JPH0232399B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides a method for controlling the profile of absolute dry basis weight (weight per 1 m ² excluding water, expressed in g/cm ² ) in a paper machine control device. This invention relates to a device for controlling the opening degree of a slice lip to match a desired profile.

<Prior Art> The configuration of a papermaking control device and its problems will be explained with reference to FIGS. 6 to 11. Figure 6 shows the overall configuration. 1 is a seed box, 2 is a seed opening valve, 3 is a fan pump, 4 is a stock inlet, 5 is a slice lip, 6 is a wire part, 7 is a suction box, and 8 is a Spray part, 9 is dryer, 10
1 is a calendar, 11 is a reel, 12 is paper that becomes a product wound on the reel, and 13 is a silo for collecting white water. Reference numeral 14 denotes a basis weight sensor that scans the product 12 in the width direction to measure its basis weight and moisture content, and is realized by, for example, a combination of a β-ray basis weight meter and a near-infrared moisture meter. 15 is a control device that processes information from the sensor to calculate the profile of the absolute dry basis weight in the width direction of the product, and operates the seed opening valve 2 and the slice lip according to the deviation from the desired profile pattern. send a signal. In addition, an operation signal is also sent to the dryer 9 in order to manage the moisture content.

FIG. 7 is a perspective view of the stock inlet 4, slice lip 5, and wire part 6, and FIG. 8 is a partially enlarged view of the slice lip 5. The slice lips 5 are lined up at a constant pitch (100 to 150 mm). A plurality of slice bolt groups 16 ₁ installed in
The opening pattern of the gap 17 caused by the slice lip 5 can be finely adjusted by manipulating the amount of delivery of each of the slice lips 16 ₂ , . . . 16 _o . Reference numerals 18 and 19 are no deckles provided to prevent the paper stock discharged from the end of the slice lip from being discharged to the outside of the wire part.

Figure 9 is a diagram explaining the basic operation, and the horizontal axis is the paper width l.
, the vertical axis represents the absolute dry basis weight BD. S ₁ , S ₂ ,...S _o
indicates the positions corresponding to the slice bolt groups 16 ₁ , 16 ₂ , . . . 16 _o . E _p is the measurement profile of the absolute dry basis weight calculated based on the information from the sensor, _p is its average value, and S _p is the desired setting profile of the absolute dry basis weight. The opening degree of the seed opening valve 2 is controlled by the operation signal based on the deviation between _p and S _p , and in a state where _p matches S _p , the deviation ε ₁ between the desired profile and the measured profile,
The opening degree of the slice lip is controlled via each slice bolt group based on ε ₂ , . . . ε _o . Adjustment of the slicing bolt causes deformation of the slicing lip in that area, changing the amount of paper stock discharged, and thus changing the absolute dry basis weight. Therefore, by adjusting the plurality of slice bolt groups based on the deviation in each bolt position, it is possible to precisely match the desired profile.

However, adjusting the opening using slice bolts has the following problems. First, the operation of the slice rip causes deformation of the part;
This is a point that affects the paper thickness of the portion corresponding to the slice lip that is centrally adjacent to the slice lip at the operating position. Therefore, the operation signal for each bolt cannot be determined independently, and it is necessary to consider the mutual interference between the operation amounts for adjacent slice bolts. For example, as shown in FIG. 10, the operation signal u _k is based on the deviation ε _k of the k-th slice bolt position S _k .
When the slice lip at position S _k is pressed down, the stock flows to the parts corresponding to the adjacent slice lips at S _k+1 and S _k-1 positions, so that the pattern of the bone-dry profile becomes as shown in the figure. It will change.
Therefore, the operation signal for each bolt must be calculated in consideration of such mutual interference, and the calculation algorithm becomes complicated.

The second problem is that when operating the slice lip with the slice bolt, there is a control over the amount of operation between adjacent positions due to the rigid properties of the slice lip. For example, when the magnitudes of the operation signals at adjacent positions change alternately as shown in FIG. 11A, the amount that can be manipulated is small, and when they monotonically change as shown in FIG. 11B, the control is gentler than in A. Therefore, if the operating signal to each bolt exceeds the control due to the characteristics of the slice lip, an unreasonable force is applied to the slice lip, making it difficult to control with high precision.

<Problems to be Solved by the Invention> The purpose of the present invention is to solve the second problem mentioned above,
To provide a control device that provides a means for calculating an operation signal so that the amount of operation to each bolt does not exceed a limit, and thereby can solve the first problem of mutual interference in a wide range of ways. It is in.

<Means for Solving the Problems> The structural feature of the present invention is that the stock discharged from the stock inlet onto the wire part is adjusted to an absolute level by controlling the opening degree of the slice bolts at a plurality of locations on the slice lip. In a paper machine control device that controls the dry basis weight to a desired profile, a bone dry basis weight measuring means and a position operation signal for the slice bolt are generated based on a deviation profile between the bone dry basis weight measurement profile and the desired profile. and an operation signal calculation means for calculating the position operation signal, and when the signal difference between adjacent position operation signals is of the same polarity, the signal difference is compared with a first set value, and when the signal difference is of different polarity, the signal difference is compared with a second set value. a smoothing means for performing a smoothing process on the profile of the position operation signal when at least one output from the comparison means is generated; repetitive execution means for repeating the execution of the operation signal calculation means and the comparison means until the output of the comparison means is no longer generated;
The present invention further includes output means for supplying the output of the operation signal calculation means to the slice bolt as a position operation signal when the output of the comparison means is not generated.

<Function> A deviation profile between the absolute dry basis weight measurement profile calculated by one scan batch measurement of the basis weight sensor and the desired setting profile is calculated and held. A position operation signal for each slice bolt is calculated based on this deviation profile. Next, the polarities of adjacent signal differences of the position operation signals are compared, and if the polarities are the same, the difference between the operation signals is compared with the first setting value, and if the polarities are different, the second setting value (more than the first setting value) is compared. is selected to be small). If even one signal difference exceeds the set value as a result of the comparison, smoothing processing is performed on the position operation signal profile of the slice bolt by moving average processing, etc., and the resulting corrected position operation signal profile is The same position operation signal computation and comparison as above is performed, and if even one signal still exceeds the set value, the smoothing process is executed again on the corrected position operation signal profile and the above process is repeated. Then, the calculated output of the position operation signal at the stage when there is nothing exceeding the set value is transmitted as an operation signal to the slice bolt.

<Example> FIG. 1 is a functional block diagram when each means of the apparatus of the present invention is processed by software, where F is a paper machine M having a slice lip 5, and a process 1.
2, the area of the basis weight sensor 14; R is the area of the control device 15; In the region R, 151 is a bone dry basis weight measuring means for calculating the bone dry basis weight E _p based on the information of the basis weight sensor 14, and 152 is a deviation profile ε between the profile of E _p and the desired setting profile S _p . deviation holding means for calculating _p and holding the deviation profile of one scanning batch in synchronization with the scanning batch signal e _b ; 153 is an operation signal calculation that calculates the position operation signal u of each slice bolt based on the deviation profile ε _p ; The means 154 compares the difference between adjacent signals of the operation signals, and when the polarities are the same, it compares the absolute value of the signal difference with the first set value L _ss , and when the polarities are different, it compares the absolute value of the signal difference with the first set value L _ds (L _ds < L _ss ), and if even one difference exceeds the set value, the comparison output is
If e _c1 occurs and a difference exceeding the set value does not occur, comparison output e _c2 is generated.

155 is a smoothing control means, which outputs a comparison
When e _c1 is received, smoothing processing is performed on the position operation signal profile u, and a corrected position operation signal profile u' is outputted to the operation signal calculation means 153. Comparison means 154 performs a comparison operation similar to that of u on this signal u'. If the comparison output e _c1 occurs as a result, the correction position operation signal profile
Further smoothing processing is performed on u′ and the above processing is repeated. This iterative process is executed until the comparison output e _c2 is generated. Reference numeral 156 indicates an iterative control means for executing this iterative process. 157 is an output means that holds the outputs u, u', etc. of the operation signal calculation means, and when the comparison output e _c2 is received, outputs the held output at that time as the operation signal output u ₀ to the slicing screw of the paper machine. send.

Next, examples of specific signal processing modes of each means will be explained. In the operation signal calculating means 153, assuming that the deviation corresponding to the k-th slice screw is ε _k , the position operation signal u _k of the slither screw is calculated by the proportional and integral operation of the following equation in order to cancel this ε _k .

U _k = k _p (ε _k +1/TIiΣε _k ⁱ ) (1) (k: 1, 2,..., N) Here, K _p is the proportional gain, T _I is the integral gain, Σε _k ⁱ
is the sum of deviations from the past to the present, and specifically, values in the longitudinal direction are integrated at each point k in the width direction, which corresponds to an integral operation. Furthermore, k is the number of the slice bolts arranged in the width direction, and i is the data number in the longitudinal direction.

Note that the deviation ε _k ⁱ in the above equation is the deviation of only the profile component, and the average value of the entire profile (bone dry basis weight in the longitudinal direction) is controlled by another method such as a seed opening valve.

Next, in the comparison means 154, as shown in FIG.
Differences Δu _{k and} Δu k+1 between adjacent operation signals for the operation signals u _k , u _{k+1 ,} and u _k+2 are calculated using the following equations.

Δu _k =u _k+1 −u _k , Δu _k+1 =u _k+2 −u _k+1 (2) (1) Condition-1 Δu _k *Δu _k+1 If >0, that is, both operation signals If the difference is changing in the same direction, Δu _k+1 ≦L _ss (3) (2) Condition −2 If Δu _k *Δu _k+1 < 0, that is, the difference between the two operation signals is If it is changing in the opposite direction, it is checked at all points for each operating signal that Δu _k+1 ≦L _ds (4). If even one point does not satisfy the above conditions, the comparison output e _c1 is output, and the position operation signal profile u
Smoothing processing is performed on.

An example of smoothing in the smoothing processing means 155 will be explained with reference to FIG. A shows an example of the position operation signal profile u, where the position S _k-1 ,
The position operation signals at S _k , S _k+1 are expressed as u _k-1 , u _k , u _k+1
It is expressed as B shows a modified position operation signal profile u' obtained by performing a moving average process on the profile of A.
Focusing on u _k , its moving average value u _k ′ is given by u _k ′=1/2j+1 _j 〓 ^i=-j u _k+1 (5). Here, j is selected to be 1 or 2, for example. When j=1, it becomes a moving average of three points, and u _k ′=1/3 (u _k+1 + u _k +u _k-1 ) (6).

As is clear from a comparison of FIG. 3A and B, the modified positional manipulation signal profile u' obtained by performing such a moving average on all positional manipulation signals has a smooth change, and the adjacent positional manipulation signals The difference becomes smaller. Therefore, the difference between adjacent values of the position operation signal of each point calculated based on this modified position operation signal profile u' becomes small, and the possibility that conditions 1 and 2 above are satisfied is lower than before the smoothing process. Increase in comparison. In this kind of smoothing processing, as the number of processing increases, the position operation signal profile becomes smoother and only a rough tendency of change remains, and the difference in position operation signals for adjacent slice bolts becomes smaller, so that the position operation signal profile becomes smoother as the number of processing increases. , it becomes possible to suppress the range of limit values for reverse direction operations.

By repeating the smoothing process, the above condition 1,
2 is satisfied, the comparison means 154 outputs a comparison output.
Since e _c2 is transmitted, the output means 157 supplies the operation signal profile at this time as the operation output u ₀ to the operation section of each slice screw of the paper machine.

FIG. 4 is a flowchart showing the processing procedure when the functions of the above-mentioned means are realized by software, and shows the deviation ε _k as a representative example. In this flowchart, if the number of smoothing processes exceeds a certain number of times (n), an error 1 output is generated as an error, and if the magnitude of the position operation signal u _k exceeds the maximum allowable value L _nax , recalculation is performed. It is provided with an additional function of causing the execution to occur, and if the number of times exceeds a certain number (m), an error is generated and an error 2 output is generated.

<Effects> The present invention avoids sudden change patterns in the position operation signal that cause unreasonable distortion in the slice lip, and improves the measurement by gradually reducing the deviation from large undulations in the position operation signal profile. The profile can be brought closer to the desired setting profile step by step and matched smoothly. FIG. 5 is data obtained by simulation using a computer, and shows how the measured profile E _p gradually matches the set profile S _p as shown by a solid line → a dashed line → a dotted line.

As a result of executing control to avoid such a sudden change pattern of position operation signals, the difference in position operation signals to adjacent slice bolts is limited to a certain range, which causes the mutual interference mentioned above as the first problem. It was also confirmed that good control results can be obtained even without processing using a special compensation algorithm.

As explained above, according to the present invention, it is possible to simplify the control of sliced bolts, which has traditionally been relatively difficult to control with high precision due to mutual interference and restrictions on the amount of operation, and to obtain good control results. This makes it easier to manage the basis weight of higher quality.

[Brief explanation of drawings]

Fig. 1 is a functional block diagram showing an embodiment of the present invention, Figs. 2 and 3 are explanatory diagrams of the operation of the comparison means and smoothing means, Fig. 4 is a flowchart showing the signal processing procedure, and Fig. 5 is a computer diagram. Diagram explaining changes in measurement profile due to simulation, Part 6
The figure is an overall configuration diagram of paper machine control, Figure 7 is a perspective view showing its partial configuration, Figure 8 is a partially enlarged view of the slice rip, Figure 9 is an explanatory diagram of basic control operation, and Figure 10 is a diagram showing the basic control operation.
FIG. 11 is an explanatory diagram regarding mutual interference, and FIG. 11 is an explanatory diagram regarding restriction of the amount of operation. 5...slice lip, 12...paper, 14...
Basis weight sensor, 15...control device, 151...measurement means, 152...deviation holding means, 153...operation signal calculation means, 154...comparison means, 155...
Smoothing control means, 156... Repetition control means, 157... Output means.

Claims (1)

[Claims] 1. In a paper machine control device that controls the absolute dry basis weight to a desired profile by adjusting the opening degree of the slice bolts at multiple locations on the slice lip, the paper stock discharged from the stock inlet onto the wire part. basis weight measurement means; operation signal calculation means for calculating a position operation signal for the sliced bolt based on a deviation profile between the absolute dry basis weight measurement profile and a desired profile; and a signal difference between adjacent position operation signals. comparing means for comparing the signal difference with a first set value when the polarities are the same, and comparing the signal difference with a second set value when the polarities are different;
a smoothing means for performing a smoothing process on the profile of the position operation signal when at least one output is generated from the comparison means; and the operation signal calculation means based on the corrected position operation signal profile output of the smoothing means; repetitive control means for repeating the execution of the comparison means until the output of the comparison means is no longer generated, and an output of the operation signal calculation means when the output of the comparison means is not generated as a position operation signal for the slice bolt. An absolute dry basis weight profile control device comprising an output means for supplying an absolute dry basis weight profile.