JPH0340101A - Negative feedback controller - Google Patents

Abstract

PURPOSE:To prevent the deterioration of an operating part owing to the mechanical wear, etc., by inhibiting an output part from outputting actually an operating signal as long as the value of a source operating signal does not exceed the blind sector value set at the output part. CONSTITUTION:A motor-driven door 7 keeps its present opening amount when an operating signal 19a is not actually outputted from a negative feedback controller 17, that is, while the value MV of the signal 19a is kept at zero. Therefore the door 7 never works as long as the value BV of a source operating signal 18a does not exceed a blind sector Y despite the change of the value PV of a water level measuring signal 9a. In other words, the signal 19a is not actually inputted to an operating part 16 as long as the value BV of the signal 18a does not increase even though the deviation value DV of a deviation signal 11a exceeds a blind sector X and fluctuates extremely owing to a fact that the waves are produced on the surface of the water in a water tank 3 by the water supplied via a water pipe 15. As a result, the working frequency of the operating part 16 is reduced. Thus it is possible to prevent the deterioration of the part 16 owing to the mechanical wear of the door 7, etc.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a negative feedback regulator used in a negative feedback control device such as a water level control device for a water tank in a water treatment facility;
In particular, the present invention relates to a regulator that can extend the life of an operating part that receives an operating signal output from the regulator and performs a mechanical operation to apply an operating amount corresponding to the operating signal to a controlled object.

[Conventional technology]

FIG. 4 is an explanatory diagram for explaining the configuration of a water level control device t2 using a conventional negative feedback regulator l.

In the figure, 3 is a storage tank open to the atmosphere that stores water 5 sent through the water supply pipe 15 by the water pump 4, and 6 is a demand WK (not shown) in which the water 5 in the storage tank 3 is stored.
A water pipe 7 is installed at the bottom of the water storage tank 3 to distribute water, and is an electric type that is installed in the middle of the water pipe 6 and adjusts the flow rate of water 5 flowing through the water pipe 6 by adjusting the opening degree. 8 is a drive in which the operating signal 1a is input and the opening degree of the signal 7 is increased or decreased by the amount of change in the opening degree represented by the signal 1a in the direction of change in the opening degree represented by the input signal la. This is a door driving device that outputs a signal 8a toward the door 7. Reference numeral 9 denotes a water level gauge 70 which detects the water level H in the storage water tank 3 and outputs a water level measurement signal 9a representing the water level H.

Reference numeral 10 denotes a variable set value water level setter that outputs a water level setting signal tOa, and the above-mentioned negative feedback regulator l receives a water level measurement signal 9a and a water level setting signal 10a, and these two manual signals will be described later. It is configured to perform signal processing to output the aforementioned operation signal Ha as a result.

Here, the operation signal 1a controls the flow rate of water flowing out from the storage tank 3 by adjusting the opening degree of the door 7 via the door drive device 8 based on the signal taVc, and as a result, the water level H is set. This is a signal to match the water level setting H8 represented by the signal 10a, and the water level control device 2 described above controls the hydrophobic door 7 described above.
It is composed of a driving device M8, a water level gauge 9, a water level setting device 1O, and a negative feedback regulator 1.

Next, the configuration and operation of the regulator 1 will be explained with reference to the configuration diagram of the regulator shown in FIG. In FIG. 5, 11 is inputted with signals 9a, tOa, and b'', and the difference between the value PV of the signal 9a and the value SV of the signal 10a (8V-PV
)K primary deviation signal tia whose signal value is the deviation DV equal to
A deviation calculating section 12 receives the signal tta and performs the calculation of equation (1) according to the value of the signal 11a, and generates a secondary deviation signal 12a having a calculated value AV as a result. In the output deviation signal converter, W in equation (1) is a positive constant representing the size of the dead zone X set in the deviation DV, and W is a positive proportionality constant. Deviation signal converter 1
2, the primary signal 11a is converted to the secondary signal 121 as described above, so it is clear that the relationship between the two signals 11a and 12a becomes as shown in the input/output characteristic line 13 shown in FIG. .

W'xDV: When h-W When AV=OD■>W AV=k(DV-W) ・-・-・・(1
) When DV<-w, AV=k(DV+W) 14 in FIG. 5 is the input of the secondary deviation signal 12a, and the nuclear signal 12
A control calculation unit that performs a predetermined control calculation such as a PID calculation on a and outputs the aforementioned operation signal Ha as a result, and the negative feedback regulator l includes the control calculation unit 14, the conversion unit 12, and the deviation calculation unit. It consists of 11.

In FIG. 4, since the water level control device 2 is configured as described above, it is clear that the water level H is maintained at the water level setting value n5VI− represented by the setting signal 10a; The device 1 is provided with a deviation signal converter 12, and the arithmetic unit 14 converts the value AV of the input signal 12a.
If is zero, the operation signal 1a will not be output, so IDVI
) Driving signal 8ab to hydrophobic n7 unless state b1 of W occurs.
''-The door 7 does not operate because there is no input. In other words, in Fig. 4, the door 7 does not operate unless a large deviation DV occurs, so the frequency of operation of the door is low. This is to suppress deterioration of the support member of the door 7, such as mechanical wear, by reducing the frequency of operation of the door 7.

A converter 12 is provided in the regulator 1 in order to extend the life of the hydrophobic door 7.

[Problem to be solved by the invention]

The negative feedback regulator l is provided with the deviation signal converter 12 as described above, but in this case, the absolute value IDV of the deviation DV
If I exceeds W even slightly, the drive signal 8a will be input to the door 7. Then.

When water is supplied from the water supply pipe 15 to the water tank 3 as shown in FIG. 4, the deviation DV is
A phenomenon that occurs in which the curve vertically crosses the dead zone X shown in FIG. 6 in a short period occurs very often.

In other words, although the regulator tVc is provided with the converter 12 in order to reduce the frequency of operation of the door 7, still,
In the case of FIG. 4, there is a problem that the door 7 deteriorates quickly because the door 7 constantly opens and closes due to the waves generated on the water surface of the water tank 3. For this reason, it is clear that increasing the size W of the dead zone X described above in the converter 12 of the regulator 1 can further reduce the frequency of operation 7, but if W is increased in this way, the water level H will naturally increase. If the water level Hs deviates significantly from the set water level Hs, the door 7 will not operate, and the fluctuation range of the water level H will become larger than before increasing W. As a result, increasing W will result in poor water level control. A new problem will arise.

An object of the present invention is to reduce the frequency of operation of an operating section such as the operating section 16 made up of the control section 7 and the drive device 8 without providing a dead zone X in the deviation DV, and to achieve negative feedback control. The object of the present invention is to obtain a negative feedback regulator capable of suppressing deterioration such as mechanical wear of the operating section without causing deterioration of controllability.

[Means to solve the problem]

In order to achieve the above object, the present invention includes: a main controller that performs a predetermined control calculation on the deviation between a measurement signal and a setting signal and outputs an original operation signal according to the result; and an output section that outputs an actual operation signal according to the difference between the value and a predetermined dead band value, and performs negative feedback control on the control amount represented by the measurement signal by giving the actual operation signal to the operation section. Configure a negative feedback regulator.

[Effect]

With the above configuration, the main control section always outputs the original operation signal based on the deviation since there is no dead band as described above for the deviation, but the value of this original operation signal is Since the output section can be configured so that the actual operation signal is not output from the output section unless the dead band 1 shift set in the output section is exceeded, the output section is more efficient than the case of the negative feedback regulator l described above. The operation frequency of the operating section can be lowered, and b) it is possible to suppress deterioration such as mechanical wear of the operating section without deteriorating the controllability of negative feedback control. A feedback regulator will be obtained.

〔Example〕

FIG. 1 is a configuration diagram of a negative feedback regulator 17 as an embodiment of the present invention, and FIG. 2 is an explanatory diagram illustrating the configuration of a water level control device 22 using the negative feedback regulator 17. Figures 1 and 2
In the figure, the major difference from FIGS. 4 and 5 is that the negative feedback regulator 17 corresponding to the negative feedback regulator 1 has a deviation calculation unit 1.1 and a primary deviation signal 1.1 output from the calculation unit 11. l
A control calculation unit 1B receives the signal 11a, performs the same control calculation as in the control calculation unit 14 described above on the signal 11a, and outputs the original operation signal tea as a result, and the control calculation unit 1B receives the signal 18a and This signal tSa
and an output section 19 that calculates the formula () according to the value BV of 12aThe above-mentioned deviation signal converter I2 that performs VC conversion is not provided.Here, the actual operation signal 19a is a signal corresponding to the operation signal 1a shown in FIGS. 4 and 5, and (formula 9 Z is a positive constant representing the size of the dead zone Y set in the value BV of the signal 18a,
K is a positive proportionality constant. In the output section I9, the original operation signal 18a is converted into the actual operation signal 19a as described above, so in this case, the input/output characteristic line of the output section 19 becomes the characteristic curve shown at 20 in FIG. It is clear that -1: The output signal 19a of the output section 19 is MV)Q
When MV<O, the signal causes the water level H to rise by closing the hydrophobic node 7 via the door driving device 8, and when MV<O, the signal causes the door 7 to be opened and the water level H to fall.

Z'-B V'--Z When MV=OBV>
Z MV=K(BV-Z) ・,=(Z
BY<-Z MV=K (BY+Z) Since the negative feedback regulator 17 is configured as described above, this regulator 17 consists of the deviation calculation unit 11 and the control calculation unit 18, and the measurement signal 9a and the setting signal - A main control unit 2 that performs a predetermined control calculation on the deviation DV from 10a and outputs the original operation signal 18a according to the result.
1, the value BY- of the original operation signal tSa, and the predetermined dead zone value Z.
an output unit 1 that outputs an actual operation signal 19a according to the difference between
It can be said that it is a regulator equipped with 9. The water level control device 22 described above is composed of the negative feedback regulator 17, the operating section 16, the water level gauge 9, and the setting device 10.

In FIGS. 1 and 2, a regulator 171'l'' is constructed as described above, and when no actual operating signal 19a is output from this regulator 1.7, i.e. the signal 19
When the value MV of a is zero, the door 7 maintains its current opening degree by 1 because this door is electrically operated.

Therefore, no matter how the value DV of the deviation signal tta shown in FIG.
The door 7 will not operate unless the dead zone Y shown in the figure is exceeded. That is, water level control using the negative feedback regulator 17 1. - According to fil 22.

When water is poured into the tank 3 from the water supply pipe 15, waves are generated in the water quotient of the tank, and the value DV of the deviation signal 11a fluctuates violently, exceeding the dead zone X shown in FIG. However, unless the value BV of the original operation signal 18a becomes large, the actual operation signal 19a is not input to the operation section 16, so the operation frequency of the operation section 16 becomes lower than in FIG. This means that deterioration of the operating section 16, such as wear and tear, is suppressed compared to when the four-section device 1 is used.

In addition, in this case, since the Confucian dead zone X is not provided for the deviation DV, the controllability of negative feedback control can be improved by appropriately setting the size Z of the dead zone Y at the value BV of the original can be prevented from becoming worse than in the case of FIG.

Although the above-mentioned embodiment is adopted in the water level control device 22 and outputs the actual operation signal 19a toward the electric operation unit 16, the regulator of the present invention can be adopted in a control device other than the water level control device. It is obvious that there is no need to explain that the signal may be outputted to an operating section other than the N-motion type, such as a hydraulic type or a pneumatic type.

〔Effect of the invention〕

As described above, one aspect of the present invention includes a main controller that performs predetermined control calculations on the deviation between the measurement signal and the setting signal and outputs an original operation signal according to the result, and Equipped with an output section that outputs an actual operation signal according to the difference from the dead zone value.

The negative feedback regulator was configured to perform negative feedback control on the control amount represented by the measurement signal by applying an actual operation signal to the operation section.

For this reason, when +s is relative as described above, in this case, there is no dead zone for the deviation as described above, so the main adjustment section always outputs the deviation (based on the original operation signal bt, this original operation signal). Since the output section can be configured so that the actual operation signal is not output from the output section unless the signal value exceeds the dead band value set at the output section, the above-mentioned negative feedback regulator l The operation frequency of the operating section can be lowered compared to the case where the operation section is operated, and therefore, one aspect of the present invention is to suppress deterioration such as mechanical wear of the operating section without causing deterioration of controllability in the negative feedback control example. The effect obtained by a negative feedback regulator that can be obtained is h''-.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention. 2 is an explanatory diagram for explaining the configuration of a water level control device employing the negative feedback regulator of FIG. 1, and FIG. 3 is an input/output characteristic diagram of the output section in FIG. 1. FIG. 4 is an explanatory diagram for explaining the configuration of a water level control device employing the negative feedback regulator shown in FIG. 5. FIG. 5 is a block diagram of a conventional negative feedback regulator, and FIG. 6 is an input/output characteristic diagram of the deviation signal converter in FIG. 1.17... Negative feedback regulator, 9a...
Water level measurement signal, tOa...water level setting signal,
16...Operation unit, 18a...Original operation signal, 19...Output unit, 19a...Actual operation signal, 21...Main Adjustment part, H...
...Water level, DV...deviation. 3- Notebook 6 Diagram

Claims (1)

[Claims] 1) A main control section that performs a predetermined control calculation on the deviation between the measurement signal and the set signal and outputs an original operation signal according to the result, and a main controller that outputs an original operation signal according to the result, and a main adjustment section that performs a predetermined control calculation on the deviation between the measurement signal and the setting signal, and a and an output section that outputs an actual operation signal, and performs negative feedback control on the control amount represented by the measurement signal by applying the actual operation signal to the operation section.