JPH07124625A - Device for controlling meandering in passing line - Google Patents

Abstract

PURPOSE:To prevent rollout from developing in the course of meandering control, in which the meandering of a steel sheet is corrected by plural meandering correction machines arranged along the continuous passing line of steel sheets, in the case where a meandering is caused so large that specific meandering correction machines have reached their correction limits. CONSTITUTION:The meandering quantity at the position of each correction machine is obtained from plural meandering correction machines 20. The position (i) is specified of the correction machine with the largest meandering quantity. The target value for control of other meandering correction machines 20 is changed in the direction of decreasing that largest meandering quantity. Meandering is corrected without using the correction machine 20 (i) that has the large control input, and the responsiveness is recovered of that meandering correction machine 20 (i).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a meandering control device used in a continuous sheet passing line such as an electrolytic cleaning line for steel sheets and a hot dip coating line.

[0002]

2. Description of the Related Art In a continuous steel sheet passing line, it is indispensable to suppress meandering of the steel sheet for stable operation. Therefore, a plurality of meandering correction machines are arranged along the threading line, and in JP-A-4-300009, each meandering correction machine is based on the meandering amount information obtained from the plurality of meandering correction machines. A meandering control method is disclosed in which the central controller centrally manages the.

In this method, each meandering correction device basically detects the amount of meandering at each disposition point and controls each steering mechanism so that the amount of meandering becomes a target value. Here, the target value is set to 0, that is, a so-called zero offset state in which the plate center coincides with the line center and is fixed. Then, when the meandering correction device of the i-th stage causes the meandering, the central controller (i
The +1) stage meandering correction machine is instructed in advance to perform a steering operation in a direction in which the meandering is suppressed to enhance the response of the meandering control. Also, the width of the meandering is prevented.

[0004]

In such a conventional meandering control method, the intended purpose is achieved when the steel sheet is moving while maintaining a state of zero offset. However, an abnormal situation that causes a large meandering, for example, base material factors such as poor flatness of the steel plate, camber, line tension / speed, levelness of the roll in the line, operation factors such as friction force between the roll surface and the steel plate, and equipment factors. Due to the synergistic variation, as shown in FIG.
When the amount of meandering reaches the correction limit at 0 (i), the steel plate edge portion eventually progresses to a state called rollout in which the steel plate edge part separates from the roll, and often causes plate breakage.

In other words, due to the synergistic effect of the meandering correction disturbance, when the operation amount for correcting the meandering becomes extremely large as compared with the other arrangement points and once reaches the correction limit, the above-mentioned feed With forward control, it is difficult to avoid rollout. This is because when the meandering correction machine reaches the correction limit, the margin of the operation amount becomes insufficient, so that the control response is extremely deteriorated, and in the extreme case, the control is not performed.

An object of the present invention is to provide a meandering control device capable of quickly correcting the meandering even when a large meandering of a particular meandering correcting machine reaches a correction limit.

[0007]

A meandering control device according to the present invention has a meandering amount detector which is arranged along a sheet passing line, each of which has a meandering amount detector for detecting the meandering amount of the plate, and a steering wheel for controlling the meandering amount. A plurality of meandering correction machines having a mechanism, the meandering amount distribution in the line is calculated from the meandering amount of each correction machine arrangement point input from the plurality of meandering correction machines, and the correction machine arrangement point of the maximum meandering amount is specified, A central controller that shifts the control target value in another meandering correction machine in the direction of reducing the amount of meandering.

[0008]

[Operation] Even when the specific meandering correction machine reaches the correction limit,
By changing the control target value in another meandering corrector and changing the meandering amount distribution in the line, the meandering is eliminated without depending on the meandering corrector that has reached the correction limit.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a system diagram showing the configuration of an example of a meandering control device embodying the present invention, FIG. 3 is a distribution diagram of the amount of meandering and roll displacement for explaining the operation, and FIG. 4 is a change with time of the amount of meandering and roll displacement. 2 is a time chart showing.

As shown in FIG. 2, the present meandering control device centrally manages a plurality of meandering correction machines 20, 20, ... Arranged at predetermined intervals in the longitudinal direction of the continuous sheet passing line of the steel sheet 10. And a central controller 30. The meandering correction machine is shown in the i-th stage and the (i-1) -th stage.

Each meandering correction machine 20 has a meandering amount detector 21 for detecting the meandering amount of the steel plate 10, and a steering roll 22 for correcting the meandering of the steel plate 10. The steering roll 22 is operated by a drive motor 23, and the operation amount is detected by an operation amount detector 24 using PLG.
The outputs of the meandering amount detector 21 and the manipulated variable detector 24 are input to the control unit 25. The control unit 25 compares the meandering amount with the target value to calculate the operation amount, and controls the drive motor 23 so that the operation amount matches the actual operation amount.

The central controller 30 is given from each controller 25 the variables of the meandering amount and operation amount of each correction machine arrangement point. Further, the line speed, the plate tension at each correction machine arrangement point, and the like are given as variables, and the distance between the correction machine arrangement points is given as a constant. Further, the permissible meandering amount and the permissible operating amount at each correction machine arrangement point are inputted as data, and the meandering distribution calculation procedure and the meandering distribution changing procedure are inputted in advance as a software processing program. Then, an instruction is given to each control unit 25 according to the calculation result based on the processing process. The contents will be specifically described below.

Consider a case where the amount of meandering exceeds an allowable range at point i, as indicated by a broken line in FIG. In that case, in the meandering correction machine 20 at point i, the steering roll 22 is operated to the limit in the direction in which the meandering is eliminated, and therefore the roll displacement reaches the limit of the allowable range. Since there is no room for roll displacement, there is a risk of rollout if left unattended.

In such a state, the central controller 30
As shown in FIG. 4, it is confirmed that there is a sufficient margin Δd for roll displacement at the point (i-1) in the previous stage, and (i-1)
The control target value f (i-1) in the meandering correction machine 20 at the point is shifted from the zero offset in the direction in which the meandering at the point i is eliminated. Within a range in which the roll displacement margin Δd at the point (i-1) does not become 0, the shift amount of the control target value f (i-1) is kept constant for a certain time until the meandering excess amount ΔL at the point i becomes 0. Increase gradually in cycles.

Thus, as shown by the solid line in FIG. 3, at point i, the amount of meandering is reduced to within the allowable range, and there is a margin in roll displacement to enable operation. However, at point (i-1), the amount of meandering becomes large and the margin of roll displacement also becomes small.
If this causes a problem, the same operation is performed at the point (i-2) in the previous stage.

As described above, the central controller 30 includes the control units 2
Based on the information of meandering amount and operation amount obtained from 5,
By positively shifting each target value, the meandering amount distribution is quickly converged within the allowable range without using the meandering correction machine 20 at the point i which has reached the operation limit. As a result, the output saturation of the meandering correction machine 20 at the point i is eliminated, and the responsiveness thereof is rapidly recovered. Therefore, rollout is avoided.

The above control is shown in response to FIG. 1A, which is shown in FIG. It can be seen that the no-control state is immediately canceled by changing the meandering amount distribution by shifting the target value. When the meandering amount distribution is converged within the allowable range, the target value is returned to zero offset.

The shift of the target value is not limited to the constant value method,
It is possible to consider that the control of the meandering amount at the point (i-1) propagates to the point i depending on the line speed or the like, or to change the shift amount according to the magnitude of the plate tension. These allow a smoother and more stable change of the meandering amount distribution.

Although the center convergence of the meandering amount distribution has been described above, the changing speed thereof should be kept constant or less, or the target of the meandering amount distribution should be set and the meandering amount distribution should be controlled to the target. Is also possible.

[0020]

DISCLOSURE OF THE INVENTION A meandering control device for a sheet passing line according to the present invention selects a meandering correction machine having a maximum operation amount,
By dynamically changing the meandering amount distribution by shifting the control target value in other meandering correction machines, saturation of the control output in each meandering correction machine is eliminated, and a large margin is given to the manipulated variable to increase the control gain. Increase the size to improve responsiveness. Therefore, it is possible to prevent the rollout and the plate breakage resulting from the rollout even when a large disturbance is applied.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an outline of a control operation in the present invention.

FIG. 2 is a system diagram showing the configuration of an example of a meandering control device embodying the present invention.

FIG. 3 is a distribution diagram of a meandering amount and a roll displacement for explaining the operation.

FIG. 4 is a time chart showing changes in meandering amount and roll displacement over time.

[Explanation of symbols]

 10 Steel Plate 20 Meandering Corrector 21 Meandering Detector 22 Steering Roll 23 Drive Motor 24 Manipulation Detector 25 Control Part 30 Central Controller

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Claims (1)

[Claims] 1. A meandering amount detector, which is arranged along a sheet passing line, each detecting a meandering amount of the plate, and
Correct the maximum meandering amount by obtaining the meandering amount distribution in the line from the meandering amount of the plurality of meandering correction machines with steering mechanism that controls the meandering amount and the meandering amount of each correction machine input point input from the plurality of meandering correction machines. A meandering control device in a sheet passing line, comprising: a central controller that specifies a machine placement point and shifts a control target value in another meandering correcting machine in a direction to reduce the meandering amount.