JPH03113501A - Controller - Google Patents

Abstract

PURPOSE:To realize PID control performing various processes for a deviation including differentiating by obtaining the differential control arithmetic output from the con trolled variable of a control subject via a differential control arithmetic means and then adding the obtained arithmetic output to a target value setting signal to obtain the target value of a PI (proportion/integration) control arithmetic means. CONSTITUTION:A differential control arithmetic means 11 performs a differential control arithmetic operation to take advantage of a measurement value differentiation advance type for the controlled variable PV received from a control subject 12. A subtraction means 13 subtracts the output of the means 11 from a target value setting signal SV' and obtains the target value SV. A deviation arithmetic means 14 subtracts the controlled variable PV from the value SV obtained by the means 13 and obtains the deviation. Furthermore a PI control arithmetic means 15 is added together with an addition means 16 which adds the disturbance D to an operation signal MV serving as the output of the means 15 and applies them to the subject 12. Then a deviation E, etc., are effectively treated for execution of the PID control (D: differentiation) by means of the advantage of the measurement value differentiation advance type. Thus it is possible to apply various processes to the deviation including differentiating.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to an adjustment device that performs PID adjustment calculations, and in particular, the present invention relates to a control device that performs PID adjustment calculations, and in particular, to control variable The present invention relates to an adjusting device that applies a differential calculation output to a deviation.

(Prior Art) PID control devices have been widely used in all industrial fields. Nowadays, digital arithmetic control systems are often used in place of analog arithmetic control systems, and have become indispensable for plant control.

The basic calculation formula for such PID control is MY(s) -KpH+(llTI-8)+(TD-8)l(l+η
・TD-8))・E(S)...(1) It is expressed as follows. However, MV (s) is the operation signal, E (s)
is the deviation, Kp is the proportional gain, T is the integral time, TD is the differential time, S is the Laplace operator, η is the coefficient, and (1/η) is the differential gain. This calculation formula is PID for deviation E.
It performs calculations and is usually called deviation PID control.

However, in the case of this PID control, the target value SV often changes stepwise, and the D (differential) operation works excessively with respect to the change in the target value SV, causing the operation signal MV to change.
There is a problem that sudden changes in the target value may cause a shock to the controlled object, or the target value follow-up characteristic may greatly overshoot, causing a vibration phenomenon.

Therefore, in recent years, "measured value differential advance type PID control" in which the D operation is executed with respect to the control amount Pv instead of the deviation has been used.

The calculation formula for this measured value differential preceding type PID control is MV(s
) −Kp[ll+1/ (T+ ・s)l ・E(s
)-1(TD-8)l(1+η・TD-8))・PV(
S)]...(2) It is expressed as follows. PV (S) is the controlled amount from the controlled object.

FIG. 5 is a block diagram of a conventional adjustment device to which such a measured value differential advance type PID control system is applied. This device calculates the deviation E between the target value SV and the controlled amount Pv from the controlled object 2 using the deviation calculation means 1, and then introduces this deviation E into the PI adjustment calculation means 3. Here, the PI adjustment calculation is performed according to the calculation formula shown on the former side of the equation (2), and the obtained PI adjustment calculation output is introduced into the subtraction means 4.

In addition, the control l1pv from the controlled object 2 is also introduced into the differential adjustment calculation means 5, where an incomplete differential calculation is performed according to the calculation formula shown in the latter part of equation (2), and the obtained incomplete differential calculation is The output MvD is introduced into subtraction means 4. Then, the subtracting means 4 subtracts the incomplete differential calculation output from the pr adjustment calculation output, and uses the obtained signal as the operation signal MV.
The signal is guided to the adding means 6, where it is added and combined with the disturbance signal and applied to the fill a target 2, thereby controlling so that the target value S V o =the control amount PV.

(Issue to be solved by the invention MB) However, although the adjustment device to which this measured value differential prior type PID control method is applied has various features, it also has the following defects. There is.

■First of all, the adjustment device to which the measured value derivative-first type PID control method is applied cannot be adequately supported by the configuration shown in Fig. 5 due to the characteristics of the controlled object 2, and it is necessary to perform various processing processes to obtain the operation signal. be. FIG. 6 is a diagram showing one example of such processing, in which a nonlinear means 7 is provided on the output side of the deviation calculation means 1, and the deviation E obtained by the deviation calculation means 1 is processed by the nonlinear means 7, for example, by dead zone processing. , after performing nonlinear processing such as deviation square processing and gap processing, the PI adjustment calculation means 3
It is configured to be introduced in

As described above, in actual plant control, nonlinear processing is often used for the deviation E in order to correspond to various characteristics of the controlled object 2, but the differential adjustment calculation output MvD is Since the differential characteristics are bypassed, the differential characteristics are not subject to nonlinear processing, so accurate nonlinear processing cannot be performed, and the differential adjustment calculation output MvD is bypassed, which adversely affects the control system and reduces controllability. It becomes.

■ Also, this measured value differential prior type PID adjustment device is
This is a one-degree-of-freedom PID adjustment device in which only one set of D parameters can be set. As a result, since the proportional gain and differential time have one degree of freedom, there is a problem that optimal control that satisfies both disturbance suppression characteristics and target value tracking characteristics cannot be performed.

Therefore, as long as the above-mentioned defects exist, the PID control function cannot be fully exerted on various control objects. In particular, in the future, plant operation control will become increasingly precise, continuous, and
Optimization, safety, etc. are required, but in order to fully meet these demands, it is necessary to promptly eliminate the above-mentioned deficiencies in PID control, which is often used in plants.

The present invention has been made in response to the above-mentioned demands, and is capable of accurately performing various nonlinear processing such as dead zones, squared deviations, gaps, etc., including differential operation, and is capable of performing two types of proportional gain and differential time. It is an object of the present invention to provide an adjustment device that can easily realize degrees of freedom.

[Structure of the invention] (Means for solving the problem) First, in order to solve the above problem, the invention corresponding to claim 1 calculates P based on the deviation between the target value and the controlled amount of the controlled object.
The adjusting device performs an I adjustment calculation to obtain an operation signal to be applied to the controlled object, the differential adjustment calculation means performing a differential adjustment calculation based on the control amount, and the differential adjustment calculation means from the target value setting signal or the deviation. means for subtracting the output of or adding the output of the differential adjustment calculation means to the control amount.

Furthermore, the invention corresponding to claim 2 is the invention corresponding to claim 1, further adding lead/delay calculation means for giving an advance or delay to the target value setting signal, and using the output of the lead/delay calculation means to calculate the target value setting signal. By subtracting the output of the differential adjustment calculation means to obtain the target value, only the P operation is controlled to have two degrees of freedom.

Furthermore, the invention corresponding to claim 3 is the invention corresponding to claim 2, further comprising a coefficient multiplier for multiplying the target value setting signal by a coefficient, and calculating the deviation between the output of the coefficient multiplier and the control amount. By performing differential adjustment calculation by the differential adjustment calculation means and subtracting the output of this differential adjustment calculation means from the output of the lead/lag calculation means to obtain the target value, P+D
This configuration performs two-degree-of-freedom control.

(Function) Therefore, the invention of claim 1 takes the above measures, and after obtaining the differential adjustment calculation output from the controlled variable of the controlled object by the differential adjustment calculation means, the differential adjustment is applied to the target value setting signal. By adding the adjustment calculation outputs and using them as the target value of the PI adjustment calculation means, it is possible to perform various processing processes on the deviation including differential operation and execute PID control.

Furthermore, the inventions of claims 2 and 3 provide a target value filter having a lead/delay calculation function for the target value setting signal, and in addition to having the same effect as the above claim 1, the two degrees of freedom of proportional gain and integral time are provided. can be realized.

(Example) Hereinafter, a first example of the present invention will be described with reference to FIG. 1. In the figure, reference numeral 11 denotes differential adjustment calculation means for performing differential adjustment calculation on the controlled variable Pv from the controlled object 12 in order to make use of the advantage of the measured value differential preceding type; Subtraction means for subtracting the output to obtain the target value SV; 14 is the target value setting means 1
15 is a deviation calculation means for subtracting the control amount P■ from the target value Sv obtained in step 3 to obtain a deviation; 15 is a PI adjustment calculation means;
16 is the operation signal MV which is the output of the PI adjustment calculation means 15.
This is an addition means that adds a disturbance to the control target 12 and applies it to the controlled object 12.

Next, the operation of the device as described above will be explained. The purpose of this device is to utilize the advantages of the measured value differential type and effectively process the deviation E etc. to execute PID control.

Therefore, first, we will consider the state of involvement of the differential adjustment calculation means 5 in the control system in the conventional device (FIG. 5), and then compare it with the state of involvement of the differential component in the device of the present invention, which is 0.

That is, the differential component MvD of the operation signal MV obtained by the control amount Pv of the controlled object 2 in the conventional device through the differential adjustment calculation means 5 is MvD(S)-1(TD-8)l(l+η・TD-8 )
1・Pv(s)...(3) It is expressed as follows. Here, when the control 1PV (s) changes step by step with the magnitude of a, that is, PV (s) m a /
When s, if the initial value in the time domain of the differential component MVD(S) is mVD (0) and the final value is my D(oo), then from the final value theorem, 111m g+vn(t)
=avD(0)=1iIIIl s-MVo(s)・PV
(s) ss rtlls, KpToos ax
□ 111 1+η・TD・ss −Dim Kp”・°8 I−−1+η ・TDIIs And from the initial value theorem, 1 Dim ll1vo(t) −mvl)(” )−p
IIIl s-MvD(s)・Pv(s)= Rlra
S-Kp""" a ×□ 1-0 1÷η·TDIIs 5 =IlIIITD°8 go-o 1+η4Dos =0 (5) is obtained.

Next, let us consider a first embodiment of the device of the present invention. Now, as in the conventional device, when the control RPV(s) changes step by step with the magnitude of a, exactly when PV(s) = a/s, the differential component MV'D (s) in the operation signal MV
The initial value in the time domain is mv'D (0), and the final value is m
v'D (op), then from the final value theorem, = my; (0) = 1im 5-K(s>・C(s>ΦPV(s>To
t+'rD・S = l1II Kpx ax-x 1-- T+ 1+η * i'
D* S−Kl)X − η (6) From the initial value theorem, N1@mvo(t) = gvo(”)To
t+'rl・S Palm IQil KpX Bx−× 5−～ T+ 1+η・TD−8D 9XBX− 1 (7) is obtained in the tungsten.

Here, between the initial values and final values of the differential components in the conventional device and the device of the present invention, mvo(0) is obtained from equations (4) and (6), and equations (5) and (7), respectively. = mvo(0) -Kl)・(a/η)...
(8)+11VD(00)=0≠l1lv'D(oo)
= Kp−a(To/T+) −(
9). That is, this equation (8) and (9
) As is clear from the equation, the initial values of the differential components in the time domain are the same between the conventional device and the device of the present invention, but the final values in the time domain are not the same.

Therefore, the final value m in the time domain of equation (7) of the device of the present invention
It is necessary to prove that yD (oo) is based on differential behavior. Therefore, in order to prove that the configuration of the device of the present invention is a differential operation, the interference type PID shown in FIG.
Let's analyze differential operation in control. This seventh
The figure shows a configuration in which a lead/lag calculating means 8 is inserted between the deviation calculating means 1 and the PI adjustment calculating means 3, and the differential component of the operation signal MY" at this time is... (10) In other words, in the device shown in FIG. 7, the control tE
When tPV(s) changes step by step with the magnitude of a, that is, when PV(s) - a/s, the initial value in the time domain of the differential component MV;(s) of the operation signal MV' is expressed as mvC(O )
, final value rnvo (oO) tT, then from the final value theorem, 1) iIIlmvo(t) = mv', (0) (l-η) -KpX xB η... (11) is obtained, Also, according to the initial value theorem, NII1mv'D(t) ``''11%/; (00) is obtained.

Here, since it can be set as η -0゜1, from equations (7) and (12), a+v'o('')=Kp-a・(TD/TI)-
sv;(oo)-Kp"a'(To/T+)0.9, which is equivalent to the differential component in FIG. 7, which is the most practical control. In other words, the configuration shown in FIG. It can be proven that the device shown in FIG. 5 is equivalent to the conventional PID control shown in FIG. 5 in terms of differential operation.

Therefore, in the device of the present invention, there is no bypass component due to differentiation, and even if the deviation E is processed to perform various deformations, such as nonlinear processing, the deformation process including the differential operation can be performed accurately, and the desired deformation can be achieved. PID control can be executed.

In the above embodiment, the control fipv is subjected to a differential adjustment calculation and subtracted from the target value setting signal Sv', but a configuration may be adopted in which, for example, the output of the differential adjustment calculation is subtracted from the deviation E, or as shown in FIG. The output of the differential adjustment calculating means 11 may be added to the control amount Pv by the adding means 17, and the deviation E may be obtained by subtracting the output of the adding means 17 from the target value Sv.

Next, FIG. 3 is a block diagram showing a second embodiment of the present invention. In this device, a target value filter, that is, a lead/lag calculating means 21 is provided for the target value setting signal SV', and a subtracting means 13 is provided on the output side of the lead/lag calculating means 217, which calculates the lead/lag. A configuration is added for subtracting the output of the differential adjustment calculation means 11 from the output of the means 21 to obtain the target value SV.

This is expressed by a response equation of the control amount Pv in the apparatus shown in FIG. Here, if the target value tracking optimal algorithm* is C(s), it can be expressed by the following arithmetic expression.

*C(s)-P(s)C(s)-Kp(α+(1/T+・5)1 (14) Here, C(s)=Kpl, t+(1/T+・s)1 From this, if the target value filter F (s), which is the lead/lag calculation means 21, is found based on this equation (14), the following is obtained. From this equation (15), the lead/lag calculation function with differential operation can be calculated. Therefore, in addition to having the same function as shown in Fig. 1, this device has the proportional gain of the disturbance suppression optimum control as Kp, and the proportional gain of the target value tracking optimum control as α·Kp. By varying this α, it is possible to realize two degrees of freedom only for the P motion.

Furthermore, FIG. 4 is a configuration diagram showing a third embodiment of the present invention. This device includes a coefficient multiplication means 31 for multiplying a target setting signal Sv by a coefficient γ, a subtraction means 32 for subtracting the output of the coefficient 5 multiplication means 31 from the control amount Pv, and a differential adjustment operation for the output of the subtraction means 32. The target value SV is obtained by subtracting the output of the differential adjustment calculation means 11 from the output of the lead/lag calculation means 21.

The response equation of the control amount Pv in the device shown in FIG. 4 is expressed as follows. Here, if the target value tracking optimal algorithm is C(s), this C(s) can be expressed by the following arithmetic expression.

C(s)=(F(s)+R(s)・K(s)Ic(s)
... (1 1,) And if we transform this equation (17), we get 0 P(s) ・C(s)+R(s) ・K(s) ・C(
s) (18) can be obtained. Here, using the relationship of equation (14), ... (19) where, K(s)=(To-s)bar+7・TD*s),C
Since (s)=Kp(1+(1/T+·s)), R(s)−γ is obtained from equation (19). In other words, the coefficient R(s) of the coefficient multiplication means 31
becomes γ.

Therefore, according to the configuration of this embodiment, the proportional gain of the disturbance suppression optimal control is Kp and the differential operation is 1, while the proportional gain of the target value tracking optimal control is α・
Kp, and the differential operation at that time is as follows. By varying the coefficient α of the target value filter and the coefficient γ of the coefficient multiplier 31, it is possible to realize two-degree-of-freedom optimal control of the P+D operation.

[Effects of the Invention] Therefore, as explained above, the present invention provides the following various effects.

First, in claim 1, the deviation can be subjected to various transformation processing including differential operation, and furthermore, the P can undergo the desired transformation.
A regulating device capable of performing ID control can be provided.

Next, in claim 2, the deviation can be subjected to various transformation processes including differential operation, and it is possible to easily control the conversion of only the P operation into two degrees of freedom.

Furthermore, in claim 3, the deviation can be processed in various ways including the differential operation, and the two-degree-of-freedom operation of the P-plus operation can be elegantly controlled.

[Brief explanation of drawings]

FIG. 1 is a block configuration diagram showing a first embodiment of the device of the present invention, FIG. 2 is a configuration diagram showing a modification of FIG. 1, and FIGS. 3 and 4 are respectively other embodiments of the device of the present invention. FIGS. 5 to 7 are block diagrams illustrating the configurations of conventional devices, respectively. 11... Differential adjustment calculation means, 12... Controlled object, 1
3... Subtraction means, 14... Deviation calculation means, 15...
- PI adjustment calculation means, 16... addition means, 17...
Adding means, 21...Advance/lag calculation means (1-1 target price filter), 31... Coefficient multiplication means.

Claims (3)

[Claims] (1) P based on the deviation between the target value and the controlled variable of the controlled object
A regulating device that performs a (proportional) I (integral) adjustment calculation to obtain an operation signal to be applied to the controlled object, comprising a differential adjustment calculation means that performs a differential adjustment calculation based on the control amount, and a target value setting signal or the deviation. and means for subtracting the output of the differential adjustment calculation means from or adding the output of the differential adjustment calculation means to the control amount, and performing PID control including D (differential). Device. (2) P based on the deviation between the target value and the controlled variable of the controlled object
A regulating device that performs an I adjustment calculation to obtain an operation signal to be applied to the controlled object, comprising: a differential adjustment calculation means that performs a differential adjustment calculation based on the control amount; and a lead/lag that causes the target value setting signal to advance or lag. It is characterized by comprising a calculation means and a target value setting means for obtaining the target value by subtracting the output of the differential adjustment calculation means from the output of the lead/lag calculation means, and providing two degrees of freedom for the P motion. Adjustment device. (3) P based on the deviation between the target value and the controlled variable of the controlled object
A control device that performs an I adjustment calculation to obtain an operation signal to be applied to the controlled object, comprising: lead/lag calculating means for giving a lead or delay to the target value setting signal; and a coefficient for multiplying the target value setting signal by a predetermined coefficient. a multiplication means; a subtraction means for subtracting the output of the coefficient multiplication means from the control amount; a differential adjustment calculation means for performing a differential adjustment calculation based on the output of the subtraction means; target value setting means for obtaining the target value by subtracting the output of the differential adjustment calculation means;
An adjusting device characterized by performing two degrees of freedom of P motion and D motion.