JPH04117504A - Target value follow-up quick responsive 2-freedom degree adjuster - Google Patents

Abstract

PURPOSE:To shorten the response time by fetching directly the control target value with a signal switching means when the arithmetic target value is approximate to the control target value for PI (proportion/integration) adjustment. CONSTITUTION:A switching command is received when a comparison/judgement means 11 decide a difference larger than a prescribed level. Then the arithmetic target value SV0 is selected. Meanwhile the control target value SV is selected at the reception of a switching command with the difference higher than the prescribed level. Then the value SV is sent to a deviation computing means 3. That is, a switching command is produced when the difference is larger than a prescribed level delta. Therefore a signal switching means 12 selects the value SV after the reception of the switching command. Thus the target value for PI adjustment is defined as SVa = SV. Consequently, the response speed is set at the value SV in a short time.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention provides a two-degree-of-freedom PI or PID (P: proportional, l: integral) using a target value filter means.

D: Differential) related to the adjustment device, in particular the target value tracking centrifugal 2-degree-of-freedom type that simultaneously optimizes the suppression characteristics against disturbances to the controlled object and the tracking characteristics against changes in the target value, while also being responsive to changes in the target value. Relating to an adjustment device.

(Prior art) Conventional target value filter type with 2 degrees of freedom P! The adjustment device is constructed as shown in FIG. That is, this adjustment device introduces the target value Sv into the target value filter means 1, performs calculation processing to make the proportional gain two degrees of freedom, and calculates the calculated target value Sv.
After obtaining o, this calculation target value Svo and the control amount Pv from the controlled object 2 are guided to the deviation calculation means 3 (SVo-PV
) is used to find the deviation E. Furthermore, the deviation E obtained by the deviation calculation means 3 is expressed as KP (1-1/(TIS
)) to the PI adjustment means 4 having a transfer function, and performs PI adjustment calculation here to obtain the operation signal MY. and,
After the operation signal MV and the disturbance are added and combined by the adding means 5, the calculation target value 5v is applied to the controlled object 2.
This is a configuration in which control is performed so that the amount of control becomes o-control amount Pv. In addition, in the above equation, KP is proportional gain, TI is integral time, and S
is the Laplace operator.

On the other hand, the target value filter means 1 includes a multiplication means 12 for multiplying a target value Sv introduced from the outside by a two-degree-of-freedom coefficient a of a proportional gain, and a coefficient means 11 for calculating the target value Sv from the target value Sv.
, a subtracting means 1□ for subtracting the output of the subtracting means 12, a first-order lag element 13 that performs a first-order lag calculation using the integration time as a time constant on the output of the subtracting means 12, and outputs the result, a first-order lag element 13 for outputting the resultant result. and the output of the coefficient means II to obtain a calculation target value SVO.

Therefore, in the case of the above configuration, the transfer function CPM(S) between Pv→MV and the transfer function CSM between S V→MV
(S) is CPM(S) --MV/PV=Kp(1+1/T+
-8) = (1)C8M(S)-MV/SV=
niBacr+1/T+◆S) ”・(2).

α is a two-degree-of-freedom coefficient for the proportional gain (a constant that can be set between O and 1). Therefore, if ST is determined so that the disturbance suppression characteristics are optimized, and then the proportional gain coefficient α for 2 degrees of freedom is determined so that the target value tracking characteristics are optimized, 2 degrees of freedom can be achieved. can.

(Problem to be Solved by the Invention) By the way, the target value filter type two-degree-of-freedom adjustment device as described above has an excellent feature of being able to simultaneously optimize the disturbance suppression characteristic and the target value tracking characteristic. There is a problem that takes a long time to settle down.

Therefore, when considering the cause of this, it is found that the target value filter means 1 has at least one stage or two or more first-order delay elements, and when the target value Sv is changed in a stepwise manner, the target value of the step change is This is because it takes time for the value S■ to reach the final value due to the influence of the first-order lag element.

Furthermore, the influence of the first-order delay will be explained from the response characteristics shown in FIG. That is, FIG. 6 shows that when the target value Sv is changed stepwise in the apparatus shown in FIG. 5, the coefficient means 1. Only the output (Sv・α) changes stepwise, but the output of the subtraction means 12 (SV・(1−α)
) gradually increases under the influence of the first-order lag element 13 and approaches the target value SV.

When the target value filter means 1 shown in FIG. 5 is expressed as a digital arithmetic expression, the equation (3) is expressed as a differential equation.

here, this For the expression, Substituting the relational expression, we get can be obtained.

moreover, Transform this formula and, can be obtained.

At time point 1, the target value Sv steps. When it changes to a dip shape, X if n≧2.

Since, In this equation (7), Δt is very small compared to T1, and cxm-yゎ-l) is also small, so the value in the latter stage of the opening equation becomes very small. Furthermore, the closer the output y0-1 is to the input X, the smaller the change in Δy. As a result, it will take a considerable amount of time for the output,y,to match the input,X,. Naturally, since this output y6 is the target value of the PI adjustment means 4, it takes a very long settling time.

The present invention has been made in view of the above-mentioned circumstances, and is a target value tracking linked type that can significantly shorten the response time compared to the conventional method without interfering with the original two-degree-of-freedom function for changes in target values. The object is to provide a two-degree-of-freedom adjustment device.

[Structure of the invention] (Means for solving the problem) First, in order to solve the above problem, the invention corresponding to claim 1 is provided with a target value filter means, and a target value obtained from the target value filter means side. A two-degree-of-freedom adjustment device that executes at least a PI (P: proportional, I: integral) adjustment calculation using a deviation between a value and a controlled amount from a controlled object, and applies the obtained operation signal to the controlled object, Comparing and determining means extracts the difference between the control target value given to the target value filter means and the calculated target value obtained by the calculation process of the target value filter means, and outputs a switching command when this difference becomes less than or equal to a predetermined value. and signal switching means for selectively outputting the control target value when receiving a switching command from the comparison and judgment means.

Next, the invention corresponding to claim 2 includes, in addition to the comparison and judgment means, a subtraction means for subtracting the calculation target value from the control target value, and a calculation target value that is normally set as a target value for the PI adjustment calculation. and a signal switching means for taking in the output of the subtracting means and adding and synthesizing it to the control target value to obtain a target value for the PI adjustment calculation when a switching command is received from the comparing and determining means. It is.

Furthermore, the invention corresponding to claim 3 is a configuration in which a first-order lag element is added to the output side of the subtraction means of the invention of claim 2, which performs a predetermined delay calculation and adds and synthesizes the control target value. .

(Operation) Therefore, the invention corresponding to claim 1 takes the above-mentioned measures, and after extracting the difference between the control target value and the calculation target value by the comparison judgment means, this difference and a predetermined predetermined value are calculated. If the difference is greater than or equal to a predetermined value, a switching command is given to the signal switching means to select the calculated target value, and when the difference is less than or equal to the predetermined value, a switching command is given to the signal switching means to select the control target value. By giving a switching command to select
When the calculated target value approaches the control target value, the signal switching means directly takes in the control target value and P! This is the target value for adjustment.

In the invention corresponding to claim 2, the calculated target value is always used as the base of the target value for the PI adjustment calculation, and the switching is performed when the difference between the control target value and the calculated target value becomes equal to or less than a predetermined value in the comparison judgment means. Issue a command. When the signal switching means receives a switching command, it becomes conductive, and adds and synthesizes the output of the subtraction means (control target value - calculation target value) to the calculation target value, which is the base for the PII clause calculation, to obtain the PII clause target. It is a value.

Next, in the invention corresponding to claim 3, the output of the subtraction means (
(control target value - calculation target value) is smoothed by a first-order lag element and added to and synthesized with the calculation target value which becomes the base for the PII clause calculation.

(Example) Hereinafter, the first example of the invention corresponding to claim 1 will be described.
This will be explained with reference to the figures. In this figure, parts that are the same as those in FIG. 5 are given the same reference numerals, and a detailed explanation thereof will be omitted, and hereinafter, only the parts that are different from the conventional apparatus will be explained. That is, in this device, between the control target value input terminal and the output terminal of the adding means 14, the control target value Sv and the calculated target value S V o which is the output of the target value filter means 1 are connected.
A comparison and judgment means 11 is provided to judge whether the difference between the two and the two has become equal to or less than a predetermined value. Calculation target value Sv.

, and receives a switching command when the difference is less than a predetermined value, and selects the control target value S■ and introduces it into the deviation calculation means 3.

Therefore, according to the configuration of the embodiment as described above, when the control target value Sv changes in a stepwise manner, the comparison judgment means 11
Now, the magnitude relationship between the difference signal from the target value SV and the calculated target value S Vo and the predetermined value δ is compared, but since it is also immediately after a step change, the relationship is 15V-8Vo I≧δ, and as a result, the comparison In response to the output of the determining means 11, the signal switching means 12 selects and outputs the calculated target value S V o. Therefore, in this case, the target value SVa to the PII node means 4 becomes Svo, and the calculated target value Svo having the same response characteristic as that in the conventional FIG. 4 is given to the PII node means 4. Note that the predetermined value δ is a value that does not affect the two degrees of freedom, and is determined based on experiments and past experience.

Thereafter, the calculated target value S V o gradually increases, but at this time, the comparison/judgment means 11 compares the difference between the target value Sv and the calculated target value Svo with the predetermined value δ, and calculates 5V-SVo.
<δ, that is, when the difference is less than or equal to the predetermined value δ, a switching command is generated. Here, the signal switching means 12 receives the switching command and selects the control target value SV, so the PI
The adjustment target value is 5Va-SV, which is shown in Figure 2 (
As shown in b), it is possible to settle to the target value Sv in a short time.

Note that the comparison/judgment means 11 and the signal switching means 12 may be realized by hardware using resistors, capacitors, or semiconductors, or may be realized by software using a computer.

Next, we will discuss the third embodiment of the invention corresponding to claim 2.
This will be explained with reference to the figures. In this case as well, the same parts as in FIG. 5 are designated by the same reference numerals, and detailed explanation thereof will be omitted, and only the different parts will be explained below.

In this embodiment, in addition to the comparison/judgment means 11 having the same function as that shown in FIG. An adding means 23 is provided for adding the output of the target value to the calculated target value S V o which is the output of the target value filter means 1, and the output of the adding means 23 is introduced into the deviation calculating means 3 as a target value for the PII clause. be.

That is, in this embodiment, the calculation target value Svo of the target value filter means 1 is always used as the base, while the comparison judgment means 11 adds the difference between the target value SV and the calculation target value Svo to the calculation target value Sv0. It has a function to determine whether to combine or not.

Therefore, according to the configuration of the embodiment as described above, the calculated target value SVo outputted from the target value filter means 1 is normally introduced into the deviation calculating means 3 via the adding means 23 as the PI adjustment target value SVa. .

When the target value Sv changes stepwise in this state, the comparison/determination means 11 compares the target value SV with the calculated target value S■.

and the predetermined value δ, but since it is immediately after the step change, there is a relationship such that 5VSVol≧δ, and since the switching command is not generated from the comparing and determining means 11, the signal switching means 22 is in a non-conducting state. It is in. As a result, the target value for PI adjustment was 5Va-8Vo.
is sent to the deviation calculation means 3.

Thereafter, the calculated target value SV o gradually increases, but at this time, the comparison/judgment means 11 compares the difference between the target value SV and the calculated target value SV o with the predetermined value δ, and calculates the difference between 5V and 8V.
When the relationship ol<δ, that is, the difference is less than or equal to the predetermined value δ, a switching command is issued. As a result, the signal switching means 22 becomes conductive and introduces the subtraction signal (SV-8vo) from the subtracting means 21 into the adding means 23, so that from this adding means 23, 5Va-3Vo + (SV-3VO) A signal of -8V, that is, a target value Sv, is directly introduced into the deviation calculating means 3. Therefore, the response characteristic to a change in the target value is as shown in FIG. 2(a), similar to FIG. 1.

Therefore, according to this embodiment, the constantly calculated target value S V
o is introduced into the deviation calculating means 3, and when the difference between the target value S■ and the calculated target value S V o becomes equal to or less than the predetermined value δ, S V
Since the configuration is such that the subtraction signal (SV 5Vo) is synthesized with o, the target value for PI adjustment can be given to the deviation calculation means 3 without any momentary interruption.

Furthermore, an embodiment of the invention corresponding to claim 3 will be described with reference to FIG. In this case as well, the same parts as in FIG.
Only the different parts will be explained.

This embodiment has substantially the same configuration as that shown in FIG. 3, with the main difference being that a first-order lag element 31 is newly added to the input side of the adding means 23.

Therefore, in this device, when the target value S changes in a stepwise manner as in FIG.
The difference between V and the calculated target value S■0 is compared with a predetermined value,
Since it is immediately after the step change, there is a relationship such that 5VSVol≧δ, and therefore, the signal switching means 22 is in a non-conductive state. As a result, the target value for PI adjustment is 5V.
a-SVo is sent to the deviation calculation means 3.

However, when the calculated target value S Vo rises to a certain value, the relationship 5V-3VOl<δ, that is, the difference becomes less than the predetermined value δ, and the comparison/judgment means 11 issues a switching command. As a result, the signal switching means 22 becomes conductive, and the output (
SV-3VO) is introduced into the first-order lag element 31, and 5Va-8Vo+(SV 5Vo)'' (1/(1+θ
Since smoothing is performed by a delay calculation of T+"S)1 and addition is performed by the adding means 23, the control target value S■ is settled with a response characteristic as shown in FIG. 2 (B).

Note that θ is 1 or less.

Therefore, according to the configuration of this embodiment, the signal switching means 22
When conductive, the addition means 23 adds and synthesizes the subtracted output (S V −S V o ) while smoothing it.
The operation signal MV can be outputted from the PI adjustment means 4 without sudden changes, and therefore no shock is given to the controlled object 2.
It does not affect the process.

Note that the present invention is not limited to the above embodiments.

Although the first-order lag element 31 is provided on the input side of the addition means 23 in FIG. 4, the first-order lag element 31 may be provided on the contact side of the signal switching means 12 shown in FIG. 1, for example. Further, in the above embodiment, the PI adjustment calculation was described, but the invention can be similarly applied to the PID (D: differential) adjustment calculation. others,
The present invention can be implemented with various modifications without departing from the gist thereof.

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

First, in the invention of claim 1, in response to a change in the target value, the response time is significantly shortened to the extent that the original two-degree-of-freedom function is not inhibited, and the adjustment target value is set to the control target value. I can do it.

Next, in claim 2, in response to a change in the target value, when the difference between the adjustment target value and the control target value becomes equal to or less than a predetermined value, the adjustment target value can be shifted to the control target value without momentary interruption. can.

Furthermore, in the invention of claim 3, when the difference between the adjustment target value and the control target value becomes equal to or less than a predetermined value, the adjustment target value can be smoothed to smoothly shift to the control target value. .

Therefore, in each of the above inventions, it is possible to significantly shorten the target value follow-up time in response to changes in the target value, greatly improve the performance of the adjustment device with target value filter means, and improve the plant operating characteristics by distributing it throughout the plant. Efficiency can be achieved.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram showing an embodiment of the invention according to claim 1, FIG. 2 is a diagram showing the step response characteristic of the target value filter in the device of the present invention, and FIG. FIG. 4 is a functional block diagram showing an embodiment of the invention according to claim 3, FIG. 5 is a functional block diagram of a conventional device, and FIG. 6 is a target value filter of the conventional device. FIG. 2 is a diagram showing step response characteristics of FIG. DESCRIPTION OF SYMBOLS 1...Target value filter means, 2...Controlled object, 3.
... Deviation calculating means, 4... PI or PID adjusting means, 11... Comparing and determining means, 12... Signal switching means,
21... Subtraction means, 22... Signal switching means, 23.
... Addition means, 31... First-order lag element. Applicant's agent Patent attorney Takehiko Suzue

Claims (3)

[Claims] (1) Target value filter means is provided, and at least PI (P: proportional, I: integral) adjustment calculation is performed using the deviation between the target value obtained from the target value filter means and the controlled amount from the controlled object. In a two-degree-of-freedom adjustment device that applies the obtained operation signal to the controlled object, the difference between the control target value given to the target value filter means and the calculated target value obtained by the calculation process of the target value filter means is determined. target value follow-up speed response with two degrees of freedom, characterized in that the control target value is directly selected and set as the target value for the PI adjustment calculation when the difference becomes equal to or less than a predetermined value. Regulator. (2) Target value filter means is provided, and the deviation between the target value obtained from the target value filter means and the control amount from the controlled object is used to execute at least a PI adjustment calculation, and the obtained operation signal is In a two-degree-of-freedom adjustment device that applies an electric current to a controlled object, the difference between the control target value applied to the target value filter means and the calculated target value obtained by the calculation process of the target value filter means is extracted, and this difference is determined to be less than or equal to a predetermined value. a comparison judgment means for outputting a switching command when the control target value is reached; a subtraction means for subtracting the calculation target value from the control target value; and a subtraction means for subtracting the calculation target value from the control target value; and a signal switching means for taking in the output of the subtracting means and adding and synthesizing it to the control target value to obtain a target value for the PI adjustment calculation when receiving a switching command from the means. Follow-up speed responsive 2 degrees of freedom adjustment device. (3) In the target value following speed responsive two degrees of freedom adjusting device according to claim 2, when a switching command is received from the comparison/judgment means, a predetermined delay calculation is performed on the output of the subtraction means to obtain the calculated target value. A target value following speed responsive two degree of freedom adjustment device characterized by adding a first-order lag element for additive synthesis.