An automatic detection and control method for holes at the head of hot-rolled strip

Abstract

The present invention discloses an automatic detection and control method for holes at the head of hot-rolled strip. An image capturing device is arranged at the outlet position of the hot-rolling roughing mill. The head image of the strip is obtained by using the image capturing device and conveyed to an image analysis and recognition system. Whether there is a cracking defect at the head of the strip is identified from the head image by the image analysis and recognition system, and the length of the cracking defect is calculated. The result is conveyed to the flying shear control system, and the flying shear cutting device is controlled by the flying shear control system to completely cut off the cracked part at the head of the strip. The present invention avoids production accidents in the rolling production line caused by the cracking of the strip head.

Description

Technical Field

[0001] The present invention relates to the production technology of hot-rolled strip steel, and more specifically, to an automatic detection and control method for holes in the head of hot-rolled strip steel. Background Art

[0002] During the production process of hot-rolled strip steel, due to certain reasons, the head of the strip steel may crack during the rough rolling process. The cracked strip steel will cause serious production accidents such as threading scrap when entering the finish rolling mill for rolling.

[0003] Currently, there is no detection system for the cracking of the strip steel head in hot-rolled production, and there is no flying shear control strategy for the cracked strip steel head. Only relying on the operator to view the image on the strip head and tail shape detector, and manually judge whether the strip steel head is cracked. If it is found that the strip steel head is cracked, the operator manually adjusts the shear amount of the flying shear head. However, this method not only has a large workload for the operator but also is prone to misjudgment. Therefore, scrap caused by missed detection of the cracked strip steel head occasionally occurs on the production line. Summary of the Invention

[0004] Aiming at the above-mentioned defects existing in the prior art, the purpose of the present invention is to provide an automatic detection and control method for holes in the head of hot-rolled strip steel to avoid production accidents on the rolling production line caused by the cracking of the strip steel head.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] An automatic detection and control method for holes in the head of hot-rolled strip steel:

[0007] An image capturing device is set at the outlet position of the hot-rolled roughing mill. The head image of the strip steel is obtained by using the image capturing device, and the head image is transmitted to the image analysis and recognition system. Through the image analysis and recognition system, it is identified whether there is a cracking defect in the head of the strip steel from the head image, and the length of the cracking defect is calculated, and the result is transmitted to the flying shear cutting control system. The flying shear cutting control system controls the flying shear cutting device to completely cut off the cracked part of the head of the strip steel.

[0008] Preferably, the process of the image analysis and recognition system for recognizing the head image and calculating the cracking defect is as follows:

[0009] 1) Determine the line height L of the head image;

[0010] 2) Determine the effective width W of the strip steel in the head image;

[0011] 3) Determine the starting position P0 for finding the cracking defect of the head of the strip steel in the head image;

[0012] 4) Calculate the pixel threshold Y of the cracking defect;

[0013] 5) Determine the size and location of the cracking defect.

[0014] Preferably, in step 2), the effective width W of the strip is calculated as follows:

[0015] W = f(1 / 2L)

[0016] In the above formula, L represents the line height of the head image, and f is a function, that is, the relationship between W and L:

[0017] W = f(W)W = 1 / 2L.

[0018] Preferably, in step 3), the starting position P0 for finding the head cracking defect of the strip is calculated as follows:

[0019] P0 = f(W*95%); or

[0020] Take the starting position of the shear line as the starting position for finding the head cracking defect of the strip;

[0021] In the above formula, W represents the effective width of the strip in the head image, and f is a function, that is, the relationship between P0 and W:

[0022] P0 = f(P0)P0 = W*95%.

[0023] Preferably, in step 4), the pixel threshold Y of the cracking defect is calculated as follows:

[0024] Y = f[(1 - 0.35)*W]

[0025] In the above formula, W represents the effective width of the strip in the head image, and f is a function, that is, the relationship between Y and W:

[0026] Y = f(Y)Y = (1 - 0.35)*W.

[0027] Preferably, step 5) further includes:

[0028] If it is determined that there is a cracking defect at the head of the strip in the head image, then the row position where the cracking defect is less than the pixel threshold Y is used as the starting position of the cracking defect, and the row position where the cracking defect is not less than the pixel threshold Y is used as the ending position of the cracking defect. The serial number difference between the two rows is the height △L3 of the cracking defect. The end position Ls of the shear line, that is, the hole, plus an adjustment margin K, namely:

[0029] △L3 = Ls + K.

[0030] Preferably, the flying shear control system controls the flying shear equipment to shear the head length △L of the stripn The calculation is as follows:

[0031] △L n = △L1 + △L2 + △L3

[0032] In the above formula, △L1 represents the optimized system shearing length of the nth strip steel, which is calculated by the optimized shearing system according to the obtained image, with the unit of mm; △L2 represents the operator attachment shearing length of the nth strip steel, which is corrected by the operator according to the actual shearing result and manually input, with the unit of mm.

[0033] An automatic detection and control method for holes at the head of hot-rolled strip steel provided by the present invention realizes automatic detection of holes at the head of strip steel and performs special shearing control of flying shear, avoiding the occurrence of rolling scrap accidents in subsequent finishing mills and ensuring that the strip steel with defects can be produced normally. Description of the Drawings

[0034] Figure 1 is a schematic diagram of the on-site layout of the image capture device in the automatic detection and control method for holes at the head of hot-rolled strip steel of the present invention;

[0035] Figure 2 is a schematic diagram of the parameter positions on the head image in the automatic detection and control method for holes at the head of hot-rolled strip steel of the present invention;

[0036] Figure 3 is a schematic flowchart of the recognition and calculation process of the image analysis and recognition system in the automatic detection and control method for holes at the head of hot-rolled strip steel of the present invention;

[0037] Figure 4 is a schematic diagram of the principle of the recognition and calculation process of the image analysis and recognition system in the automatic detection and control method for holes at the head of hot-rolled strip steel of the present invention. Detailed Embodiments

[0038] In order to better understand the above technical solutions of the present invention, the technical solutions of the present invention will be further described below with reference to the drawings and embodiments.

[0039] Combined with Figure 1 as shown, an automatic detection and control method for holes at the head of hot-rolled strip steel provided by the present invention:

[0040] An image capturing device 1 is set at the exit position of the hot rolling roughing mill (the position between the conventional hot continuous rolling roughing mill and the finishing mill 100). The head image of the strip 2 is obtained by using the image capturing device 1 and sent to the image analysis and recognition system 4. Whether there is a cracking defect at the head of the strip 2 is recognized from the head image by the image analysis and recognition system 4, and the length of the cracking defect is calculated. The calculation result is sent to the flying shear control system 5, and the flying shear control system 5 controls the flying shear cutting device 3 to completely cut off the cracked part of the head of the strip 1 and then enter the finishing mill 100 to ensure the normal and smooth production of the strip 2.

[0041] Combined with Figure 2 As shown, the recognition and calculation process of the head image by the image analysis and recognition system 4 is as follows:

[0042] 1) Determine the line height L of the head image, that is:

[0043] Input the effective line height L of the head image;

[0044] 2) Determine the effective width W of the strip in the head image, that is:

[0045] The width at the center position of the line height L is the effective width W of the strip 2, W = f(1 / 2L);

[0046] In the above formula, L represents the line height of the head image, and f represents;

[0047] The up and down 5 line pixel deviation of the center position of the head image is not greater than 10 pix as the effective width W of the strip 2, otherwise take the width at the position 20 lines plus the center position of the head image as the effective width W of the strip 2;

[0048] 3) Determine the starting position P0 for finding the cracking defect at the head of the strip 2 in the head image, that is:

[0049] P0 = f(W * 95%)

[0050] In the above formula, W represents the effective width of the strip 2 in the head image, and f represents;

[0051] The starting position P0 for finding the cracking defect at the head of the strip 2 is the 95% position of the effective width W of the strip starting from the starting point of the head image, or directly take the starting position of the shear line as the starting position P0 for finding the cracking defect at the head of the strip 2;

[0052] 4) Calculate the pixel threshold Y of the cracking defect, that is, the pixel threshold Y for whether there is a cracking defect is calculated as:

[0053] Y = f[(1 - 0.35) * W]

[0054] In the above formula, W represents the effective width of the strip steel in the head image, and f represents;

[0055] The basis for judging whether the strip steel 2 has a cracking defect is that the number of row pixels after the starting point of image search is less than 65% of the effective width W of the strip steel 2 in the head image, and it is less than the pixel threshold Y for 5 consecutive rows;

[0056] 5) Determine the size and position of the cracking defect, that is:

[0057] If it is determined that there is a cracking defect at the head of the strip steel 2 in the head image, the row position where the cracking defect is less than the pixel threshold Y is used as the starting position of the cracking defect, and the row position where the cracking defect is not less than the pixel threshold Y is used as the ending position of the cracking defect. The serial number difference between the two rows is the height △L3 of the cracking defect, that is:

[0058] △L3 = Ls + K.

[0059] In the above formula, Ls represents the ending position of the hole, and K represents the correction amount at this position.

[0060] The image analysis and recognition system 4 transmits the recognition and calculation results to the flying shear control system 5, and the flying shear control system 5 controls the flying shear cutting device 3 to cut the head length △L of the strip steel 2 n The calculation is as follows:

[0061] △L n = △L1 + △L2 + △L3

[0062] In the above formula, △L1 represents the optimized system cutting length of the nth strip steel, in mm; △L2 represents the operator accessory cutting length of the nth strip steel, in mm.

[0063] Embodiment

[0064] Refer again to Figure 1As shown in the figure, in the automatic detection and control method for the head holes of hot-rolled strip in this embodiment, an image capturing device 1 is set at the outlet position of the hot-rolling roughing mill (at the position between the conventional hot continuous rolling roughing mill and the finishing mill 100). In addition, it is also equipped with a hot metal detector 6, a laser speed detector 7, a strip head and tail shape detector 8, a pulse transmitter, etc. Among them, the image capturing device 1 uses an industrial color area array camera with 2M pixels to capture the head image of the strip 2; the hot metal detector 6 uses the infrared sensing detection principle to detect whether the strip 2 is in place, so as to judge the position of the strip 2 and initiate the shearing action; the laser speed detector 7 is used to detect the running speed of the strip 2, which is used as a basis for calculating the shearing amount; the strip head and tail shape detector 8 uses a high-speed linear array sensor with 2048 pixels to measure the accurate positions of the head and tail of the strip 2, which is an important basis for determining the shearing action; the pulse transmitter is mainly used to measure the shearing blade angle and rotational speed of the flying shear of the flying shear device 3.

[0065] In this embodiment, the flying shear device 3 includes upper and lower drums, and two shearing blades are fixedly installed at intervals on each drum, which are respectively used for cutting the head and tail of the strip 2.

[0066] Combined with Figure 3 and Figure 4 As shown in the figure, the recognition and calculation process of the image analysis and recognition system in the automatic detection and control method for the head holes of hot-rolled strip in this embodiment is as follows:

[0067] 1) After the strip 2 comes out of the roughing mill, the head image of the strip 2 is captured by the image capturing device 1, and the head image is transmitted to the image analysis and recognition system 4 for recognizing whether there are cracking defects at the head of the strip 2, and the analysis and recognition result is transmitted to the flying shear control system 5;

[0068] 2) When the strip enters the area of the finishing mill 100, the head position of the strip 2 is detected by the hot metal detector 6, indicating that the strip 2 enters the flying shear area, and the flying shear control system 5 starts to enter the shearing control cycle;

[0069] 3) After the strip 2 enters the detection area of the laser speed detector 7, the laser speed detector 7 generates a real-time speed signal of the strip 2 and transmits it to the flying shear control system 5. The flying shear control system 5 judges the real-time speed data of the strip 2 and comprehensively determines the current speed of the strip 2 in combination with the speeds of the rolling mill and the roller table;

[0070] 4) When the strip 2 runs to the inlet position of the flying shear device 3, the strip head and tail shape detector 8 detects the head position of the strip 2. The flying shear control system 5 starts to accurately track the strip 2, and at the same time calculates the length △L that needs to be sheared at the current head position of the strip 2 n ;

[0071] 5) When the strip steel 2 reaches the shearing start point at its head position, the flying shear shearing control system 5 controls the flying shear shearing device 3 to start the shearing action according to the length ΔL n ;

[0072] 6) After the strip steel 2 is sheared, it enters the next shearing cycle.

[0073] Those of ordinary skill in the art should recognize that the above embodiments are only used to illustrate the present invention, rather than to limit the present invention. As long as within the scope of the spirit of the present invention, changes and modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. An automatic detection and control method for holes at the head of hot-rolled strip steel, characterized in that: An image capturing device is arranged at the outlet position of the hot-rolled roughing mill. The head image of the strip steel is obtained by using the image capturing device, and the head image is transmitted to the image analysis and recognition system. Whether there is a cracking defect at the head of the strip steel is identified from the head image through the image analysis and recognition system, and the length of the cracking defect is calculated, and the result is transmitted to the flying shear control system. The flying shear control system controls the flying shear cutting device to completely cut off the cracked part of the head of the strip steel. The process of the image analysis and recognition system for recognizing the head image and calculating the cracking defect is as follows: 1) Determine the line height L of the head image; 2) Determine the effective width W of the strip steel in the head image; 3) Determine the starting position P0 for searching for the head cracking defect of the strip steel in the head image; 4) Calculate the pixel threshold Y of the cracking defect; 5) Determine the size and position of the cracking defect. In step 2), the calculation of the effective width W of the strip steel is as follows: W = f(1 / 2L) In the above formula, L represents the line height of the head image, and f represents: when the deviation of the upper and lower 5 line pixels at the center position of the head image is not greater than 10 pix, it is used as the effective width W of the strip steel; otherwise, the width at the position 20 lines plus the center position of the head image is used as the effective width W of the strip steel.

2. The automatic detection and control method for the head hole of hot-rolled strip steel according to claim 1, characterized in that, In step 3), the calculation of the starting position P0 for searching for the head cracking defect of the strip steel is as follows: P0 = f(W * 95%); or Take the starting position of the shear line as the starting position for searching for the head cracking defect of the strip steel; In the above formula, W represents the effective width of the strip steel in the head image, and f represents: the starting position P0 for searching for the head cracking defect of the strip steel is the 95% position of the effective width W of the strip steel starting from the starting point of the head image, or directly take the starting position of the shear line as the starting position for searching for the head cracking defect of the strip steel.

3. The automatic detection and control method for head holes of hot-rolled strip steel according to claim 1, characterized in that In step 4), the calculation of the pixel threshold Y of the cracking defect is as follows: Y = f[(1 - 0.35) * W] In the above formula, W represents the effective width of the strip steel in the head image, and f represents: the basis for judging whether there is a cracking defect in the strip steel is that the line pixels after the starting point of the image search are less than 65% of the effective width W of the strip steel in the head image, and it is continuously 5 lines less than the pixel threshold Y.

4. The automatic detection and control method for the head hole of hot-rolled strip steel according to claim 3, characterized in that, Step 5) further includes: If it is determined that there is a cracking defect at the head of the strip steel in the head image, the line position where the cracking defect is less than the pixel threshold Y is used as the starting position of the cracking defect, and the line position where the cracking defect is not less than the pixel threshold Y is used as the ending position of the cracking defect. The serial number difference between the two lines is the height △L3 of the cracking defect, that is: △L3 = Ls + K In the above formula, Ls represents the ending position of the cracking defect, and K represents the correction amount at this position.

5. The automatic detection and control method for head holes of hot-rolled strip steel according to claim 4, characterized in that, The flying shear cutting control system controls the flying shear cutting equipment to cut the head length ΔL of the strip steel n The calculation is as follows: △L n = △L1 + △L2 + △L3 In the above formula, △L1 represents the optimized system shear length of the nth strip steel, in units of mm; △L2 represents the operator's attachment shear length of the nth strip steel, in units of mm.

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