Method for positioning welding points of reinforcement mesh of underground continuous wall

Abstract

The application belongs to the technical field of building construction, and discloses a method for positioning welding points of a steel mesh of an underground continuous wall, which is used for positioning intersection points of horizontal and vertical steels in the steel mesh. Firstly, a three-dimensional coordinate system is established, and a three-dimensional point cloud data set of the steel mesh is obtained. Then, the three-dimensional point cloud data in the three-dimensional point cloud data set is preprocessed, and a preprocessed point set is obtained. After that, the slope value of the connecting line between two adjacent points is sequentially calculated for each point in the preprocessed point set, and the information of the intersection points of the horizontal and vertical steels is obtained according to the change of the slope value. Finally, the welding point position is offset by a fixed distance based on the intersection point position, and the welding output end of a welding device is moved to the welding point position to realize welding. Through the above setting, the method for positioning welding points of the steel mesh of the underground continuous wall can efficiently and accurately realize the positioning and welding of the welding points of the steel mesh.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and in particular to a method for locating welding points of steel mesh in underground continuous walls. Background Technology

[0002] like Figure 1 As shown, in the welding of the steel mesh, spot welding is required at the intersection of the transverse reinforcement 1 and the longitudinal reinforcement 2 to complete the welding of the steel mesh.

[0003] Before welding, the locations of the weld points must first be determined, and then the welding torch is used by computer control to weld these points. In small steel mesh, due to the small diameter of the steel bars, the actual positions of the steel bar points are consistent with the design positions under the action of steel bar straightening equipment, and the weld point positions are highly regular and easy to determine. However, for steel mesh in large wall reinforcement cages, the diameter of the steel bars is larger, making it more difficult to straighten and arrange the steel bars neatly. This results in a significant difference between the weld point positions after placement and the design positions, and the actual weld point positions are less regular, making it impossible to achieve automatic weld point positioning through simple control methods.

[0004] To address the aforementioned problems, existing technologies generally employ mechanical solder joint positioning methods based on relative positioning technology. For example... Figure 1 As shown, a touch switch 3 and a welding torch 4 are respectively installed on the base 5. In the direction of the welding torch's forward movement (e.g., ... Figure 1 (As shown by the middle arrow), the touch switch 3 is in front of the welding torch 4. When the touch switch 3 touches the longitudinal reinforcement 2, the touch switch 3 sends a trigger signal. Since the distance between the touch switch 3 and the welding torch 5 is a fixed value, after receiving the trigger signal from the touch switch 3, the computer control system drives the base 5 to move the fixed distance in the direction of the arrow, so that the welding torch 5 is located at the welding point, thereby realizing the mechanical positioning of the welding point of the steel mesh.

[0005] However, the aforementioned mechanical weld point positioning method requires point-by-point positioning, meaning each point must trigger a signal from switch 3, then the welding torch 4 must be moved to a fixed offset before welding can begin. This results in very low positioning efficiency. For welding large steel mesh panels, where the number of weld points can reach tens of thousands, the inefficiency of this identification process and the slow welding speed have already hampered the application of welding robots. Summary of the Invention

[0006] The purpose of this invention is to provide a method for locating weld points of steel mesh in underground continuous walls, which can efficiently and accurately locate and weld the weld points of the steel mesh.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] A method for locating weld points of reinforcing mesh in diaphragm walls, used to locate the intersections of transverse and longitudinal bars in the reinforcing mesh, comprising:

[0009] Step 1: Establish a three-dimensional coordinate system and obtain a set of three-dimensional point cloud data of the steel mesh;

[0010] Step 2: Preprocess the 3D point cloud data in the 3D point cloud dataset to obtain a preprocessed point set;

[0011] Step 3: For each point in the preprocessing point set, calculate the slope of the line connecting two adjacent points in turn, and obtain the information of the intersection of the horizontal and vertical reinforcements based on the change of the slope value.

[0012] Step 4: Offset the intersection point by a fixed distance to the welding point, and move the welding output end of the welding device to the welding point to complete the welding.

[0013] Optionally, in step one, a three-dimensional coordinate system is established with the end center of the horizontal rib as the origin, the radial direction of the horizontal rib as the X-axis, the axial direction of the horizontal rib as the Y-axis, and the radial direction of the horizontal rib perpendicular to the X-axis and Y-axis as the Z-axis.

[0014] Optionally, in step two, the preprocessing of the three-dimensional point cloud data includes: setting a first value interval and a second value interval on the X-axis and Z-axis respectively, and excluding the three-dimensional point cloud data located outside the first value interval and the second value interval to obtain a preprocessed point set.

[0015] Optionally, in step three, the preprocessed point set is traversed sequentially along the Y-axis direction, and for each Y-axis coordinate, the coordinate point with the largest coordinate in the Z-axis direction is selected to form the first point set.

[0016] Optionally, the first set of points is traversed sequentially along the Y-axis. For the first set of points after traversal, the slope of the line connecting each pair of adjacent points is calculated. When the slope of the line connecting some points in the first set along the Y-axis to their adjacent previous and next points is positive and negative, respectively, these points are defined as the intersection points of the horizontal and vertical ribs.

[0017] Optionally, in step two, the preprocessing of the three-dimensional point cloud data includes: setting a third value interval and a fourth value interval on the X-axis to filter the preprocessed point set whose X-axis coordinates are located in the third value interval or the fourth value interval, and setting a fifth value interval in the Z-axis direction to exclude the three-dimensional point cloud data located outside the fifth value interval, so as to obtain two sets of preprocessed point sets corresponding to the third value interval and the fourth value interval respectively.

[0018] Optionally, in step three, the two sets of preprocessed point sets are traversed sequentially along the Y-axis direction. For each Y-axis coordinate in the two sets of preprocessed point sets, the coordinate with the largest Z-axis coordinate is selected to form the second and third point sets.

[0019] Optionally, the second and third point sets are traversed sequentially along the Y-axis. For the traversed second point set, the slope of the line connecting each pair of adjacent points is calculated. When the slope of the line connecting some points in the second point set to their adjacent previous and next points along the Y-axis is positive and negative respectively, these points are defined as the first sequence along the Y-axis. For the traversed third point set, the slope of the line connecting each pair of adjacent points is calculated. When the slope of the line connecting some points in the third point set to their adjacent previous and next points along the Y-axis is positive and negative respectively, these points are defined as the second sequence along the Y-axis. The average of the first and second sequences is calculated sequentially along the Y-axis to obtain the intersection points of the horizontal and vertical ribs.

[0020] Optionally, in step four, the X-axis and Z-axis coordinates of the intersection point are located using the welding device.

[0021] Optionally, in step one, the steel mesh is scanned by laser and the point signals reflected by the steel mesh are received to form a three-dimensional point cloud data set.

[0022] The beneficial effects of this invention are:

[0023] This invention provides a method for locating weld points in a diaphragm wall steel mesh. The method locates the intersections of transverse and longitudinal reinforcement bars in the mesh. First, a three-dimensional coordinate system is established, and a three-dimensional point cloud data set of the steel mesh is acquired to comprehensively reflect its actual shape, including detailed location information of the transverse and longitudinal reinforcement bars and their intersections. Then, the three-dimensional point cloud data is preprocessed to obtain a preprocessed point set, ensuring the accuracy and reliability of subsequent analysis. Next, for each point in the preprocessed point set, the slope value of the line connecting adjacent points is calculated to reflect the changing trend of the reinforcement bar direction. Abrupt changes in slope value often correspond to the intersections of transverse and longitudinal reinforcement bars, allowing operators to obtain information about the intersections based on slope changes. This not only improves the accuracy of weld point location but also avoids the tedious point-by-point touching process of traditional mechanical positioning methods, significantly improving positioning efficiency. Finally, the welding point is determined by offsetting a fixed distance from the intersection point. The welding output end of the welding device is moved to the welding point to perform welding, thereby improving the accuracy and stability of the welding operation. With the above settings, the method for locating weld points of the underground continuous wall steel mesh in this application can efficiently and accurately realize the positioning and welding operations of weld points of the steel mesh. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the welding operation of a welding device on a steel mesh in the prior art;

[0025] Figure 2 This is a schematic diagram of the lower mesh in the steel mesh provided in an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the steel mesh in the embodiment of the present invention;

[0027] Figure 4 This is a schematic diagram of a three-dimensional point cloud data set in a three-dimensional coordinate system provided in an embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of the first point set in the three-dimensional coordinate system provided in an embodiment of the present invention;

[0029] Figure 6 This is a schematic diagram of the second and third point sets in the three-dimensional coordinate system provided in the embodiment of the present invention.

[0030] In the picture:

[0031] 1. Horizontal ribs; 2. Vertical ribs; 3. Touch switch; 4. Welding torch; 5. Base; 6. Intersection points; 7. Welding points; 8. First point set; 9. Second point set; 10. Third point set. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0033] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0035] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, 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 the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0036] like Figure 1 As shown, in the welding of the steel mesh, spot welding is required at the intersection of the transverse reinforcement 1 and the longitudinal reinforcement 2 to complete the welding of the steel mesh.

[0037] Before welding, the location of the weld points must first be determined, and then the welding torch 4, controlled by a computer, welds these points. In small steel mesh, due to the small diameter of the reinforcing bars, the actual position of the reinforcing bar points matches the design position under the action of the reinforcing bar straightening equipment, resulting in a strong regularity in the weld point position and easy determination. However, for the steel mesh of large wall reinforcement cages, the diameter of the reinforcing bars is larger, making it more difficult to straighten and arrange the reinforcing bars neatly. This results in a significant difference between the weld point position after placement and the design position, leading to poor regularity in the actual weld point position and making it impossible to achieve automatic weld point positioning through simple control methods.

[0038] To address the aforementioned problems, existing technologies generally employ mechanical solder joint positioning methods based on relative positioning technology. For example... Figure 1 As shown, a touch switch 3 and a welding torch 4 are respectively installed on the base 5. In the forward direction of the welding torch 4 (e.g., ... Figure 1 (As shown by the middle arrow), the touch switch 3 is in front of the welding torch 4. When the touch switch 3 touches the longitudinal reinforcement 2, the touch switch 3 sends a trigger signal. Since the distance between the touch switch 3 and the welding torch 4 is a fixed value, after receiving the trigger signal from the touch switch 3, the computer control system drives the base 5 to move the fixed distance in the direction of the arrow, so that the welding torch 4 is located at the welding point, thereby realizing the mechanical positioning of the welding point of the steel mesh.

[0039] However, the aforementioned mechanical weld point positioning method requires point-by-point positioning, meaning each point must trigger a signal from switch 3, then the welding torch 4 must be moved to a fixed offset before welding can begin. This results in very low positioning efficiency. For welding large steel mesh panels, where the number of weld points can reach tens of thousands, the inefficiency of this identification process and the slow welding speed have already hampered the application of welding robots.

[0040] To solve the above technical problems, such as Figures 1-6 As shown, this embodiment provides a method for locating weld points of steel mesh in a diaphragm wall, used to locate the intersection point 6 of the transverse reinforcement 1 and the longitudinal reinforcement 2 in the steel mesh, which includes:

[0041] Step 1: Establish a three-dimensional coordinate system and obtain a set of three-dimensional point cloud data of the steel mesh.

[0042] Step 2: Preprocess the 3D point cloud data in the 3D point cloud dataset to obtain a preprocessed point set.

[0043] Step 3: For each point in the preprocessing point set, calculate the slope value of the line connecting two adjacent points in turn, and obtain the information of the intersection point 6 of the horizontal rib 1 and the vertical rib 2 based on the change of the slope value.

[0044] Step 4: Offset the welding point 7 by a fixed distance from the intersection point 6. Move the welding output end of the welding device to the welding point 7 to complete the welding.

[0045] In this embodiment, a three-dimensional coordinate system is first established, and a three-dimensional point cloud data set of the reinforcing mesh is acquired to comprehensively reflect the actual shape of the reinforcing mesh, including detailed location information of the transverse bars 1, longitudinal bars 2, and their intersection points 6. Then, the three-dimensional point cloud data in the three-dimensional point cloud data set is preprocessed to obtain a preprocessed point set, ensuring the accuracy and reliability of subsequent analysis and processing. Next, for each point in the preprocessed point set, the slope value of the line connecting adjacent points is calculated sequentially to reflect the changing trend of the reinforcing bar direction. The abrupt change in slope value often corresponds to the position of the intersection point 6 of the transverse bars 1 and longitudinal bars 2, allowing operators to obtain information about the intersection point 6 of the transverse bars 1 and longitudinal bars 2 based on the change in slope value. This not only improves the accuracy of weld point positioning but also avoids the tedious point-by-point touching process in traditional mechanical positioning methods, significantly improving positioning efficiency. Finally, the welding point 7 is obtained by offsetting a fixed distance from the intersection point 6. The welding output end of the welding device is moved to the welding point 7 to perform welding, thereby improving the accuracy and stability of the welding operation. With the above settings, the underground continuous wall steel mesh weld point positioning method of this embodiment can efficiently and accurately realize the weld point positioning and welding operation of the steel mesh.

[0046] The specific details of the above methods are explained below:

[0047] Specifically, in step one, the steel mesh is scanned using a laser, and the point signals reflected from the steel mesh are received to form a three-dimensional point cloud data set. For example, if the steel mesh is scanned using a laser scanner positioned directly above it, the laser beam emitted by the scanner will strike the surface of the steel mesh and reflect back to the scanner. The scanner receives these reflected signals and measures the time required for them to travel from emission to reception. Using the time of flight of the laser beam and the geometric characteristics of the scanner, the three-dimensional coordinates corresponding to each reflected signal are calculated. These points collectively constitute the three-dimensional point cloud data set of the steel mesh. It is understood that those skilled in the art are familiar with the working principle of the above-described technique, and will not elaborate further here.

[0048] Specifically, the reinforcing mesh consists of an upper mesh and a lower mesh, therefore, the workers need to locate the weld points of the upper and lower mesh sequentially. For example... Figure 2 As shown, for the lower mesh of the steel mesh, the horizontal bars 1 are located below multiple longitudinal bars 2 and are set perpendicular to the extension direction of the longitudinal bars 2, as shown. Figure 3 As shown, for the upper part of the steel mesh, the transverse bars 1 are located above multiple longitudinal bars 2 and are perpendicular to the extension direction of the longitudinal bars 2. To standardize the welding point positioning operations for both the upper and lower meshes, in step one, the center of the end of the transverse bar 1 is used as the origin of the coordinate system for both the upper and lower meshes, thus providing a reference point for the entire steel mesh and facilitating the positioning and measurement of all subsequent points. A three-dimensional coordinate system is established with the radial direction of the transverse bar 1 as the X-axis (a straight line extending outward from the center along the cross-section of the transverse bar 1), the axial direction of the transverse bar 1 as the Y-axis (along the extension direction of the transverse bar 1), and the radial direction of the transverse bar 1 perpendicular to both the X and Y axes as the Z-axis. By establishing this three-dimensional coordinate system, each point in the steel mesh can be represented by its coordinate values ​​in the X, Y, and Z axes. This representation method is not only intuitive but also facilitates computer processing and analysis, providing convenience for automated welding point positioning.

[0049] The following steps involve locating point 6 of the lower mesh:

[0050] Specifically, such as Figure 2 and Figure 4 As shown, in step two, the preprocessing of the 3D point cloud data of the lower mesh includes: setting a first value interval and a second value interval on the X-axis and Z-axis respectively; traversing each point in the 3D point cloud data set; checking whether its X-coordinate and Z-coordinate fall within the first value interval and the second value interval respectively; and excluding the 3D point cloud data located outside the first value interval and the second value interval to obtain a preprocessed point set, which provides a better foundation for subsequent analysis and processing.

[0051] More specifically, based on the actual dimensions of the transverse reinforcement 1 and the characteristics of the scanned data, a first value range is set on the X-axis. This first value range should cover the radial range of the transverse reinforcement 1. The second value range depends on the thickness of the steel mesh, the arrangement of the longitudinal reinforcement 2, and the quality of the scanned data. This range should be large enough to include all intersection points 6 of the transverse and longitudinal reinforcement 1, but not too large to avoid introducing unnecessary background noise.

[0052] Specifically, such as Figure 2 , Figure 4 and Figure 5 As shown, for the lower mesh, in step three, the preprocessed point set is traversed sequentially along the Y-axis direction. For each Y-axis coordinate, the coordinate point with the largest coordinate in the Z-axis direction is selected to form the first point set 8, so as to identify the point located at the top of the longitudinal rib 2 on each cross section (the plane perpendicular to the Y-axis) of the lower mesh. Since the coordinates of the top of the longitudinal rib 2 in the lower mesh are the same as those of the intersection point 6 on the Y-axis, the position of the intersection point 6 of the transverse rib 1 and the longitudinal rib 2 can be determined in the subsequent selection process of the first point set 8.

[0053] More specifically, such as Figure 2 and Figure 5 As shown, for the lower mesh, the first point set 8 is traversed sequentially along the Y-axis. For the traversed first point set 8, the slope value of the line connecting each two adjacent points is calculated. The formula for calculating the slope value is (Z2-Z1) / (Y2-Y1), where (Y1,Z1) and (Y2,Z2) are the coordinates of two adjacent points in the first point set 8, and Y2>Y1. The slope values ​​of the lines connecting other points are calculated similarly. Traversing the slope value sequence, we find those point pairs whose slope suddenly changes from positive to negative (or from negative to positive). When the slope values ​​of some points in the first point set 8 along the Y-axis are positive and negative respectively, it indicates that these points are located at the top of the longitudinal rib 2 in the lower mesh. Therefore, these points are defined as the intersection point 6 of the transverse rib 1 and the longitudinal rib 2, thus realizing the positioning of the intersection point 6 in the lower mesh.

[0054] The following steps involve locating point 6 of the network mesh:

[0055] Specifically, such as Figure 3 and Figure 4As shown, in step two, the preprocessing of the 3D point cloud data of the mesh includes: setting a third and fourth value interval on the X-axis to filter preprocessed point sets whose X-axis coordinates are located in the third or fourth value interval, so as to ensure that the intersection points 6 can be filtered 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 on the Z-axis direction. Each point in the 3D point cloud data set of the mesh is traversed. For each point, it is checked whether its X-coordinate is located within the third or fourth value interval and whether its Z-coordinate is located within the fifth value interval. Then, the 3D point cloud data outside the fifth value interval is excluded to obtain two sets of preprocessed point sets corresponding to the third and fourth value intervals respectively. That is, one set of preprocessed point sets contains all points whose X-coordinates are located within the third value interval and whose Z-coordinates are located within the fifth value interval, and the other set of preprocessed point sets contains all points whose X-coordinates are located within the fourth value interval and whose Z-coordinates are located within the fifth value interval. These point sets will be purer and more focused on specific geometric features or regions, providing a better foundation for subsequent analysis and processing.

[0056] Specifically, such as Figure 3 , Figure 4 and Figure 6 As shown, for the mesh, in step three, the two sets of preprocessed point sets are traversed sequentially along the Y-axis. For each Y-axis coordinate in the two sets of preprocessed point sets, the coordinate with the largest Z-axis coordinate is selected to form the second point set 9 and the third point set 10, so as to identify the point located at the top of the longitudinal rib 2 on each cross section (the plane perpendicular to the Y-axis) of the mesh. Since the coordinates of the top of the longitudinal rib 2 in the mesh are the same as those of the intersection point 6 on the Y-axis, the position of the intersection point 6 of the transverse rib 1 and the longitudinal rib 2 in the mesh can be determined in the subsequent selection process of the second point set 9 and the third point set 10.

[0057] More specifically, the second point set 9 and the third point set 10 are traversed sequentially along the Y-axis. For the second point set 9 after traversal, the slope value of the line connecting each two adjacent points is calculated. When the slope values ​​of the lines connecting some points in the second point set 9 to their adjacent previous and next points along the Y-axis are positive and negative, respectively, these partial points are defined as the first sequence in sequence along the Y-axis.

[0058] For the third point set 10 after traversal, calculate the slope value of the line connecting each two adjacent points. When the slope values ​​of the lines connecting some points in the third point set 10 to their adjacent previous and next points along the Y-axis are positive and negative respectively, define these partial points as the second sequence in the Y-axis direction. Calculate the average value of the first and second sequences in the Y-axis direction to obtain the intersection point 6 of the horizontal rib 1 and the vertical rib 2.

[0059] The slope value for the formation of the first and second sequences is calculated using the formula (Z2-Z1) / (Y2-Y1), where (Y1,Z1) and (Y2,Z2) are the coordinates of two adjacent points, and Y2>Y1. The slope values ​​of the lines connecting other points are calculated using the same formula. The slope value sequence is traversed to find pairs of points where the slope suddenly changes from positive to negative (or from negative to positive), thus forming the first or second sequence. Then, the average value of corresponding points in the first and second sequences is calculated sequentially along the Y-axis to determine the position of intersection point 6, thereby improving the positioning accuracy of intersection point 6 in the network mesh.

[0060] Specifically, in step four, the X-axis and Z-axis coordinates of the intersection point 6 are located using the welding device. It can be understood that the welding device includes a fork-shaped limiting mechanism mounted on the base 5. When preparing to weld the reinforcing mesh, the fork-shaped limiting mechanism is inserted into the horizontal reinforcing bar 1, ensuring that the X-axis coordinate of the welding torch 4 is consistent with the X-axis coordinate of the horizontal reinforcing bar 1. This means the welding device can locate the X-axis coordinate of the intersection point 6. Furthermore, the welding device also includes a vertical clamping cylinder mechanism mounted on the base 5. When the welding torch 4 is in position, the upper surface of the clamped reinforcing bar is used as a reference point. The distance from the torch tip of the welding torch 4 to the upper surface of the reinforcing bar is equal to the vertical distance from the upper surface of the reinforcing bar to the weld point. This means the vertical clamping cylinder mechanism can automatically determine the Z-axis coordinate of the weld point. Since there is a fixed distance offset between the intersection point 6 of the horizontal reinforcing bar 1 and the longitudinal reinforcing bar 2 and the actual welding point 7, this is equivalent to the welding device being able to locate the Z-axis coordinate of the intersection point 6. Furthermore, those skilled in the art know how to determine the X-axis and Z-axis coordinates of intersection point 6, so we will not go into detail here.

[0061] The above method will be illustrated with specific examples below:

[0062] I. Algorithm for locating the coordinates of the solder joints on the lower mesh:

[0063] S1: Preprocessing of the original point set: The center of the circle at one end of the horizontal rib 1 in the following mesh is the origin of the three-dimensional coordinate system. The upper limit of the second value interval is "diameter of horizontal rib 1 + diameter of vertical rib 2 + 50mm", and the lower limit of the second value interval is "diameter of horizontal rib 1". The first value interval is defined as (-20mm, +20mm). Points that are not in the first or second value interval are excluded to form a preprocessed point set XYC, where the coordinates of each point contain three components (x, y, z).

[0064] S2: Sort the preprocessed point set XYC in ascending order of Y-coordinate to form the sequence XCP.

[0065] S3: Traverse the sequence XCP from smallest to largest, find the maximum z value corresponding to each y coordinate, and form the first point set 8, i.e. the sequence XPZ, where the coordinates of each point contain two components (y, z).

[0066] S4: Traverse the sequence XPZ from smallest to largest Y-coordinate, calculating the slope of the line connecting adjacent points one by one. The formula for calculating the slope is (z2-z1) / (y2-y1), where (y1,z1) and (y2,z2) are the coordinates of the two adjacent points, and y2>y1. The slope of the line connecting other points is calculated by analogy. Traverse the slope value sequence and find those point pairs where the slope suddenly changes from positive to negative (or from negative to positive). When the slope of the line connecting some points in the first point set 8 to their adjacent previous and next points along the Y-axis is positive and negative respectively, define the Y-axis coordinates of these points as the Y-axis coordinates of the intersection point 6 of the horizontal rib 1 and the vertical rib 2 in the lower mesh.

[0067] II. Algorithm for locating solder joint coordinates of wire mesh:

[0068] S1: Preprocessing of the original point set: The center of the circle at one end of the horizontal rib 1 in the above mesh is the origin of the three-dimensional coordinate system. The upper limit of the fifth value interval is set as "diameter of horizontal rib 1 + diameter of vertical rib 2 + 50mm". The third and fourth value intervals are set on the X-axis as (-40mm, -20mm) and (+20mm, +40mm) respectively. Points outside this range are excluded to form the preprocessed point sets SYCL and SYCR, where the coordinates of each point contain three components (x, y, z).

[0069] S2: Sort the preprocessed point sets SYCL and SYCR in ascending order of their Y-coordinates to form sequences SPL and SPR.

[0070] S3: Traverse the sequences SPL and SPR from smallest to largest along the Y-axis, find the maximum value of the z value corresponding to each y coordinate, and form the second point set 9 (i.e., sequence SPLZ) and the third point set 10 (i.e., sequence SPRZ), where the coordinates of each point contain two components (y, z).

[0071] S4: Traverse the sequence SPLZ from smallest to largest Y-coordinate, calculating the slope of the line connecting adjacent points one by one. The formula for calculating the slope is (z2-z1) / (y2-y1), where (y1,z1) and (y2,z2) are the coordinates of the two adjacent points, and y2>y1. The slope of the line connecting other points is calculated using the same formula. Traverse the slope value sequence, looking for point pairs where the slope suddenly changes from positive to negative (or from negative to positive). When the slope of the line connecting some points in the second point set 9 to their adjacent previous and next points along the Y-axis is positive and negative respectively, record the y-coordinate of the current point as SLY1. SLY1 is the y-coordinate of the intersection of the first longitudinal rib 2 and the transverse rib 1 in the lower mesh of the second point set 9. Calculate the y-coordinates of the remaining intersections of longitudinal rib 2 and transverse rib 1 in the same way, SLY2, SLY3, ... up to SLYn (where n is a positive integer greater than 1).

[0072] S5: Traverse the sequence SPRZ from smallest to largest y-coordinate, calculating the slope of the line connecting adjacent points one by one. The formula for calculating the slope is (z2-z1) / (y2-y1), where (y1,z1) and (y2,z2) are the coordinates of the two adjacent points, and y2>y1. The slope of the line connecting other points is calculated similarly. Traverse the slope value sequence, looking for point pairs where the slope suddenly changes from positive to negative (or from negative to positive). When the slope of the line connecting some points in the second point set 9 to their adjacent previous and next points along the y-axis is positive and negative respectively, record the y-coordinate of the current point as SRY1. SRY1 is the y-coordinate of the intersection of the first longitudinal rib 2 and the transverse rib 1 of the mesh in the third point set 10. Calculate the y-coordinates of the remaining intersections of longitudinal rib 2 and transverse rib 1 in the same way, SRY2, SRY3, ... up to SRYn (where n is a positive integer greater than 1).

[0073] S6: Calculate the average value of SLY1 and SRY1. This value is the coordinate SY1 of the intersection point of the first longitudinal rib 2 and the transverse rib 1 in the mesh. Calculate the coordinates SY2, SY3...SYn of the intersection point of the longitudinal rib 2 and the transverse rib 1 in sequence (where n is a positive integer greater than or equal to 1) in the same way.

[0074] 3. After calculating the Y-axis coordinates of the intersection points of the longitudinal reinforcement 2 and transverse reinforcement 1 in the upper and lower mesh sheets, the X-axis and Z-axis coordinates of the intersection point 6 are located by the welding device. This allows us to obtain the location information of all transverse reinforcement 1 and longitudinal reinforcement 2 at the intersection point 6. Since there is a fixed offset between the intersection point 6 and the welding point 7 of the steel mesh (which is well known to those skilled in the art and will not be described in detail here), the welding point 7 is obtained by offsetting the intersection point 6 by a fixed distance. The welding output end of the welding device (i.e., the welding torch 4) is moved to the welding point 7 to achieve welding, thereby efficiently and accurately realizing the positioning and welding operation of all welding points 7.

[0075] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for locating weld points of reinforcing mesh in underground continuous wall, used to locate the intersection points (6) of transverse bars (1) and longitudinal bars (2) in the reinforcing mesh, characterized in that, include: Step 1: Establish a three-dimensional coordinate system and obtain a three-dimensional point cloud data set of the steel mesh. Take the end center of the horizontal bar (1) as the origin of the coordinate system, the radial direction of the horizontal bar (1) as the X-axis direction, the axial direction of the horizontal bar (1) as the Y-axis direction, and the radial direction of the horizontal bar (1) perpendicular to the X-axis and Y-axis directions as the Z-axis direction. Step 2: Preprocess the 3D point cloud data in the 3D point cloud dataset to obtain a preprocessed point set; Step 3: For each point in the preprocessing point set, calculate the slope value of the line connecting two adjacent points in turn, and obtain the information of the intersection point (6) of the horizontal reinforcement (1) and the vertical reinforcement (2) based on the change of the slope value. Step 4: Based on the intersection point (6), offset by a fixed distance to obtain the welding point (7), move the welding output end of the welding device to the welding point (7) to achieve welding; For the lower mesh in the steel mesh, the horizontal bar (1) is located below the multiple longitudinal bars (2). In step two, the preprocessing of the three-dimensional point cloud data includes: setting a first value range and a second value range on the X-axis and Z-axis respectively, and excluding the three-dimensional point cloud data located outside the first value range and the second value range to obtain a preprocessed point set. For the lower mesh in the steel mesh, in step three, the pre-processed point set is traversed sequentially along the Y-axis direction. For each Y-axis coordinate, the coordinate point with the largest coordinate in the Z-axis direction is selected to form the first point set (8). The first point set (8) is traversed sequentially along the Y-axis direction. For the traversed first point set (8), the slope value of the line connecting each two adjacent points is calculated. When the slope values ​​of the lines connecting some points in the first point set (8) with their adjacent previous and next points along the Y-axis direction are positive and negative respectively, these points are defined as the intersection points (6) of the horizontal reinforcement (1) and the longitudinal reinforcement (2).

2. The method for locating welding points of reinforcing mesh in underground continuous wall according to claim 1, characterized in that, For the mesh in the steel mesh, the transverse bar (1) is located above the multiple longitudinal bars (2). In step two, the preprocessing of the three-dimensional point cloud data includes: setting a third value interval and a fourth value interval on the X-axis to filter the preprocessed point set whose X-axis coordinate is located in the third value interval or the fourth value interval, and setting a fifth value interval in the Z-axis direction to exclude the three-dimensional point cloud data located outside the fifth value interval, so as to obtain two sets of preprocessed point sets corresponding to the third value interval and the fourth value interval respectively.

3. The method for locating welding points of reinforcing mesh in underground continuous wall according to claim 2, characterized in that, For the mesh in the steel mesh, in step three, the two sets of preprocessed point sets are traversed sequentially along the Y-axis. For each Y-axis coordinate in the two sets of preprocessed point sets, the coordinate with the largest Z-axis coordinate is selected to form the second point set (9) and the third point set (10). The second point set (9) and the third point set (10) are traversed sequentially along the Y-axis. For the second point set (9) after traversal, the slope value of the line connecting each two adjacent points is calculated. When some points in the second point set (9) are located along the Y-axis with their adjacent previous and next points, the slope value is calculated. When the slope values ​​of the connecting lines are positive and negative, these partial points are defined as the first sequence in the Y-axis direction. For the third set of points (10) after traversal, the slope value of the connecting line between each two adjacent points is calculated. When the slope values ​​of the connecting lines between the partial points in the third set of points (10) and their adjacent previous and next points in the Y-axis direction are positive and negative, these partial points are defined as the second sequence in the Y-axis direction. The average value of the first and second sequences is calculated in the Y-axis direction to obtain the intersection point (6) of the horizontal rib (1) and the vertical rib (2).

4. The method for locating welding points of reinforcing mesh in underground continuous wall according to claim 1, characterized in that, In step four, the X-axis and Z-axis coordinates of the intersection point (6) are located by the welding device.

5. The method for locating weld points of reinforcing mesh in underground continuous wall according to any one of claims 1-4, characterized in that, In step one, the steel mesh is scanned by laser and the point signals reflected by the steel mesh are received to form a three-dimensional point cloud data set.

Images