JPH04178209A - Device for controlling bent of plate on hot finish rolling mill - Google Patents

Abstract

PURPOSE:To stably execute the hot finish rolling by picture processing a bent of the end part of steel strip at each stand of hot finish rolling by using the two dimensional picture element, measuring the bent amount and setting by controlling the difference of roll gap for the next stand. CONSTITUTION:An image pickup of the bent of top end of the steel strip picture with the CCD camera set at the rear stage of the 4th stand is transmitted to the picture processing part 1, the scanning signal is executed with binarization processing with the analogue signal processing part 2, the central value of the bent amount of the top end part of steel strip is abstracted and inputted to the strip bent amount arithmetic part 3. The arithmetic part 3 measures the camber amount and the camber length, calculates the bent rate and outputs to the levelling amount arithmetic part 4. The arithmetic part 4 obtains the levelling rate corresponding to the strip bent amount, the data is inputted to the set levelling arithmetic part 5, also the difference of the right and left levellings actually measured at the 4-th stand is inputted from the right and left deviation of gap arithmetic part 7, and the difference of the levelling of the 5-th stand is set. Based on this set value, the roll gap of the 5-th stand is corrected and controlled.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention aims to reduce the bending of a steel strip at a predetermined stand when the tip of the steel strip is pushed out from a predetermined stand during hot f1 earth pressure rolling. rolling conditions and total A on the exit side? IL
The present invention relates to a plate bending control device in a hot finishing rolling mill that controls tip plate bending by setting the work roll gap difference (leveling) in the width direction of the steel strip in the next stand according to the amount of camber.

(Prior art) Generally, a hot rolling finishing mill in a rolling mill has a fifth
As shown in the figure, 6 to 7 stands are arranged, and each stand is provided with a rolling position control device 9 that sets the rolling position of the work roll on the left and right sides in the width direction of the steel strip S, and the rolling position control device 9 is installed on each stand. A side guide device 91 is installed to restrict the movement of the steel strip in the left and right directions, and a louver 92 is also placed on the exit side to adjust the tension of the steel strip.

When a steel strip is rolled, the parts where tension is applied are rolled almost constantly and are therefore stable, but the leading and trailing ends are unstable because no tension is applied to them. That is, bending occurs at the leading and trailing ends, and when it becomes large, so-called "pecking" occurs, resulting in poor rolling, and in some cases, rolling becomes impossible.

In the past, there was an idea to solve such problems using automatic control technology, but this has not been realized because the benefits are relatively small in terms of investment efficiency. On the other hand, it is possible to measure the camber in total by 711 using a width meter, lateral vibration meter, etc., but it is technically quite difficult to determine the 1-1 camber between stands online. Camber: Using an optical measuring instrument, measure the board width at a specific position (usually the center point) at 3 fixed points equally spaced, and calculate the amount of local chamfer)
Even if a stand is used, there are problems with placement and responsiveness in spaces where the distance between stands is small.

(Problems to be Solved by the Invention) As described above, currently there is no suitable means for measuring the bending of the leading and trailing ends of the steel strip between the stands in a hot finishing rolling mill.

In view of the current situation, the present invention measures the bending length (camber) of the leading and trailing ends of the steel strip with high precision and high responsiveness using an optical imaging means using a two-dimensional imaging device such as a CCD. The purpose of this invention is to provide a plate bending control device in a hot finishing rolling mill that measures well.

(Means for Solving the Problems) In order to achieve the above object, the present invention summarizes the following configuration. In other words, (1) a camera section that converts the steel strip in a predetermined tapping stand of a hot finishing rolling mill into a video signal with a two-dimensional imaging device through a lens, and the video output signal of the two-dimensional imaging device is converted into a video signal for each line scanning signal; An analog signal processing unit that processes signals and outputs the median value in the width direction of the steel strip, and a complete plate bending calculation unit that calculates the amount of plate bending by applying an approximate curve to the median value in the width direction and a predetermined longitudinal position of the steel strip. an image processing section consisting of an image processing section, a leveling amount calculation section that calculates a correction leveling amount from rolling characteristics according to a plate bending amount signal of the image processing camber meter, and a left and right rolling position of the predetermined stand: lA.
A gap left/right deviation calculation section that obtains a work roll gap signal from the I device and calculates its deviation value, a correction leveling amount from the leveling amount calculation section, and a left and right work roll gap calculation section from the gap left and right deviation calculation section. A set leveling amount calculating section calculates the leveling setting amount for the next stand and subsequent stands according to the deviation value, and a left and right leveling star of the work roll is placed on the next stand and subsequent stands according to the leveling setting amount from the set leveling amount calculating section. A plate bending control device for a hot finishing rolling mill, characterized by comprising a rolling reduction position control device for correction.

(2) - The plate in the hot finishing rolling mill described in the preceding paragraph, characterized in that when determining the leveling amount set value in the set leveling amount calculation section, it is determined using a constant rule of leveling amount / exit side plate thickness between stands Bending control device.

(3) a lowering position control device that corrects the left and right leveling amount of the work roll in the stands after the next stand according to the leveling setting amount from the setting leveling amount calculating section;
The heat IL'J tf described in the preceding paragraph is characterized by being constituted by a side guide opening degree control device that corrects the opening degree of the next stand of the leveling correction stand. be.

The present invention will be explained in detail below.

FIG. 1 shows the flow of the control device of the present invention,
A two-dimensional image sensor such as a television camera or a CCD surface element is used as a light receiving element of the camera section 1 above the exit side of a predetermined stand F1 for hot finishing rolling, and a hot steel strip as shown in FIG. The tip image is taken with the line scanning direction substantially matching the width direction of the steel strip. As shown in Fig. 3, it is desirable to set this two-dimensional image sensor so that the steel strip extending from a predetermined stand enters the image pickup device.If necessary, the number of image sensors is not limited to one, but multiple. You may provide more than one.

The output signal from the light receiving element of the camera IO is transmitted to the image processing unit 1
This image processing section 1 is manually operated by an analog signal processing section 2.
and a plate bending amount calculating section 3.

The analog signal processing unit 2 processes the output signal of the light receiving element for each line scanning signal, extracts and outputs the median value in the steel strip width direction, and sends this median value to the plate bending amount calculation unit via a human interface. 3, and based on the combinations (n pieces) of the median value for each line scanning signal and the line scanning position signal (longitudinal position of the steel strip),
The amount of board curvature (camber) is calculated by applying a circular or elliptic function to a large amount of data.

The output from the analog signal processing section is not limited to the median value, but may be the side end chain of the M band, for example, if the steel strip width is a constant value.

The amount of camber is determined by narrowing the interval of line scanning, which is measured by averaging the amount of chiten bar on several surfaces after the length of the steel strip that has started from the predetermined stand Fi reaches a predetermined length. As the number of measured values (n) increases, the accuracy of the camber amount improves.

In this way, the output signal from the plate bending amount calculating section 3 is manually input to the leveling calculating section 4. In this leveling calculation unit 4, for example, as shown in FIG. 4, based on many experimental results or actual results, the relationship between the amount of plate bending of the input side steel strip and the leveling ratio (leveling amount / exit side thick plate) is proportional. Since there is a close relationship, the correction leveling amount is measured by applying such rolling characteristics, and this signal is sent to the setting leveling amount calculating section 5.
Enter. On the other hand, receiving the left and right working roll gap amount signals from the rolling position measuring device included in the left and right rolling position control device 6 of the finishing rolling mill Fi, the signal from the calculating section 7 that calculates the left and right roll gap deviation is transmitted. The set leveling amount calculation unit 5 inputs the setting leveling amount calculation unit 5, and the calculation unit calculates the sum together with the correction level signal from the leveling amount calculation unit 4, and sets the subsequent stands after the next stand (which should be corrected).
Calculate the leveling amount. This calculation result (signal) is the lower position measuring device v! in the subsequent stands after the next stand.
! 8, and the leveling amount from the next stand onwards is corrected to a value that will not cause camber.

When determining the leveling amount setting value in the setting leveling calculation section, control accuracy can be improved by determining it using the law that the leveling amount/output side plate thickness is a constant value between stands.

Furthermore, the left and right leveling amount of the work roll is compensated for the next stand and subsequent stands according to the leveling amount setting value, and slight (negligible)
When a bend m occurs, it is effective to adopt a method of simultaneously correcting the opening degree of the entrance side guide of the stand next to the corrected stand.

Among the finishing rolling machines, this plate bending 1. Theoretically, it is desirable for the designated stand on which the control device is installed to be close to the final stand, but the steel strip before the final stand is faster and the image processing unit may not be able to respond sufficiently, so this is not practical. In general, it is preferable to select the area before the middle stand. It is also often appropriate to carry out the test at a plurality of predetermined stands.

FIG. 2 shows the specific operation of the above-described signal processing section of the present invention. That is, first, a CCD camera 10 installed on the exit side of the rough rolling mill R1 images the rolled steel strip S onto a CCD two-dimensional image sensor 12 through a lens 11 built into the camera, and the image output from the CCD 12 is performed. When the signal is input to the monitor M, an image of the steel/strip S is generated using the line scanning signal 13 as shown in the figure. This CC
The output signal of D12 is manually input to the analog signal processing section 2. The analog signal processing unit 2 receives C, which is a video signal of the steel strip.
Line scanning signals 211, 213, . . . each line scanning signal 13 in the output signal of the CD 12 has the horizontal axis as the time axis and the vertical axis as the voltage or brightness axis.
A block 21 converts this into a threshold M2J2.214 and compares it with a comparator, and as a result the line scanning signals 211.2H,...
23.225, and the ON level corresponding to the width dimension of the steel strip is 222.224.226. Block 2 that becomes...
2 and its ON level 222.224.22[i,...
Median value of 231, 232.233. . . . by an amplifier circuit. The analog signal processing unit 2 or 3 calculates the median value of the steel strip in each line scanning signal, 231.232.233. ... (Specifically, a signal corresponding to the time from the base point of each line scanning signal to the median value of the steel strip) is sequentially output.

The plate bending amount calculation unit 3 that receives the output outputs the output signal as a digital signal via the input/output interface, and converts the output signal into a digital signal to calculate the steel strip center ti of each line scanning signal.
=, = The line scanning signal and the longitudinal position signal of the representative steel strip (stored in advance) are combined and memorized, and after the tip of the steel strip reaches a predetermined position, the memorization of several screens is performed. From the combination data, apply a circular or elliptical function to the boat fishing using the minimum approximation method, targeting only those with a effect, and calculate the camber necessary to calculate the plate bending ff1ca+ of the screen from the approximate function. m
l) and a block 31 for determining the camber length;
A block 32 calculates the sheet bending EiCal for each screen from g and L, calculates the average value of only valid values several times among each Cat, and calculates it as the sheet bending fik C of the steel strip.
It is composed of a block 33 denoted by a.

The plate-curved melon calculation section 3 uses a microcomputer because it involves numerical calculations, but it is desirable that the calculation speed be as fast as possible from the viewpoint of responsiveness.

(Example) In a 6-high hot finishing mill in which a CCD camera is placed at the rear stage of each of the 1st to 4th stands, an i
The leveling amount was corrected at the fifth stand.

The image of the tip of the steel strip captured by the CCD camera installed at the rear of the 4th stand is transmitted to the image processing section 1 shown in Fig. 2, and the analog signal processing section 2 converts the scanning signal into 2t.
The amount of bending (camber) at the tip of the steel strip is
) is extracted, and this signal is manually input to the board bending amount calculating section 3 which performs digital processing. In the calculation unit 3, the input signal is received by the microcomputer via the interface, and the camber mp (dragon) and camber length L are calculated.
(rn) is set as 1#I, and the curvature ratio Ca-II/L is calculated. In the actual measurement, the board bending of DS with camber ffill-too l and camber length L = 2m was measured, so C
a −50 dragon/m is output to the leveling amount calculation section 4.

In the leveling amount calculating section 4, the human power from the plate bending amount calculating section 3, that is, the plate bending mCCa-5011IIl/m)
The leveling rate Δh, /h4 (where h4 - fourth stand exit side plate thickness, Δh4 - fourth to fourth stand ring legs, that is, the gap difference between DS and WS (work side)) is determined. The calculation unit 4 calculates, based on experimental or actual DM data, that the predetermined stand outlet plate bending mN/L (DS, WS) and the leveling ratio Δh/h have a constant proportional relationship as shown in FIG. Something has been entered. That is, from this input data, the leveling amount calculation section 4 calculates Δh 4/h 4 - 0.038. Next, this data is input manually to the setting leveling calculation unit 5, and the actually measured left and right (D
S, WS) The leveling difference of 0.01m+* is input manually from the gap left/right deviation calculation unit 7, and based on the re-input result, the leveling difference of DS-WS of the 5th stand is 0.04B.
In other words, ((1,01+0.038)) is set.Based on this set value, the left and right rolling position control device of the fifth stand is operated, and the roll of the fifth stand is operated before the end of the steel strip is bitten. Correct gap control.

As a result, board bending (camber) on the exit side of the fifth stand was prevented.

(Effects of the Invention) As explained above, the present invention uses a two-dimensional imaging device such as a CCD to image-process the bending of the end of the steel strip in each stand during hot finishing rolling, and determines the amount of bending. It is possible to control and set the roll gap difference of the next stand with quick response and with high precision, and hot finish rolling can be carried out extremely stably.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the apparatus of the present invention, Fig. 2 is a diagram showing a detailed implementation flow of the main parts of the present invention, Fig. 3 is a diagram showing the situation of the steel strip head on the exit side of the rolling stand, and Fig. 4 is the bending amount and leveling rate (ratio) of the exit steel strip (tip) at a specified rolling stand.
FIG. 5 is a diagram showing the arrangement of each stand of the hot rolling mill 11.

Claims (3)

[Claims] (1) A camera unit that converts the steel strip at the exit side of a predetermined stand of a hot finishing mill into a video signal with a two-dimensional image sensor through a lens, and the video output signal of the two-dimensional image sensor as a line scanning signal. an analog signal processing unit that processes and outputs the widthwise median value of the steel strip; and a plate bending amount calculating unit that calculates the plate bending amount by applying an approximate curve to the widthwise median value and a predetermined longitudinal position of the steel strip. an image processing unit comprising an image processing unit, a leveling amount calculation unit that calculates a correction leveling amount from rolling characteristics in accordance with the plate bending amount signal of the image processing camber meter, and a work roll gap signal from the left and right rolling position measuring device of the predetermined stand. the left-right deviation calculation section of the gap which calculates the deviation value, the correction leveling amount from the leveling amount calculation section and the left-right deviation value of the work roll gap from the left-right deviation calculation section of the gap, from the next stand onwards. A set leveling amount calculation unit that calculates the leveling set amount in the stand, and a reduction position control device that corrects the left and right leveling amount of the work roll in the stands after the next stand according to the leveling setting amount from the set leveling amount calculation unit. A plate bending control device for a hot finishing rolling mill, characterized in that: (2) The hot finishing rolling mill according to claim 1, wherein the leveling amount set value in the set leveling amount calculating section is determined using a constant rule of leveling amount/output side plate thickness between stands. Plate bending control device. (3) a lowering position control device that corrects the left and right leveling amount of the work roll in the stands after the next stand according to the leveling setting amount from the setting leveling amount calculating section;
2. The plate bending control device for a hot finishing rolling mill according to claim 1, further comprising a side guide opening degree control device for correcting the opening degree of a stand next to the leveling correction stand.