10 to the preceding function storage unit 6a, and stored in the preceding function storage unit 6a. The stored parameters are updated to the newly input parameters. In this way, the preceding function unit 6 is determined and changed.

The determination and change of the preceding function unit 6 are performed every time the parameter for which the model of the controlled object process 20 is identified is input to the process parameter input unit 9. Therefore, the preceding function controller of the present embodiment uses the preceding function unit 6 that improves stability in place of the internal model 16 of the IMC, so that stable control is performed even if there is an error in model identification of the controlled process 20. be able to.

In this embodiment, the preceding function unit 6
The preceding tracking transfer function Gf of 1 is similar to the approximate transfer function of the controlled process 20 of equation (9) as shown in equation (7).
Although defined by the characteristics of the next delay and the dead time, if it is possible to output the preceding follow-up amount yf that follows the target value r before the control amount y of the control target process 20, the formula (7) is obtained.
Other than this, for example, it may be a transfer function with a high-order delay of a second-order delay or more. Further, in this embodiment, the gain K of the preceding function unit 6
f, the time constant Tf is determined based on the process parameter,
Although changed, the effect can be obtained by changing only the gain Kf or the time constant Tf.

FIG. 4 is a diagram showing the target value followability when the preceding function controller of this embodiment and the conventional IMC controller are used for controlling the height of the liquid level in the tank, y
1 is the control amount y by the preceding function controller, y2 is IM
The control amounts y and ym by the C controller are reference control amounts output from the internal model of the IMC controller. In FIG. 4, the target value r (dashed line) is 0 cm and the height of the liquid surface is 4 cm.
Is a simulation result in which a control amount y (solid line), which is the height of the liquid surface of the control result, is obtained. Also, the IMC controller here is
The one in which the preceding function unit 6 in FIG. 2 is replaced with an internal model is used.

Here, the gain of the control target process 20 which is the liquid in the tank is 4, the time constant is 10 seconds, the dead time is 20 seconds, and the gain Kp obtained as a result of model identification of the control target process 20 is 4, The time constant Tp is 10 seconds and the dead time Lp is 20 seconds. Therefore, regarding the parameters of the preceding function unit 6 of this embodiment, assuming that the proportional constants of the preceding function parameter calculation unit 10 are α = 1.5 and β = 0.7, the gain Kf is calculated from the parameters model-identified as described above. 6, the time constant Tf is 7 seconds, and the dead time Lf is 20 seconds.

Since the internal model of the IMC uses the result of model identification of the controlled object process 20 as it is, the gain is 4, the time constant is 10 seconds, and the dead time is 20 seconds. Further, the time constant T1 of the target value filter unit 2 in the preceding function controller and the IMC controller is set to 24
Seconds, and the time constant T2 of the target value / disturbance filter unit 4a is 6 seconds. That is, the example of FIG. 4 shows a case where there is no error in model identification.

Similar to FIG. 4, FIGS. 5 to 8 are diagrams showing the target value followability of the preceding function controller of this embodiment and the conventional IMC controller. In each example, the same values as those in the example of FIG. 4 are used except for the parameters shown below, and the internal model of the IMC uses the model identification result as it is.

In FIG. 5, the gain Kp resulting from the model identification of the controlled process 20 is 6, and the gain Kf of the preceding function unit 6 is 9. Therefore, it shows the case where the gain Kp is erroneously identified in a large amount in the internal model identification.
Further, FIG. 6 shows a case where the gain Kp is 2, the gain Kf of the preceding function unit 6 is 3, and the gain Kp is erroneously identified to be small.

Further, in FIG. 7, the time constant Tp of the result of model identification is set to 15 seconds, and the time constant Tf of the preceding function part 6 is 1
0.5 seconds. Therefore, it shows a case where the time constant Tp is erroneously identified with a large value in the internal model identification. Further, in FIG. 8, the time constant Tp is 5 seconds, the time constant Tf of the preceding function part 6 is 3.5 seconds, and the time constant Tp is erroneously identified to be small.

As shown in FIGS. 4 to 8, it is understood that according to the preceding function controller of this embodiment, a stable control response can be obtained even if there is an error in model identification. On the other hand, in the conventional IMC controller, particularly when the gain Kp is erroneously identified to be small as shown in FIG. 6, the control is in an oscillatory unstable state.

The unstable state as described above cannot be sufficiently solved by the adjustment by the filter time constant which is usually performed in the IMC. FIG. 9 is a diagram showing the target value followability of the conventional IMC controller in which the filter time constant is adjusted.
FIG. 9 shows the time constant T of the target value filter unit 2 in the example of FIG.
1 for 48 seconds, the time constant T2 of the target value / disturbance filter unit 4a
This is an example in which is changed to 12 seconds, but the vibrational response is reduced. Further, at this time, the rise of the control response is delayed in all cases.

[0047]

According to the present invention, by providing the preceding function storing section, the preceding function calculating section, and the preceding function parameter calculating section, the preceding function calculating section follows the target value before the control amount of the controlled process. Since the preceding tracking amount that changes to ensure control stabilization is output, it is possible to perform highly accurate and reliable control even when the model identification of the control target process includes an error, and change the characteristics of the control target process. Can also be accommodated. Further, since it is possible to prevent the occurrence of troubles due to the identification error of the process to be controlled, it is possible to reduce the work load on the operator who does not have specialized control knowledge.

[Brief description of drawings]

FIG. 1 is a block diagram of a preceding function controller showing an embodiment of the present invention.

FIG. 2 is a block diagram of a control system using the preceding function controller of FIG.

FIG. 3 is a diagram showing an example of target value followability of the preceding function controller of FIG.

FIG. 4 is a diagram of a preceding function controller of FIG. 1 and a conventional IMC.
It is a figure which shows the target value followability of a controller.

5 is a block diagram of the preceding function controller of FIG. 1 and a conventional IMC.
It is a figure which shows the other example of target value following property in a controller.

FIG. 6 is a diagram of the preceding function controller of FIG. 1 and a conventional IMC.
It is a figure which shows the other example of target value following property in a controller.

FIG. 7 is a diagram of the preceding function controller of FIG. 1 and a conventional IMC.
It is a figure which shows the other example of target value following property in a controller.

FIG. 8 is a diagram of the preceding function controller of FIG. 1 and a conventional IMC.
It is a figure which shows the other example of target value following property in a controller.

FIG. 9 is a diagram showing another example of target value followability in a conventional IMC controller.

FIG. 10 is a block diagram of a control system using a conventional IMC controller.

[Explanation of symbols]

 1 Target value input unit 2 Target value filter unit 3 First subtraction processing unit 4 Manipulation amount calculation unit 4a Target value / disturbance filter unit 4b Manipulation unit 6 Preceding function unit 6a Preceding function storage unit 6b Preceding function computing unit 8 Second Subtraction processing unit 9 Process parameter input unit 10 Preceding function parameter calculation unit

Claims (3)

[Claims] 1. A target value filter unit for outputting an input target value for control with a characteristic that a transfer function has a time delay, and a first subtraction processing unit for subtracting a feedback amount from the output of the target value filter unit. The target value that outputs the output of the first subtraction processing unit with the characteristic of a time delay of the transfer function, the disturbance filter unit, and the operation amount that is output to the controlled process based on the preceding function parameter.
A manipulated variable calculation unit including an operation unit that calculates from the output of the disturbance filter unit, a preceding function storage unit that stores the preceding function parameter and updates it when a new preceding function parameter is input, and a control result. A preceding function computing unit that computes a preceding follow-up amount that changes following the target value prior to the controlled variable of the controlled process from the manipulated variable based on the preceding function parameter; and the preceding function calculation from the controlled variable of the controlled process. A second subtraction processing unit that subtracts the preceding tracking amount output from the unit and outputs the feedback amount; and a preceding function parameter that calculates a preceding function parameter based on a parameter obtained by model-identifying the process to be controlled. A preceding function controller, comprising: a preceding function parameter calculation unit for outputting to a storage unit. 2. The precedence function controller according to claim 1, wherein the precedence function parameter calculation unit multiplies a value obtained by multiplying a gain in the parameters obtained by model-identifying the control target process by a number greater than 1 in the precedence function parameter. Preceding function controller characterized by the gain of. 3. The preceding function controller according to claim 1, wherein the preceding function parameter calculation unit sets a value obtained by multiplying a time constant among parameters obtained by model-identifying the process to be controlled by a number smaller than 1 to the preceding function parameter. Preceding function controller characterized by a time constant inside.