Steel plate meandering amount measuring device, steel plate meandering amount measuring method, hot rolling equipment for hot-rolled steel strip, and hot rolling method for hot-rolled steel strip

Abstract

Provided are a steel plate meandering amount measuring device, a meandering amount measuring method, a hot rolling equipment and a hot rolling method, which can accurately measure the meandering amount of a steel plate during rolling. ds (N) and the edge of the working side z ws (N) When both reliability is high, the meandering amount calculation device (6) of the meandering amount measuring device (4) uses the current driving side edge portion z ds (N) and the edge of the working side z ws (N) Calculate the meandering amount of the steel plate (10). ds (N) and the edge of the working side z ws (N) If only one side has high reliability, the driving side edge portion z at the current moment with high reliability is ds (N) or working side edge z ws (N) is used as a reference, and the edge portion on the other side is interpolated and calculated using the number of pixels W from the plate width update unit (65).

Description

Technical Field

[0001] The present invention relates to a steel plate meandering amount measuring device for measuring the meandering amount of a steel plate being rolled using a rolling mill having multiple rolling stands, a steel plate meandering amount measuring method, hot rolling equipment for hot-rolled steel strips, and a hot rolling method for hot-rolled steel strips. Background Art

[0002] Generally, when rolling steel plates in a hot finishing mill with multiple rolling stands, a phenomenon known as meandering sometimes occurs, where the center of the steel plate's width is offset from the center of the work rolls in the rolling stands. When this meandering increases, the steel plate may come into contact with the side guides installed at the mill's entry and buckle. Rolling in this state can cause roll damage known as "squeezing." Therefore, steel plate rolling operations require appropriate rolling conditions and control to minimize meandering.

[0003] Conventionally, "meaning control using a differential load method" and "meaning control using a sensor method" are known for controlling the meandering amount of a steel plate.

[0004] "Differential load type meandering control" means changing the leveling amount (roll gap difference, i.e., the gap gap difference between the operating side and the driving side of the rolling stand) of the rolling stand as the control target in proportion to the differential load between the operating side and the driving side detected by the load detector installed in the rolling stand.

[0005] In addition, "sensor-based meandering control" means changing the leveling amount of the rolling mill stand serving as the control target in proportion to the meandering amount measured by a meandering amount measuring device, wherein the meandering amount measuring device is installed between the rolling stand preceding the rolling stand serving as the control target and the rolling stand serving as the control target.

[0006] Conventionally, Non-Patent Document 1 states that "differential load-based meandering control" reduces its meandering suppression effect within the actual control gain setting range as the plate width increases, making it ineffective as a control method. To address this issue, a control system has been proposed that employs "meandering meter-based meandering control." A meandering amount measuring device periodically measures the amount of meandering between the rolling stand immediately preceding the controlled rolling stand and the current one, and then adjusts the leveling amount of the controlled rolling stand.

[0007] Furthermore, there is a problem that a large amount of steam and smoke is generated between the rolling stands in the hot finishing mill, and the measurement field of the camera in the meandering amount measuring device is blocked by the steam and smoke, making it impossible to measure the meandering amount of the steel plate with high accuracy.

[0008] In order to solve this problem, the following method has been proposed in the above-mentioned non-patent document 1: after calculating the point where the differential intensity becomes the largest according to the scanning line of the camera (corresponding to the edge of the steel plate), the edge line is estimated using the weighted least squares method with the differential intensity as the weighting coefficient.

[0009] Furthermore, in order to solve the above-mentioned problem, a meandering measurement method of a plate material as shown in Patent Document 1 has been proposed.

[0010] The method for measuring the meandering of a plate shown in Patent Document 1 comprises: a step of photographing the surface of the plate from a direction inclined in the rolling direction relative to a perpendicular line of the rolling line using a two-dimensional photographing device, a step of detecting the edge position of the plate according to the scanning line by detecting the change in concentration value of the photographed image according to the scanning line in the plate width direction, a step of calculating an approximate straight line by applying the least squares method to each edge position detected according to the scanning line, a step of calculating the position of the intersection of the approximate straight line and a specified scanning line, and a step of calculating the amount of meandering based on the position of the intersection.

[0011] Furthermore, in order to solve the above-mentioned problem, an edge detection method disclosed in Patent Document 2 has been proposed in the past.

[0012] The edge detection method disclosed in Patent Document 2 includes: an imaging step of capturing an area containing edge lines of a plurality of moving components using imaging means; a differential image generation step of generating differential images by calculating differential intensities of pixels in each of the plurality of temporally consecutive images obtained in the imaging step; and a composite differential image generation step of generating a composite partial image by combining the plurality of temporally consecutive differential images obtained in the differential image generation step. Furthermore, the edge detection method includes a straight line identification step of identifying the differential intensities of pixels located on a straight line and the maximum straight line in the composite differential image obtained in the composite differential image generation step; and a determination step of determining whether the differential intensities of the pixels are greater than a threshold value.

[0013] Prior art literature

[0014] Non-patent literature

[0015] Non-patent document 1: Development of steel plate meandering control technology in thin plate hot rolling, Iron and Steel, Vol. 95 (2009), No. 1, pp. 43-50

[0016] Patent Literature

[0017] Patent Document 1: Japanese Patent Application Laid-Open No. 2004-141956

[0018] Patent Document 2: Japanese Patent No. 5454404 Summary of the Invention

[0019] Problems to be solved by the invention

[0020] In addition, a large amount of steam and smoke is generated between the rolling stands in the hot finishing mill, but sometimes only one edge of the steel plate is covered by the steam and smoke, and the edge cannot be detected. For the other edge, it is not covered by the steam and smoke and can be detected.

[0021] Here, in any of the previous methods of measuring the meandering of the plate shown in non-patent document 1, patent document 1, and the edge detection method shown in patent document 2, the meandering amount is calculated only when the edges on both sides of the steel plate can be detected. Therefore, there is the following problem: when one edge cannot be detected but the other edge can be detected, the meandering amount of the steel plate cannot be detected.

[0022] Therefore, the present invention is made to solve the previous problem, and its purpose is to provide a steel plate meandering amount measuring device, a steel plate meandering amount measuring method, a hot rolling equipment for hot rolled steel strip, and a hot rolling method for hot rolled steel strip, which can accurately measure the meandering amount of the steel plate when measuring the meandering amount of the steel plate during rolling, not only when both edges of the steel plate are detected, but also when one edge of the steel plate is covered by steam or the like and edge detection cannot be performed, and the other edge is not covered by steam or the like and edge detection can be performed.

[0023] Means for solving problems

[0024] In order to solve the above-mentioned problems, a device for measuring the amount of meandering of a steel plate according to one embodiment of the present invention measures the amount of meandering of a steel plate being rolled by a rolling mill having a plurality of rolling stands, the device for measuring the amount of meandering of the steel plate being rolled, the device comprising: a photographing device, the photographing device being arranged between adjacent rolling stands, for periodically photographing the surface of the steel plate being rolled; and a meandering amount calculating device, the meandering amount calculating device calculating the amount of meandering of the steel plate based on a plurality of photographed images photographed by the photographing device, the meandering amount calculating device comprising: a front-edge detection unit for calculating a brightness difference between adjacent ones of the plurality of photographed images periodically photographed by the photographing device in the width direction, and defining a portion at which the absolute value of the brightness difference is maximum on the driving side in the width direction of the steel plate as a driving-side edge portion z of the steel plate. ds A plurality of locations are detected, and the location where the absolute value of the brightness difference is the largest on the working side in the width direction of the steel plate is defined as the working side edge location z of the steel plate.ws measuring reliability determination unit, which is detected from the plurality of driving side edge portions z before correction edge detection unit detected ds and the working side edge z ws The extracted driving side edge portion (z ds (i), i = 1, 2, ... N) and the edge of the working side (z ws The sum α of the absolute values ​​of the changes expressed by the following formula (1) and formula (2) in each of (i), i=1, 2, ... N) is: ds , α ws If the current driving side edge portion z is greater than the specified threshold, ds (N), working side edge z ws (N) If the reliability is judged to be low and the value is less than a predetermined threshold, the current driving side edge portion z ds (N), working side edge z ws (N) is determined to be highly reliable; the plate width updating portion is determined to be the driving side edge portion z at the current moment in the measurement reliability determination portion. ds (N) and the edge of the working side z ws (N) If both are highly reliable, calculate the current driving side edge position z ds (N) and the edge of the working side z ws (N) The number of pixels W' corresponding to the plate width calculated by both parties is updated to the calculated W', and the edge portion z of the driving side is determined to be the current time. ds (N) and the edge of the working side z ws (N) is low in reliability, the number of pixels W corresponding to the plate width is maintained at the number of pixels W; and a meandering amount calculation unit that is determined by the measurement reliability determination unit to be the current driving side edge portion z ds (N) and the edge of the working side z ws (N) When both are highly reliable, use the current driving side edge z ds (N) and the edge of the working side z ws (N) Calculate the meandering amount of the steel plate, and determine the driving side edge portion z at the current moment. ds (N) and the edge of the working side z ws If only one of the two (N) has high reliability, the current driving side edge portion z with high reliability is ds (N) or working side edge z ws(N) is used as a reference to interpolate the edge portion on the other side using the number of pixels W from the plate width update unit, and the current driving side edge portion z with high reliability is used. ds (N) or working side edge z ws (N) and the edge portion on the other side after interpolation calculation, the meandering amount of the steel plate is calculated, and the edge portion z on the driving side at the current moment is determined to be ds (N) and the edge of the working side z ws (N) If both are of low reliability, the meandering amount of the steel plate is not calculated.

[0025] [Mathematical formula 1]

[0026]

[0027] [Mathematical formula 2]

[0028]

[0029] Furthermore, a gist of a hot rolling facility for a hot-rolled steel strip according to another aspect of the present invention is to include the above-mentioned meandering amount measuring device for a steel plate.

[0030] In addition, a method for measuring the amount of meandering of a steel plate according to another embodiment of the present invention measures the amount of meandering of a steel plate being rolled using a rolling mill having a plurality of rolling stands, and the method for measuring the amount of meandering of the steel plate is characterized in that it includes: a photographing step of periodically photographing the surface of the steel plate during rolling using a photographing device disposed between adjacent rolling stands; a pre-correction edge detection step of calculating the brightness difference between adjacent portions in the width direction of each of the plurality of photographed images periodically photographed in the photographing step, and defining a portion on the driving side of the steel plate in the width direction at which the absolute value of the brightness difference is the largest as a driving side edge portion z of the steel plate. ds A plurality of portions are detected, and the portion where the absolute value of the brightness difference becomes the largest on the working side in the width direction of the steel plate is taken as the working side edge portion z of the steel plate. ws Determine the reliability of the step, in the plurality of driving side edge portions z detected in the edge detection step before correction ds and the working side edge z ws The extracted driving side edge portion (z ds (i), i = 1, 2, ... N) and the edge of the working side (z ws The sum α of the absolute values ​​of the changes expressed by the above formulas (1) and (2) in each of (i), i=1, 2, ... N) is ds , α ws If the current driving side edge portion z is greater than the specified threshold,ds (N), working side edge z ws (N) If the reliability is judged to be low and the value is less than a predetermined threshold, the current driving side edge portion z ds (N), working side edge z ws (N) is determined to be highly reliable; the plate width updating step is performed, in which the driving side edge portion z is determined to be the current moment in the reliability determination step. ds (N) and the edge of the working side z ws (N) If both are highly reliable, calculate the current driving side edge position z ds (N) and the edge of the working side z ws (N) The number of pixels W' corresponding to the plate width calculated by both parties is updated to the calculated W', and the edge portion z of the driving side is determined to be the current time. ds (N) and the edge of the working side z ws When at least one of (N) has low reliability, the number of pixels W corresponding to the panel width is maintained at the number of pixels W; and

[0031] The meandering amount calculation step is a step of determining the driving side edge portion z at the current moment in the measurement reliability determination step. ds (N) and the edge of the working side z ws (N) When both are highly reliable, use the current driving side edge z ds (N) and the edge of the working side z ws (N) Calculate the meandering amount of the steel plate, and determine the driving side edge portion z at the current moment. ds (N) and the edge of the working side z ws If only one of the two (N) has high reliability, the current driving side edge portion z with high reliability is ds (N) or working side edge z ws (N) is used as a reference, and the edge portion on the other side is interpolated using the number of pixels W from the plate width update step, and the edge portion z at the current moment of high reliability is used. ds (N) or working side edge z ws (N) and the edge portion on the other side after interpolation calculation, the meandering amount of the steel plate is calculated, and the edge portion z on the driving side at the current moment is determined to be ds (N) and the edge of the working side z ws (N) When both reliability values ​​are low, the meandering amount of the steel plate is not calculated.

[0032] Furthermore, a hot rolling method of a hot-rolled steel strip according to another aspect of the present invention is gist of a step of measuring the amount of meandering of a steel plate being rolled in a rolling mill having a plurality of rolling stands using the above-mentioned method for measuring the amount of meandering of a steel plate.

[0033] Effects of the Invention

[0034] According to the steel plate meandering amount measuring device, steel plate meandering amount measuring method, hot rolling equipment for hot-rolled steel strip and hot rolling method for hot-rolled steel strip of the present invention, it is possible to provide a steel plate meandering amount measuring device, steel plate meandering amount measuring method, hot rolling equipment for hot-rolled steel strip and hot rolling method for hot-rolled steel strip, which can accurately measure the meandering amount of the steel plate when measuring the meandering amount of the steel plate during rolling, not only in the case where both edges of the steel plate can be detected, but also in the case where one edge of the steel plate is covered by steam or the like and edge detection cannot be performed, and the other edge is not covered by steam or the like and edge detection can be performed. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic configuration diagram of a hot rolling facility equipped with a meandering amount measuring device according to one embodiment of the present invention.

[0036] Figure 2 It is composed Figure 1 The functional block diagram of the meandering amount calculation device of the meandering amount measuring device shown.

[0037] Figure 3 It shows Figure 1 Flowchart of the processing flow of the meandering amount measuring device shown.

[0038] Figure 4 Is used to illustrate Figure 1 FIG. 1 is a diagram showing an image captured by a line sensor camera of an imaging device of a meandering amount measuring device.

[0039] Figure 5 The diagram is used to explain the detection of the driving side edge portion and the working side edge portion of the steel plate in an environment without steam and smoke.

[0040] Figure 6 The diagram is used to explain the detection of the driving side edge portion and the working side edge portion of a steel plate in an environment with steam and smoke.

[0041] Figure 7 The diagram shows a two-dimensional image obtained by connecting a plurality of images periodically captured by a line sensor camera along the longitudinal direction of a steel plate in the examples of the present invention and the comparative example.

[0042] Figure 8 The present invention and the comparative example are shown in FIG. Figure 7The state shown is a diagram of the state in which the brightness difference between adjacent pixels in the width direction of the steel plate is calculated and the portion where the absolute value of the brightness difference becomes the largest is detected as the driving side edge portion and the working side edge portion of the steel plate.

[0043] Figure 9 This is an explanatory diagram of the case where the driving side edge portion and the working side edge portion of a steel plate are estimated using a comparative example, and the meandering amount of the steel plate is calculated using the estimated driving side edge portion and the working side edge portion. (a) shows the estimated value of the working side edge portion, (b) shows the estimated value of the driving side edge portion, and (c) shows the calculated value of the meandering amount of the steel plate.

[0044] Figure 10 This is an explanatory diagram of using an example of the present invention to detect and determine the driving side edge portion and the working side edge portion of a steel plate, and using the determined driving side edge portion and the working side edge portion to calculate the meandering amount of the steel plate, (a) shows the value of the determination result of the working side edge portion, (b) shows the value of the determination result of the driving side edge portion, and (c) shows the calculated value of the meandering amount of the steel plate.

[0045] Figure 11 This is a graph comparatively showing calculated values ​​of the meandering amount of the steel plate calculated by the examples of the present invention and the comparative examples. DETAILED DESCRIPTION

[0046] The following describes embodiments of the present invention with reference to the accompanying drawings. The embodiments described below illustrate devices and methods for embodying the technical concepts of the present invention. The technical concepts of the present invention do not necessarily define the materials, shapes, structures, and configurations of the components described below. Furthermore, the drawings are schematic. Therefore, it should be noted that the relationship and ratio between thickness and planar dimensions may differ from reality, and that the drawings may also include portions with different dimensional relationships and ratios.

[0047] exist Figure 1 Schematic structure of a hot rolling facility including a meandering amount measuring device according to one embodiment of the present invention is shown in FIG.

[0048] In the hot rolling mill 1 for hot-rolled steel strips, the cast slabs heated in a heating furnace (not shown) are subjected to a rough rolling process, a finishing rolling process, and a cooling process to be manufactured into steel plates of a predetermined width and thickness and then coiled. Figure 1 ), cooling equipment (not shown), winding equipment (not shown) and a meandering amount measuring device 4 installed in the finishing mill 2.

[0049] In the finishing process, Figure 1The finishing mill 2 shown performs tandem rolling for simultaneously finishing steel plates 10. The finishing mill 2 includes a plurality of (n: n ≥ 3) rolling stands F1 to Fn for finish rolling the steel plates 10. Each of the rolling stands F1 to Fn is provided with a leveling device 3 for adjusting the reduction on the operating and driving sides.

[0050] Each leveling device 3 adjusts the reduction amount of a reduction device (not shown) installed on the operating side of each rolling stand F1 to Fn and the reduction amount of a reduction device (not shown) installed on the driving side of each rolling stand F1 to Fn.

[0051] In addition, in order to perform "sensor-based meandering control", the finishing mill 2 is provided with a meandering amount measuring device 4 for measuring the meandering amount of the steel plate 10 being finish-rolled by the finishing mill 2, and a meandering control device 7 for calculating the roll opening difference based on the meandering amount of the steel plate 10 calculated by the meandering amount measuring device 4 and sending the calculated roll opening difference to the leveling device 3 set in the rolling stand Fn serving as the control object, wherein the roll opening difference is the opening difference between the roll gaps on the operating side and the driving side in the rolling stand Fn serving as the control object.

[0052] The meandering amount measuring device 4 includes a line sensor camera 5 as an imaging device that periodically images the surface of the steel plate 10 during finish rolling, and a meandering amount calculating device 6 that calculates the meandering amount of the steel plate 10 based on a plurality of images captured by the line sensor camera 5. In this embodiment, the rolling stand to be controlled is the final stage rolling stand Fn, and the line sensor camera 5 is installed between the rolling stand Fn to be controlled and a rolling stand Fn-1 upstream of the rolling stand Fn.

[0053] The line array sensor camera 5 is a one-dimensional shooting device, which is composed of a CCD (charge coupled device: Charge-coupled Device) imaging sensor element, etc. Figure 4 The surface of the steel plate 10 that is being rolled is photographed in a manner that is transverse to the width direction of the steel plate 10. Figure 4 2 shows a captured image 20 captured by the line sensor camera 5. The line sensor camera 5 periodically captures the surface of the steel plate 10 traveling from the upstream stand side to the downstream stand side, and obtains a plurality of captured images 20 at a predetermined period.

[0054] The meandering amount calculation device 6 calculates the meandering amount of the steel plate 10 based on the plurality of captured images 20 captured by the line array sensor camera 5, as shown in FIG. Figure 2As shown, the apparatus comprises a captured image acquisition unit 61, a front-correction edge detection unit 62, a front-correction edge holding unit 63, a measurement reliability determination unit 64, a plate width update unit 65, a meandering amount calculation unit 66, and an output unit 67. The meandering amount calculation unit 6 is a computer system having a calculation and processing function. By executing various dedicated computer programs pre-stored on the hardware, the functions of the captured image acquisition unit 61, the front-correction edge detection unit 62, the front-correction edge holding unit 63, the measurement reliability determination unit 64, the plate width update unit 65, the meandering amount calculation unit 66, and the output unit 67 can be realized in software (steps S3 to S9 to be described later).

[0055] The captured image acquisition unit 61 of the meandering amount calculation device 6 acquires a plurality of captured images 20 of the surface of the steel plate 10 periodically captured by the line sensor camera 5 .

[0056] In addition, the pre-correction edge detection unit 62 calculates the brightness difference between adjacent portions in the width direction of each of the plurality of captured images 20 acquired by the captured image acquisition unit 61, and defines the portion where the brightness difference is maximum on the driving side in the width direction of the steel plate 10 as the driving side edge portion z of the steel plate 10. ds A plurality of portions are detected, and the portion where the brightness difference is the largest on the working side in the width direction of the steel plate 10 is defined as the working side edge portion z of the steel plate 10. ws Multiple detected.

[0057] Specifically, the pre-correction edge detection unit 62 detects the edge of each captured image 20 from the center portion in the width direction ( Figure 4 The brightness difference of adjacent pixels from the center line CL in the width direction of the steel plate in the captured image 20 shown in the figure to the driving side and the working side at both ends in the width direction is calculated, and the driving side portion where the absolute value of the brightness difference becomes the largest is defined as the driving side edge portion z of the steel plate 10. ds A plurality of portions are detected, and the portion on the working side where the absolute value of the brightness difference becomes the largest is defined as the working side edge portion z of the steel plate 10. ws Multiple detected.

[0058] Here, if the space between the rolling stand Fn and the rolling stand Fn-1 where the linear array sensor camera 5 is installed is free of steam and smoke, then Figure 5 As shown, the absolute value of the luminance difference between adjacent pixels in the width direction becomes the largest at the driving side portion (driving side edge portion z ) indicated by P1. ds ) is consistent with the actual edge portion d on the driving side of the steel plate 10. In addition, the absolute value of the brightness difference between adjacent pixels in the width direction is the largest at the working side portion (working side edge portion z ws ) is consistent with the edge portion w of the actual working side of the steel plate 10.

[0059] On the other hand, if there is steam or smoke between the rolling stand Fn and the rolling stand Fn-1 where the linear array sensor camera 5 is installed, then Figure 6 As shown, the absolute value of the luminance difference between adjacent pixels in the width direction becomes the largest at the driving side portion (driving side edge portion z ) indicated by P1. ds ) is sometimes not consistent with the actual edge portion d of the driving side of the steel plate 10. In addition, the absolute value of the brightness difference between adjacent pixels in the width direction becomes the largest at the working side portion (working side edge portion z ws ) may not coincide with the edge portion w of the actual working side of the steel plate 10. The reason for this is that electromagnetic waves including visible light and infrared rays are scattered by steam and smoke.

[0060] In addition, the correction front edge holding unit 63 holds the driving side edge portions z of the plurality of steel plates 10 detected by the correction front edge detection unit 62. ds and the working side edge z ws .

[0061] In addition, the reliability determination unit 64 measures the driving side edge portions z of the plurality of steel sheets 10 held by the pre-correction edge holding unit 63. ds and the working side edge z ws The extracted driving side edge portion (z ds (i), i = 1, 2, ... N) and the edge of the working side (z ws The sum α of the absolute values ​​of the changes expressed by the following equations (1) and (2) for each of (i), i=1, 2, ... N) is: ds , α ws When the current driving side edge portion z ds (N), working side edge z ws (N) If the reliability is determined to be low and the value is less than the predetermined threshold value β, the current driving side edge portion z ds (N), working side edge z ws (N) The reliability is determined to be high.

[0062] [Mathematical formula 3]

[0063]

[0064] [Formula 4]

[0065]

[0066] That is, the measurement reliability determination unit 64 obtains the driving side edge portions z of the plurality of steel sheets 10 held by the pre-correction edge holding unit 63. ds and the working side edge z ws data.

[0067] Then, the reliability determination unit 64 measures the driving side edge portions z of the plurality of steel plates 10 obtained. ds Extract the driving side edge parts (z ds (i), i=1, 2, ... N), calculate the extracted driving side edge portion (z ds The sum α of the absolute values ​​of the changes expressed by the above formula (1) for (i), i=1, 2, ... N) is ds In addition, similarly, the reliability determination unit 64 measures the working side edge portions z of the plurality of steel plates 10 obtained. ws Extract the working side edge parts (z ws (i), i = 1, 2, ... N), calculate the past N times of the extracted working side edge part (z ws The sum α of the absolute values ​​of the changes expressed by the above formula (2) for (i), i=1, 2, ... N) is ws .

[0068] Then, the measurement reliability determination unit 64 determines the sum α of the absolute values ​​of the changes in the driving side edge portion. ds and the sum of the absolute values ​​of the changes in the edge of the working side α ws The value of the threshold β is the amount of change between one edge in the width direction (driving side edge) and the other edge in the width direction (working side edge) of the steel plate 10, and is set to a value that is acceptable based on experience for a normal steel plate 10.

[0069] Then, the reliability determination unit 64 measures the sum α of the absolute values ​​of the changes in the driving side edge portion. ds If the current driving side edge portion z is greater than the predetermined threshold value β, ds (N) The reliability is judged to be low. If the sum of the absolute values ​​of the changes in the working side edge portion αws is greater than the predetermined threshold value β, the working side edge portion z at the current moment is changed to ws (N) The reliability is determined to be low. In addition, the reliability determination unit 64 measures the sum α of the absolute values ​​of the changes in the driving side edge portion. ds If the current driving side edge z is smaller than the predetermined threshold value β, ds (N) is judged to be highly reliable, and the sum of the absolute values ​​of the changes in the edge of the working side is α wsIf the current working side edge z is smaller than the specified threshold value β, ws (N) The reliability is determined to be high.

[0070] In addition, the measurement reliability determination unit 64 determines that the current driving side edge portion z ds (N) and the edge of the working side z ws (N) When both reliability are high, the plate width updating unit 65 of the meandering amount calculation device 6 calculates the plate width according to the current driving side edge portion z. ds (N) and the edge of the working side z ws (N) The number of pixels W' corresponding to the panel width calculated by both parties is updated to the calculated number W' (the initial value of W is the number of pixels corresponding to the set panel width). In addition, the measurement reliability determination unit 64 determines that the current driving side edge portion z ds (N) and the edge of the working side z ws If the reliability of at least one of (N) is low, the panel width updating unit 65 maintains the number of pixels W corresponding to the panel width at the number of pixels W. It should be noted that the number of pixels corresponding to the set panel width, which is the initial value of W, is sent to the panel width updating unit 65 of the meandering amount calculation device 6 from a host computer (not shown).

[0071] The meandering amount calculation unit 66 uses the current driving side edge portion z detected by the pre-correction edge detection unit 62. ds (N) and the edge of the working side z ws (N) Measure the driving side edge portion z at the current moment determined by the reliability determination unit 64. ds (N) and the edge of the working side z ws The meandering amount of the steel plate 10 is calculated based on the reliability evaluation result of (N) and the number of pixels W corresponding to the plate width stored in the plate width updating unit 65 .

[0072] Specifically, as shown in Table 1, the driving side edge portion z is determined to be the current driving side edge portion z by the measurement reliability determination unit 64. ds (N) and the edge of the working side z ws (N) When both reliability are high (case 1), the meandering amount calculation unit 66 uses the current driving side edge portion z ds (N) and the edge of the working side z ws (N) Calculate the meandering amount of the steel plate. Specifically, in the case of Example 1, if the mill center coordinate is set to 0, the coordinate amount of the center of the steel plate 10 is the meandering amount, so the meandering amount calculation unit 66 calculates z ds (N) and z ws The average value of (N) = (z ds (N)+zws (N)) / 2 is taken as the meandering amount of the steel plate 10.

[0073] [Table 1]

[0074]

[0075] In addition, as shown in Table 1, the driving side edge portion z is determined to be the current driving side edge portion z by the measurement reliability determination unit 64. ds (N) and the edge of the working side z ws (N) When only one side has high reliability (in the case of Case 2 and Case 3), the meandering amount calculation unit 66 sets the driving side edge portion z at the current moment with high reliability to ds (N) or working side edge z ws (N) is used as a reference, and the edge portion on the other side is interpolated and calculated using the pixel number W from the plate width update unit 65, and the driving side edge portion z at the current moment with high reliability is used. ds (N) or working side edge z ws (N) and the edge portion on the other side obtained by interpolation calculation, the meandering amount of the steel plate 10 is calculated.

[0076] That is, as shown in Table 1, when it is determined that only the driving side edge portion z ds (N) When the reliability is high (case 2), the meandering amount calculation unit 66 sets the driving side edge portion z at the current moment with high reliability to ds (N) is used as a reference, and the edge portion on the other side is interpolated and calculated using the number of pixels W from the plate width update unit 65, and the current driving side edge portion z with high reliability is used. ds (N) and the edge portion on the other side obtained by interpolation calculation, the meandering amount of the steel plate 10 is calculated. In the case of Example 2, at the current driving side edge portion z with high reliability, ds (N) The position obtained by adding the following value, which is 1 / 2 of the value obtained by multiplying the length x of one pixel by the number of pixels W corresponding to the plate width, is regarded as the center of the steel plate 10. ds (N) + W x / 2 is defined as the meandering amount of the steel plate 10. The center coordinate of the rolling mill is 0.

[0077] In addition, as shown in Table 1, when it is determined that only the edge portion z of the working side at the current moment is ws (N) When the reliability is high (case 3), the meandering amount calculation unit 66 calculates the working side edge portion z at the current moment with high reliability. ws (N) is used as a reference to interpolate the edge portion on the other side using the number of pixels W from the plate width update unit 65, and use the highly reliable current working side edge portion z ws(N) and the edge portion of the other side obtained by interpolation calculation, the meandering amount of the steel plate 10 is calculated. In the case of case 3, the edge portion z of the working side at the current moment with high reliability is used. ws The position obtained by subtracting 1 / 2 of the value obtained by multiplying the length x of each pixel by the number of pixels W corresponding to the plate width from (N) is regarded as the center of the steel plate 10, and z is calculated. ws (N)-W×x / 2 is defined as the meandering amount of the steel plate 10. The center coordinate of the rolling mill is 0.

[0078] In addition, as shown in Table 1, the driving side edge portion z is determined to be the current driving side edge portion z by the measurement reliability determination unit 64. ds (N) and the edge of the working side z ws (N) When both reliability levels are low (case 4), the meandering amount calculation unit 66 does not calculate the meandering amount of the steel plate 10 .

[0079] Furthermore, the output unit 67 of the meandering amount calculation device 6 sends the meandering amount of the steel plate 10 calculated by the meandering amount calculation unit 66 to the meandering control device 7 .

[0080] The snaking control device 7 calculates the roll gap difference based on the snaking amount of the steel plate 10 from the output part 67 of the snaking amount calculation device 6, and sends the calculated roll gap difference to the leveling device 3 provided in the rolling stand Fn serving as the control object. The roll gap difference is the gap difference between the rolls on the operating side and the driving side in the rolling stand Fn serving as the control object.

[0081] Based on the roll gap difference sent from the meandering control device 7, the leveling device 3 adjusts the roll gap difference of the rolling stand Fn, which is the target of control, and the roll gap difference of the rolling stand Fn, which is the target of control, so that the roll gap difference of the rolling stand Fn becomes the roll gap difference sent from the meandering control device 7. As a result, the leveling amount of the rolling stand Fn, which is the target of control, changes in proportion to the meandering amount of the steel plate 10, thereby suppressing the meandering amount of the steel plate 10.

[0082] Thus, according to the steel plate meandering amount measuring device 4 of this embodiment, the meandering amount calculating device 6 includes a measurement reliability determining unit 64 that determines the reliability of the steel plate meandering amount at the driving side edge portion (z ds (i), i = 1, 2, ... N) and the edge of the working side (z ws The sum α of the absolute values ​​of the changes expressed by the above equations (1) and (2) in each of (i), i=1, 2, ... N) is ds , α ws If the current driving side edge portion z is greater than the specified threshold, ds (N), working side edge zws (N) If the reliability is judged to be low and the value is less than a predetermined threshold, the current driving side edge portion z ds (N), working side edge z ws (N) The reliability is determined to be high. In addition, the meandering amount calculation device 6 includes a meandering amount calculation unit 66, which measures the driving side edge portion z determined by the reliability determination unit 64 at the current moment. ds (N) and the edge of the working side z ws (N) When both reliability are high, use the current driving side edge z ds (N) and the edge of the working side z ws (N) Calculate the meandering amount of the steel plate 10, and determine the driving side edge portion z at the current moment. ds (N) and the edge of the working side z ws (N) If only one side has high reliability, the driving side edge portion z at the current moment with high reliability is ds (N) or working side edge z ws (N) is used as a reference, and the edge portion on the other side is interpolated and calculated using the pixel number W from the plate width update unit 65, and the driving side edge portion z at the current moment with high reliability is used. ds (N) or working side edge z ws (N) and the edge portion on the other side obtained by interpolation calculation, calculate the meandering amount of the steel plate 10, and determine the edge portion z on the driving side at the current moment. ds (N) and the edge of the working side z ws (N) When both reliability levels are low, the meandering amount of the steel plate 10 is not calculated.

[0083] Thus, a steel plate meandering amount measuring device 4 can be provided that can accurately measure the meandering amount of the steel plate 10, not only when the two edges of the steel plate 10 are detected, but also when one edge of the steel plate 10 is covered by steam or smoke and the edge cannot be detected, and the other edge is not covered by steam or smoke and the edge can be detected.

[0084] The meandering amount calculation device 6 includes an output unit 67 for outputting the meandering amount of the steel plate 10 calculated by the meandering amount calculation unit 66 to the meandering control device 7. Thus, the meandering control device 7 can appropriately control the leveling of the rolling stand Fn as the control target based on the meandering amount measured by the meandering amount measurement device 4.

[0085] Furthermore, the hot rolling mill 1 of the hot-rolled steel strip of the present embodiment includes a meandering amount measuring device 4. Thus, it is possible to provide a hot rolling mill 1 of the hot-rolled steel strip that can accurately measure the meandering amount of the steel plate 10, not only when both edges of the steel plate 10 are detected, but also when one edge of the steel plate 10 is covered by steam or smoke and cannot be detected, while the other edge is not covered by steam or smoke and can be detected.

[0086] Next, refer to Figure 3 The flowchart shown in FIG. 1 illustrates a process flow of the meandering amount measuring device 4 showing a meandering amount measuring method according to one embodiment of the present invention.

[0087] First, finish rolling of the steel plate 10 is started. In step S1, the line sensor camera 5 determines whether the leading end of the steel plate 10 is detected. The line sensor camera 5 is provided with a steel plate detection sensor (not shown) for detecting the leading and trailing ends of the steel plate 10.

[0088] Then, if the determination result of the line sensor camera 5 is yes (if the front end portion is detected), the process proceeds to step S2 , and if the determination result is no (if the front end portion is not detected), the process returns to step S1 .

[0089] In step S2 , the line sensor camera 5 periodically images the surface of the steel plate 10 that is advancing during rolling, so as to cross the width direction of the steel plate 10 (imaging step).

[0090] Next, the process proceeds to step S3 , where the captured image acquisition unit 61 of the meandering amount calculation device 6 acquires a plurality of captured images 20 of the surface of the steel plate 10 periodically captured by the line sensor camera 5 (captured image acquisition step).

[0091] Next, the process proceeds to step S4, where the correction front edge detection unit 62 calculates the brightness difference between adjacent portions in the width direction of each of the plurality of captured images 20 acquired in step S3, and detects the portion where the brightness difference becomes maximum on the driving side in the width direction of the steel plate 10 as the driving side edge portion z of the steel plate 10. ds The portion where the brightness difference becomes the largest on the working side in the width direction of the steel plate 10 is detected as the working side edge portion z of the steel plate 10. ws (Corrected front edge detection step).

[0092] Next, the process proceeds to step S5, and the front edge holding section 63 holds the plurality of driving side edge portions z detected in step S4. ds and the working side edge z ws (Correct the front edge holding step).

[0093] Next, the process proceeds to step S6, where the reliability determination unit 64 measures the driving side edge z of the plurality of steel sheets 10 held in step S5. ds and the working side edge z ws The extracted driving side edge portion (z ds (i), i = 1, 2, ... N) and the edge of the working side (z ws The sum α of the absolute values ​​of the changes expressed by the above equations (1) and (2) in each of (i), i=1, 2, ... N) is ds , α ws When the current driving side edge portion z ds (N), working side edge z ws (N) If the reliability is judged to be low and the value is less than the predetermined threshold value β, the current driving side edge portion z ds (N), working side edge z ws (N) The reliability is determined to be high (measurement reliability determination step).

[0094] Next, the process proceeds to step S7, and the driving side edge portion z is determined to be the current driving side edge portion z in step S6. ds (N) and the edge of the working side z ws (N) When both reliability are high, the plate width updating unit 65 calculates the plate width according to the current driving side edge portion z. ds (N) and the edge of the working side z ws (N) The number of pixels W' corresponding to the plate width calculated by both parties is updated to the calculated number W' of pixels corresponding to the plate width (the initial value of W is the number of pixels corresponding to the set plate width). ds (N) and the edge of the working side z ws When the reliability of at least one of (N) is low, the panel width updating unit 65 maintains the number of pixels W corresponding to the panel width at the number of pixels W (panel width updating step).

[0095] Next, the process proceeds to step S8, and the driving side edge portion z is determined to be the current driving side edge portion z in step S6. ds (N) and the edge of the working side z ws (N) When both reliability are high, the meandering amount calculation unit 66 uses the current driving side edge portion z ds (N) and the edge of the working side z ws (N) Calculate the meandering amount of the steel plate 10. In addition, in step S6, it is determined that the current driving side edge portion z ds (N) and the edge of the working side z ws(N) If only one side has high reliability, the meandering amount calculation unit 66 sets the driving side edge portion z at the current moment with high reliability to ds (N) or working side edge z ws (N) is used as a reference, and the edge portion on the other side is interpolated using the number of pixels W from step S7, and the edge portion z at the current time of the driving side with high reliability is used. ds (N) or working side edge z ws (N) and the edge portion on the other side obtained by interpolation calculation, the meandering amount of the steel plate 10 is calculated. ds (N) and the edge of the working side z ws (N) When both reliability levels are low, the meandering amount calculation unit 66 does not calculate the meandering amount of the steel sheet 10 (meandering amount calculation step).

[0096] Next, the process proceeds to step S9 , and the output unit 67 of the meandering amount calculation device 6 sends the meandering amount of the steel plate 10 calculated in step S8 to the meandering control device 7 (output step).

[0097] Finally, the process proceeds to step S10, where the linear array sensor camera 5 determines whether the tail end of the steel plate 10 has been detected. If the linear array sensor camera 5 determines that the tail end has been detected, the process ends. If the determination result is negative (the tail end has not been detected), the process returns to step S2.

[0098] Thus, the processing of the meandering amount measuring device 4 ends.

[0099] Thus, according to the meandering amount measuring method of this embodiment, in the measurement reliability determination step (step S6), the driving side edge portion (z ds (i), i = 1, 2, ... N) and the edge of the working side (z ws The sum α of the absolute values ​​of the changes expressed by the above equations (1) and (2) in each of (i), i=1, 2, ... N) is ds , α ws If the current driving side edge portion z is greater than the specified threshold, ds (N), working side edge z ws (N) If the reliability is judged to be low and the value is less than a predetermined threshold, the current driving side edge portion z ds (N), working side edge z ws (N) The reliability is determined to be high. In the meandering amount measuring method, in the meandering amount calculating step (step S8), the driving side edge portion z is determined to be high at the current moment in the measurement reliability determining step (step S6).ds (N) and the edge of the working side z ws (N) When both reliability are high, use the current driving side edge z ds (N) and the edge of the working side z ws (N) Calculate the meandering amount of the steel plate 10. ds (N) and the edge of the working side z ws (N) If only one side has high reliability, the driving side edge portion z at the current moment with high reliability is ds (N) or working side edge z ws (N) is used as a reference, and the edge portion on the other side is interpolated and calculated using the pixel number W from the plate width update unit 65, and the driving side edge portion z at the current moment with high reliability is used. ds (N) or working side edge z ws (N) and the edge portion on the other side obtained by interpolation calculation, the meandering amount of the steel plate 10 is calculated. ds (N) and the edge of the working side z ws (N) When both reliability levels are low, the meandering amount of the steel plate 10 is not calculated.

[0100] Thus, a method for measuring the meandering amount of a steel plate can be provided, which can not only detect both edges of the steel plate 10 when measuring the meandering amount of the steel plate during rolling, but also accurately measure the meandering amount of the steel plate 10 even when one edge of the steel plate 10 is covered by steam or smoke and cannot be detected, and the other edge is covered by steam or smoke and can be detected.

[0101] The meandering amount measuring method of this embodiment also includes an output step (step S9) of outputting the meandering amount of the steel plate 10 calculated in the meandering amount calculating step (step S8) to the meandering control device. Thus, the meandering control device 7 can appropriately control the leveling of the rolling stand Fn, which is the control target, based on the meandering amount measured in the meandering amount measuring step.

[0102] The hot rolling method of a hot-rolled steel strip according to the present embodiment includes a step of measuring the amount of meandering of a steel plate 10 being rolled in a finishing mill 2 having a plurality of rolling stands F1 to Fn using the meandering amount measuring method. This provides a method for hot rolling a hot-rolled steel strip that can accurately measure the amount of meandering of the steel plate 10 during rolling, not only in situations where both edges of the steel plate 10 can be detected, but also in situations where one edge of the steel plate 10 is covered by steam or fume, making edge detection impossible, while the other edge is covered by steam or fume, making edge detection possible.

[0103] Although the embodiments of the present invention have been described above, the present invention is not limited thereto, and various changes and improvements can be made.

[0104] For example, the imaging device does not need to be a line sensor camera 5 but may also be an area sensor camera.

[0105] In addition, it is also possible that, in the pre-correction edge detection unit 62 (pre-correction detection step), when calculating the luminance difference between adjacent pixels in the width direction of the captured image 20, the luminance difference between adjacent pixels is calculated not only from the width-wise central portion of the captured image 20 to each of the driving side and the working side at both ends in the width direction, but also from the working side at one width-wise end of the captured image 20 to the width-wise central portion and to the driving side at one width-wise end of the captured image 20.

[0106] Alternatively, in the plate width updating section 65 (plate width updating step), the plate width may be updated based on the current driving side edge portion z. ds (N) and the edge of the working side z ws (N) When the number of pixels W' corresponding to the plate width calculated by both parties is within the preset upper and lower limits, the number of pixels W corresponding to the plate width is updated to the calculated W'. When the calculated W' deviates from the preset upper and lower limits, the number of pixels W corresponding to the plate width is maintained at the pixel number W. In this way, when the number of pixels W' calculated by the plate width updating unit 65 (plate width updating step) deviates from the number of pixels corresponding to the normal plate width of the steel plate 10, the plate width update operation is not required, and the processing time in the meandering amount calculation process can be shortened. In addition, the "preset upper and lower limits" refers to the upper and lower limits of the number of pixels corresponding to the normal plate width of the steel plate 10.

[0107] In addition, the linear array sensor camera 5 serving as a shooting device is arranged between the rolling stand Fn serving as the control object and a rolling stand Fn-1 on its upstream side, but is not limited to this. It can also be arranged between any of the adjacent rolling stands F1 and F2, F2 and F3,..., Fn-1 and Fn.

[0108] In addition, the meandering amount measuring device 4 and meandering amount measuring method of this embodiment are used to measure the meandering amount of the steel plate 10 being rolled using the finishing mill 2 of the hot rolling equipment 1, but can also be used to measure the meandering amount of the steel plate being rolled using the continuous cold rolling mill of the cold rolling equipment.

[0109] Example

[0110] The present inventors use a hot rolling equipment 1 having 7 rolling stands F1 to F7 to perform finish rolling on a steel plate 10. At this time, a linear array sensor camera 5 arranged between the rolling stand F6 and the rolling stand F7 as the control object is used to periodically photograph the surface of the steel plate 10. A meandering amount calculation device 6 is used to calculate the meandering amount of the steel plate 10 in the comparative example and the present invention example based on multiple captured images 20 captured by the linear array sensor camera 5.

[0111] Here, in Figure 7 , a two-dimensional image is shown in which a plurality of images 20 captured periodically by the line array sensor camera 5 are connected along the longitudinal direction of the steel plate 10. Figure 7 In the two-dimensional image shown, what appears to be clouds is water vapor present on the surface of the steel plate 10. Water vapor and smoke may be present on the surface of the steel plate 10 not only in winter but also in summer. The present invention can accurately measure the amount of meandering of the steel plate, not only in winter but also in summer, even when one edge of the steel plate 10 is covered by steam or the like and cannot be detected, while the other edge is not covered by steam or the like and can be detected.

[0112] With respect to this two-dimensional image, the meandering amount of the steel plate 10 was calculated in the comparative example and the example of the present invention.

[0113] In the comparative example, the meandering amount of the steel plate 10 is calculated in the next step.

[0114] Step 1: Calculate the brightness difference between adjacent points in the width direction of the two-dimensional image, and take the point where the absolute value of the brightness difference is the largest on the driving side of the steel plate 10 in the width direction as the driving side edge point z of the steel plate 10. ds A plurality of edges are detected, and the portion where the absolute value of the brightness difference becomes the largest on the working side in the width direction of the steel plate 10 is defined as the working side edge portion z of the steel plate. ws Multiple detected.

[0115] Step 2: For the past 100 times including the current time, the driving side edge part (z ds (i), i = 1, 2, ... 100) and the edge of the working side (z ws (i), i = 1, 2, ... 100) are regressed to find the driving side edge part (z ds (i), i = 1, 2, ... 100) and the edge of the working side (z ws (i), i=1, 2, ... 100) and estimate the driving side edge portion and the working side edge portion at the current moment based on the approximate straight line.

[0116] Step 3: Using the current driving side edge portion and the working side edge portion estimated in step 2, the meandering amount of the steel plate 10 is calculated.

[0117] In addition, in the example of the present invention, the meandering amount of the steel plate 10 is calculated in the next step.

[0118] Step 1: Calculate the brightness difference between adjacent points in the width direction of the two-dimensional image, and take the point where the absolute value of the brightness difference is the largest on the driving side of the steel plate 10 in the width direction as the driving side edge point z of the steel plate 10. ds A plurality of edges are detected, and the portion where the absolute value of the brightness difference becomes the largest on the working side in the width direction of the steel plate 10 is defined as the working side edge portion z of the steel plate. ws Multiple detected.

[0119] Step 2: In the past N=20 times including the current time, the driving side edge portion (z ds (i), i = 1, 2, ... N = 20) and the edge of the working side (z ws The sum α of the absolute values ​​of the changes expressed by the above equations (1) and (2) in each of (i), i=1, 2, ... N=20) is ds , α ws If the current driving side edge portion z ds (N), working side edge z ws (N) If the reliability is determined to be low and the value is less than the predetermined threshold value β, the current driving side edge portion z ds (N), working side edge z ws (N) is determined to be highly reliable. Here, β is set to 30 px (number of pixels) × the length of each 1 px (one pixel) (2 mm) = 60 mm. It should be noted that in β, the number of pixels is preferably 5 or more and 100 or less, and more preferably 10 or more and 50 or less.

[0120] Step 3: The driving side edge portion z determined in step 2 at the current moment ds (20) and the edge of the working side z ws (20) When both reliability are high, calculate the current driving side edge position z ds (20) and the edge of the working side z ws (20) The number of pixels W' corresponding to the plate width calculated by both parties is updated to the calculated W', and the edge portion z of the driving side is determined to be the current moment. ds (20) and the edge of the working side z ws When the reliability of at least one of (20) is low, the number of pixels W corresponding to the panel width is maintained at the number of pixels W.

[0121] Step 4: The driving side edge portion z determined in step 2 at the current momentds (20) and the edge of the working side z ws (20) When both reliability is high, use the current driving side edge z ds (20) and the edge of the working side z ws (20) Calculate the meandering amount of the steel plate 10, and determine the driving side edge portion z at the current moment. ds (20) and the edge of the working side z ws (20) If only one side has high reliability, the edge portion z of the driving side with high reliability at the current moment will be ds (20) or the edge of the working side z ws (20) As a reference, the number of pixels W from step 3 is used to interpolate the edge portion on the other side, and the current driving side edge portion z with high reliability is used. ds (20) or the edge of the working side z ws (20) and the edge portion of the other side obtained by interpolation calculation, calculate the meandering amount of the steel plate 10, and determine the edge portion z on the driving side at the current moment. ds (20) and the edge of the working side z ws (20) When the reliability of both sides is low, the meandering amount of the steel plate 10 is not calculated.

[0122] In the comparative example and the present invention, after executing step 1 and detecting the driving side edge portion and the working side edge portion of the steel plate 10, Figure 8 As shown, the driving side edge portion is shown with a solid line, and the working side edge portion is shown with a dotted line. Figure 8 It is understood that due to the strong influence of steam, the detected driving side edge portion and working side edge portion may not necessarily be the edge of the steel plate 10 but may be the inside of the steel plate 10 .

[0123] Then, in Figure 9 The results of calculating the meandering amount of the steel plate 10 using the comparative example are shown in FIG. Figure 9 In the figure, the unit of the driving side edge portion, the working side edge portion and the amount of snaking is expressed in px (pixels). Figure 9 As shown in (c), in the comparative example, the measured value of the meandering amount changes by about 50px around 4000 in the data order. This is because Figure 9As shown in (b), the estimated driving-side edge of the steel plate 10 is poor around data order 4000. When this fluctuating meandering amount is output to the meandering control device 7 and leveling control is performed, the leveling setting in the controlled rolling stand F7 becomes poor, promoting meandering of the steel plate 10. It should be noted that even when the number of past data used in the regression is changed from 100 to another value, good results are not obtained. Furthermore, the tail end portion after data order 14000 is also strongly affected by steam.

[0124] Therefore, in the comparative example, when measuring the amount of meandering of the steel plate 10 during rolling, if one edge of the steel plate 10 is covered by steam and smoke and the edge (driving side edge) cannot be detected, and the other edge (working side edge) is covered by steam and smoke and the edge detection can be performed, the amount of meandering of the steel plate 10 cannot be accurately measured.

[0125] On the other hand, Figure 10 The results of calculating the meandering amount of the steel plate 10 using the present invention example are shown in FIG. Figure 10 In the diagram, the units of the driving side edge, working side edge and meandering amount are also expressed in px (pixels). Figure 10 As shown in (c), in the present invention example, the measured values ​​of the amount of meandering become substantially uniform, and the influence of the amount of meandering on the measured values ​​due to steam is alleviated. In the comparative example, the driving side of the steel plate 10 at data order approximately 4000 is covered by steam and smoke, making it impossible to detect the edge of the driving side.

[0126] Therefore, in the example of the present invention, when measuring the amount of meandering of the steel plate 10 during rolling, the amount of meandering of the steel plate 10 can be accurately measured when one edge of the steel plate 10 is covered by steam and smoke and the edge (driving side edge) cannot be detected, and the other edge (working side edge) is covered by steam and smoke and the edge detection can be performed.

[0127] It should be noted that in the example of the present invention, the positions where the meandering amount becomes 0px after the data sequence is 14000 are low reliability positions at both edges, and since the output to the meandering control device 7 is not controlled, there is no actual damage.

[0128] In addition, Figure 11 Calculated values ​​of meandering amounts of steel plates calculated using the examples of the present invention and the comparative examples are shown in FIG. Figure 11 In the example of the present invention, compared with the comparative example, the data sequence is from 0 (the front end of the steel plate 10) to 14000 (the tail end of the steel plate 10), the meandering amount of the steel plate 10 becomes roughly uniform, the meandering amount can be appropriately measured, and the leveling operation of the meandering control using the meandering amount can be expected to be appropriate.

[0129] Description of Reference Signs

[0130] 1Hot rolling equipment

[0131] 2 Finishing mill (rolling mill)

[0132] 3 Leveling device

[0133] 4. Snake amount measuring device

[0134] 5-line sensor camera (shooting device)

[0135] 6Snake amount calculation device

[0136] 7Snake control device

[0137] 10 steel plates

[0138] 20 capture images

[0139] 61 captured image acquisition unit

[0140] 62 Correction of the front edge detection unit

[0141] 63 Modify the front edge holding part

[0142] 64 Measurement reliability judgment unit

[0143] 65 board width update department

[0144] 66 Snake Amount Calculation Department

[0145] 67 output unit

[0146] F1~Fn rolling stands

Claims

1. A device for measuring the amount of meandering of a steel plate, for measuring the amount of meandering of a steel plate being rolled in a rolling mill having a plurality of rolling stands, wherein: The invention comprises: an imaging device, the imaging device being provided between adjacent rolling stands and periodically imaging the surface of the steel plate traveling during rolling; and a meandering amount calculation device, the meandering amount calculation device calculating the meandering amount of the steel plate based on a plurality of images captured by the imaging device. The meandering amount calculation device comprises: The correction front edge detection unit calculates the brightness difference between adjacent images in the width direction of each of the plurality of images periodically captured by the imaging device, and defines a portion where the absolute value of the brightness difference becomes the largest on the driving side in the width direction of the steel plate as the driving side edge portion z of the steel plate. ds A plurality of locations are detected, and the location where the absolute value of the brightness difference is the largest on the working side in the width direction of the steel plate is defined as the working side edge location z of the steel plate. ws Multiple detected; The measurement reliability determination unit is configured to determine the reliability of the plurality of driving side edge portions z detected by the pre-correction edge detection unit. ds and the working side edge z ws The extracted driving side edge portion (z ds (i), i = 1, 2, ... N) and the edge of the working side (z ws The sum α of the absolute values ​​of the changes expressed by the following formula (1) and formula (2) in each of (i), i=1, 2, ... N) is: ds , α ws If the current driving side edge portion z is greater than the specified threshold value, ds (N), working side edge z ws (N) If the reliability is judged to be low and the value is less than a predetermined threshold, the current driving side edge portion z ds (N), working side edge z ws (N) judged to be highly reliable; The plate width updating unit is a unit that determines that the current driving side edge portion z is ds (N) and the edge of the working side z ws (N) If both are highly reliable, calculate the current driving side edge position z ds (N) and the edge of the working side z ws (N) The number of pixels W' corresponding to the plate width calculated by both parties is updated to the calculated W', and the edge portion z of the driving side is determined to be the current time. ds (N) and the edge of the working side z ws If at least one of (N) has low reliability, the number of pixels W corresponding to the panel width is maintained at the number of pixels W; as well as The meandering amount calculation unit determines that the driving side edge portion z at the current moment is ds (N) and the edge of the working side z ws (N) When both are highly reliable, use the current driving side edge z ds (N) and the edge of the working side z ws (N) Calculate the meandering amount of the steel plate, and determine the driving side edge portion z at the current moment. ds (N) and the edge of the working side z ws If only one of the two (N) has high reliability, the current driving side edge portion z with high reliability is ds (N) or working side edge z ws (N) is used as a reference to interpolate the edge portion on the other side using the number of pixels W from the plate width update unit, and the current driving side edge portion z with high reliability is used. ds (N) or working side edge z ws (N) and the edge portion on the other side after interpolation calculation, the meandering amount of the steel plate is calculated, and the edge portion z on the driving side at the current moment is determined to be ds (N) and the edge of the working side z ws (N) If both are of low reliability, the meandering amount of the steel plate is not calculated. [Mathematical formula 1] [Mathematical formula 2] 2. The device for measuring the meandering amount of a steel plate according to claim 1, wherein: In the plate width updating section, the plate width is calculated based on the current driving side edge portion z ds (N) and the edge of the working side z ws (N) When both parties calculate the number of pixels W' corresponding to the board width, if the calculated W' is within the preset upper and lower limits, the number of pixels W corresponding to the board width will be updated to the calculated W'; if the calculated W' deviates from the preset upper and lower limits, the number of pixels W corresponding to the board width will be maintained at the pixel number W.

3. The device for measuring the meandering amount of a steel plate according to claim 1 or 2, wherein: The meandering amount calculation device includes a front-correction edge holding unit for holding a plurality of driving-side edge portions z of the steel plates detected by the front-correction edge detection unit. ds and the working side edge z ws The measurement reliability determination unit obtains the driving side edge portions z of the plurality of steel plates held by the pre-correction edge holding unit. ds and the working side edge z ws Each in.

4. The device for measuring the meandering amount of a steel plate according to claim 1 or 2, wherein: The meandering amount calculation device includes an output unit that outputs the meandering amount of the steel plate calculated by the meandering amount calculation unit to a meandering control device.

5. The device for measuring the meandering amount of a steel plate according to claim 3, wherein: The meandering amount calculation device includes an output unit that outputs the meandering amount of the steel plate calculated by the meandering amount calculation unit to a meandering control device.

6. Hot rolling equipment for hot rolled steel strip, characterized in that A device for measuring the amount of meandering of a steel plate according to any one of claims 1 to 5 is provided.

7. A method for measuring the amount of meandering of a steel plate, comprising measuring the amount of meandering of a steel plate being rolled using a rolling mill having a plurality of rolling stands, the method comprising: a photographing step of periodically photographing the surface of the steel plate during rolling using a photographing device disposed between adjacent rolling stands; In the corrected front edge detection step, the brightness difference between adjacent images in the width direction of each of the plurality of images periodically captured in the capturing step is calculated, and the portion where the absolute value of the brightness difference becomes the largest on the driving side in the width direction of the steel plate is defined as the driving side edge portion z of the steel plate. ds A plurality of portions are detected, and the portion where the absolute value of the brightness difference becomes the largest on the working side in the width direction of the steel plate is taken as the working side edge portion z of the steel plate. ws Multiple detected; In the step of determining the reliability of the measurement, the plurality of driving side edge portions z detected in the step of detecting the edge before correction are detected. ds and the working side edge z ws The extracted driving side edge portion (z ds (i), i = 1, 2, ... N) and the edge of the working side (z ws The sum α of the absolute values ​​of the changes expressed by the following formula (1) and formula (2) in each of (i), i=1, 2, ... N) is: ds , α ws If the current driving side edge portion z is greater than the specified threshold value, ds (N), working side edge z ws (N) If the reliability is judged to be low and the value is less than a predetermined threshold, the current driving side edge portion z ds (N), working side edge z ws (N) judged to be highly reliable; The plate width updating step is a step of determining the driving side edge portion z at the current moment in the measurement reliability determination step. ds (N) and the edge of the working side z ws (N) If both are highly reliable, calculate the current driving side edge position z ds (N) and the edge of the working side z ws (N) The number of pixels W' corresponding to the plate width calculated by both parties is updated to the calculated W', and the edge portion z of the driving side is determined to be the current time. ds (N) and the edge of the working side z ws When at least one of (N) has low reliability, the number of pixels W corresponding to the panel width is maintained at the number of pixels W; and The meandering amount calculation step is a step of determining the driving side edge portion z at the current moment in the measurement reliability determination step. ds (N) and the edge of the working side z ws (N) When both are highly reliable, use the current driving side edge z ds (N) and the edge of the working side z ws (N) Calculate the meandering amount of the steel plate, and determine the driving side edge portion z at the current moment. ds (N) and the edge of the working side z ws If only one of the two (N) has high reliability, the current driving side edge portion z with high reliability is ds (N) or working side edge z ws (N) is used as a reference, and the edge portion on the other side is interpolated using the number of pixels W from the plate width update step, and the edge portion z at the current moment of high reliability is used. ds (N) or working side edge z ws (N) and the edge portion on the other side after interpolation calculation, the meandering amount of the steel plate is calculated, and the edge portion z on the driving side at the current moment is determined to be ds (N) and the edge of the working side z ws (N) If both are of low reliability, the meandering amount of the steel plate is not calculated. [Mathematical formula 1] [Mathematical formula 2] 8. The method for measuring the meandering amount of a steel plate according to claim 7, wherein: In the plate width updating step, the driving side edge portion z is calculated based on the current time. ds (N) and the edge of the working side z ws (N) When both parties calculate the number of pixels W' corresponding to the board width, if the calculated W' is within the preset upper and lower limits, the number of pixels W corresponding to the board width will be updated to the calculated W'; if the calculated W' deviates from the preset upper and lower limits, the number of pixels W corresponding to the board width will be maintained at the pixel number W.

9. The method for measuring the meandering amount of a steel plate according to claim 7 or 8, wherein: The plurality of driving side edge portions z of the steel plates detected in the pre-correction edge detection step are included. ds and the working side edge z ws The step of holding the corrected front edge is performed, and in the step of determining the reliability of the measurement, the driving side edge portions z of the plurality of steel plates held in the step of holding the corrected front edge are obtained. ds and the working side edge z ws Each in.

10. The method for measuring the meandering amount of a steel plate according to claim 7 or 8, wherein: The method includes an output step of outputting the meandering amount of the steel plate calculated in the meandering amount calculation step to a meandering control device.

11. The method for measuring the meandering amount of a steel plate according to claim 9, wherein: The method includes an output step of outputting the meandering amount of the steel plate calculated in the meandering amount calculation step to a meandering control device.

12. A hot rolling method for a hot rolled steel strip, characterized in that: include: A step of measuring the amount of meandering of a steel plate being rolled in a rolling mill having a plurality of rolling stands using the method for measuring the amount of meandering of a steel plate according to any one of claims 7 to 11.

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