Method for positioning welding points of rebar mesh

Abstract

A method for positioning welding points of a rebar mesh, used for positioning intersection points (6) between transverse ribs (1) and longitudinal ribs (2) in the rebar mesh. The method comprises: establishing a three-dimensional coordinate system and acquiring a three-dimensional point cloud data set of the rebar mesh (S10); preprocessing three-dimensional point cloud data in the three-dimensional point cloud data set to obtain a preprocessed point set (S20); for each point in the preprocessed point set, sequentially calculating slope values of connecting lines between every two adjacent points, and on the basis of changes in the slope values, obtaining information on intersection points between the transverse ribs and the longitudinal ribs (S30); and offsetting from the intersection points by a fixed distance to determine welding points (7), and moving a welding output end of a welding device to the welding points to perform welding (S40). According to the method, welding points can be accurately positioned and welding can be performed at the welding points, thereby improving the accuracy and stability of welding operations.

Description

Rebar mesh welding point positioning method

[0001] The present application claims priority to the Chinese patent application No. 202411357125.X, filed on September 27, 2024, to the Chinese Patent Office, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of building construction, for example to a rebar mesh welding point positioning method. BACKGROUND

[0003] As shown in FIG. 1, in the rebar mesh welding, the intersection points of the horizontal rebar 1 and the vertical rebar 2 need to be spot welded, so as to realize the welding work of the rebar mesh.

[0004] Before the welding work, the position of the welding point needs to be determined first, and then the welding gun is controlled by the computer to weld the welding point. In small rebar mesh, due to the small diameter of the rebar, the actual position of the rebar point and the design position have small difference under the action of the rebar straightening equipment, and a simple positioning method can be used for welding point positioning. However, for the rebar mesh of large continuous wall rebar cage, the diameter of the rebar is large and in a natural curved state, it is difficult to straighten the rebar and place it according to the design position, so that the position of the welding point after placement has a large difference with the design position, and the position of the actual welding point is random, so that the welding point cannot be automatically positioned by a simple control method.

[0005] In order to solve the above problems, the related art generally adopts a mechanical welding point positioning method based on relative positioning technology. As shown in FIG. 1, a touch switch 3 and a welding gun 4 are arranged on the base 5. In the forward direction of the welding gun (as shown by the arrow in FIG. 1), the touch switch 3 is in front of the welding gun 4. When the touch switch 3 touches the vertical rebar 2, the touch switch 3 sends a trigger signal. Since the distance between the touch switch 3 and the welding gun 4 is a fixed value, after receiving the trigger signal of the touch switch 3, the computer control system drives the base 5 to move the fixed value distance in the direction of the arrow, so that the welding gun 4 is located at the welding point position, thereby realizing the mechanical positioning of the rebar mesh welding point.

[0006] However, the above mechanical welding point positioning method needs to be positioned point by point, that is, each point needs to send a signal by the touch switch 3, then move the welding gun 4 by a fixed offset, and finally perform welding work, so that the positioning efficiency is very low. For welding large rebar mesh, since the number of welding points is in the tens of thousands, the above identification process is low in efficiency and slow in welding speed, which has affected the application of the welding robot. SUMMARY

[0007] The present application provides a rebar mesh welding point positioning method, which can efficiently and accurately realize the welding point positioning of the rebar mesh.

[0008] The application provides a reinforcing mesh welding point positioning method for positioning intersection positions of horizontal and vertical reinforcing meshes in a reinforcing mesh, comprising:

[0009] A three-dimensional coordinate system is established, and a three-dimensional point cloud data set of the reinforcing mesh is obtained;

[0010] The three-dimensional point cloud data in the three-dimensional point cloud data set is preprocessed, and a preprocessed point set is obtained;

[0011] For each point in the preprocessed point set, the slope value of the line between two adjacent points is sequentially calculated, and the information of the intersection positions of the horizontal and vertical reinforcing meshes is obtained according to the change of the slope value;

[0012] The welding point positions are offset by a fixed distance based on the intersection positions, and the welding output end of the welding device is moved to the welding point positions to realize welding.

[0013] Optionally, the three-dimensional coordinate system is established, comprising:

[0014] The three-dimensional coordinate system is established with the center of the end of the horizontal reinforcing mesh as the coordinate origin, the radial direction of the horizontal reinforcing mesh parallel to the axis direction of the vertical reinforcing mesh as the X-axis direction, the axis direction of the horizontal reinforcing mesh as the Y-axis direction, and the radial direction of the horizontal reinforcing mesh perpendicular to the X-axis direction and the Y-axis direction as the Z-axis direction.

[0015] Optionally, the three-dimensional point cloud data in the three-dimensional point cloud data set is preprocessed, comprising:

[0016] The first and second value intervals are set on the X-axis and Z-axis respectively, and the three-dimensional point cloud data outside the first and second value intervals is excluded to obtain the preprocessed point set.

[0017] Optionally, for each point in the preprocessed point set, the slope value of the line between two adjacent points is sequentially calculated, and the information of the intersection positions of the horizontal and vertical reinforcing meshes is obtained according to the change of the slope value, comprising:

[0018] The preprocessed point set is sequentially traversed according to the Y-axis direction, and for each Y-axis coordinate, the coordinate point with the largest Z-axis direction coordinate is screened to form a first point set.

[0019] Optionally, for each point in the preprocessed point set, the slope value of the line between two adjacent points is sequentially calculated, and the information of the intersection positions of the horizontal and vertical reinforcing meshes is obtained according to the change of the slope value, comprising:

[0020] The first point set is sequentially traversed according to the Y-axis direction, and for the traversed first point set, the slope value of the line between each adjacent two points is calculated; when part of the points in the first point set have positive and negative slope values of the line between the adjacent upper and lower points along the Y-axis direction, the part of the points are defined as the intersection points of the horizontal and vertical muscles.

[0021] Optionally, the three-dimensional point cloud data in the three-dimensional point cloud data set is preprocessed, including:

[0022] A third value interval and a fourth value interval are set on the X-axis to screen the preprocessed point set whose X-axis coordinates are located in the third value interval or the fourth value interval, and a fifth value interval is set in the Z-axis direction to exclude the three-dimensional point cloud data located outside the fifth value interval to obtain two groups of preprocessed point sets corresponding to the third value interval and the fourth value interval respectively.

[0023] Optionally, for each point in the preprocessed point set, the slope value of the line between adjacent two points is sequentially calculated, and the information of the intersection points of the horizontal and vertical muscles is obtained according to the change of the slope value, further including:

[0024] The two groups of preprocessed point sets are sequentially traversed according to the Y-axis direction respectively, and for each Y-axis coordinate in the two groups of preprocessed point sets, the coordinate with the largest Z-axis direction coordinate is screened to form a second point set and a third point set.

[0025] Optionally, for each point in the preprocessed point set, the slope value of the line between adjacent two points is sequentially calculated, and the information of the intersection points of the horizontal and vertical muscles is obtained according to the change of the slope value, including:

[0026] The second point set and the third point set are sequentially traversed according to the Y-axis direction respectively, for the traversed second point set, the slope value of the line between each adjacent two points is calculated, when part of the points in the second point set have positive and negative slope values of the line between the adjacent upper and lower points along the Y-axis direction, the part of the points are sequentially defined as a first sequence according to the Y-axis direction; for the traversed third point set, the slope value of the line between each adjacent two points is calculated, when part of the points in the third point set have positive and negative slope values of the line between the adjacent upper and lower points along the Y-axis direction, the part of the points are sequentially defined as a second sequence according to the Y-axis direction, and the average value of the first sequence and the second sequence is sequentially calculated according to the Y-axis direction to obtain the intersection points of the horizontal and vertical muscles.

[0027] Optionally, the welding point position is offset by a fixed distance based on the intersection point position, and the welding output end of the welding device is moved to the welding point position to realize welding, including:

[0028] The X-axis coordinate and the Z-axis coordinate of the intersection point position are positioned by the welding device.

[0029] Optionally, a three-dimensional coordinate system is established, and a three-dimensional point cloud data set of the reinforcement mesh is acquired, including:

[0030] The reinforcement mesh is scanned by a laser, and a point signal reflected by the reinforcement mesh is received to form the three-dimensional point cloud data set. BRIEF DESCRIPTION OF DRAWINGS

[0031] Fig. 1 is a schematic diagram of a welding device welding a point of a reinforcement mesh in an embodiment;

[0032] Fig. 2 is a schematic diagram of a lower mesh of a reinforcement mesh provided by the embodiment of the application;

[0033] Fig. 3 is a schematic diagram of an upper mesh of a reinforcement mesh provided by the embodiment of the application;

[0034] Fig. 4 is a schematic diagram of a three-dimensional point cloud data set in a three-dimensional coordinate system provided by the embodiment of the application;

[0035] Fig. 5 is a schematic diagram of a first point set in a three-dimensional coordinate system provided by the embodiment of the application;

[0036] Fig. 6 is a schematic diagram of a second point set and a third point set in a three-dimensional coordinate system provided by the embodiment of the application;

[0037] Fig. 7 is a flowchart of a method for positioning a welding point of a reinforcement mesh provided by the embodiment of the application.

[0038] In the drawings: 1, horizontal reinforcement; 2, vertical reinforcement; 3, touch switch; 4, welding gun; 5, base; 6, intersection position; 7, welding position; 8, first point set; 9, second point set; 10, third point set. DETAILED DESCRIPTION

[0039] The application will be described in detail below with reference to the drawings and embodiments. The specific embodiments described herein are used to explain the application, and for ease of description, some of the structures related to the application are shown in the drawings rather than all the structures.

[0040] In the description of the application, unless explicitly defined and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0041] In the present application, unless specifically defined and limited otherwise, the first feature is "on" or "under" the second feature can include that the first feature and the second feature are in direct contact, or that the first feature and the second feature are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "over" the second feature includes that the first feature is directly above and obliquely above the second feature, or indicates that the first feature is higher in horizontal height than the second feature. The first feature "under", "below" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or indicates that the first feature is lower in horizontal height than the second feature.

[0042] In the description of the present embodiment, the terms "upper", "lower", "left", "right" and the like orientation or position relationship are based on the orientation or position relationship shown in the drawings, which is for the convenience of description and simplification of operation, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation. In addition, the terms "first", "second" are only used to distinguish in description, and have no special meaning.

[0043] As shown in FIGS. 1-7, the present embodiment provides a reinforcing mesh welding point positioning method for positioning the intersection position 6 of the horizontal reinforcement 1 and the vertical reinforcement 2 in the reinforcing mesh, which comprises:

[0044] S10, a three-dimensional coordinate system is established, and a three-dimensional point cloud data set of the reinforcing mesh is obtained.

[0045] S20, the three-dimensional point cloud data in the three-dimensional point cloud data set is preprocessed, and a preprocessed point set is obtained.

[0046] S30, for each point in the preprocessed point set, the slope value of the line connecting the adjacent two points is sequentially calculated, and the information of the intersection position 6 of the horizontal reinforcement 1 and the vertical reinforcement 2 is obtained according to the change of the slope value.

[0047] S40, offsetting a fixed distance from the intersection position 6 is the welding position 7, and moving the welding output end of the welding device to the welding position 7 to realize welding.

[0048] In the embodiment, first, a three-dimensional coordinate system is established, and a three-dimensional point cloud data set of the reinforcement mesh is obtained, thereby comprehensively reflecting the actual shape of the reinforcement mesh, including detailed position information of the cross reinforcement 1, the longitudinal reinforcement 2 and the intersection position 6. Then, the three-dimensional point cloud data in the three-dimensional point cloud data set is preprocessed, and a preprocessed point set is obtained, so as to ensure the accuracy and reliability of subsequent analysis and processing. Then, for each point in the preprocessed point set, the slope value of the line between the adjacent two points is sequentially calculated, so as to reflect the change trend of the reinforcement trend. The mutation point of the slope value often corresponds to the position of the intersection position 6 of the cross reinforcement 1 and the longitudinal reinforcement 2, so that the operator can obtain the information of the intersection position 6 of the cross reinforcement 1 and the longitudinal reinforcement 2 according to the change of the slope value, not only improves the positioning accuracy of the welding point, but also avoids the tedious point-by-point touching process in the traditional mechanical positioning method, and significantly improves the positioning efficiency. Finally, the welding point 7 is obtained by offsetting a fixed distance from the intersection position 6, and the welding output end of the welding device is moved to the welding point 7 to realize welding, thereby improving the accuracy and stability of the welding operation. Through the above setting, the reinforcement mesh welding point positioning method of the embodiment can efficiently and accurately realize the welding point positioning and welding operation of the reinforcement mesh.

[0049] The specific content of the above method will be described below.

[0050] In some embodiments, in S10, the reinforcement mesh is scanned by laser, and the point signals reflected by the reinforcement mesh are received to form a three-dimensional point cloud data set. For example, the reinforcement mesh is scanned by a laser scanner located directly above the reinforcement mesh. The laser beam emitted by the laser scanner hits the surface of the reinforcement mesh and is reflected back to the scanner. The scanner receives these reflected signals and measures the time required from emission to reception. Using the flight time of the laser beam and the geometric characteristics of the scanner, the three-dimensional coordinate point corresponding to each reflected signal is calculated. These points together constitute the three-dimensional point cloud data set of the reinforcement mesh.

[0051] In some embodiments, the reinforcement mesh includes an upper mesh and a lower mesh, so the weld point positions of the upper mesh and the lower mesh need to be positioned in turn by the operator. As shown in FIG. 2, for the lower mesh in the reinforcement mesh, the cross bar 1 is located below the plurality of longitudinal bars 2 and is perpendicular to the extension direction of the longitudinal bars 2, as shown in FIG. 3, for the upper mesh in the reinforcement mesh, the cross bar 1 is located above the plurality of longitudinal bars 2 and is perpendicular to the extension direction of the longitudinal bars 2. In order to unify the weld point positioning operation for the upper mesh and the lower mesh, in S10, the upper mesh and the lower mesh are both taken with the end center of the cross bar 1 as the coordinate origin, thereby providing a reference point for the entire reinforcement mesh, facilitating the positioning and measurement of all subsequent points. And the radial direction of the cross bar 1 parallel to the axis direction of the longitudinal bar 2 is taken as the X-axis direction, that is, the X-axis is a straight line direction extending outward from the center of the cross bar 1 along the cross section of the cross bar 1, and the axis direction of the cross bar 1 is taken as the Y-axis direction, that is, the Y-axis is along the extension direction of the cross bar 1, and the radial direction of the cross bar 1 perpendicular to the X-axis direction and the Y-axis direction is taken as the Z-axis direction to establish a three-dimensional coordinate system. By establishing the above three-dimensional coordinate system, each point in the reinforcement mesh can be represented by its coordinate values in the X-axis, Y-axis and Z-axis directions. This representation method is not only intuitive, but also facilitates computer processing and analysis, providing convenience for automatic weld point positioning.

[0052] The intersection point 6 of the lower mesh is positioned and processed as follows:

[0053] In some embodiments, as shown in FIG. 2 and FIG. 4, in S20, the three-dimensional point cloud data of the lower mesh is preprocessed, including: setting a first value interval and a second value interval on the X-axis and the Z-axis respectively, traversing each point in the three-dimensional point cloud data set, checking whether its X coordinate and Z coordinate respectively fall within the first value interval and the second value interval, and excluding the three-dimensional point cloud data outside the first value interval and the second value interval to obtain a preprocessed point set, providing a better basis for subsequent analysis and processing.

[0054] In some embodiments, according to the actual size of the cross bar 1 and the characteristics of the scanning data, the first value interval is set on the X-axis, which should cover the radial range of the cross bar 1. And the second value interval depends on the thickness of the reinforcement mesh, the arrangement of the longitudinal bar 2 and the quality of the scanning data, which should be large enough to include all intersection points 6 connected by the cross bar 1 and the longitudinal bar 2, but not too large to avoid introducing unnecessary background noise.

[0055] In some embodiments, as shown in FIG. 2, FIG. 4 and FIG. 5, for the lower mesh, in S30, the pre-processed point set is sequentially traversed in the Y-axis direction, and for each Y-axis coordinate, the coordinate point with the largest Z-axis direction coordinate is screened to form a first point set 8 to identify the point on the top end of the longitudinal rib 2 in each cross section (a plane perpendicular to the Y-axis) of the lower mesh. Since the point on the top end of the longitudinal rib 2 in the lower mesh has the same Y-axis coordinate as the intersection point 6, the position of the intersection point 6 of the horizontal rib 1 and the longitudinal rib 2 can be determined in the subsequent screening process of the first point set 8.

[0056] In some embodiments, as shown in FIG. 2 and FIG. 5, for the lower mesh, the first point set 8 is sequentially traversed in the Y-axis direction, and for the traversed first point set 8, the slope value of the line between each adjacent two points is calculated. The calculation formula of the slope value is (Z2-Z1) / (Y2-Y1), where (Y1, Z1) and (Y2, Z2) are the coordinates of the adjacent two points in the first point set 8, and Y2>Y1. The slope value of the line between other points is calculated by analogy. The slope value sequence is traversed to find those point pairs whose slope suddenly changes from positive to negative (or from negative to positive). When part of the points in the first point set 8 have positive and negative slope values along the Y-axis direction with respect to the line between the adjacent previous point and the adjacent next point, it indicates that these part of the points are located on the top end of the longitudinal rib 2 in the lower mesh, and these part of the points are defined as the intersection point 6 of the horizontal rib 1 and the longitudinal rib 2, thereby realizing the positioning of the intersection point 6 in the lower mesh.

[0057] The positioning of the intersection point 6 of the upper mesh is as follows:

[0058] In some embodiments, as shown in FIG. 3 and FIG. 4, in S20, the three-dimensional point cloud data of the upper mesh is pre-processed, including: setting a third value interval and a fourth value interval on the X-axis to screen the pre-processed point set with the X-axis coordinate located in the third value interval or the fourth value interval, so as to ensure that the intersection point 6 can be screened and calculated on both sides of the horizontal rib 1 along the X-axis direction, thereby improving the positioning accuracy. A fifth value interval is set in the Z-axis direction, and each point in the three-dimensional point cloud data set of the upper mesh is traversed. For each point, it is checked whether the X coordinate is located in the third value interval or the fourth value interval and whether the Z coordinate is located in the fifth value interval. Then, the three-dimensional point cloud data located outside the fifth value interval is excluded to obtain two groups of pre-processed point sets corresponding to the third value interval and the fourth value interval, respectively. That is, one group of pre-processed point set contains all points with X coordinate located in the third value interval and Z coordinate located in the fifth value interval, and the other group of pre-processed point set contains all points with X coordinate located in the fourth value interval and Z coordinate located in the fifth value interval. These point sets will be more pure and focused on specific geometric features or regions, providing a better basis for subsequent analysis and processing.

[0059] In some embodiments, as shown in FIG. 3, FIG. 4 and FIG. 6, for the upper wire mesh, in S30, two groups of pre-processed point sets are traversed in the Y-axis direction in turn, for each Y-axis coordinate in the two groups of pre-processed point sets, the coordinate with the largest Z-axis direction coordinate is screened to form the second point set 9 and the third point set 10, so as to identify the point on the top end of the longitudinal rib 2 in each cross section (a plane perpendicular to the Y-axis) of the upper wire mesh, since the point on the top end of the longitudinal rib 2 in the upper wire mesh has the same Y-axis coordinate as the intersection point 6, so that the position of the intersection point 6 of the horizontal rib 1 and the longitudinal rib 2 in the upper wire mesh is determined in the subsequent screening process of the second point set 9 and the third point set 10.

[0060] In some embodiments, the second point set 9 and the third point set 10 are traversed in the Y-axis direction in turn, for the traversed second point set 9, the slope value of the line between each adjacent two points is calculated, when the slope value of the line between the adjacent previous point and the adjacent next point of some points in the second point set 9 in the Y-axis direction is positive and negative respectively, these points are defined as the first sequence in the Y-axis direction in turn.

[0061] For the traversed third point set 10, the slope value of the line between each adjacent two points is calculated, when the slope value of the line between the adjacent previous point and the adjacent next point of some points in the third point set 10 in the Y-axis direction is positive and negative respectively, these points are defined as the second sequence in the Y-axis direction in turn, and the average value of the first sequence and the second sequence is calculated in the Y-axis direction in turn to obtain the intersection point 6 of the horizontal rib 1 and the longitudinal rib 2.

[0062] Wherein, for the formation of the first sequence and the second sequence, the calculation formula of the slope value is (Z2-Z1) / (Y2-Y1), wherein (Y1,Z1) and (Y2,Z2) are the coordinates of the adjacent two points, and Y2>Y1, and the slope value of the line between other points is calculated by analogy. The slope value sequence is traversed, and those point pairs whose slope suddenly changes from positive to negative (or from negative to positive) are found to form the first sequence or the second sequence, and then the average value of the corresponding points in the first sequence and the second sequence is calculated in the Y-axis direction in turn to determine the position of the intersection point 6, thereby improving the positioning accuracy of the intersection point 6 in the upper wire mesh.

[0063] In some embodiments, in S40, the X-axis coordinate and the Z-axis coordinate of the intersection position 6 are positioned by the welding device. The welding device includes a fork limiting mechanism arranged on the base 5. When preparing to weld the reinforcement mesh, the fork limiting mechanism is inserted into the cross bar 1, so that the X-axis coordinate of the welding gun 4 is consistent with the X-axis coordinate of the cross bar 1, that is, the X-axis coordinate of the intersection position 6 can be positioned by the welding device. In addition, the welding device also includes a vertical pressing cylinder mechanism arranged on the base 5. When the welding gun 4 is in place, the distance from the gun head position of the welding gun 4 to the upper surface of the steel bar is equal to the vertical distance from the upper surface of the steel bar to the welding point, that is, the Z-axis coordinate of the to-be-welded welding point can be automatically determined by the vertical pressing cylinder mechanism. Since there is a fixed distance offset between the intersection position 6 of the cross bar 1 and the longitudinal bar 2 and the actual welding point position 7, that is, the Z-axis coordinate of the intersection position 6 can be positioned by the welding device.

[0064] The above method will be described by way of example in conjunction with specific examples as follows:

[0065] I. Positioning algorithm for welding point coordinates of the lower mesh:

[0066] S1: Preprocessing of the original point cloud set: The center of one end of the cross bar 1 in the lower mesh is taken as the origin of the three-dimensional coordinate system, the upper limit point of the second value interval is taken as "the diameter of the cross bar 1 + the diameter of the longitudinal bar 2 + 50mm", the lower limit point of the second value interval is taken as "the diameter of the cross bar 1", the first value interval is defined as (-20mm, +20mm), and the points not in the first value interval and the second value interval are excluded to form the preprocessed point set XYC, wherein the coordinates of each point include three components (x, y, z).

[0067] S2: The preprocessed point set XYC is sorted in ascending order according to the Y-axis coordinate to form the sequence XCP.

[0068] S3: The sequence XCP is traversed in ascending order to find the maximum value of the z value corresponding to each y coordinate to form the first point set 8, that is, the sequence XPZ, wherein the coordinates of each point include two components (y, z).

[0069] S4: Traverse the sequence XPZ in ascending order of Y coordinate, calculate the slope value of the line between two adjacent points one by one, the calculation formula of the slope value is (z2-z1) / (y2-y1), where (y1,z1) and (y2,z2) are the coordinates of the two adjacent points, and y2>y1, the slope value of the line of other points is calculated by analogy. Traverse the slope value sequence, find those point pairs whose slope suddenly changes from positive to negative (or from negative to positive), when the slope values of the line between the first point set 8 and its adjacent upper and lower points are positive and negative respectively, define the Y axis coordinate of these points as the Y axis coordinate of the intersection point 6 of the horizontal rib 1 and the vertical rib 2 in the lower mesh.

[0070] II. Upper mesh welding point coordinate positioning algorithm:

[0071] S1: Original point cloud set preprocessing: Take the center of the upper mesh horizontal rib 1 as the origin of the three-dimensional coordinate system, and take "horizontal rib 1 diameter + vertical rib 2 diameter + 50mm" as the upper limit of the fifth value interval, set the third and fourth value intervals on the X axis as (-40mm, -20mm) and (+20mm, +40mm) respectively, and exclude points outside this range to form the preprocessing point sets SYCL and SYCR, where each point coordinate contains (x, y, z) three components.

[0072] S2: Sort the preprocessing point sets SYCL and SYCR in ascending order of Y coordinate respectively to form sequences SPL and SPR.

[0073] S3: Traverse the sequences SPL and SPR in ascending order of Y axis direction respectively, find the maximum value of z corresponding to each y coordinate to form the second point set 9 (i.e. sequence SPLZ) and the third point set 10 (i.e. sequence SPRZ) respectively, where each point coordinate contains (y, z) two components.

[0074] S4: traverse the sequence SPLZ in ascending order of Y coordinates, calculate the slope value of the line between two adjacent points one by one, the calculation formula of the slope value is (z2-z1) / (y2-y1), wherein (y1,z1) and (y2,z2) are the coordinates of two adjacent points, and y2>y1, the slope value of the line between other points is calculated by analogy. Traverse the slope value sequence, find those point pairs whose slope suddenly changes from positive to negative (or from negative to positive), when the slope values of the lines between the current point and its adjacent upper and lower points in the second point set 9 are positive and negative respectively, record the y coordinate of the current point as SLY1. SLY1 is the y coordinate of the intersection point of the first longitudinal reinforcement 2 and the cross reinforcement 1 of the lower mesh. According to the above method, the y coordinates of the intersection points of the remaining longitudinal reinforcements 2 and the cross reinforcement 1 are calculated in turn as SLY2, SLY3……until SLYn (wherein n is a positive integer greater than 1).

[0075] S5: traverse the sequence SPRZ in ascending order of y coordinates, calculate the slope value of the line between two adjacent points one by one, the calculation formula of the slope value is (z2-z1) / (y2-y1), wherein (y1,z1) and (y2,z2) are the coordinates of two adjacent points, and y2>y1, the slope value of the line between other points is calculated by analogy. Traverse the slope value sequence, find those point pairs whose slope suddenly changes from positive to negative (or from negative to positive), when the slope values of the lines between the current point and its adjacent upper and lower points in the second point set 9 are positive and negative respectively, record the y coordinate of the current point as SRY1. SRY1 is the y coordinate of the intersection point of the first longitudinal reinforcement 2 and the cross reinforcement 1 of the upper mesh. According to the above method, the y coordinates of the intersection points of the remaining longitudinal reinforcements 2 and the cross reinforcement 1 are calculated in turn as SRY2, SRY3……until SRYn (wherein n is a positive integer greater than 1).

[0076] S6: calculate the average value of SLY1 and SRY1, which is the intersection point coordinate SY1 of the first longitudinal reinforcement 2 and the cross reinforcement 1 in the upper mesh. According to the above method, the intersection point coordinates SY2, SY3……SYn (wherein n is a positive integer greater than or equal to 1) of the longitudinal reinforcements 2 and the cross reinforcement 1 are calculated in turn.

[0077] III. After the coordinates of the intersection points of the longitudinal reinforcements 2 and the cross reinforcements 1 in the upper mesh and the lower mesh in the Y axis direction are calculated, the X axis coordinate and the Z axis coordinate of the intersection point 6 are positioned by the welding device, and the position information of all cross reinforcements 1 and longitudinal reinforcements 2 at the intersection point 6 is obtained. Since there is a fixed offset between the intersection point 6 and the welding point 7 of the steel mesh, the welding point 7 is offset by a fixed distance based on the intersection point 6, and the welding output end (i.e. the welding gun 4) of the welding device is moved to the welding point 7 to realize welding, thereby efficiently and accurately positioning and welding all welding points 7.

[0078] The application can accurately locate the welding point 7 and realize welding at the welding point 7, thereby improving the accuracy and stability of the welding operation.

Claims

1. A method for positioning welding points of a reinforcing mesh, for positioning intersection points (6) of a cross bar (1) and a longitudinal bar (2) in the reinforcing mesh, comprising: establishing a three-dimensional coordinate system and obtaining a three-dimensional point cloud data set of the reinforcing mesh; preprocessing three-dimensional point cloud data in the three-dimensional point cloud data set and obtaining a preprocessed point set; for each point in the preprocessed point set, sequentially calculating a slope value of a line between two adjacent points, and obtaining information of the intersection points (6) of the cross bar (1) and the longitudinal bar (2) according to the change of the slope value; offsetting a fixed distance from the intersection points (6) to obtain welding points (7), and moving a welding output end of a welding device to the welding points (7) to realize welding.

2. The reinforcing mesh weld spot positioning method of claim 1, wherein, The establishment of the three-dimensional coordinate system comprises: taking a center of an end of the cross bar (1) as a coordinate origin, taking a radial direction of the cross bar (1) parallel to an axis direction of the longitudinal bar (2) as an X-axis direction, taking an axis direction of the cross bar (1) as a Y-axis direction, and taking a radial direction of the cross bar (1) perpendicular to the X-axis direction and the Y-axis direction as a Z-axis direction to establish the three-dimensional coordinate system.

3. The method of reinforcing mesh spot positioning according to claim 2, wherein, The preprocessing of the three-dimensional point cloud data in the three-dimensional point cloud data set comprises: respectively setting a first value interval and a second value interval on the X-axis and the Z-axis, and excluding three-dimensional point cloud data located outside the first value interval and the second value interval to obtain the preprocessed point set.

4. The method of reinforcing mesh spot positioning according to claim 3, wherein, The sequentially calculating of the slope value of the line between the two adjacent points for each point in the preprocessed point set, and the obtaining of the information of the intersection points (6) of the cross bar (1) and the longitudinal bar (2) according to the change of the slope value, comprises: sequentially traversing the preprocessed point set according to the Y-axis direction, and for each Y-axis coordinate, screening a coordinate point with the largest Z-axis direction coordinate to form a first point set (8).

5. The method of reinforcing mesh spot positioning according to claim 4, wherein, The sequentially calculating of the slope value of the line between the two adjacent points for each point in the preprocessed point set, and the obtaining of the information of the intersection points (6) of the cross bar (1) and the longitudinal bar (2) according to the change of the slope value, comprises: sequentially traversing the first point set (8) according to the Y-axis direction, for the traversed first point set (8), calculating the slope value of the line between each two adjacent points, and when a part of points in the first point set (8) has a positive slope value and a negative slope value along the Y-axis direction with respect to a line between an adjacent previous point and an adjacent next point, defining the part of points as the intersection points (6) of the cross bar (1) and the longitudinal bar (2).

6. The method of reinforcing mesh spot positioning according to claim 2, wherein, The preprocessing of the three-dimensional point cloud data in the three-dimensional point cloud data set comprises: setting a third value interval and a fourth value interval on the X-axis to screen the preprocessed point set with an X-axis coordinate located in the third value interval or the fourth value interval, and setting a fifth value interval in the Z-axis direction to exclude three-dimensional point cloud data located outside the fifth value interval to obtain two groups of preprocessed point sets corresponding to the third value interval and the fourth value interval respectively.

7. The method of reinforcing mesh spot positioning according to claim 6, wherein, The sequentially calculating of the slope value of the line between the two adjacent points for each point in the preprocessed point set, and the obtaining of the information of the intersection points (6) of the cross bar (1) and the longitudinal bar (2) according to the change of the slope value, further comprises: The two groups of pretreatment point sets are traversed in the Y-axis direction, and for each Y-axis coordinate in the two groups of pretreatment point sets, the coordinate with the largest Z-axis direction coordinate is screened to form a second point set (9) and a third point set (10).

8. The method of reinforcing mesh spot positioning according to claim 7, wherein, For each point in the pretreatment point set, the slope value of the line between the two adjacent points is sequentially calculated, and the information of the intersection point (6) of the horizontal rib (1) and the vertical rib (2) is obtained according to the change of the slope value, including: The second point set (9) and the third point set (10) are traversed in the Y-axis direction, respectively, and for the traversed second point set (9), the slope value of the line between each two adjacent points is calculated, and when the slope values of the lines between the adjacent upper point and the adjacent lower point of the part of the points in the second point set (9) in the Y-axis direction are positive and negative, respectively, the part of the points are sequentially defined as a first sequence in the Y-axis direction; For the traversed third point set (10), the slope value of the line between each two adjacent points is calculated, and when the slope values of the lines between the adjacent upper point and the adjacent lower point of the part of the points in the third point set (10) in the Y-axis direction are positive and negative, respectively, the part of the points are sequentially defined as a second sequence in the Y-axis direction, and the average value of the first sequence and the second sequence is sequentially calculated in the Y-axis direction to obtain the intersection point (6) of the horizontal rib (1) and the vertical rib (2).

9. The method of reinforcing mesh spot positioning according to claim 2, wherein, The offset of the intersection point (6) by a fixed distance is the welding point (7), and the welding output end of the welding device is moved to the welding point (7) to realize welding, including: The X-axis coordinate and the Z-axis coordinate of the intersection point (6) are positioned by the welding device.

10. The reinforcing mesh spot locating method according to any one of claims 1 to 9, wherein, The three-dimensional coordinate system is established, and the three-dimensional point cloud data set of the steel mesh is obtained, including: The steel mesh is scanned by a laser, and the point signals reflected by the steel mesh are received to form the three-dimensional point cloud data set.

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