JPS5875207A - Pid controller - Google Patents

Abstract

PURPOSE:To use a PID controller with simple switching to I-PD characteristics, by changing consecutively the coefficient element. CONSTITUTION:A basic PID controller gives feedback control to a control object so as to obtain the coincidence between the degree of control and the target value. A coefficient element 30 is provided to a control system to vary the coefficients 0-1 and to control the control value. The target value SV is multiplied by alpha (0<=alpha<=1) with the element 30 and then added with the control degree -PV having an inverted code. I-PD control characteristics are obtained in the case of alpha=0; while the PID characteristics are obtained at alpha=1. Furthermore, the blended characteristics of I-PD and PID and secured at 0<alpha<1. Thus the characteristics can be varied in accordance with the request even under operation of a plant.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a P-type controller that performs feedback control of the control pair 9 using proportional action, integral action, and differential action.

Conventional PID (proportional, integral, differential) controllers, for example,
It is configured as shown in Figures (al~(Cm).

In the figure, SV is a target value, pv is a control value, / is a sign inversion element, ko and j are addition elements, 3 is an integral characteristic element, and its transfer function is expressed as //TI·S. Here, T is the integral time and day is the Lapfus operator. ≠ is a differential characteristic element, and its transfer function is represented by TD-8.

Here TD is differential time. Also, 6 is the proportional gain,
It is a coefficient element with p.

Note that, instead of the differential characteristic element l having a total differential characteristic with a transfer function of TD-8 as in the illustrated example,
For example, those having imperfect differential characteristics with a transfer function of TD-8/(7+γ·TD-8) are also often used.

Additive element! Then, the control side difference E is generated by adding the control -Bpv with the sign inverted by the sign inversion element / and the target value SV. Incidentally, an anti-decay element may be used for the sign inversion element l and the addition element -, but since the mechanical pressure is equal, the one shown is representative.

Control (a difference E is given to integral element 3 as a signal for integral control operation and integrated. The output signal of integral element 3 is sent to adder j,
*(t)J) or //(FIG. 1(Q)') is added to the output of o and e-i element l. The output of addition element j is given a coefficient element tK and multiplied by a proportional gain yKp. The output of the coefficient element t is repeated:! IMV, which is applied to the controlled object as the output of the controller.
There are cases where the proportional gain KP is multiplied by the control deviation ko, and there are cases where it is included in the integral element 3 and the extortion element µ, but since they are functionally equivalent, the configuration shown in the figure is representative.

FIG. 1 (aJ shows the case where a normal PID control paddle 4 is provided, and the control side difference E is used for both the proportional control operation signal IO and the differential control operation signal 20.

Although this type of P controller can improve either the controllability against target value changes or the controllability against disturbances, it may not be possible to improve both of them.

The first rule is control! This shows a case where a PID control function is provided, and the control deviation E is used as the proportional control operation signal 10, and the control t-PV with the sign reversed is used as the differential control operation signal J/. . This type of P
The controller is adopted when it is undesirable for the control I- to suddenly change when the target value is changed, but when it is not possible to make both the controllability against the change in the target value and the controllability against disturbances P- favorable. Figure 1 shows the case where the knee PD control function is provided, and the proportional control operation signal 1/ and the differential control operation signal 1 are controlled by -54, both of which have inverted signs.
Knee PV is used. When a controller of this type is used, good controllability is achieved both with respect to changes in the target value and with respect to external causes that enter the control point. Regarding controllability when changing the value, PIDf
When tflla has one egg (Figure 7 (at and (b)
)) Controllability may be inferior to that of )).

In this way, the controller can have various controllability, but
It is difficult to know which type of controller is suitable for the lil+ control in question until you actually perform the control using that controller, and it is difficult to make a decision in advance. There are many. However, as is clear from Figures 1(a) to ((J), the configurations differ depending on the type, and for this reason, wired logic controllers have different shapes.For this reason, when selecting one model, there are various In addition, when making a decision by testing in an actual plant, there was an inconvenience that pressure control had to be temporarily interrupted when replacing the model.

In addition, even in digital controllers that use microprocessors as arithmetic elements, the type of controller can be changed (ROM (read-only memory)).
It was necessary to change the details of the age of the driver, and it would not work unless the control was interrupted once the ROM was replaced.

The purpose of the present invention is to provide a versatile PI whose characteristics can be easily switched.
The object of the present invention is to provide a D controller.

The present invention provides a PID controller that performs feedback control of control so that the wholesale control amount matches a target value, and provides six coefficient elements by continuously adjusting coefficient values, and provides a target value for the coefficient elements. input value, control 1 or control deviation, add or subtract the output of the coefficient element from the control amount or the output of another coefficient element, use it as a control operation signal other than the integral control operation signal, and calculate the coefficient value. A controller is provided in which the characteristics of the controller can be changed between PID control characteristics, I-FD control characteristics, and a compromise between the two characteristics.

The second Pi(a) shows an embodiment of the present invention. The controller of this embodiment is constructed by adding a coefficient element 30 and #force element ρ to the controller with the speed-following knee FD control characteristic shown in FIG. 1 (OAK).Coefficient element , J(
') is set to P# so that its coefficient value α can be changed within the range of θ to /.

Mekaki value SV is a coefficient element, ? Multiplied by α by 0, this elevation is added to the control amount -PV with its sign inverted in the Kaga element 110. The output signal of the addition element sheath is added to the addition part I3I element j as a signal for proportional control operation /2, and the opportunity control 1\! It is emphasized that the differentiation is made as the effect of h and n. Other than the above, this controller is the same as the controller shown in FIG. 1(C).

When the coefficient value α of the coefficient ψ30 in this controller 1t is set to O, it becomes equivalent to the controller with the knee FD control characteristic shown in FIG. 7<Q). On the other hand, when the coefficient value α is set to /busy, Figure 1 (L
This is equivalent to a controller with normal PID control characteristics of l. Moreover, if O<α</, then the controller will have characteristics that are a compromise between the ■-FD control characteristics and the normal P control characteristics.

In this way, by making it possible to change α continuously between θ and /, even during plant control, the characteristics of the controller can be changed between the knee FD control characteristics and the normal PI.
It can be changed continuously between the D characteristics and the characteristics most suitable for the requirements.

FIG. 2(b) shows an embodiment of the present invention in which the controller in FIG. λ fat is modified. That is, the output of the added FW element is used as the proportional control operation signal /, 2, and the differential control operation signal 2/ is used as:
The sign is inverted and the control amount -pv is used. This controller has a coefficient element, a coefficient value α of 30, and O
If set as , it becomes equivalent to the controller in Figure 1 (Cl).

On the other hand, if α=/, like the controller fb+ in Fig. 1,
It has control characteristics from the controlled variable differential type P.

Further, when O α<l, the control has a characteristic that is a compromise between the knee FD control characteristic and the controlled variable differential type PID control characteristic.

FIG. 3 (aJ shows another embodiment of the present invention. The controller of this embodiment is the conventional controller shown in FIG. 1 (0) with a first coefficient element 31 and , second coefficient element, 7
This is the sum of

The first coefficient element 3/ multiplies the control deviation E by the coefficient value α. The second coefficient element, ? 2 is the complement of / of the coefficient value α (
/-α) is multiplied by the control amount -PV whose sign is inverted. The addition element is the first and second coefficient element 3/and ?
, 2 are added to W+. The output of the multiplying element is used as the proportional control scale action signal/3 and the signal force for the differential control action. The characteristics of this controller change depending on the setting of the coefficient (+tα), similar to the controller shown in FIG. 2 (al).

Figure 3 (b+ shows another embodiment of the present invention in which the controller in Figure 3 (al) is modified. In other words, the output of The signal 13 is used only as the differential control operation signal 21, and the sign-inverted control (t-PV) is used. In this controller, α
When , the characteristics change as in the case of the controller shown in FIG. 2 (El).

Figures 1 (aJ and (1)l show other embodiments of the present invention, which are modified versions of Figure 3 (al and ('b), respectively. That is, Figures 3 (aJ and (1) 1) Instead of the second coefficient element 3.2 of l (which has a coefficient value (/-α)), a coefficient element 33 with a coefficient value α equal to the first coefficient element 3/ is provided, and an addition element Using the additive calculation element Hiroko in place of !/, subtracting the output of the second coefficient element 33 from the output of the first count element 3/, and further inverting the sign, the control amount -P
This is to add V. The configuration and effects of other parts are shown in Figures 3 (IL) and (t), respectively.
It is similar to the controller of ll.

In each of the controllers of the above embodiments, instead of the differential element t having the perfect-order differential characteristic of T1)·S, the differential element t may have an incomplete differential characteristic or a higher-order differential characteristic. It can also be used.

Further, the proportional gain Kp can be multiplied by the control difference E, or can be included in the integral element 3 or the differential element≠. Furthermore, a functionally equivalent configuration can be achieved by not using the sign inversion element / and using a subtraction element in place of the addition element. Therefore, the "controlled amount" as used in the claims shall also include the amount with the opposite sign. Furthermore, if the differential control operation is not required, the differential time TD can be set to θ, or the differential element G can be removed from the configuration.

As described above, according to the present invention, the characteristics can be changed by adjusting the coefficient values, and a controller can be obtained from a versatile P. With the controller of the present invention,
Even during control of an actual plant, characteristics can be changed without interrupting control by gradually changing the coefficient values.

This makes it possible not only to adjust the proportional gain, integral time, and time, but also to modify the control characteristics to be more suitable while observing the control situation of the actual plant.

[Brief explanation of drawings]

Figures 7(a) to (c) are block diagrams showing conventional controllers; Figures 2(a), (bl), Figures 3(aJ, (b)
) and Fig. (aJ, (bl is a block diagram showing different embodiments of the present invention). C. Sign inversion element, λ, j, l/-0.IN... Addition element, 3. ... Integral element, l... Differential element, 6,
,? 0, 3/, 32°33...coefficient element, invasion...addition/subtraction element. Applicant's agent: Figure 1 (a) (b)

Claims (1)

[Claims] / In a controller that performs feedback control of a controlled object so that the controlled amount matches a target value, a coefficient element whose coefficient value can be continuously adjusted is provided, and the coefficient element is A target value, a controlled amount, or a control deviation is input, and the output of the coefficient element is added or subtracted from the controlled amount or the output of another coefficient element, and used as a control operation signal other than the integral control operation signal, and the coefficient value is By adjusting the characteristics P
A P-type controller that can be converted between ID control characteristics, I-FD control characteristics, and a combination of both characteristics. λ, in the controller according to claim 7, the outputs of the coefficient elements added or subtracted are used as signals for proportional control operation and signals for differential control operation, and the characteristics are controlled more than normal P. A P-type controller that can be changed between the characteristics, knee PD control characteristics, and a compromise between both characteristics. 3. Claim 7 In the controller of the pirate, the output of the coefficient element is added or subtracted, and the signal is used as the signal for proportional control operation, and the control amount is used as the signal for differential control operation, and the characteristic is determined. Controlled variable distribution type P, TD control characteristics and I-
A PID controller that can change between FD control characteristics and a compromise between the two. In the controller according to claim 1, "C, the output of the coefficient element and the control amount whose sign has been inverted are added by an addition element, and the output of the addition element is subjected to integral control. A controller from P used as a control operation signal other than the operation signal ν. j. In the controller described in claim 1, the first
and a second coefficient element whose coefficient value is the complement of l of the coefficient value of the first coefficient element, input the busy control difference of the first coefficient element, and coefficient! A control amount whose sign has been inverted is input, the outputs of the first and second coefficient elements are added by an addition element, and the output of the kernel addition element is used as a control operation signal other than an integral control operation signal. P
More control. t, in the controller according to claim 1, first and first coefficient elements having mutually equal coefficient values are provided, a control deviation is inputted to the first coefficient element, and the second Input a controller whose sign is inverted from 1 to the coefficient element of , subtract the output of the first coefficient element from the output of the first coefficient element with the addition/subtraction element, add the control amount whose sign is inverted, and A controller from P that uses the output of the addition/subtraction unit as a signal for control operation other than the signal for integral control operation.