JPH0429796B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device for controlling a paper machine, which is the final step in the paper manufacturing industry, and particularly relates to a paper machine control device with improved control characteristics in the paper width direction.

(Prior Art) FIG. 5 is a schematic diagram of a paper machine control device known from Japanese Patent Publication No. 57-24435. In the figure,
1 is a seed box for storing a raw material liquid containing pulp, etc., 2 is a seed port valve that controls the amount of raw material liquid supplied from the seed box 1, 3 is a silo for storing white water, and 4 is a seed box for mixing the raw material liquid and white water. The feeding fan pump 5 is an inlet box equipped with a plurality of discharge ports (slice lips) corresponding to the width of the paper, and stores the liquid sent from the fan pump 4. 6 is a wire part for extracting the pulp part of the liquid released from the slice lip, and 7 is a suction box for dehydrating the raw material on the wire part 6, which makes the white water mixed with the raw material fall into the silo 3 under negative pressure. 8 is a press part that thins the dehydrated raw material, 9 is a dryer that dries the paper to a preset moisture content, 10 is a calender that performs polishing, and 11 is a reel that winds up the finished paper. 12 is a basis weight moisture content detection unit (hereinafter referred to as BM meter); 13 is a control unit that controls the absolute dry amount and moisture content of paper detected by BM meter 12 to be equal to their respective set values; 2, the steam pressure of the dryer 9, and the papermaking speed.

The device configured as described above operates as follows. The raw material liquid supplied from the seed box 1 passes through the seed port valve 2 and is sent to the inlet box 5 by the mixing fan pump 4 with white water supplied from the silo 3. The liquid discharged from the inlet box 5 onto the wire part 6 is dehydrated and dried while passing through the wire part 6, the suction box 7, the press part 8, the dryer 9, etc., and then wound onto the reel 11. The basis weight of the paper is kept constant by controlling the seed opening valve 2 and the like using a control signal from the control unit 13 based on the output of the BM meter 12.

FIG. 6 is an explanatory diagram of paper width direction profile control, where A is an explanatory diagram showing a developed sheet of paper from inlet box 5 to a total of 12 BM scanning lines, and B is an explanatory diagram showing a spread of paper from inlet box 5 to a total of 12 scanning lines, and B is an explanatory diagram showing a plurality of profiles (for example, 40) provided in the width direction of the paper. C is a distribution map of the absolute dry basis weight measured by a BM meter having a plurality of observation points (for example, 360 points) in the width direction of the paper.

The degree of opening of each slice lip is controlled independently to keep the target absolute dry basis weight constant in the width direction.

FIG. 7 is a functional block diagram showing control of the paper width direction profile. In the figure, reference numeral 21 denotes an operating section for independently operating the opening degrees of a plurality of slice lips. 22 is the paper making process, which consists of multiple steps such as pressing, drying, and polishing. 23 is
The BM meter detection unit measures bone dry basis weight, moisture content, paper thickness, etc. while scanning at a rate of, for example, once every 40 seconds. 24 is a display section that displays, for example, the basis weight profile shown in FIG. 6C. 25 is BM meter detection section 2
A control signal U is sent to the operation unit 21 based on the data Y of No. 3.
The control unit outputs , allowing the operator to switch between automatic and manual control.

(Problems to be Solved by the Invention) FIG. 8 shows the absolute dry basis weight distribution when only a single slice lip is opened. With respect to the width w of the slice lip, the basis weight is also distributed in the area of adjacent slice lips. If the absolute dry basis weight at a certain point deviates from the target, it is necessary to control a plurality of slice lips, and there is a problem in that the automatic control of the control unit 25 cannot achieve the same control as manual operation by a skilled operator.

Furthermore, as shown in the figure, there was a problem in that if a cross flow occurred due to some kind of disturbance, the automatic system could not follow it at all.

The present invention solves these problems,
The purpose of the present invention is to realize a paper machine control device that automatically performs paper width direction profile control similar to that of a skilled operator and that produces paper with a target profile even when disturbances occur.

(Means for Solving the Problems) The present invention achieves the above object by providing a plurality of slice lips in the width direction of the paper and supplying an amount of raw material corresponding to the opening degree, and a plurality of slice lips supplied from the slice lips. It is equipped with a process section that dehydrates and dries raw materials to obtain a predetermined paper quality, and a detection section that decomposes and detects the paper quality of the paper sent from this process section in the paper width direction, and the paper quality profile detected by this detection section. In a paper machine that operates the opening degree of the slice lip based on, an identification unit that identifies an interference transfer matrix that displays the relationship between the opening degree of the slice lip and a paper quality profile in a steady state with respect to this opening degree; a command profile generating unit that generates a transient paper quality profile that is passed through when the paper machine is operated by a skilled person to reach a target paper quality profile; a transient paper quality profile that is generated by the command profile generating unit; Target paper quality profile,
a model matching section that inputs the interference transfer matrix output from the identification section and calculates a gain when manipulating the slice lip opening; the gain calculated by this model matching section; the target paper quality profile; The present invention is characterized in that it is further provided with a control section which inputs the paper quality profile detected by the detection section, calculates the operating amount of the opening degree of the slice lip, and outputs it to the slice lip.

(Function) Each of the above-mentioned components has the following function. The identification unit stores the identified steady-state model of paper machine control. The command profile generating section stores desirable transient paper quality profiles performed by an expert and transmits them in chronological order. The model matching section calculates the gain of the slice rip operation amount necessary to realize the transient paper quality profile in a steady state. The control section operates the slice lip according to instructions from the model matching section.

(Example) The present invention will be explained below using the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, parts having the same functions as those in FIG. 7 are designated by the same reference numerals, and their explanations will be omitted.

In the figure, 26 indicates the opening degree of the slice lip;
The identification section identifies the relationship between this opening degree and the paper quality profile in a steady state.Identification here means finding a steady model when the paper machine operating conditions and paper quality are constant; for example, in a steady state.
ARMA (Auto Regulating Moving Average)
A model is used. Reference numeral 27 denotes a command profile generation unit that stores a transient paper quality profile that is passed through when a skilled person operates the paper machine to reach a target paper quality profile, and generates this transient paper quality profile in chronological order. 28 is the steady ARMA of the paper machine
The model matching section, which inputs the model, transient paper quality profile, and target paper quality profile, calculates the gain of the slice rip operation amount necessary to realize the transient paper quality profile with the steady ARMA model. 29 is a control unit that calculates using the gain of the model matching unit 28 and the deviation between the paper quality profile detected by the detection unit 23 and the target paper quality profile, and the opening degree of the slice lip is determined based on the calculation result. For example, control using PI control.

Uop is the manipulated variable (identification manipulated variable) under conditions (identification conditions) that include the amount of information necessary to estimate the unknown parameters of the steady ARMA model, and Yop is the paper quality profile obtained in the steady state for the identified manipulated variable Uop. isle, M^ is a matrix representing the stationary ARMA model of the paper machine, and here it is called the interference transfer matrix.
is the target paper quality profile, and Yc is the transient paper quality profile stored in the command profile generating section 27, which consists of the first step to the Mth step where the paper quality reaches a steady state and settles.

Although the broken lines in the figure indicate offline processing and the solid lines indicate online processing, it is also possible to perform all online processing.

The operation of the device configured in this manner will be described next. FIG. 2 is a flowchart showing the operation of the apparatus shown in FIG. 1, in which (A) represents offline processing and (B) represents online processing.

The interference transfer matrix M^ is identified online based on the measured data Yop for the open-loop manual slice slip operation of the paper machine. Note that offline processing is performed because the amount of identification calculation is enormous, but online processing may also be used if there is a sufficient degree of slice rip operation and calculation can be performed quickly enough.

First, the identified manipulated variable Uop is input to the operating section 21 (S1), and the measurement data Yop in a steady state corresponding thereto is read out from the detecting section 23 (S2). here,
The components of Uop and Yop are expressed as follows.

U ^T _pp = (u ₁ , u ₂ ,..., u _r ) (1) Y ^T _pp = (y ₁ , y ₂ ,..., y _o ) (2) Here, r is the total number of slice lips, for example 40
There are three slice lips, and u _i (i=1, 2, . . . , r) is the opening degree of each slice lip. n is the total number of measurement points of the detection unit 23, for example, 360 points, and y _i (i=1, 2,...,
n) is a paper quality measurement quantity such as basis weight at each measurement point.

The identification unit 26 uses the identification operation amount Uop and the paper quality profile Yop to find the interference transfer matrix M^ by the method of least squares (S3).

M^=Y _pp U ^T _pp U _pp ) ^-1 (3) The interference transfer matrix M^ has the following relationship, and
As long as the operating conditions and paper quality remain constant, this model can be considered stationary.

Y _pp = M^ U _pp (4) Also, the steady ARMA model of the paper machine is the following general formula:
Since it is expressed by (5), the relationship with the interference transfer matrix M is as shown in equation (6).

1+α ₁₁ α ₁₂ …α _1o α ₂₁ 1+α ₂₂ …α _2o ： : : α _o1 α _o2 …1+α _oo y ₁ y ₂ : y _o = β ₁₁ β ₁₂ …β _1r β ₂₁ β ₂₂ …β _2r ： : : β _o1 β _o2 …β _ro u ₁ u ₂ : u _r (5) M=1+α ₁₁ α ₁₂ …α _1o α ₂₁ 1+α ₂₂ …α _2o : : : α _o1 α _o2 …1+α _oo ^-1 β ₁₁ β ₁₂ …β _1r β ₂₁ β ₂₂ ...β _2r : : : β _o1 β _o2 ...β _or (6) Next, the model matching unit 28 calculates the necessary slice rip operation amount U using equation (3) and the transient paper quality profile Yc. Calculate (S4).

U=[M^) ^T M^] ^-1 (M^) ^T Yc(i), (i=1,...,M) (7) Furthermore, it was determined by an experiment conducted by an expert as shown in Figure 3. Since the transient paper quality profile Yc(i) is generated using finite measurement data, it does not match the target paper quality profile in one round, and usually it takes N rounds to converge to the target paper quality profile. In addition, in the round during the convergence, the data of the transient paper quality profile Yc is obtained based on the data that has become a steady value in the previous round.

Next, the model matching unit 28 determines the gain matrix from equation (7) (S5).

= (Φ ^T Φ) ^-1 Φ ^T U (8) Here, the gain matrix is determined by the control unit 29 using equation (9).
Displays the gains K _P and K _I when performing PI control,
When expressed in terms of components, it becomes as shown in equation (10).

U=−K _P ΔY−K _I ΣΔY (9) U ^j _i = _N 〓 ^k=1 {−K _p ^ik ΔY ^j _ik (M) −K ^ik _IM 〓 ^l=1 ΔY ^j _ik (l)} (10 ) Here, i is the slice lip number, j is the number of cycles, and k is the measurement point number, i = 1, 2,
..., r, j=1,2,...,N, k=1,2,...,
Consists of n.

K ^ik _P : P control gain between the i-th slice lip and the k-th measurement point.

K ^ik _I : I control gain between the i-th slice lip and the k-th measurement point.

Δy ^j _ik (M): Deviation between the i-th slice lip and the k-th measurement point in the j-th round, M is the number of settling steps in one round of operation, and is the difference between the M of the command profile generator 27 and It's the same. Note that the deviation refers to the difference between the measured value y ^j _ik and the target value y _ik .

ΣΔy ^j _ik (l): The sum of the deviations between the i-th slice rip and the k-th measurement point in the j-th round, which is the cumulative deviation between the target value _ik and the transient paper quality profile y ^j _ik . There is.

When the gain matrix 〓 is expressed by equation (11) and the manipulated variable matrix U is expressed by equation (12), equation (9) can be expressed by equation (13).

〓 ^T = ([K ¹¹ _I K ¹¹ _I ) (K ¹² _I K ¹² _I )…(K ¹ⁿ _P K ¹ⁿ _I )
] [(K ²¹ _P K ²¹ _I ) (K ²² _P K ²² _I )…(K ²ⁿ _P K ²ⁿ _I )]… [(K ^r1 _P K ^r1 _P ) (K ^r2 _P K ^r2 _I )…(K ^rn _P K ^rn _P )〕
(11) U ^T = {[U ¹ ₁ U ² ₁ …U ^N ₁ ] [U ¹ ₂ U ² ₂ … U ^N ₂ ] … [U ¹ _r U ² _r …U ^N _r ]} (12) U= Φ (13) Here, the small matrix Φ _pq that constitutes Φ is defined for [ ] in equations (11) and (12).

Φ＝Φ ₁₁ Φ ₁₂ …Φ _1o Φ ₂₁ Φ ₂₂ …Φ _2o : : : Φ _r1 Φr ₂ …Φ _ro (14) Here, P=1, 2, . . . , r Φ _pq =0 (for p≠q) In this way, the gain matrix 〓 is determined off-line. FIG. 2B is a flowchart of online processing using the identified gain matrix 〓.

The control unit 29 calculates the manipulated variable U using the gain matrix 〓 identified by the model matching unit 28, the target paper quality profile, and the paper quality profile measured by the detector 23 (S11). The operating section 21 operates the slice lip according to the command from the control section 29 (S12). The process section 22 makes paper (S13), and the detection section 23 outputs the paper quality profile Y of this paper (S14). This operation is repeated until paper of the required length is produced (S15).

FIG. 3 is an explanatory diagram of an experiment to obtain data to be stored in the command profile generation section 27, where A indicates the operation amount U _c of the slice lip instructed by an expert, and B indicates the paper quality profile Yc detected by the detection section 23. are shown in chronological order. Such an operation is performed, for example, when changing paper from low-quality paper with large variations to high-quality paper with uniform quality. In addition, U ^l _i in the figure is the i-th
It shows the manipulated variable in the l-th cycle of the th slice lip, and _Yik shows the k-th measurement point corresponding to the i-th slice lip.

The expert operates the slice rip N times to converge to the target paper quality profile, and in the command profile generation section 27, the paper quality profile that reaches convergence is determined by operating the slice rip each time. The first transient profile Yc that occurs
The steps from the step to the Mth slap to be settled are stored respectively.

In addition, using this manipulated variable U _c and transient profile Y _c , the identification manipulated variable U _pp and the measurement data for identification are
The identification unit 26 may identify the paper machine by assuming that Y _pp .

FIG. 4 is an explanatory diagram showing a specific example of the online processing in FIG. 2B, where A indicates the amount of operation of the slice rip commanded by the control section 29, and B indicates the paper quality profile detected by the detection section 23, shown in chronological order. There is.

In advance, the operating conditions and paper quality interference transfer matrix M^ and gain matrix 〓 for the target paper quality profile are determined and recorded in the model matching section 28. Next, in the first round, the control unit 29 controls the model matching unit 28
Find the manipulated variable using the gain 〓 outputted by , and perform the slice rip operation U ¹ _i based on this result,
The paper quality is stabilized through M steps of the transient profile of the command profile generating section 27. The next round is performed based on this settled paper quality profile, and this is repeated thereafter, converging to the target paper quality profile in the Nth round.

In the above embodiment, all the deviations Δy _ik (k=1, 2,..., n) are fed back to each slice lip, but the feedback is given to each two slice lips that have a large influence adjacent to the slice lip in question. The corresponding deviation (about 40 points if n=360 and r=40) may be fed back. This has the advantage of shortening calculation time.

If the paper quality or operating conditions change, the interference transfer matrix M may be re-identified and the gain matrix 〓 may be determined.

(Effects of the Invention) As explained above, the present invention has the following effects.

Since the control unit 29 performs control based on paper quality profile control by an expert, the reliability of the papermaking process is improved.

Since the control unit 29 is in control, paper of the same quality can always be produced even if a disturbance occurs.

Fixed value control allows you to ignore the effects of dead time.
Changes in control characteristics due to dead time do not pose much of a problem.

When performing PI (proportional integral) control as in the embodiment, the PI gain of the slice rip operation can be automatically adjusted according to the commanded paper quality profile.

[Brief explanation of drawings]

FIG. 1 is a configuration block diagram showing an embodiment of the present invention, FIG. 2 is a flowchart showing the operation of the device shown in FIG. 1,
FIG. 3 is an explanatory diagram of experimental data for determining the transient paper quality profile _Yc , and FIG. 4 is an explanatory diagram of a specific example of online processing of the apparatus shown in FIG. FIG. 5 is a schematic diagram of the conventional apparatus, FIG. 6 is an explanatory diagram of paper width direction profile control, FIG. 7 is a functional block diagram of paper width direction profile control, and FIG. 8 is an explanatory diagram of problems. 21...Operation section, 22...Process section, 23...
...Detection section, 26...Identification section, 27...Command profile generation section, 28...Model matching section, 2
9...Control unit.

Claims (1)

[Claims] 1. A plurality of slice lips provided in the paper width direction and supplying an amount of raw material corresponding to the opening degree, and a process section that dehydrates and dries the raw material supplied from the slice lips to obtain a predetermined paper quality. and a detection unit that separates and detects the paper quality of the paper sent from the process unit in the paper width direction, and operates the opening degree of the slice lip based on the paper quality profile detected by the detection unit. an identification unit that identifies an interference transfer matrix that displays the relationship between the opening degree of the slice lip and the paper quality profile in a steady state with respect to the opening degree; and an identification unit that identifies a target paper quality profile by operating the paper machine by an expert. a command profile generation unit that generates a transient paper quality profile to be passed through when reaching the target paper quality profile; a transient paper quality profile generated by the command profile generation unit, the target paper quality profile, and an interference transfer matrix output from the identification unit; a model matching section that calculates the gain when operating the slice lip opening degree, the gain calculated by the model matching section, the target paper quality profile, and the paper quality profile detected by the detection section. A control unit for controlling a paper machine machine, comprising: a control unit that inputs an input amount, calculates an opening degree operation amount of the slice lip, and outputs the same to the slice lip.