JPH08225856A - Control of meandering of strip - Google Patents

Abstract

PURPOSE: To suitably correct meandering without promoting the meandering even if the meandering having shorter wave length than the distance between conveying rolls is developed. CONSTITUTION: In a method for controlling the meandering of a strip, in which a meandering displacement measuring meter 10 for measuring the meandering displacement of the strip 1 is arranged on the upstream side of a meandering correcting device 21 for correcting the meandering of the strip 1 under being conveyed toward the downstream side, and a feedforward control of the meandering correcting device 21 is executed based on the measured value from this measuring meter 10, the meandering displacement of the strip 1 in every moment is measured at every fixed time with the meandering displacement measuring meter 10. The average value σ of the meandering displacement is calculated from the meandering displacement group in the range of a fixed length L1 in the conveying direction of the strip 1 containing an arbitrary point P in the same direction, and the meandering correcting device 21 is controlled so that the average value σ becomes almost zero when the arbitrary point P reaches the meandering correcting device 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method for preventing strip meandering in a strip in, for example, continuous annealing equipment. The present invention relates to a meandering correction control method for correcting the meandering that occurs in a strip furnace.

[0002]

2. Description of the Related Art For example, in a continuous annealing apparatus, the traveling direction of the strip is changed by 180 degrees through strip conveying rolls installed above and below, and the strip is continuously predetermined while passing vertically through the apparatus. Has been heat treated. In this case, it is ideal that the strip always passes through the center of the transport roll, but the strip is subjected to various disturbances while passing through the inside of the device, and passes through a position deviated from the roll center to the left and right. There are often cases. In particular, in the vicinity of the welding line 2 as shown in FIG. 1, so-called "dogleg welding" is likely to occur, and meandering due to the camber of the strip 1 is likely to occur.

Due to the occurrence of such meandering of the strip 1 in the furnace, its deceleration is inevitably reduced, and not only the productivity is remarkably reduced, but also when the meandering is large, the strip edge reaches the furnace wall and damages the equipment. It may cause. As a method for correcting the meandering of the strip 1, a steering device (meandering correcting device) is installed in the middle of the equipment, and a meandering displacement amount measuring device for measuring the widthwise position of the strip is provided in the vicinity of the downstream side thereof. On the basis of the above, proportional control or integral control corrects the strip meandering at each place where the steering roll is installed.

However, in such feedback control, it is difficult to adjust the gain, and when a large gain is taken, the response is too fast and unreasonable force is applied to the strip, which causes scratches and defective shape, but is too small. There is a drawback that the response becomes poor and a sufficient meandering correction effect cannot be obtained, and the proper gain depends on the size of the strip.

In order to overcome such a problem, for example, a method of providing a sensor for measuring the strip tension distribution upstream of the steering roll and performing feedforward control of the steering roll based on the measured value is disclosed in, for example, Japanese Unexamined Patent Publication (Kokai) No. It is disclosed in Japanese Patent Laid-Open No. 5-179494.

[0006]

However, in any of the control methods including the feedforward control described above, each position is dealt with based on the measurement information at each of the finely divided positions in the longitudinal direction of the strip. It is point-based control. Therefore, for example, when the strip has an S-shaped camber having a wavelength shorter than the distance between the transport rolls, if the steering device is driven by the above-described point-corresponding control, the rolls downstream of the steering device are driven. Not only is the strip meandering in position uncorrected, but rather it may encourage meandering.

In view of such circumstances, the present invention provides a strip meandering control method capable of properly correcting the meandering without promoting the meandering even if the meandering of a wavelength shorter than the distance between the transport rolls occurs. The purpose is to do.

[0008]

In order to achieve the above object,
The present invention has taken the following technical means. That is, the method of the present invention provides a meandering displacement measuring device for measuring the meandering displacement amount of the strip on the upstream side of the meandering correcting device for correcting the meandering of the strip conveyed toward the downstream side, and measuring from this measuring device. In a strip meandering control method for performing feed-forward control of the meandering correction device based on a value, the meandering displacement amount of the strip is measured by the meandering displacement measuring device every predetermined time, and the strip An average value of the meandering displacement amount is calculated from a meandering displacement amount group in a constant length range in the same direction including an arbitrary point in the transport direction, and when the arbitrary point reaches the meandering correction device, the average value is substantially zero. The meandering correction device is controlled so as to satisfy the following (claim 1).

Further, in this case, it is preferable that the constant length for calculating the mean value of the above-mentioned meandering displacement amount is set to be equal to or less than the distance between the transport rolls for guiding the strip and more than half of this distance. (Claim 2).

[0010]

In the present invention, the point-to-point control such that the value of the meandering displacement amount detected at a certain arbitrary point P itself is set to approximately zero is not used, but the same direction including the arbitrary point P in the transport direction of the strip 1 is used. By calculating the mean value σ of the meandering displacement amount from the meandering displacement amount group in the range of the constant length L1 in, and operating the meandering correcting device 21 at the arbitrary point P so that the mean value σ becomes substantially zero. The line-to-point control is performed.

Therefore, for example, meandering of a wavelength shorter than the distance between the carrier rolls 13 occurs in the range of the constant length L1 of the strip 1, and at some arbitrary point P within the range, it is compared with other positions. Even if an extremely protruding meandering displacement amount is detected, the meandering displacement amount is detected by a constant length L.
Only the average value σ in the range of 1 is operated by the meandering correction device 21, and the meandering correction device 21 does not directly operate the excessive meandering displacement amount at the arbitrary point P.

Therefore, it is possible to very efficiently prevent the meandering of the strip 1 having a short wavelength which frequently occurs near the welded portion 2 which may not be properly corrected in the past but may be deteriorated.

[0013]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 shows a schematic configuration of continuous annealing equipment to which the present invention is applied. In the figure, the continuous annealing equipment is equipped with a heating zone 3, a soaking zone 4, a primary cooling zone 5, a reheating zone 6, an overaging zone 7 and a secondary cooling zone 8 in order from the line entry side, and a strip. The product 1 is continuously subjected to a predetermined heat treatment while passing through the inside of the furnace through the transfer rolls 13 installed above and below in each of the furnace parts 3 to 8 to become a product.

In the present embodiment, in order to correct the traveling position of the strip 1 in the continuous annealing equipment, between the heating zone 3 and the soaking zone 4 and between the primary cooling zone 5 and the reheating zone 6. ,
Two steering devices (meandering correction devices) 21 are installed. As shown in FIG. 3, the steering device 21 includes a pair of front and rear steering rolls 9, a link 9A connecting the shafts of the pair of rolls 9, and a link 9A.
And a hydraulic cylinder 11 connected to a middle portion thereof, and operating the hydraulic cylinder 11 to connect the link 9A to the strip 1
By swinging in the width direction, the steering roll 9
This is for finely adjusting the orbit of the strip 1 guided by.

Here, in the prior art, as shown in FIG. 4, the steering roll 9 is controlled so that the meandering displacement amount measured by the meandering displacement measuring device 10 installed on the downstream side of the steering roll 9 becomes zero. The amount was determined and controlled. According to such control, as shown in FIG. 5, when there is a short wavelength meander, after a certain period of time, only the offset amount in the same size as the short wavelength meander and in the opposite direction is corrected within a short range. Therefore, as shown in FIG. 6, there is almost no meandering correction function on the transport roll 13 located downstream of the steering roll 9.

In particular, when the cambers 2 and 16 which respectively bend in the opposite directions of the short wavelength as shown in FIG.
On the downstream-side transport roll 13, the controller 12 reacts with the preceding camber 2 to cause the transport roll 13 to meander, and the subsequent camber 16 itself rides on the meandering.
On the contrary, as shown in, there is a possibility that a large meandering exceeding the limit value may occur.

On the other hand, in this embodiment, as shown in FIG. 9, the steering roll 9 (steering device 2
A meandering displacement measuring device 10 is installed on the upstream side of 1), and the measuring device 10 measures the meandering displacement amount of the strip 1 every moment at regular intervals. Then, a constant length L in the same direction including the arbitrary point P in the transport direction of the strip 1
The mean value σ of the meandering displacement amount is calculated from the meandering displacement amount group in the range of 1, and the steering roll 9 is controlled so that the mean value σ becomes approximately zero. Even meandering can be corrected well.

The control method will be described in more detail below. That is, the meandering displacement measuring device 10 has a constant period t (second /
The meandering displacement amount of the strip 1 is sampled and measured at each time), and each value for each constant period t is stored in the storage operation device 20.
Is stored in The memory computing device 20 has a strip passing speed v (m /
Sec) is set and input, and in this device 20, N = sampled for a fixed length L1 (m).
An average value .sigma. Of the meandering displacement amount of L1 / v.times.t points is calculated, and a value calculated by multiplying the mean value .sigma. By a coefficient G corresponds to the constant point P in the N sampling ranges. Two
The offset amount of 1 is given to the controller 12.

The distance D between the upstream meandering amount measuring device 10 and the downstream meandering amount measuring device 10, the reference length L1 for calculating the mean value σ of the meandering displacement amount, and the strip conveying speed. From v and v, the time until the point P reaches the steering device 21 is calculated, and the steering device 21 is controlled so that the meandering displacement at that position becomes zero by the mean value σ of the meandering displacement amount.

As a result, for example, as shown in FIG. 10, even if there is a continuous short wavelength reverse direction meandering which has conventionally caused a large meandering direction, an excessive meandering displacement amount at a certain position reverses as it is. It is no longer operated as an offset amount, and it becomes possible to control to a meandering level that does not hinder the passage of the plate. The reference length L1 for calculating the mean value σ of the meandering displacement amount is the upper and lower conveyance rolls 13 shown in FIG.
It is meaningless for the meandering control mechanism to take more than the distance between a and 13b, and if the distance between the conveying rolls 13a and 13b is half or less, a sufficient correction effect for short wavelength meandering can be obtained. I will not be able to. Therefore, one between the transfer rolls
If the distance between 3a and 13b is represented by Lo, the reference length L1 must be set within the range of 0.5.times.Lo.ltoreq.L1.ltoreq.Lo.

Further, the meandering displacement measuring device 10 needs to be installed at a position upstream of the steering device 21 by the reference length L1 or more for calculating the average value σ of the above-mentioned meandering displacement amount. However, if the number of transport rolls 13 in the furnace exceeds two, the meandering displacement of the strip 1 is affected by the meandering of the strip 1 due to the roll profile, and the measured meandering displacement information cannot be correctly reflected in the meandering correction. Should be installed upstream of the steering device 21 at a distance not exceeding 2Lo.

The meandering displacement measuring device 10 may be, for example, a photoelectric tube, an image sensor, or any other electromagnetic induction type device. Based on this, the present invention does not depend on the position of the steering device 21 inside or outside the annealing furnace, and can obtain a good meandering correction effect for short wavelength meandering.

[0023]

As described above, according to the present invention,
Since it is possible to extremely efficiently prevent the meandering of the short wavelength strip 1 near the welded portion 2 which may not be properly corrected in the past but may be rather deteriorated, the frequent occurrence of the meandering at the welded portion 2 of the strip 1 can be prevented. Therefore, it is possible to significantly reduce the number of decelerations that have been performed, productivity is significantly improved, operator load is significantly reduced, and equipment damage is reduced, so that maintenance costs can be saved.

[Brief description of drawings]

FIG. 1 is a diagram showing a camber of a strip that is likely to occur at a welded portion.

FIG. 2 is a schematic view showing a general continuous annealing equipment.

FIG. 3 is a diagram showing a configuration of a general steering roll.

FIG. 4 is a diagram showing a configuration of a conventional meandering correction device.

FIG. 5 is a view showing an example of a strip having a short-wave “V” -shaped camber.

FIG. 6 is a view for explaining a meandering correction state in a conventional method of a strip having a short-wave “V” -shaped camber.

FIG. 7 shows an example of a strip having short wavelength “S” shaped camber.

FIG. 8 is a schematic diagram showing a meandering correction state of a meandering method having a short wavelength “S” -shaped camber according to a conventional method.

FIG. 9 is a diagram showing a configuration of a meandering correction device of the present invention.

FIG. 10 is a schematic diagram showing a meandering correction state in the present invention of a meandering having a short wavelength “S” -shaped camber.

FIG. 11 is a diagram illustrating a distance between transport rolls.

[Explanation of symbols]

 1 strip 9 steering roll 10 meandering displacement measuring device 13 transport roll 13a upper transport roll 13b lower transport roll 21 meandering correction device (steering device) L1 constant length (reference length) Lo roll distance P arbitrary point σ average value

Claims (2)

[Claims] 1. A meandering displacement measuring device (10) for measuring the meandering displacement amount of the strip (1) is provided upstream of a meandering correcting device (21) for correcting the meandering of the strip (1) conveyed toward the downstream side. ) Is provided, and the meandering correction device (21) is feed-forward-controlled based on the measurement value from the measuring device (10), the meandering control method of the strip comprises: The amount of meandering displacement of the strip (1) is measured at regular intervals, and the amount of meandering displacement within a range of a constant length (L1) in the same direction including the arbitrary point (P) in the transport direction of the strip (1) is measured. Calculate the mean value (σ) of the meandering displacement from the group,
The meandering correction device (21) is controlled such that the average value (σ) becomes approximately zero when the arbitrary point (P) reaches the meandering correction device (21). Method. 2. The constant length (L1) for calculating the mean value (σ) of the meandering displacement is equal to or less than the distance (Lo) between the transport rolls (13a) (13b) guiding the strip (1). The strip meandering control method according to claim 1, wherein the distance (Lo) is set to half or more.