Method and system for controlling the shape of steel plates

Abstract

This invention provides a method and system for controlling the shape of steel plates, which can improve measurement accuracy by using different types of measuring devices in a complementary manner. [Solution] A method for controlling the shape of a steel sheet, comprising: a first device that calculates a shape index at the outermost edge in the width direction of the rolled steel sheet by imaging a self-illuminating rolled steel sheet and performing image processing; and a second device that calculates a shape index at a position inside the outermost edge in the width direction of the rolled steel sheet using a plurality of distance measuring instruments arranged in the width direction of the rolled steel sheet, wherein the method includes a step of performing control by correcting the measurement value of one of the first device and the second device to correspond to the measurement position of the other device.

Description

[Technical Field]

[0001] The present invention relates to a method and system for controlling the shape of a steel sheet when rolling it using a rolling mill. [Background technology]

[0002] Conventional methods for controlling the shape of steel plates include, for example, the method described in Patent Document 1. The method disclosed in Patent Document 1 is a shape measurement method for measuring the shape of a strip-shaped object, which includes the following steps. The first step is an imaging step in which an image of the thermal radiation light of the strip-shaped object is captured. At this time, imaging is performed so that the angle θ between the plane α, which is a reference plane on the surface of the strip-shaped object, and the optical axis of the camera is not 90 degrees, and the angle φ between the orthogonal projection of the optical axis of the camera onto the plane α and the transport direction p of the strip-shaped object is not 0 degrees. The second step is an image processing step in which an index of the shape of the edge portion of the strip-shaped object is calculated. The calculation of the shape index is performed by calculating the contour profile of the strip-shaped object from the image obtained in the first step. Specifically, the steel plate, which is a strip-shaped object, is imaged, and the contour of the steel plate is extracted by binarizing the self-illuminating portion and the other portion, and the shape index of the outermost end in the width direction of the steel plate is calculated.

[0003] Furthermore, an example of a conventional steel plate shape control device is the device described in Patent Document 2. The device disclosed in Patent Document 2 has the following configuration. A plurality of distance measuring devices are provided in the width direction of a strip-shaped body that moves in the longitudinal direction to measure the distance to the surface of the strip-shaped body, and a speed detector is provided to detect the movement speed of the strip-shaped body. Based on the distance signals and speed signals obtained from each of these distance measuring devices and speed detectors, each arc length indicating the surface length of the strip-shaped body is calculated, and the flatness of the strip-shaped body is obtained from each arc length. Each distance measuring device is a twin-beam type distance measuring device that irradiates a pair of parallel measuring beams of light, spaced at minute intervals in the longitudinal direction, onto a measurement position on the surface of the strip-shaped body, and simultaneously measures the distance to each irradiation position spaced at minute intervals on the surface of the strip-shaped body. From the distance to each irradiation position measured by this distance measuring device, an inclination value at the corresponding measurement position is calculated, and based on the inclination value corresponding to each movement direction position of the strip-shaped body, the arc length at a predetermined distance with vibration components removed is calculated. In other words, the apparatus disclosed in Patent Document 2 uses a so-called twin-beam type distance measuring instrument that calculates the shape index of a steel plate by irradiating a strip-shaped rolled material such as a steel plate being conveyed in the longitudinal direction with measuring beams on the upstream and downstream sides. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2024 / 190031 [Patent Document 2] Patent No. 2605158 [Overview of the project] [Problems that the invention aims to solve]

[0005] The method for calculating shape indices from the contour of a steel plate, as disclosed in Patent Document 1, allows measurement at the outermost edge in the width direction of the steel plate without being affected by the meandering of the steel plate. However, as shown in Figure 1, there was a problem in that imaging was hindered by external factors such as water, steam, and mist. Here, in the images shown in Figures 1(a) and (b), reference numeral 1 denotes a steel plate (rolled steel plate). Furthermore, in a configuration such as the one disclosed in Patent Document 2, where measurements are taken inside the outermost edge in the width direction of the steel plate and the shape index of the steel plate is calculated, a negative correlation is observed between the displacement of the steel plate meandering (amount of meandering change) and the shape index displacement (difference in elongation rate (amount of change)) on the DR and OP sides, as shown in Figure 2. In other words, there was a problem that if the steel plate meandered, the measurement position would shift, potentially affecting the calculated shape index.

[0006] Here, if only one of the devices configured to calculate a shape index of a steel plate from the contour of the steel plate by imaging, or the device configured to calculate a shape index of a steel plate using a twin-beam method is used, it is thought that the problem described in Patent Documents 1 and 2 arises in that the shape index cannot be used as a control parameter when a measurement abnormality occurs. The present invention has been made to solve the above-mentioned problems in the prior art. That is, the present invention aims to provide a steel plate shape control method and system that uses the above two types of devices to correct the measurement value from one device to a position equivalent to the measurement position from the other device, thereby enabling mutual complementarity between the two devices when a measurement abnormality occurs. [Means for solving the problem]

[0007] A first aspect of the present invention that advantageously solves the above problems is a method for controlling the shape of a steel sheet, which uses a first device that calculates a shape index at the outermost edge in the width direction of the rolled steel sheet by imaging a self-illuminating rolled steel sheet and performing image processing, and a second device that calculates a shape index at a position inside the outermost edge in the width direction of the rolled steel sheet using a plurality of distance measuring instruments arranged in the width direction of the rolled steel sheet, and is characterized by including a step of performing control by correcting the measurement value of one of the first device and the second device to a position corresponding to the measurement position of the other device.

[0008] Furthermore, in the steel plate shape control method according to the first embodiment described above, (a) In order to make the measured values ​​of the first and second devices that calculate the shape index at different parts equivalent, the position of the rolled steel sheet in the width direction is taken as the x-axis and the vertical displacement of the rolled steel sheet is taken as the y-axis, and the shape of the rolled steel sheet in the width direction is considered as a quadratic function, and (b) further including a step of changing the rolling conditions of the rolling mill so that the obtained shape index approaches the target value. These would be more preferable solutions.

[0009] A second aspect of the present invention that advantageously solves the above problems is a steel plate shape control system comprising: a first device that calculates a shape index at the outermost edge in the width direction of the rolled steel plate by imaging a self-illuminating rolled steel plate and performing image processing; a second device that calculates a shape index at a position inside the outermost edge in the width direction of the rolled steel plate using a plurality of distance measuring instruments arranged in the width direction of the rolled steel plate; and a calculation means that corrects the measurement value of one of the first device and the second device to correspond to the measurement position of the other.

[0010] Furthermore, in the steel plate shape control system according to the second embodiment described above, (c) The calculation means calculates the shape of the rolled steel sheet in the width direction as a quadratic function, with the width direction position of the rolled steel sheet as the x-axis and the vertical displacement of the rolled steel sheet as the y-axis, in order to make the measured values ​​of the first and second devices that calculate the shape index at different parts equivalent, and (d) Furthermore, the rolling condition changing means is provided to change the rolling conditions of the rolling mill so that the obtained shape index approaches the target value. These would be more preferable solutions. [Effects of the Invention]

[0011] According to the steel plate shape control method and system of the present invention, the shape index of the steel plate calculated by two different measuring devices can be used interchangeably depending on the situation. Therefore, if one device becomes unusable due to a measurement error or the like, it is possible to correct and use the measurement value from the other device, resulting in virtually uninterrupted measurement and increased reliability of the measurement value. [Brief explanation of the drawing]

[0012] [Figure 1] These are photographs showing the effects of external factors such as water surface and mist on imaging in an optical measuring device that calculates the shape index of a steel plate using self-luminous images. Figure 1(a) shows the effect of steam, and Figure 1(b) shows the effect of water surface. [Figure 2] This graph shows the relationship between the meandering displacement of a steel plate and the shape index displacement in a laser-type measuring device that calculates the shape index of a steel plate using laser light. [Figure 3] This is a schematic cross-sectional view illustrating the method for calculating the steepness of a steel plate. [Figure 4] This is a schematic cross-sectional view illustrating the method for calculating the elongation rate of a steel plate. [Figure 5] This is a schematic diagram showing a steepness distribution model in the width direction of a steel plate in one embodiment of the present invention. [Figure 6] This is a perspective view showing the arrangement of the equipment according to the above embodiment. [Figure 7] This is a configuration diagram showing the configuration of the control device according to the above embodiment. [Figure 8] This diagram shows the configuration of the optical measuring device according to the above embodiment, which calculates the shape index of a steel plate using a self-illuminating image. [Figure 9] This is a schematic diagram showing the image processing in measurement using the optical measuring device according to the above embodiment. Figure 9(a) is a self-illuminating image of the steel plate before binarization, Figure 9(b) is the image after binarization, Figure 9(c) shows the process of searching for the contour of the edge portion, and Figure 9(d) shows the contour of the extracted edge portion. [Figure 10] This is a perspective view showing the positional relationship between the camera and the steel plate during measurement using the optical measuring device according to the above embodiment. [Figure 11] This diagram shows the configuration of the laser measuring device according to the above embodiment, which calculates the shape index of a steel plate using laser light. [Figure 12] This is a schematic diagram showing the component arrangement and function of the sensor portion of the laser measuring device according to the above embodiment. [Figure 13] This is a top view showing the positional relationship between the measuring unit and the steel plate of the laser measuring device according to the above embodiment. [Figure 14] This is a schematic diagram illustrating the measurement principle of the laser measuring device according to the above embodiment. [Figure 15] This is a configuration diagram showing the configuration of the calculation means in one embodiment of the present invention. [Modes for carrying out the invention]

[0013] The embodiments of the present invention will be described in detail below. The following embodiments are illustrative of structures and methods for realizing the technical idea of ​​the present invention, and do not limit the configuration to those described below. That is, the technical idea of ​​the present invention can be modified in various ways within the technical scope described in the claims.

[0014] [First Embodiment] <Method for controlling the shape of steel plates> The first embodiment of the present invention is a method for controlling the shape of a steel plate. Its outline will be described in detail below. Figure 6 is a perspective view showing the arrangement of equipment used in the steel sheet shape control method according to this embodiment. In Figure 6, reference numeral 1 denotes a rolled steel sheet, reference numeral 2 denotes a rolling mill, reference numeral 3 denotes an optical measuring device (hereinafter also referred to as the first device), and reference numeral 4 denotes a laser measuring device (hereinafter also referred to as the second device). Here, the rolled steel sheet 1 is rolled in the rolling mill 2 and moves towards the front right (downstream side) in Figure 6. An optical measuring device 3 that calculates the shape by photographing the self-illuminating steel sheet and a laser measuring device 4 that calculates the shape by measuring the vertical displacement with a laser are arranged on the exit side of the rolling mill 2.

[0015] Figure 7 is a configuration diagram showing the configuration of the control equipment used in the steel sheet shape control method according to this embodiment. In Figure 7, reference numeral 5 denotes the control panel 5, reference numeral 6 denotes the higher-level system, and reference numeral 7 denotes the mill drive panel. The optical measuring device 3 and the laser measuring device 4 are connected to the control panel 5 and transmit the calculated steel sheet shape index to the control panel 5. The control panel 5 is connected to the higher-level system 6 and calculates the control parameters of the rolling mill 2 based on the steel sheet information received from the higher-level system 6, other measurement data such as sheet feeding position, and the steel sheet shape index received from the optical measuring device 3 and the laser measuring device 4. Here, the steel sheet information includes sheet thickness, sheet width, steel type, and temperature. The control panel 5 also performs feedback control such as leveling by transmitting a control signal to the mill drive panel 7. Therefore, the steel sheet shape control method according to this embodiment can be said to be a feedback control method for improving shape defects using two different types of measuring devices. The first device, the optical measuring device 3, and the second device, the laser measuring device 4, will be described in detail below. In one embodiment, a configuration is also conceivable in which a laser measuring device 4 is placed on the upstream side of the rolled steel sheet and an optical measuring device 3 is placed on the downstream side.

[0016] (1st device) The outline of the first device, the optical measuring device 3, is as follows. Figure 8 is a configuration diagram showing the equipment configuration of the optical measuring device 3. The optical measuring device 3 consists of a camera 3-1 and an image processing device 3-2. The image of the rolled steel sheet 1 captured by the camera 3-1 is transmitted to the image processing device 3-2, and the elongation shape is calculated based on the radiance of the rolled steel sheet 1 in the obtained steel sheet image. Below, the process of calculating the shape index of the rolled steel sheet 1 using the image processing device 3-2 based on the image obtained from the camera 3-1 will be described.

[0017] Figure 9 is a schematic diagram showing image processing in measurement by the optical measuring device 3, illustrating the principle of shape index calculation processing performed by the image processing device 3-2. Figure 9(a) is a self-emissive image of the steel plate captured by camera 3-1, before binarization processing. Figure 9(b) is the image after binarization processing has been applied to the same self-emissive image of the steel plate. Figure 9(c) is an image showing the process of searching for the contour of the steel plate edge, illustrating the process of calculating the contour profile of the steel plate as a one-dimensional vector. Figure 9(d) is an image showing the extracted contour of the steel plate edge. In other words, while Figures 9(a) and (b) are schematic diagrams showing the binarization processing, Figures 9(c) and (d) are schematic diagrams showing the process of calculating the contour profile of the steel plate as a one-dimensional vector. In binarization processing, the self-emissive parts of the steel plate are made white, and the other parts are made black to extract the region. Furthermore, in the contour search of the steel plate, the contour profiles of the upper and lower ends are calculated as one-dimensional vectors by searching for the outermost contour in the vertical direction at each point on the horizontal axis of the image.

[0018] Here, as shown in Figure 10, the image is captured obliquely to the conveying direction of the rolled steel sheet 1, so the resolution differs in the wave height direction and the wave pitch direction. Also, the resolution differs at the front end and the back end because the distance from camera 3-1 is different. Therefore, geometric correction of the resolution is performed separately for the wave height direction and the wave pitch direction on the obtained contour profile. Geometric correction of the resolution is also performed separately for the front end and the back end. Finally, the contour profile obtained in the previous step is used as a sinusoidal curve to obtain a shape index of the outermost edge in the steel sheet width direction. Furthermore, the first device, the optical measuring device 3, is configured to self-detect measurement abnormalities by calculating trend fluctuations in the contour profile. As described above, the first device, the optical measuring device 3, is a device that calculates a shape index at the outermost edge in the width direction of the rolled steel sheet by imaging the self-illuminating rolled steel sheet and performing image processing.

[0019] (Second device) The outline of the second device, the laser measuring device 4, is as follows. Figure 11 is a configuration diagram showing the equipment configuration of the laser measuring device 4. The laser measuring device 4 consists of a sensor section 4-1 and a calculation unit 4-2. As shown in Figure 12, the sensor section 4-1 has five measuring units 4-5, each consisting of two laser projectors 4-3 and two laser receiving cameras 4-4, arranged in the width direction of the rolled steel sheet. In Figure 12, reference numeral 1 indicates the rolled steel sheet. Here, the arrangement of the measuring units 4-5 as distance measuring instruments can be changed according to the width of the steel sheet, but in order to avoid the laser beam irradiation range being outside the rolled steel sheet, they are set dmm inward from the outermost edge in the width direction of the steel sheet, as shown in Figure 13. In Figure 13, reference numeral W indicates the width of the rolled steel sheet. The vertical distance to the surface of the steel sheet measured by the measuring units 4-5 is transmitted to the calculation unit 4-2, and an elongation shape index is calculated based on the obtained distance data. The following describes the process for calculating the shape index of the rolled steel sheet 1 from the distance data obtained using the calculation unit 4-2.

[0020] Figure 14 is a schematic diagram illustrating the principle of elongation shape measurement using the laser measuring device 4. Laser light emitted from two laser projectors 4-3 is reflected from the surface of the steel plate and images are formed on each laser receiving camera 4-4, and an analog signal corresponding to the vertical position of the rolled steel plate 1 is transmitted. As shown in Figure 14, the small arc length dS of the steel plate can be calculated by trigonometry using the difference df(L) of the vertical position of the steel plate obtained by each laser receiving camera 4-4 and the distance dL between the projectors and receiving devices. By integrating the obtained small arc lengths dS, the arc length S of the rolled steel plate 1 in section ab shown in Figure 14 is obtained, and by applying this together with the straight length L of section ab to equation (2) described later, the elongation rate, which is an elongation shape index, can be calculated. As described above, the second device, the laser measuring device 4, is a device that calculates a shape index at a position inside the outermost edge in the width direction of the rolled steel sheet using a plurality of distance measuring instruments arranged in the width direction of the rolled steel sheet.

[0021] (Control process) In this embodiment, if an anomaly is detected by the measurement anomaly detection function of the optical measuring device 3 while the measurement value of the first device, the optical measuring device 3, is being used for control, the measurement value of the second device, the laser measuring device 4, is corrected to correspond to the outermost edge in the width direction of the steel plate and used for control. Furthermore, if a certain amount of steel plate meandering is detected by another sensor while the measurement value of the laser measuring device 4 is being used for control with correction, the control is switched to the measurement value of the optical measuring device 3. In other words, the steel plate shape control method according to this embodiment includes a step (control step) of correcting the measurement value of one of the first device, the optical measuring device 3, and the second device, the laser measuring device 4, to correspond to the measurement position of the other. The calculation method for correcting the measurement value of the laser measuring device 4 is described below.

[0022] Commonly used parameters for the shape of steel sheets include steepness and elongation. In the rolled steel sheet 1 shown in Figure 3, when the wave pitch is l and the wave height is δ, the steepness λ is expressed by the following equation (1). (Formula 1) λ = δ / l

[0023] Also, in the rolled steel sheet 1 shown in FIG. 4, when the arc length of the sheet wave is S and the straight length of the steel sheet is L, the elongation rate ε is expressed by the following formula (2). (Formula 2) ε = (S - L) / L

[0024] Here, when the sheet wave is approximated by a sine curve, the relationship between the steepness λ and the elongation rate ε is expressed by the following formula (3). (Formula 3) ε = (π / 2) 2 ·(δ / l) 2 ≒2.47·λ 2

[0025] FIG. 5 is a schematic diagram showing a steepness distribution model in the width direction of the steel sheet for correcting the measured values. In this model, the width direction position of the rolled steel sheet is taken as the x-axis, and the steepness at each point in the width direction position is taken as the y-axis, and the width direction shape of the steel sheet is represented by a quadratic function. Here, the single elongation where one end of the rolled steel sheet is elongated is used as the primary component, and the ear elongation where both ends of the rolled steel sheet are elongated and the belly elongation where the center of the rolled steel sheet is elongated are used as the secondary components. The steepness at the outermost end of the steel sheet is y OP , y DR , and the steepness at the center of the steel sheet is y CE . Then, the steepness distribution in the width direction of the steel sheet can be expressed as in the following formula (4). In the following formula (4), x e represents the measurement position of the optical measuring device 3. (Formula 4) y = {(y OP + y DR ) / 2 - y CE}·(x / x e ) 2 + {(y OP + y DR ) / 2}·(x / x e ) + y CE Here, the x-axis coordinate at the center of the steel sheet is 0, and x e and -x e indicate the x coordinates of the outermost ends of the steel sheet. Also, when viewed from the front of the steel sheet, the right side is x > 0 and the left side is x < 0.

[0026] The measurement positions of the optical measuring device 3 are set to x = x. e -x e The measurement positions of the laser measuring device 4 are set to x = x q -x q The steepness measured by the laser measuring device 4 is given by y = y(x q ), y(-x q Assuming this is the case, the steepness measured by the optical measuring device 3, that is, the steepness at the outermost edge in the width direction of the steel plate, can be expressed using the measured value of the laser measuring device 4 as shown in the following equations (5) and (6). (Formula 5) y OP =((x e 2 / x q 2 +x e / x q )·y(x q )+(x e 2 / x q 2 -x e / x q )·y(-x q )+2·((x q 2 -x e 2 ) / x q 2 )·y CE ) / 2 (Formula 6) y DR =((x e 2 / x q 2 -x e / x q )·y(x q )+(x e 2 / x q 2 +x e / x q )·y(-x q )+2·((x q 2 -x e 2 ) / x q 2 )·y CE ) / 2

[0027] Here, by using the above formula (3), the elongation rates ε(x q ), ε(-x q ) at the measurement position by the laser type measuring device 4 are used to obtain the elongation rate ε OP , ε DR , and the one-sided elongation rate ε OP -ε DR as shown in the following formulas (7), (8), and (9). Here, ε CE represents the elongation rate at the center in the width direction of the rolled steel sheet. (Formula 7) ε OP =(x e 2 ·(x e +x) 2 ·ε(x q )+x e 2 ·(x e -x) 2 ·ε(-x q )+4(x 2 -x e 2 ) 2 ·ε CE +2x e 2 ·(x e 2 -x 2 )·ε(x q ) 1 / 2 ·ε(-x q ) 1 / 2 +4x e ·(x e +x)·(x e 2 +x 2 )·ε(x q ) 1 / 2 ·ε CE 1 / 2 +4x e ·(x e -x)·(x e 2 +x 2 )·ε(-x q ) 1 / 2 ·ε CE 1 / 2 ) / 4x 4 (Formula 8) εDR =(x e 2 ·(x e -x) 2 ·ε(x q )+x e 2 ·(x e +x) 2 ·ε(-x q )+4(x 2 -x e 2 ) 2 ·ε CE +2x e 2 ·(x e 2 -x 2 )·ε(x q ) 1 / 2 ·ε(-x q ) 1 / 2 +4x e ·(x e -x)·(x e 2 +x 2 )·ε(x q ) 1 / 2 ·ε CE 1 / 2 +4x e ·(x e +x)·(x e 2 +x 2 )·ε(-x q ) 1 / 2 ·ε CE 1 / 2 ) / 4x 4 (Equation 9) ε OP -ε DR =(x e 2 ·(ε(x q )-ε(-x q ))+4·(x q 2 +x e 2 )·ε CE 1 / 2 ·(ε(x q ) 1 / 2 -ε(-x q ) 1 / 2 ))·x e / 2x q 3

[0028] Therefore, the elongation ε(x) measured by the laser measuring device 4 q ), ε(-x q ), and the measurement position x of the laser measuring device 4 q By substituting this into equation (9) above, a value equivalent to the elongation rate measured by the optical measuring device 3, that is, an elongation rate corrected to correspond to the outermost edge in the width direction of the steel plate, can be obtained. In this way, in the control process according to this embodiment, by adjusting the shape index, the laser measuring device 4 can be controlled and applied when an abnormality occurs in the optical measuring device 3, and the optical measuring device 3 can be controlled and applied when the steel plate meanders or when an abnormality occurs in the laser measuring device 4. In other words, by selecting and applying the appropriate device according to the situation, stable shape control of the steel plate can be achieved. Accordingly, if one device becomes unusable due to a measurement abnormality, etc., it becomes possible to calculate the shape index of the steel plate with the other device, which has the effect of increasing the reliability of the measured value. Furthermore, as described above, in the control process according to this embodiment, in order to make the measured values ​​of the optical measuring device 3 and the laser measuring device 4, which calculate shape indices at different parts, equivalent, the position in the width direction of the rolled steel sheet is taken as the x-axis and the vertical displacement of the rolled steel sheet is taken as the y-axis, and the shape in the width direction of the rolled steel sheet is considered as a quadratic function.

[0029] In this embodiment, it is preferable to further include a step of changing the rolling conditions of the rolling mill so that the obtained shape index approaches the target value. Feedback control for improving shape defects, which is performed based on the measured shape index of the rolled steel sheet, can be applied to changing the rolling conditions. Examples of feedback control include the following. For example, when using an optical measuring device 3 as the first device and a laser measuring device 4 as the second device, the shape index calculated mutually complementary by each device is transmitted to the control panel 5. In the control panel 5, control parameters are calculated based on steel sheet information (e.g., sheet thickness, sheet width, steel type, temperature, etc.) acquired from the higher-level system 6, other measurement data such as sheet passing position, and the acquired shape index. Next, a control signal reflecting the control parameters is transmitted from the control panel 5 to the mill drive panel 7, enabling control of the rolling mill 2. In addition to the mill drive panel 7 which is responsible for controlling the rolling mill 2, the control panel 5 may also be connected to control devices (not shown) which are responsible for controlling other devices or functions. This allows for various controls to be implemented to maintain uniform plate thickness and flatness, in addition to controlling the rolling mill 2, in the event of shape defects in the rolled steel sheet due to, for example, side elongation, edge elongation, and / or lateral elongation. For example, by connecting the control panel 5 to various corresponding control devices, it is also possible to perform controls such as roll gap adjustment, plate crown control, side guide adjustment, edge drop control, and tension control.

[0030] [Second Embodiment] <Steel plate shape control system> A second embodiment of the present invention is a steel plate shape control system. Its outline will be described in detail below. The steel sheet shape control system according to this embodiment is for performing the steel sheet shape control method according to the first embodiment, and comprises the first device, the second device, and a calculation means for correcting the measurement value of one of the first device and the second device to a measurement position corresponding to the other device. In addition to the first device, the second device, and the calculation means, the steel sheet shape control system according to this embodiment also uses a rolling mill 2 as shown in Figure 6 and various control devices as shown in Figure 7. That is, similar to the first embodiment, the steel sheet shape control system according to this embodiment is configured to control the shape of the rolled steel sheet under the interaction of these devices, means and various control devices.

[0031] In this embodiment, the calculation means specifically refers to the calculation means 8 shown in Figure 15. The calculation means 8 comprises an input unit 8-1, an calculation processing unit 8-2, a storage unit 8-3, an output unit 8-4, and a control unit 8-5. The input unit 8-1 receives measurement results from the first device and / or the second device and transmits the measurement results to the calculation processing unit 8-2. Examples of the input unit 8-1 include various communication interfaces and wireless input devices that can continuously receive measurement results from the first device and / or the second device. The arithmetic processing unit 8-2 performs calculations to correct the measurement value of one of the first and second devices to correspond to the measurement position of the other device, based on the measurement results of the first and / or second devices received from the input unit 8-1. Specifically, in order to make the measurement values ​​of the first and second devices, which calculate shape indices at different parts using the formulas described in the first embodiment, equivalent, the calculation is performed by considering the shape of the rolled steel plate in the width direction as a quadratic function, with the position in the width direction of the rolled steel plate as the x-axis and the vertical displacement of the rolled steel plate as the y-axis. Examples of the arithmetic processing unit 8-2 include a CPU (Central Processing Unit), an ALU (Arithmetic Logic Unit), and a DSP (Digital Signal Processing Unit), which are capable of numerical processing and data analysis. The storage unit 8-3 stores, for example, the measurement results received from the first and / or second devices by the input unit 8-1 and the calculation results from the arithmetic processing unit 8-2. This contributes to uninterrupted measurement and increases the reliability of the measurement values. Examples of storage devices include RAM, ROM, cache memory, non-volatile memory, HDD, and SSD. The output unit 8-4 receives the calculation result from the arithmetic processing unit 8-2 and outputs the calculation result to a control device or the like. The output unit 8-4 may also be configured to generate a control signal based on the received calculation result and further output the control signal. Examples of the output unit 8-4 include a wireless communication module and a communication interface. The control unit 8-5 controls the reception of measurement results from the input unit 8-1, the calculation of correction values ​​in the arithmetic processing unit 8-2, the storage of measurement results and calculation results in the storage unit 8-3, and the output in the output unit 8-4. The control unit 8-5 can be, for example, a control device such as various control controllers, or a control program such as firmware.

[0032] Of the examples given above as the input unit 8-1, arithmetic processing unit 8-2, storage unit 8-3, output unit 8-4, and control unit 8-5, only one of each may be used individually, or two or more may be used in combination as needed. Furthermore, the arithmetic means 8 in this embodiment may be built into, for example, one of the various control devices shown in Figure 7, or it may be provided as an independent separate device. In the latter case, a wired or wireless connection state is established between the arithmetic means 8 and the first device, the second device, and / or the various control devices.

[0033] In this embodiment, for example, when performing measurements using only the first device while operating the second device, if a measurement anomaly is detected in the first device, the control application is switched to the second device, which was operating simultaneously. Here, even while the measurement by the first device is being performed normally, the measurement values ​​from the second device are continuously input to the input unit 8-1 of the calculation means 8 and stored in the storage unit 8-3. As a result, even after switching the control application, it is possible to use the measurement value immediately before the measurement anomaly was detected, thereby achieving substantially continuous measurement. Furthermore, even after switching to the second device, if steel plate meandering or the like occurs, it is possible to switch back to applying control to the first device, where the effect of the measurement anomaly has disappeared. In this way, the steel plate shape control system according to this embodiment selectively and complementaryly uses two different measuring devices. In addition, the control unit 8-5 can also perform control such as filtering, processing optimization, automatic memory management, and predictive output control on the input unit 8-1, calculation processing unit 8-2, storage unit 8-3, and output unit 8-4, respectively, using a machine learning model. Furthermore, there are no particular restrictions on the type of machine learning model, as long as it can achieve the various controls described above.

[0034] In this embodiment, it is preferable to have a rolling condition changing means for changing the rolling conditions of the rolling mill so that the obtained shape index approaches a target value. The shape index calculated complementaryly by the first device, the optical measuring device 3, and the second device, the laser measuring device 4, is transmitted to the control panel 5, which is the rolling condition changing means. In the control panel 5, control parameters are calculated based on steel plate information (e.g., plate thickness, plate width, steel type, temperature, etc.) acquired from the higher-level system 6, other measurement data such as plate passage position, and the acquired shape index. Next, a control signal reflecting the control parameters is transmitted from the control panel 5 to the mill drive panel 7, enabling control of the rolling mill 2. Here, in addition to the mill drive panel 7 which is responsible for controlling the rolling mill 2, the control panel 5 may also be connected to control devices (not shown) which are responsible for controlling other devices and functions. This allows for various controls to be made to maintain uniform plate thickness and flatness in addition to controlling the rolling mill 2, in the event of shape defects in the rolled steel plate due to side elongation, edge elongation, and / or belly elongation. For example, by connecting the control panel 5 to various corresponding control devices, it is possible to perform controls such as roll gap adjustment, plate crown control, side guide adjustment, edge drop control, and tension control. [Examples]

[0035] The present invention will be described in detail below based on examples. However, the present invention is not limited to the examples shown below.

[0036] (Example 1) In Example 1, the shape of the rolled steel sheet was controlled using both a laser measuring device (twin-beam type) and an optical measuring device (self-illuminating type). Specifically, while operating the laser measuring device, the configuration was first used to calculate the elongation rate and single-sided elongation rate, which are shape indicators of the outermost edge in the width direction of the rolled steel sheet, using only the optical measuring device. The rolled steel sheet extending from the rolling mill was imaged from an oblique upward direction, and its contour was extracted from the obtained self-luminous image to calculate the steepness. Then, the elongation rate was calculated based on the steepness calculated in this way. Here, the optical measuring device (self-luminous type) has the advantage of a fast response and is not affected by the meandering of the steel sheet, but it is also susceptible to environmental influences such as steam. In this embodiment, the generation of mist hindered imaging by the optical measuring device, resulting in a measurement anomaly. However, the measurement anomaly was immediately detected by the self-detection function of the optical measuring device, and the control application was switched from the optical measuring device to the laser measuring device (twin-beam type).

[0037] As a laser measuring device, one was used that calculates the elongation rate at a position inside the outermost edge in the width direction of the rolled steel sheet using laser triangulation. Specifically, a twin-beam type device was used with 5 measurement points in the width direction of the steel sheet, and control applied to the central 3 points in the same direction. Here, by performing the calculation as described in the first embodiment, the measurement value from the laser measuring device was corrected to correspond to the measurement position (outermost edge in the width direction of the steel sheet) of the optical measuring device. While the laser measuring device has the advantage of being less susceptible to environmental influences such as steam and enabling stable measurements, it also has the disadvantage of being susceptible to the effects of steel sheet meandering. In this embodiment, after switching the control application, the measurement by the laser measuring device remained stable for a certain period of time, but the steel sheet began to meander, and a meandering amount exceeding a predetermined amount was detected by other sensors. Therefore, the control application was switched back to the optical measuring device, which was no longer affected by mist.

[0038] In both the optical and laser measuring devices described above, the measured shape indicators, such as elongation, were transmitted to the control panel and, along with other information, to a higher-level system. Based on the steel sheet information from the higher-level system, the control panel generated a control signal and transmitted it to the mill drive panel. The mill drive panel controlled the rolling mill based on this control signal. In this embodiment, shape defects due to uneven elongation occurred during measurement with the optical measuring device. Therefore, leveling control was performed on the rolled steel sheet using a control signal based on the measured shape indicators. As a result, the shape defects were eliminated, and uniform plate thickness and flatness could be maintained. Thus, in this embodiment, the device's control application was switched as appropriate depending on the situation, enabling stable shape control of the rolled steel sheet. This resulted in increased reliability of the measured values ​​and prevented a decrease in yield caused by cutting off defective parts.

[0039] (Comparative Example 1) In Comparative Example 1, the shape control of the rolled steel sheet was performed using only a laser measuring device (twin-beam type). As with Example 1, a twin-beam laser measuring device was used, with five measurement points in the width direction of the steel sheet, and control applied to the three central points in the same direction. Here, since the laser measuring device calculates the shape index at a position inside the outermost edge in the width direction of the rolled steel sheet, it is susceptible to the influence of steel sheet meandering due to a negative correlation (correlation between steel sheet meandering displacement and shape index displacement) as shown in Figure 2. In this comparative example as well, steel sheet meandering occurred, and the measurement position shifted, which affected the calculation of the shape index. Here, because the configuration used only a laser measuring device, even if steel sheet meandering occurred, it was not possible to switch the application of control to other devices, and stable shape control of the rolled steel sheet could not be achieved. Consequently, the reliability of the measured values ​​was low with a configuration using only a laser measuring device, and it was not possible to prevent a decrease in yield. On the other hand, shape defects due to uneven elongation occurred before the steel sheet meandered. Therefore, leveling control was applied to the rolled steel sheet using a control signal based on measured values ​​of shape indicators, and the shape defects were temporarily resolved.

[0040] (Comparative Example 2) In Comparative Example 2, the shape of the rolled steel sheet was controlled using only an optical measuring device (self-illuminating type). As with Example 1, the optical measuring device used was capable of imaging the rolled steel sheet from an oblique upward direction and calculating the steepness and elongation rate from the obtained self-illuminating image. The device was configured to calculate the shape index of the outermost edge in the width direction of the rolled steel sheet based on the self-illuminating image, but imaging was hindered by the generation of mist. Here, an anomaly was detected by the measurement anomaly detection function of the optical measuring device, but since no other measuring device was used, it was not possible to switch the control application to another device, and stable shape control of the rolled steel sheet could not be achieved. Consequently, with a configuration using only an optical measuring device, the reliability of the measured values ​​was low, and it was not possible to prevent a decrease in yield. On the other hand, shape defects due to uneven elongation occurred before the harmful effects of the mist became apparent. Therefore, leveling control was applied to the rolled steel sheet using a control signal based on measured shape indicators, and the shape defects were temporarily resolved. [Industrial applicability]

[0041] The steel sheet shape control method and system according to the present invention are configured to improve measurement accuracy by using different types of measuring devices in a complementary manner, and are particularly useful in processes in which steel sheets are rolled using a rolling mill or the like in order to improve yield in subsequent processes. [Explanation of symbols]

[0042] 1 Rolled steel sheet 2. Rolling mill 3 Optical measuring device 3-1 Camera 3-2 Image Processing Device 4. Laser measuring device 4-1 Sensor section 4-2 Arithmetic unit 4-3 Laser Projector 4-4 Laser receiving camera 4-5 Measurement Unit 5. Control Panel 6. Higher-level system 7 Mill drive panel

Claims

1. A method for controlling the shape of a steel sheet, comprising: a first device that calculates a shape index at the outermost edge in the width direction of the self-illuminating rolled steel sheet by imaging the rolled steel sheet and performing image processing; and a second device that calculates a shape index at a position inside the outermost edge in the width direction of the rolled steel sheet using a plurality of distance measuring instruments arranged in the width direction of the rolled steel sheet, wherein the method includes a step of performing control by correcting the measurement value of one of the first device and the second device to correspond to the measurement position of the other device.

2. The steel plate shape control method according to claim 1, characterized in that, in order to make the measured values ​​of the first and second devices that calculate the shape index at different parts equivalent, the position of the rolled steel plate in the width direction is taken as the x-axis and the displacement of the rolled steel plate in the vertical direction is taken as the y-axis, and the shape of the rolled steel plate in the width direction is considered as a quadratic function.

3. Furthermore, the method for controlling the shape of a steel sheet according to claim 1 or 2 is characterized by including a step of changing the rolling conditions of the rolling mill so that the obtained shape index approaches a target value.

4. A first device that captures an image of a self-illuminating rolled steel sheet and performs image processing to calculate a shape index at the outermost edge in the width direction of the rolled steel sheet, A second device that calculates a shape index at a position inside the outermost edge in the width direction of the rolled steel sheet using a plurality of distance measuring instruments arranged in the width direction of the rolled steel sheet, A calculation means for correcting the measurement value of one of the first device and the second device to a measurement position corresponding to the other device, A steel plate shape control system characterized by comprising the following features.

5. The steel plate shape control system according to claim 4, characterized in that the calculation means calculates the shape of the rolled steel plate in the width direction as a quadratic function, with the position of the rolled steel plate in the width direction as the x-axis and the displacement of the rolled steel plate in the vertical direction as the y-axis, in order to make the measured values ​​of the first and second devices that calculate the shape index at different parts equivalent.

6. Furthermore, the steel plate shape control system according to claim 4 or 5 is characterized by having a means for changing the rolling conditions of the rolling mill so that the obtained shape index approaches a target value.

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