JP4854602B2 - Method for detecting the shape of rolled material - Google Patents

Description

  The present invention relates to a rolled material shape detection method for detecting a rolled material shape profile.

Conventionally, Patent Document 1 discloses a method for detecting a shape profile of a rolled material rolled by a rolling mill. In the method for detecting the shape of a rolled material in Patent Document 1, a shape detection roller capable of measuring the tension of the rolled material is brought into contact with the rolled material, and the shape profile of the rolled material is detected based on the tension of the rolled material detected by the shape detection roller. is doing.
As shown in Patent Document 1, in a method of measuring a tension by bringing a shape detection roller into contact with a rolled material, a sensor element is generally used to measure the tension of the rolled material. The heat-resistant temperature of this sensor element is approximately 300 ° C., and in the case of hot rolling where the temperature of the rolled material exceeds 300 ° C., the technique of Patent Document 1 may not be applied.

Therefore, as shown in Patent Document 2, various techniques for detecting the shape of the rolled material in the case of hot rolling have been considered.
In the flatness measuring apparatus for a steel sheet of Patent Document 2, a non-contact type distance meter is arranged on the lower side of the rolled material, and the shape profile of the rolled material is detected by measuring the distance to the surface of the rolled material. It was. In the technique of this Patent Document 2, although the flatness of the rolled material (whether the rolled material is undulated in the thickness direction) can be detected, the detailed shape profile of the rolled material cannot be detected. It was. Patent Documents 3 and 4 disclose techniques capable of detecting the shape profile of a rolled material.

The technique of patent document 3 and patent document 4 uses the optical cutting method, irradiates slit light with respect to a hot rolling material, images the reflected light from a rolling material with an imaging device, and imaged rolling The shape profile of the rolled material is detected by processing the image of the material.
JP-A-7-185634 JP-A-4-143608 JP-A-48-59858 JP 61-40503 A

In the techniques according to Patent Documents 3 and 4, it is possible to analyze data measured in advance and detect a rough shape profile of the rolled material from the analysis data, but the detected shape profile of the rolled material is detailed. The fact is that information cannot be obtained, that is, the characteristics of the shape profile cannot be obtained.
In view of the above problems, an object of the present invention is to provide a method for detecting the shape of a rolled material that can very easily detect the characteristics of the shape profile of the rolled material after rolling.

In order to achieve the above object, the present invention has taken the following measures. That is, the technical means for solving the problems in the present invention is a rolled material shape detection method for detecting characteristics of a shape profile obtained by measuring a rolled material rolled by a rolling mill, and the rolling is performed in advance. A basis function capable of expressing the flatness pattern of the material is defined, the measured shape profile of the rolled material is series-expanded with the basis function, and the shape profile characteristic of the rolled material is detected based on the coefficient of the series expansion. In the point.
It is preferable to employ an orthogonal function as the basis function. Moreover, it is preferable to employ a Chebyshev function having orthogonality as the basis function.

The series expansion coefficient is preferably used for rolling control of a rolling mill.
The most preferable rolled material shape detection method of the present invention is a rolled material shape detection method for detecting characteristics of a shape profile obtained by measuring a rolled material rolled by a rolling mill, A basis function capable of expressing the flatness pattern of the rolled material is defined, and the thickness change along the width direction of the measured shape profile of the rolled material is series-expanded by the basis function, and based on the coefficient of the series expansion Some of them detect the characteristics of the shape profile of the rolled material.
The most preferable rolled material shape detection method of the present invention is a rolled material shape detection method for detecting characteristics of a shape profile obtained by measuring a rolled material rolled by a rolling mill, wherein the measurement The change in thickness along the width direction of the shape profile of the rolled material is represented by a basis function capable of expressing an ear wave, a basis function capable of expressing a medium elongation, and a composite elongation or quarter combining the ear wave and the medium elongation. There is one in which series expansion is performed with a basis function capable of expressing elongation, and a shape profile characteristic of the rolled material is detected based on a coefficient of the series expansion.

  According to the present invention, the characteristics of the shape profile of the rolled material after rolling can be detected very easily.

Hereinafter, a method for detecting the shape of a rolled material according to the present invention will be described.
FIG. 1 is a diagram showing a device configuration from a rolling mill 1 to a shape detection device 2, a cooling device 3, and a winding device 4. In addition, in the transfer direction of a rolling material, the side (winding device 4 side) which is transferred is called a downstream side, and the opposite side (rolling machine 1 side) is called an upstream side.
The rolling mill 1 is for rolling the rolled material 5 and is disposed on the most upstream side. The pair of work rolls 6 and 6, the pair of backup rolls 7 and 7 for backing up the work rolls 6 and 6, and the rolling mill 1 and a rolling control device 8 for controlling the rolling speed of the rolled material 5. The cooling device 3 cools the rolled material 5 and includes a plurality of continuous cooling banks 9 and 9, and discharges cooling water from cooling nozzles 9 a provided in the respective cooling banks 9 and 9. Thus, the rolled material 5 is cooled. The winding device 4 winds the rolled material 5 cooled by the cooling device 3. ,
As shown in FIGS. 1 and 2, the shape detection device 2 measures the shape profile of the rolled material 5 rolled by the rolling mill 1, and with respect to the shape profile obtained by the measurement, ear waves, medium elongation, The characteristics of the shape profile of the rolled material 5 can be detected by analyzing how much flatness patterns such as composite elongation and quarter elongation are included.

The shape detection device 2 is disposed between the rolling mill 1 and the cooling device 3, and an irradiation unit 10 that irradiates slit light, an imaging unit 11 that images reflected light from the irradiated slit light, and shape detection control. Device 12.
The irradiating unit 10 generates slit light by passing point laser light through a cylindrical lens, and irradiates the slit light toward the surface so as to face the width direction of the rolled material 5.
The imaging unit 11 captures reflected light reflected from the surface of the rolled material 5 when irradiated with slit light, and is composed of, for example, a two-dimensional CCD camera. The captured image is transmitted to the shape detection control device 12. The angle (holding angle) formed by the laser projection axis of the irradiation unit 10 and the optical axis of the imaging unit 11 is set in a range of 30 ° to 150 °.

The shape detection control device 12 analyzes the image transmitted from the imaging unit 11 and detects the shape profile of the rolled material 5 from the image or controls the imaging unit 11. The shape detection control device 12 controls the imaging unit 11. 13, an analysis computer 14 for analyzing an image, and a monitor 15 for displaying a captured image or the like.
The control computer 13 includes an imaging control unit 16 that adjusts the luminance of the imaging unit 11 and controls lens aperture and the like, and an image storage unit 17 that stores the captured image. The image storage unit 17 is configured by, for example, a frame memory, and stores a captured image with 640 × 480 pixels.

The analysis computer 14 includes an image recognition unit 18 and an analysis unit 19.
The image recognition unit 18 extracts the line from the reflected light (slit light) in the image stored in the image storage unit 17, and uses the coordinates of the line as two-dimensional (x axis, z axis) image coordinate data. Remember. The x axis in the image coordinate data corresponds to the width direction of the rolled material 5, and the z axis in the image coordinate data corresponds to the transport direction of the rolled material 5.
Further, the image recognition unit 18 obtains a shape profile using the principle of triangulation based on the image coordinate data, normalizes the obtained shape profile, and normalizes coordinate data of two dimensions (x axis, y axis). Remember as.

The horizontal axis (x axis) in the normalized coordinate data stored in the image recognition unit 18 corresponds to the width direction of the rolled material 5, and the horizontal axis (y axis) in the normalized coordinate data is the rolling. It corresponds to the thickness direction of the material 5.
FIG. 3 shows a normalized shape profile. As shown in FIG. 3, for example, the image recognition unit 18 normalizes the width direction of the shape profile to coordinates of ± 1, and normalizes the thickness direction of the shape profile to coordinates where the lower limit is 0 and the upper limit is +1. .
The analysis unit 19 includes a basis function that can express the flatness pattern of the rolled material 5 such as ear waves, medium elongation, and quarter elongation. By using this basis function, the normalized shape profile is expanded in series, so that the degree of the flatness pattern included in the shape profile can be obtained and the shape profile characteristics of the rolled material 5 after rolling can be detected. .

  As the basis function, the Chebyshev function represented by the equation (1) is adopted.

The Chebyshev function is a function that most easily expresses the flatness pattern of the rolled material 5 such as ear waves, medium elongation, and quarter elongation.
The Chebyshev function and the flatness pattern of the rolled material will be described.
FIG. 4 illustrates the Chebyshev function from the 0th order to the 4th order. In the following description, the horizontal axis of the figure corresponds to the width direction of the rolled material 5, and the vertical axis of the figure represents the rolled material 5. This is considered in correspondence with the degree of flatness in the thickness direction.
Thus, when the relationship between the Chebyshev function from the 0th order to the 4th order and the shape profile of the rolled material 5 is seen, the rolled material 5 is in a recessed state within a range in which the value indicating the degree of flatness is negative. It can be considered that the rolled material 5 is protruding in a range where the value indicating the degree of flatness is positive.

For convenience of explanation, hereinafter, a value indicating the degree of flatness may be simply referred to as flatness. As shown in FIG. 4A, the 0th-order Chebyshev function is T ₀ (x) = 1 and is a straight line having a constant value, so that the offset due to the installation accuracy of the irradiation unit 10 and the imaging unit 11 is offset. It is possible to represent a disturbance of (position shift).
As shown in FIG. 4B, the first-order Chebyshev function is a straight line having a constant inclination with T ₁ (x) = x, and is therefore caused by the installation accuracy of the irradiation unit 10 and the imaging unit 11. Can be expressed.

As shown in FIG. 4C, the second-order Chebyshev function T ₂ (x) has the smallest flatness at the base point of −1, and the maximum value (+1) and the minimum value (−1) on the horizontal axis. Since the flatness is the largest curve at +1, it is possible to express an ear wave that rises at both ends in the width direction of the rolled material 5.
Further, since the secondary Chebyshev function T ₂ (x) has a flatness at the base point of +1 and the flatness at the maximum value and the minimum value of the horizontal axis can be −1, the center of the rolled material 5 in the width direction It is possible to express the middle elongation that the club side rises.

As shown in FIG. 4D, the cubic Chebyshev function [T ₃ (x)] has a flatness of 0 → + 1 → −1 in the range on the left side from the base point, and the flatness in the range on the right side. Since it is a curve from 0 → -1 → 0, it is possible to express a state in which there are contrasting irregularities on both sides of the rolled material 5 from the center of the rolled material 5.
As shown in FIG. 4E, the fourth-order Chebyshev function [T ₄ (x)] has a flatness of +1 for the minimum value (−1) on the horizontal axis and an intermediate value (− on the negative side of the horizontal axis). -1 at the vicinity of 0.7, +1 at the base point, -1 at the intermediate value on the positive side of the horizontal axis (around +0.7), and +1 at the maximum value of the horizontal axis (+1). It is possible to express a composite elongation that is a combination of the intermediate elongation and the intermediate elongation.

The fourth-order Chebyshev function [T ₄ (x)] has a flatness of −1 for the minimum value (−1) on the horizontal axis, +1 for the intermediate value on the negative side of the horizontal axis (around −0.7), Since the curve is −1 at the base point, +1 at the intermediate value on the positive side of the horizontal axis (around +0.7), and −1 at the maximum value (+1) on the horizontal axis, the quarter elongation is obtained by inverting the composite elongation up and down. Can be expressed.
When the Chebyshev function represented by Expression (1) is used, the shape profile y is as shown in Expression (2).

  In this embodiment, in Expression (2), N is an expansion coefficient and N = 4, and Expression (2) 'is obtained. This expression (2) ′ is included in the analysis unit 19. The expansion coefficient N is preferably in the range of 4-6.

The analysis unit 19 performs series expansion of the shape profile of the rolled material 5 by Equation (2) ′, and obtains coefficients C _{0 to} C ₄ for series expansion. That is, the coefficients C _{0 to} C ₄ are obtained by expanding the shape profile with the Chebyshev function.
In obtaining the series expansion coefficient, the coefficient is obtained by using the orthogonal condition in the Chebyshev function expressed by the equation (3).

  From equation (3), the coefficient of series expansion can be expressed as in equation (4).

The integration represented by the equation (4) can be easily calculated with practical accuracy at several integration points by, for example, Gauss's numerical integration method. In the equations (3) and (4), ε _n is ε _n = 2 when n = 0, and ε _{n is} other than n = 0 (n = 1, 2, 3,...). _n = 1.
The analysis unit 19 transmits the coefficient of series expansion obtained by the equation (4) and its change over time to the shape profile of the rolled material 5 to the rolling control unit or displays it on the monitor 15.
The operation of the shape detection device 2 and the method for detecting the shape of the rolled material 5 in the present invention will be described with reference to FIG.

As shown in FIG. 5, when the rolled material 5 is rolled by the rolling mill 1 and the tip of the rolled material 5 comes out from the work rolls 6, 6 on the most downstream side, it is directed toward the surface of the rolled material 5 by the irradiation unit 10. Then, the slit light is irradiated (S1).
The reflected light reflected from the surface of the rolled material 5 is imaged by the imaging unit 11, the image is transmitted to the control computer 13 and stored in the image storage unit 17, and the image is transmitted to the analysis computer 14 ( S2). A line of reflected light is extracted from the image sent from the imaging unit 11 via the control computer 13 by the image recognition unit 18 of the analysis computer 14 (S3).

The extracted line of reflected light is converted into coordinates by the image recognition unit 18 and stored as image coordinate data, and the shape profile is calculated by applying the principle of triangulation to the reflected light (light cutting line) ( S4). The calculated shape profile is normalized (S5).
Normalized coordinate data obtained by normalizing the image coordinate data is transmitted to the analysis unit 19, and the shape profile of the rolled material 5 is expanded in series using the basis function provided in the analysis unit 19 (S6). A coefficient obtained by series expansion of the shape profile of the rolled material 5 is stored in the analysis computer 14 or the like (S7).

Coefficients obtained by expanding the shape profile of the rolled material 5 from the analysis computer 14 of the shape detection control device 12 are transmitted to the monitor 15 to display the degree of each coefficient, and the coefficients are transmitted to the rolling control unit 8. (S8). The rolling control unit 8 adjusts the rolling load and the roll gap based on the coefficient.
It is determined whether or not the rolling material 5 is passing through the image picked up by the imaging unit 11 based on whether or not the slit light is at a predetermined position. If there is a slit light), the process returns to S2, and imaging of the rolled material 5 is repeated (S9). If the rolling material 5 is not passing through (there is slit light at a predetermined position), the imaging by the imaging unit 11 is stopped and the shape detection is ended.

FIG. 6 shows the distribution of coefficients when the shape profile of the rolled material 5 from the front end to the rear end of the rolled material 5 is analyzed by the shape detecting device 2 and the shape detecting method of the rolled material 5 of the present invention. .
As shown in FIG. 6, the characteristics of the shape profile of the rolled material 5 can be detected by expressing the degree of appearance of each coefficient in the series expansion of the Chebyshev function.
For example, as shown in FIG. 6 (c), since the coefficient C2 increases toward the plus side as the rolled material 5 goes to the rear end (tail end), the rolled material 5 gradually becomes an ear wave state. You can see that. Further, when looking at the balance of each coefficient at each position in the rolled material 5, for example, when the coefficient C4 is very large compared to other coefficients, the shape profile of the rolled material 5 is a quarter elongation or a composite elongation. It can be seen that

  As described above, a basis function capable of expressing a plurality of flatness patterns of the rolled material 5 is determined in advance, and the shape profile of the rolled material 5 obtained from the image is expanded in series with the basis function, and the coefficient of the series expansion is displayed. Thus, the degree of the flatness pattern included in the shape profile can be understood, and the characteristics of the shape profile can be detected. Further, since the orthogonal function is adopted as the basis function, the shape profile of the rolled material 5 can be easily expanded in series. Since the coefficient when the shape profile of the rolled material 5 is expanded in series is stored (stored), the capacity of the storage unit can be reduced as compared with the case of directly storing the image. Therefore, as compared with the case of storing an image, it is possible to store a large number of shape profiles of the rolled material 5 as data for a long period of time, and it is possible to shorten a sampling cycle that is an interval at which an image is taken.

It is the equipment figure which provided the shape detection apparatus in the rolling line. It is a block diagram of a shape detection apparatus. It is the figure which normalized the coordinate data. It is a figure which shows the relationship between a Chebyshev function and a flatness pattern. It is a figure which shows the operation | movement flow of the shape detection of a rolling material. It is a figure which shows distribution of the coefficient at the time of analyzing a shape profile.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rolling machine 2 Shape detection apparatus 5 Rolled material 10 Irradiation part 11 Imaging part 12 Shape detection control apparatus 13 Control computer 14 Analysis computer 15 Monitor 16 Imaging control part 17 Image storage part 18 Image recognition part 19 Analysis part

Claims (6)

A method for detecting the shape of a rolled material, which detects the characteristics of the shape profile obtained by measuring the rolled material rolled by a rolling mill,
A basis function capable of expressing the flatness pattern of the rolled material is determined in advance, and the thickness change along the width direction of the measured shape profile of the rolled material is series-expanded by the basis function, and the coefficient of the series expansion is obtained. A method for detecting a shape of a rolled material, comprising detecting a shape profile characteristic of the rolled material on the basis thereof. A method for detecting the shape of a rolled material, which detects the characteristics of the shape profile obtained by measuring the rolled material rolled by a rolling mill,
The measured thickness change along the width direction of the shape profile of the rolled material is expressed as a basis function capable of expressing an ear wave, a basis function capable of expressing a medium elongation, and a composite elongation combining an ear wave and a medium elongation. Alternatively , a rolled material shape detection method, wherein a series expansion is performed with a basis function capable of expressing a quarter elongation, and a shape profile characteristic of the rolled material is detected based on a coefficient of the series expansion. The method for detecting the shape of a rolled material according to claim 1 , wherein an orthogonal function is adopted as the basis function. 3. The rolled material shape detection method according to claim 1 , wherein a Chebyshev function having orthogonality is adopted as the basis function. 5. The rolled material shape detection method according to claim 1 , wherein the series expansion coefficient is used for rolling control of a rolling mill. The method for detecting a shape of a rolled material according to any one of claims 1 to 5 , wherein a light cutting method is used when measuring the shape profile of the rolled material.

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