Steel plate thickness online measurement method and device

Abstract

The invention discloses a steel plate thickness online measurement method and device. The device comprises at least one pair of linear laser displacement sensors and a control processing unit. The line laser displacement sensor comprises an upper line laser displacement sensor and a lower line laser displacement sensor which are located above and below a steel plate on a production line respectively, the vertical positions of the upper line laser displacement sensor and the lower line laser displacement sensor correspond, and the scanning directions are crossed. The first point clouds are distributed on the upper surface of the steel plate in the moving direction of the production line, and the second point clouds are distributed on the lower surface of the steel plate in the transverse direction perpendicular to the moving direction of the production line; the control processing unit is respectively connected with each line laser displacement sensor, and synchronously obtains each first point cloud and each second point cloud scanned by each line laser displacement sensor; and the Euclidean distances between the first point clouds and the second point clouds are calculated, and the minimum value of the Euclidean distances is obtained and serves as the thickness of the steel plate. According to the invention, deformation errors of the steel plate in all directions are overcome, and online, dynamic and high-precision thickness detection of the steel plate is realized.

Description

Technical Field

[0001] This invention belongs to the field of online measurement technology for sheet metal production lines, specifically, it relates to a method and device for online measurement of steel plate thickness. Background Technology

[0002] As a crucial material in engineering structures and manufacturing, the accuracy of steel plate thickness has a vital impact on product quality, engineering safety, and cost control. Steel plates undergo multiple processes during production, such as rolling and cutting. Wear and tear on machinery and improper control of production process parameters can all lead to deviations in steel plate thickness. Therefore, real-time monitoring of the accurate thickness of steel plates is essential in steel plate production.

[0003] Mainstream methods for measuring steel plate thickness include ultrasonic measurement, X-ray measurement, and magnetic induction measurement, but these methods all have some limitations. For example, ultrasonic measurement has certain requirements on the sound wave propagation characteristics of the material; X-ray radiation poses certain health hazards, and its transmissibility is affected by the material's density and chemical composition; magnetic induction measurement has certain requirements on the material's magnetic permeability and magnetization characteristics, etc.

[0004] In addition to the methods mentioned above, in recent years, some solutions have introduced visual or laser measurement technologies into steel plate thickness measurement. These methods, which utilize light propagation for measurement, are fast, non-contact, and less affected by the material. However, optical measurement technology has very strict requirements on the position and flatness of the steel plate. Due to the influence of rolling processes, heat treatment, transportation, and roller movement, the steel plate may exhibit local warping, wavy shapes, edge deformation, etc., resulting in differences in its actual thickness at different locations.

[0005] The information disclosed in this background section is only intended to enhance the understanding of the background technology of this application, and therefore may include prior art that is not known to those skilled in the art. Summary of the Invention

[0006] This invention addresses the problem of inaccurate measurement of steel plate thickness using visual or laser methods due to potential issues such as local warping, wavy lines, or edge deformation in the steel plate. It proposes an online method and apparatus for measuring steel plate thickness, thereby improving the accuracy and reliability of steel plate thickness measurement.

[0007] To achieve the above-mentioned objectives, the present invention employs the following technical solution: A method for online measurement of steel plate thickness, applied to a steel plate production line; the production line includes a roller conveyor and multiple rollers for conveying steel plates; the method includes the following steps; At least one pair of vertically aligned line laser displacement sensors are respectively installed above and below the steel plate, and the scanning directions are cross-shaped. At the same time, multiple first point clouds distributed along the moving direction of the production line on the upper or lower surface of the steel plate and multiple second point clouds distributed along the transverse direction perpendicular to the moving direction of the production line are collected. Obtain the Euclidean distance between each of the first point clouds and each of the second point clouds; The minimum value of each of the aforementioned Euclidean distances is the steel plate thickness.

[0008] In some specific embodiments, obtaining the Euclidean distance between each of the first point clouds and each of the second point clouds includes: Set the world coordinate system; The relative spatial position and pose of each of the line laser displacement sensors are calibrated; the upper sensing coordinate system, the lower sensing coordinate system, and the transformation matrix from the upper sensing coordinate system, the lower sensing coordinate system to the world coordinate system are obtained; Transform each of the first point clouds and each of the second point clouds to the world coordinate system coordinates; The Euclidean distances are obtained based on the world coordinate system coordinates corresponding to each of the first point clouds and each of the second point clouds.

[0009] In some specific embodiments, it also includes: The steel plate temperature was obtained when the first point cloud and the second point cloud were collected. The final steel plate thickness is obtained by adjusting the steel plate thickness based on the steel plate temperature.

[0010] An online steel plate thickness measurement device is installed on a steel plate production line; the production line includes a roller conveyor and multiple rollers for conveying the steel plate; it includes at least one pair of linear laser displacement sensors and a control processing unit. At least one pair of line laser displacement sensors, including an upper line laser displacement sensor and a lower line laser displacement sensor, are located above and below the steel plate on the production line, respectively, with corresponding vertical positions and cross-shaped scanning directions, for acquiring multiple first point clouds distributed along the moving direction of the production line on the upper or lower surface of the steel plate, and multiple second point clouds distributed along the horizontal direction perpendicular to the moving direction of the production line on the lower or upper surface of the steel plate. The control processing unit is connected to each of the line laser displacement sensors, and synchronously acquires each of the first point clouds and each of the second point clouds scanned by each of the line laser displacement sensors; calculates the Euclidean distance between each of the first point clouds and each of the second point clouds, and obtains the minimum value of each of the Euclidean distances as the thickness of the steel plate.

[0011] In some specific embodiments, the control processing unit is configured with a world coordinate system, an upper sensor coordinate system, and a lower sensor coordinate system, and is configured with transformation matrices from the upper sensor coordinate system and the lower sensor coordinate system to the world coordinate system, and configured as follows: The first point cloud and the second point cloud are transformed to the world coordinate system coordinates according to the transformation matrix. The Euclidean distances are obtained based on the world coordinate system coordinates corresponding to each of the first point clouds and each of the second point clouds.

[0012] In some specific embodiments, the system includes two pairs of the aforementioned line laser displacement sensors, as well as a frame and two linear modules; The frame is vertically arranged along the direction of the rollers and includes an upper beam and a lower beam that tend to be parallel, and two side beams that are fixedly connected to the two ends of the upper beam and the lower beam, respectively; the two linear modules are respectively arranged along the length direction of the upper beam and the lower beam, on the lower side of the upper beam and the upper side of the lower beam, and are respectively connected to the control processing unit. Two pairs of line laser displacement sensors are respectively installed on the upper beam and the lower beam, and one pair is fixedly set at one end of the frame; the other pair is respectively set on the two linear modules.

[0013] In some specific embodiments, a photoelectric sensor is also included, which includes a transmitter and a receiver; the transmitter and the receiver are respectively disposed on the upper beam and the lower beam, and connected to the control processing unit; The control processing unit controls a hardware trigger to synchronously acquire a frame of data from a pair of line laser displacement sensors based on the occlusion signal obtained from the receiving end, in order to obtain the thickness of the steel plate.

[0014] In some specific embodiments, the frame further includes an upper box, a lower box, and a side box that respectively accommodate the upper beam, the lower beam, and each of the side beams, and these boxes are interconnected; the lower side plate of the upper box, the upper side plate of the lower box, the positions corresponding to the linear module, the paired linear laser displacement sensors, and the photoelectric sensors are made of tempered glass. External air knives are respectively provided on both sides of the lower side plate of the upper box and the upper side plate of the lower box in the direction of the roller conveyor, for forming an isolation air curtain in the light emission area of ​​the linear laser displacement sensor and the photoelectric sensor; an air inlet and an air outlet are formed on the upper box for air intake and air exhaust.

[0015] In some specific embodiments, a temperature detection unit is also included, which is an infrared temperature sensor, disposed on the upper box, the lower box, or the side box, and connected to the control processing unit, for detecting the temperature of the steel plate and transmitting it to the control processing unit; The control processing unit is configured to correct the steel plate thickness based on the steel plate temperature to obtain the final steel plate thickness.

[0016] In some specific embodiments, it also includes: The gantry frame is a square frame that spans the roller conveyor and is vertically installed, and is fixed relative to the production line. The lifting module is connected to the frame and the gantry, and electrically connected to the control processing unit. The control processing unit is configured with a measurement position and a maintenance position. When configured as the measurement position, the lifting module is lowered to lower the lower laser displacement sensor below the roller. When configured as the maintenance position, the lifting module is raised to raise the lower laser displacement sensor above the roller.

[0017] Compared with the prior art, the advantages and positive effects of the present invention are: The online steel plate thickness measurement method and apparatus of the present invention acquires contour data of the upper and lower surfaces of the steel plate, i.e., two-dimensional point cloud data of the upper and lower surfaces, by setting line laser displacement sensors above and below the steel plate respectively to form a cross-shaped scanning structure. The minimum Euclidean distance between the two sets of point clouds is then calculated in three-dimensional space, which is the closest distance between the upper and lower surfaces of the steel plate, i.e., the thickness of the steel plate. This method significantly suppresses thickness measurement errors introduced by local deformations such as warping and shaking of the steel plate, achieving online, dynamic, and high-precision thickness detection of steel plates.

[0018] Furthermore, the online steel plate thickness measurement method and device, by synchronously triggering upper and lower laser sensors and simultaneously acquiring point cloud data from the upper and lower surfaces, automatically cancels out distance offsets caused by jumps and warps when calculating the distance between two points. This exhibits strong anti-interference capabilities and good robustness against common dynamic deformations such as vertical jumps in the steel plate, wavy bending along the production line's movement direction, and warping around the roller conveyor span. It is particularly suitable for high-speed, continuous production online inspection environments, eliminating the need for the steel plate to remain absolutely flat and stable, and providing strong online measurement capabilities.

[0019] Other features and advantages of the present invention will become clearer after reading the detailed embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram illustrating the principle of the online steel plate thickness measurement method according to the embodiment; Figure 2 This is a schematic diagram of the structure of the online steel plate thickness measurement device according to an embodiment; Figure 3 This is a schematic diagram of the structure of the online steel plate thickness measurement device according to an embodiment; Figure 4 This is a schematic diagram of the structure of the online steel plate thickness measurement device according to an embodiment; Figure 5 This is a schematic diagram of the structure of the online steel plate thickness measurement device according to an embodiment; Figure 6 This is a schematic diagram of the structure of the online steel plate thickness measurement device according to an embodiment; Figure 7 This is a schematic diagram of the structure of the online steel plate thickness measurement device according to an embodiment.

[0022] In the picture, 1. Production line; 11. Roller conveyor; 12. Roller; 2. Steel plate; 3. Linear laser displacement sensor; 31. Upper linear laser displacement sensor; 32. Lower linear laser displacement sensor; 4. Frame; 41. Upper beam; 42. Lower beam; 43. Upper box; 431. Air inlet; 432. Air outlet; 44. Lower box; 441. Upper side plate; 45. Side box; 46. External air knife; 47. Side beam; 5. Temperature detection unit; 6. Photoelectric sensor; 61. Transmitter; 62. Receiver; 7. Gantry frame; 8. Electrical control cabinet; 9. Air cooler; 10. Lifting module; 30. Linear module; 401. Base; 402. Bolt; 403. First displacement adjustment module; 404. Second displacement adjustment module. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. In the description of embodiments, specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0026] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0027] In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0028] Reference Figure 1 , Figure 2 , Figure 3 This invention discloses an online steel plate thickness measurement device, which is installed on a production line 1 for conveying hot steel plates 2; the production line 1 includes a roller conveyor 11 and multiple rollers 12; the steel plates 2 are conveyed by the rotation of the rollers 12.

[0029] The online steel plate thickness measurement device includes at least one pair of linear laser displacement sensors 3, which includes an upper linear laser displacement sensor 31 and a lower linear laser displacement sensor 32, respectively located above and below the steel plate 2 on the production line 1, and their positions correspond in the vertical direction. Their scanning directions are cross-shaped, and they are used to acquire multiple first point clouds distributed on the upper or lower surface of the steel plate 2 along the moving direction of the production line 1, and multiple second point clouds distributed on the lower or upper surface of the steel plate 2 along the horizontal direction perpendicular to the moving direction of the production line 1.

[0030] The online steel plate thickness measurement device also includes a control and processing unit, which is connected to each of the linear laser displacement sensors 3. It synchronously acquires each first point cloud and each second point cloud scanned by each linear laser displacement sensor 3, and calculates the Euclidean distance between each first point cloud and each second point cloud based on the coordinates of each first point cloud and each second point cloud. The minimum value of each Euclidean distance is obtained as the steel plate thickness.

[0031] Where Euclidean distance is the same as Euclidean distance.

[0032] Reference Figure 1 The present invention also discloses an online method for measuring the thickness of steel plates, applicable to a production line for hot steel plates, comprising the following steps: S1. At least one pair of linear laser displacement sensors 3 are respectively set above and below the steel plate 2, which correspond to each other in the vertical direction and cross each other in the scanning direction; and multiple first point clouds and multiple second point clouds are simultaneously collected by the above-mentioned pair of linear laser displacement sensors 3, which are respectively located on the upper surface or the lower surface of the steel plate 2; each first point cloud can be multiple point clouds distributed along the moving direction of the production line 1 on the upper surface or the lower surface of the steel plate 2; each second point cloud can be multiple point clouds distributed along the transverse direction perpendicular to the moving direction of the production line 1 on the lower surface or the upper surface of the steel plate 2. S2. Obtain the Euclidean distance between each first point cloud and each second point cloud; that is, calculate the Euclidean distance from each first point cloud to each second point cloud based on the coordinates of each first point cloud and each second point cloud. S3. The minimum value of each Euclidean distance is the steel plate thickness.

[0033] The online steel plate thickness measurement method and apparatus of the present invention acquires the contour data (i.e., two-dimensional point cloud data) of the upper and lower surfaces of the steel plate 2 by setting line laser displacement sensors 3 above and below the steel plate 2 respectively and forming a cross-shaped scanning structure. The method obtains the contour data of the upper and lower surfaces of the steel plate 2 on two mutually perpendicular vertical sections, and calculates the minimum Euclidean distance between the two sets of point clouds in three-dimensional space, which is the closest distance between the upper and lower surfaces of the steel plate 2, i.e., the steel plate thickness. This method greatly suppresses the thickness measurement error introduced by local deformation such as warping and shaking of the steel plate 2, and achieves online, dynamic, and high-precision thickness detection of the steel plate 2.

[0034] Furthermore, the online steel plate thickness measurement method and device, by synchronously triggering upper and lower laser sensors and simultaneously acquiring point cloud data from the upper and lower surfaces, automatically cancels out distance offsets caused by jumps and warps when calculating the distance between two points. This exhibits strong anti-interference capabilities and good robustness against common dynamic deformations such as vertical jumps of the steel plate 2, wavy bending along the movement direction of production line 1, and warping along the span direction of roller conveyor 11. It is particularly suitable for high-speed, continuous production online inspection environments, eliminating the need for the steel plate 2 to maintain absolute flatness and stability, and providing strong online measurement capabilities.

[0035] The specific composition and principle of the online steel plate thickness measurement method and device of the present invention will be described in detail below through specific embodiments.

[0036] In some specific embodiments, refer to Figure 1 In the online measurement method for steel plate thickness, obtaining the Euclidean distance between each first point cloud and each second point cloud includes: S21. Set the world coordinate system; S22. The relative spatial position and attitude of each line laser displacement sensor 3 are calibrated; the transformation matrix from the upper sensing coordinate system, the lower sensing coordinate system, and the upper sensing coordinate system, the lower sensing coordinate system to the world coordinate system is obtained. S23. Transform each first point cloud and each second point cloud to world coordinate system coordinates; S24. Obtain the Euclidean distances based on the world coordinates corresponding to each first point cloud and each second point cloud.

[0037] Specifically, the relative spatial position and orientation of the upper and lower line laser displacement sensors 3 are precisely calibrated using a high-precision calibrator. That is, the transformation relationship between the upper sensing coordinate system where the upper line laser displacement sensor 31 is located and the lower sensing coordinate system where the lower line laser displacement sensor 32 is located is obtained.

[0038] A unified world coordinate system is established, and transformation matrices T1 and T2 are obtained to transform the upper and lower sensor coordinate systems to the world coordinate system. All measurement data will ultimately be transformed into the world coordinate system for calculation. The cross-shaped two-dimensional contour point clouds collected by the upper laser displacement sensor 31 and the lower laser displacement sensor 32 are matched in three-dimensional space, and the steel plate thickness is accurately determined by finding the shortest distance in three-dimensional space between the two contour point clouds.

[0039] When the steel plate 2 passes through the detection area, a frame of data from the upper and lower linear laser displacement sensors 3 is synchronously acquired by a unified hardware trigger.

[0040] The set of all first point clouds is {U} = {Uu1, Uu2, ..., UuM}, with a quantity of M; where Uui = (ux_i, uy_i, uz_i), which are the three-dimensional coordinates of the upper or lower sensor coordinate system. Assume the movement direction of production line 1 is X-axis, and the span direction of roller conveyor 11 is Y-axis; since its laser scanning line is along the X or Y direction, the ux or uy coordinate values ​​of these points are approximately the same.

[0041] The set of each second point cloud is {L} = {Ll1, Ll2, ..., LlN}, with a quantity of N; where Llj = (lx_j, ly_j, lz_j), which is the three-dimensional coordinate of the lower or upper sensing coordinate system. Assume the movement direction of production line 1 is X-axis, and the span direction of roller conveyor 11 is Y-axis; since its laser scanning line is along the Y-axis or X-axis, the ly or lx coordinate values ​​of these points are approximately the same.

[0042] Unify the coordinates of each first point cloud and each second point cloud into the world coordinate system; U_W = T1 * U; L_W = T2 * L; where U_W is the first world coordinate set transformed from the first point cloud set to the world coordinate system; L_W is the second world coordinate set transformed from the second point cloud set to the world coordinate system.

[0043] Then the sets of coordinates of each first point cloud and each second point cloud in the world coordinate system are respectively the first world coordinate set U_W = {Wu1, Wu2, ..., WuM} and the second world coordinate set L_W = {Wl1, Wl2, ..., WlN}.

[0044] Iterate through each point in each first-world coordinate set, calculate its Euclidean distance to all points in each second-world coordinate set, and find the minimum of all distances.

[0045] For the i-th point Wui = (Wx_i, Wy_i, Wz_i) in each first world coordinate set, calculate its distance to the j-th point Wlj = (Wx_j, Wy_j, Wz_j) in each second world coordinate set, d_ij = sqrt( (Wx_i - Wx_j) 2 + (Wy_i - Wy_j) 2 + (Wz_i - Wz_j) 2 ).

[0046] For a point Wui in the first world coordinate set, its nearest distance d_i_min to the entire second world coordinate set is: d_i_min = min( d_i1, d_i2, ..., d_iN ).

[0047] The final steel plate thickness is the minimum of the nearest distances from all points in the first world coordinate set to points in the second world coordinate set: Thickness = min( d_1_min, d_2_min, ..., d_M_min ).

[0048] In an embodiment of the online steel plate thickness measurement device, the control processing module performs the calculations and minimum value acquisition in the above-described online steel plate thickness measurement method.

[0049] In some specific embodiments, refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 The online steel plate thickness measurement device includes two pairs of linear laser displacement sensors 3, as well as a frame 4 and two linear modules 30.

[0050] The frame 4 is vertically arranged along the direction of the roller 12, including an upper beam 41 and a lower beam 42 that tend to be parallel, and two side beams 47 that are fixedly connected to the two ends of the upper beam 41 and the lower beam 42 respectively; two linear modules 30 are respectively arranged on the lower side of the upper beam 41 and the upper side of the lower beam 42 along the length direction of the upper beam 41 and the lower beam 42, and are respectively connected to the control processing unit and controlled by the control processing unit.

[0051] Two pairs of linear laser displacement sensors 3 are installed on the upper beam 41 and the lower beam 42 respectively, and one pair is fixedly set at one end of the frame 4; the other pair is set on the two linear modules 30 respectively.

[0052] The online steel plate thickness measurement device of this embodiment uses another pair of linear laser displacement sensors 3 on the linear modules 30 of the upper beam 41 and the lower beam 42, and adjusts the position of the other pair of linear laser displacement sensors 3 through the two linear modules 30 to measure the thickness at the middle position of the steel plate 2 in the width direction; it is suitable for measuring the thickness at the middle position of steel plates 2 with different widths; a pair of linear laser displacement sensors 3 are fixedly installed at one end of the upper beam 41 and the lower beam 42 to measure the thickness located on one side of the steel plate 2 in the width direction.

[0053] In some specific embodiments, refer to Figure 7 In the online steel plate thickness measurement device, the upper linear laser displacement sensor 31 and the lower linear laser displacement sensor 32, calibrated by a high-precision calibrator, are fixedly connected to the frame 4 or the linear module 30 via a base 401 and multiple bolts 402, and their levelness is adjusted by the bolts 402. In addition, a first displacement adjustment module 403 and a second displacement adjustment module 404 are provided on the base 401 of the linear laser displacement sensor 3, which is fixedly connected to the frame 4 and the linear module 30. Each linear laser displacement sensor 3 adjusts its position in the X direction through the first displacement adjustment module 403 and adjusts its position in the Y direction through the second displacement adjustment module 404, ensuring that the central axes of the two linear laser displacement sensors 3 that are facing each other are coaxial and perpendicular to the horizontal plane. In addition, it ensures that the collected first point cloud and second point cloud accurately correspond to the positions on the upper and lower sensing coordinate systems, thereby improving the accuracy of steel plate thickness measurement.

[0054] In some specific embodiments, refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 The online steel plate thickness measurement device also includes a photoelectric sensor 6, which includes a transmitter 61 and a receiver 62; the transmitter 61 and the receiver 62 are respectively installed on the upper beam 41 and the lower beam 42 and are connected to the control and processing unit.

[0055] The control processing unit controls the hardware trigger to synchronously acquire a frame of data from the paired line laser displacement sensors 3 based on the occlusion signal obtained by the receiver 62, in order to obtain the thickness of the steel plate.

[0056] The delay time after the blocking signal can be determined based on the moving speed of production line 1.

[0057] In some specific embodiments, refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 In the online steel plate thickness measurement device, the frame 4 also includes an upper box 43, a lower box 44, and a side box 45 that respectively accommodate the upper beam 41, the lower beam 42, and each side beam 47, and they are interconnected; the lower side plate of the upper box 43 and the upper side plate 441 of the lower box 44 correspond to the positions of the linear module 30, the paired linear laser displacement sensor 3, and the photoelectric sensor 6, which are made of tempered glass.

[0058] External air knives 46 are respectively provided on both sides of the roller conveyor 11 along the lower side plate of the upper box 43 and the upper side plate 441 of the lower box 44, for forming an isolation air curtain in the light-emitting area of ​​the online laser displacement sensor 3 and the photoelectric sensor 6.

[0059] In this embodiment, the online steel plate thickness measuring device uses an upper box 43 and a lower box 44 that enclose the upper beam 41 and the lower beam 42 to enclose the space where measuring equipment such as the line laser displacement sensor 3 is located, thus isolating the steel plate production line 1 from dust intrusion and protecting the line laser displacement sensor 3.

[0060] In addition, by setting tempered glass, light propagation of the line laser displacement sensor 3 and photoelectric sensor 6 is realized, and measurement and detection functions are achieved. External air knives 46 are set on the lower side plate of the upper box 43 and the two sides of the upper side plate 441 of the lower box 44 respectively. Clean compressed air is continuously sprayed to form an isolation air curtain to isolate the optical path area from the dusty environment, improve the light transmittance, and thus improve the measurement stability and reliability.

[0061] In some specific embodiments, refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 The upper box 43 has an air inlet 431 and an air outlet 432 for air intake and exhaust.

[0062] The online steel plate thickness measurement device also includes a cooler 9, which is used to cool the circulating air. It is connected to the air inlet 431 and the air outlet 432 respectively, and blows the cool air into the frame 4 through the air inlet 431 to cool the laser displacement sensors 3.

[0063] In this embodiment, the online steel plate thickness measurement device uses a cooling fan 9 and a pipe formed by the upper box 43, lower box 44, and side box 45 on the frame 4 to physically cool each laser displacement sensor 3, suppressing its high-temperature drift and improving the accuracy of steel plate thickness measurement.

[0064] In some specific embodiments, refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 The online steel plate thickness measurement device also includes a temperature detection unit 5, which is an infrared temperature sensor. It is installed on the upper box 43, the lower box 44, or the side box 45 and is connected to the control and processing unit to detect the steel plate temperature and transmit it to the control and processing unit.

[0065] The control processing unit is configured to correct the steel plate thickness based on the steel plate temperature to obtain the final steel plate thickness.

[0066] In embodiments of the online steel plate thickness measurement method, the method further includes: Obtain the steel plate temperature at the time of collecting each first point cloud and each second point cloud; The final steel plate thickness is obtained by adjusting the steel plate thickness based on the steel plate temperature.

[0067] The online steel plate thickness measurement method and device of this embodiment uses an infrared temperature detection unit 5 to synchronously detect the steel plate temperature, and corrects the steel plate thickness to the final steel plate thickness at room temperature.

[0068] In some specific embodiments, refer to Figure 1 , Figure 3 The online steel plate thickness measurement device also includes a gantry frame 7 and a lifting module 10.

[0069] The gantry 7 is a square frame that spans the roller conveyor 11 and is vertically installed, fixed relative to the production line 1. The lifting module 10 is connected to the frame 4 and the gantry 7, and is electrically connected to the control processing unit. The control processing unit is equipped with a measurement position and a maintenance position. When configured as the measurement position, the lifting module 10 is lowered to lower the lower laser displacement sensor 32 below the roller 12, and the steel plate 2 passes through the frame 4. When configured as the maintenance position, the lifting module 10 is raised to raise the lower laser displacement sensor 32 above the roller 12 for easy maintenance.

[0070] In some specific embodiments, refer to Figure 2 , Figure 3 The online steel plate thickness measurement device also includes an electrical control cabinet 8, which is fixedly mounted on the gantry frame 7, and the control processing unit is located inside the electrical control cabinet 8.

[0071] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions claimed by the present invention.

Claims

1. A method for measuring the thickness of a steel sheet on line, applied to a production line for steel sheets; said production line comprising a roller bed, a plurality of rollers for conveying the steel sheet; characterized in that, The method comprises the following steps: At least one pair of vertical line laser displacement sensors are arranged above and below the steel plate respectively, and the scanning directions of the two sensors are cross, and the upper surface or the lower surface of the steel plate is scanned to obtain a plurality of first point clouds distributed along the moving direction of the production line and a plurality of second point clouds distributed along the transverse direction perpendicular to the moving direction of the production line; The Euclidean distance between each first point cloud and each second point cloud is obtained; The minimum value of each Euclidean distance is the thickness of the steel plate.

2. The steel sheet thickness on-line measuring method according to claim 1, characterized by, The method comprises the following steps: A world coordinate system is set; The relative spatial position and pose of each line laser displacement sensor are calibrated to obtain an upper sensor coordinate system, a lower sensor coordinate system, and a transformation matrix of the upper sensor coordinate system and the lower sensor coordinate system to the world coordinate system; Each first point cloud and each second point cloud are transformed to the world coordinate system; The Euclidean distance between each first point cloud and each second point cloud is obtained according to the world coordinate system corresponding to each first point cloud and each second point cloud.

3. The steel sheet thickness on-line measuring method according to claim 1 or 2, characterized by, The method further comprises the following steps: The temperature of the steel plate when each first point cloud and each second point cloud is collected is obtained; The thickness of the steel plate is corrected according to the temperature of the steel plate to obtain the final thickness of the steel plate.

4. An apparatus for on-line measurement of thickness of a steel sheet provided on a production line of the steel sheet; the production line including a roller table and a plurality of rollers for conveying the steel sheet; characterized by, The method comprises the following steps: At least one pair of line laser displacement sensors are arranged above and below the steel plate respectively, and the vertical positions of the two sensors correspond to each other, and the scanning directions of the two sensors cross, and the upper surface or the lower surface of the steel plate is scanned to obtain a plurality of first point clouds distributed along the moving direction of the production line and a plurality of second point clouds distributed along the transverse direction perpendicular to the moving direction of the production line; A control processing unit is connected with each line laser displacement sensor, and synchronously obtains each first point cloud and each second point cloud scanned by each line laser displacement sensor; calculates the Euclidean distance between each first point cloud and each second point cloud, and obtains the minimum value of each Euclidean distance as the thickness of the steel plate.

5. The apparatus for on-line measurement of the thickness of a steel sheet according to claim 4, wherein The control processing unit is provided with a world coordinate system, an upper sensor coordinate system, and a lower sensor coordinate system, and is configured with a transformation matrix of the upper sensor coordinate system and the lower sensor coordinate system to the world coordinate system, and is configured to: According to the transformation matrix, each first point cloud and each second point cloud are transformed to the world coordinate system; According to the world coordinate system corresponding to each first point cloud and each second point cloud, the Euclidean distance between each first point cloud and each second point cloud is obtained.

6. The apparatus for on-line measurement of the thickness of a steel sheet according to claim 5, wherein The method comprises the following steps: Two pairs of line laser displacement sensors are arranged, and a frame and two linear modules are further arranged; The frame is vertically arranged along the direction of the roller, and comprises parallel upper beams and lower beams, and two side beams respectively fixedly connected with two ends of the upper beams and the lower beams; the two linear modules are respectively arranged on the lower side of the upper beams and the upper side of the lower beams along the length direction of the upper beams and the lower beams, and are respectively connected with the control processing unit. Two pairs of said linear laser displacement sensors are respectively arranged on said upper beam and said lower beam, and one pair is fixedly arranged at one end of said frame body, and the other pair is respectively arranged on two said linear modules.

7. The apparatus for on-line measurement of the thickness of a steel sheet according to claim 6, wherein An optoelectronic sensor is further included, which comprises a transmitting end and a receiving end, and said transmitting end and said receiving end are respectively arranged on said upper beam and said lower beam and connected with said control processing unit. Said control processing unit controls a hardware trigger to synchronously collect one frame of data of said linear laser displacement sensors according to a shielding signal obtained by said receiving end, so as to obtain said steel plate thickness.

8. The steel sheet thickness on-line measuring apparatus according to claim 7, characterized by Said frame body further comprises an upper box body, a lower box body and side box bodies for respectively accommodating said upper beam, said lower beam and said side beams, which are in communication with each other; the lower side plate of said upper box body and the upper side plate of said lower box body are made of tempered glass and correspond to the positions of said linear modules, said linear laser displacement sensors and said optoelectronic sensor. External air knives are arranged on both sides of the roller direction of the lower side plate of said upper box body and the upper side plate of said lower box body, so as to form an isolated air curtain in the light-emitting area of said linear laser displacement sensors and said optoelectronic sensor; an air inlet and an air outlet are formed on said upper box body, so as to introduce air and exhaust air.

9. The steel sheet thickness on-line measuring apparatus according to claim 8, characterized by A temperature detection unit is further included, which is an infrared type temperature sensor and is arranged on said upper box body or said lower box body or side box body and connected with said control processing unit, so as to detect the temperature of the steel plate and transmit the temperature to said control processing unit. Said control processing unit is configured to correct said steel plate thickness according to said steel plate temperature to obtain a final steel plate thickness.

10. The device for on-line measurement of the thickness of a steel sheet according to any one of claims 4 to 9, characterized in that, Further comprising: A gantry, which is a square frame body and is arranged vertically across said roller and fixedly arranged relative to said production line; A lifting module, which is connected with said frame body and said gantry and electrically connected with said control processing unit; said control processing unit is configured with a measurement position and a maintenance position, and is configured to control said lifting module to descend when at said measurement position so as to make said lower linear laser displacement sensor descend below said roller, and is configured to control said lifting module to ascend when at said maintenance position so as to make said lower linear laser displacement sensor ascend above said roller.

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