Method, medium, and apparatus for teaching-free welding of a workpiece to a lap joint pipe clamp

Abstract

The application provides a teaching-free welding method, medium and equipment for a clamping workpiece lap type pipe clamp, and the method comprises the following steps: acquiring a pipe clamp workpiece point cloud, determining an equation of the clamping workpiece according to the pipe clamp workpiece point cloud, and segmenting the pipe clamp point cloud and the clamping workpiece point cloud; determining a bevel plane equation according to the equation of the clamping workpiece; determining two end planes of the lap pipe clamp according to the bevel plane equation and the pipe clamp point cloud, and obtaining a bevel position point cloud according to the two end planes; extracting the point cloud with the maximum curvature in the left and right ends of the bevel position point cloud as a welding seam point, and connecting the welding seam points to form a welding seam, so that the problem that the existing welding method has low efficiency and unstable quality when welding non-standardized or special-shaped workpieces is solved.

Description

Technical Field

[0001] This invention relates to the field of automated welding technology, and in particular to a teach-free welding method, medium, and equipment for clamping workpieces using overlapping pipe clamps. Background Technology

[0002] Lap-joint pipe clamp welding is a method for fixing serpentine pipes. It involves placing the upper pipe clamp on top of the lower pipe clamp and welding at the bevel of the overlap. This welding method has the advantages of simple structure, convenient operation, and suitability for different pipe diameters and wall thicknesses. However, since the weld of the lap-joint pipe clamp is located at the bevel of the two pipe clamps, it is necessary to pay attention to controlling the shape and size of the weld to avoid defects such as porosity and incomplete penetration. This poses a great challenge to the welding technology of lap-joint pipe clamps.

[0003] Two commonly used techniques in lap-joint pipe clamp welding are robot-taught welding and manual welding. Robot-taught welding is an automated welding technology that allows the robot to automatically weld according to a pre-set motion path and process parameters. Robot-taught welding can complete the welding tasks of most standardized workpieces, but it is not very adaptable to non-standard or irregularly shaped workpieces, requiring adjustments to the path and parameters, which is time-consuming and labor-intensive. Moreover, robot-taught welding lacks a perception and feedback mechanism for external information, and cannot adjust the welding state in a timely manner. During the welding process, excessively high temperatures can cause deformation and twisting of the lap-joint pipe clamps, easily leading to welding deviations or errors.

[0004] Therefore, existing welding methods still suffer from low efficiency and unstable quality when welding non-standard or irregularly shaped workpieces. Summary of the Invention

[0005] Based on this, the purpose of this application is to provide a teachless welding method, medium, and equipment for clamping workpieces using overlapping pipe clamps, in order to solve at least one of the technical problems mentioned in the background art.

[0006] In a first aspect, this application provides a teach-free welding method for clamping workpieces using lap-type pipe clamps, comprising:

[0007] S1: Obtain the point cloud of the pipe clamp workpiece;

[0008] S2: Based on the point cloud of the pipe clamp workpiece, determine the equation for clamping the workpiece, and segment the point cloud of the pipe clamp and the point cloud of the clamped workpiece.

[0009] S3: Determine the equation of the bevel plane based on the equation for clamping the workpiece;

[0010] S4: Based on the bevel plane equation and the pipe clamp point cloud, determine the two end planes of the overlapping pipe clamp, and obtain the bevel position point cloud based on the two end planes;

[0011] S5: Extract the point cloud with the largest curvature at both ends of the bevel location point cloud, use it as the weld point, and connect them to form the weld.

[0012] Furthermore, the specific steps of step S1 include:

[0013] Obtain the initial workpiece point cloud;

[0014] The initial workpiece point cloud is filtered to obtain the filtered workpiece point cloud.

[0015] A preset threshold is used to segment and filter the workpiece point cloud, resulting in the pipe clamp workpiece point cloud.

[0016] Furthermore, the specific steps of step S2 include:

[0017] S21: Set the workpiece model, and randomly select m points from the point cloud of the pipe clamp workpiece as assumed interior points, fit and determine the parameters of the workpiece model, and obtain the current workpiece equation;

[0018] S22: Determine the actual interior points based on the distance between each point in the point cloud of the pipe clamp workpiece and the current workpiece equation, and count the number of actual interior points;

[0019] S23: If the actual number of interior points is less than the preset interior point threshold and the iteration termination condition has not been met, return to step S21; if the actual number of interior points is not less than the preset interior point threshold or the iteration termination condition has been met, execute step S24.

[0020] S24: Use the current workpiece equation as the equation for clamping the workpiece; use the actual internal points as the point cloud for clamping the workpiece; use the point cloud other than the clamping point cloud in the pipe clamp workpiece point cloud as the pipe clamp point cloud.

[0021] Furthermore, the specific steps of step S22 include:

[0022] S221: Obtain the assumed number of points and the actual number of points, and determine whether the actual number of points is greater than the assumed number of points;

[0023] S222: If so, then use the actual interior points to fit and determine the parameters of the workpiece model to obtain the updated current workpiece equation;

[0024] S223: Calculate the distance between each point in the point cloud of the pipe clamp workpiece and the updated current workpiece equation, determine the updated internal points, and count the number of updated internal points;

[0025] S224: Determine whether the updated number of interior points is greater than the actual number of interior points; if yes, then use the updated interior points as the actual interior points and return to step S222; otherwise, continue to step S23.

[0026] Furthermore, the specific steps of step S3 include:

[0027] S31: Determine the angle between the direction vectors of the axes of the equations of two workpieces, and update the direction vector for clamping the workpieces based on the angle.

[0028] S32: Calculate the average value of the updated workpiece clamping direction vector to obtain the coefficients of the bevel equation, and then determine the bevel plane equation.

[0029] Furthermore, the specific steps of step S31 include:

[0030] Calculate the angles between each pair of the workpiece equation axis direction vectors obtained in step S2 in sequence.

[0031] Determine if the included angle is greater than a set threshold. If so, reverse the direction vector of one of the workpiece equation axes; otherwise, leave it unchanged.

[0032] Furthermore, the specific steps of step S4 include:

[0033] Substitute the point cloud coordinates of the pipe clamp into the bevel plane equation to obtain the two end planes of the pipe clamp;

[0034] Extract all point clouds from the pipe clamp point cloud that are less than the distance threshold between the two ends of the plane and consider them as the bevel location point cloud; the distance threshold can be set arbitrarily by the staff.

[0035] Furthermore, the specific steps of step S5 include:

[0036] Extract the point cloud coordinates at the two endpoints of each bevel as the initial position of the weld.

[0037] Based on the initial position of the weld, find the point cloud within the radius of the weld and calculate the feature value of each point cloud;

[0038] The curvature of each point cloud is calculated based on the eigenvalues. The point clouds with the largest curvature at the two ends of each bevel are identified and used as the starting point point cloud and the ending point cloud of the weld, respectively. These points are then connected to form a weld.

[0039] Furthermore, the method also includes:

[0040] Construct a straight line model based on the weld points distributed on both sides of the pipe clamp point cloud;

[0041] Determine whether the distance between the weld seam on both sides and the corresponding straight line model is greater than a set threshold; if it is less than the threshold, it is a normal weld seam; if it is not less than the threshold, it is an abnormal weld seam.

[0042] Furthermore, the method also includes:

[0043] The abnormal weld is projected onto the linear model to obtain the corrected weld;

[0044] Determine if the length of the corrected weld is within the set range. If so, update the abnormal weld with the corrected weld; otherwise, delete the abnormal weld.

[0045] Furthermore, the method also includes:

[0046] Determine whether the distance between any two center points of the remaining welds is within a set distance threshold range. If it is less than the threshold, remove two welds; if it is greater than the threshold, there is a problem of missed identification, and the final weld result is obtained.

[0047] Secondly, this application also provides a computer storage medium storing executable program code; the executable program code is used to execute the teachless welding method for clamping workpiece lap joint pipe clamps as described in any one of the first aspects.

[0048] Thirdly, this application also provides a terminal device, including a memory and a processor; the memory stores program code executable by the processor; the program code is used to execute the teachless welding method for clamping workpiece lap joint pipe clamps as described in any one of the first aspects.

[0049] The aforementioned no-teachability welding method, medium, and equipment for lap-type pipe clamps for clamping workpieces calculates the clamping workpiece equation from the workpiece point cloud within the clamp workpiece point cloud. Based on this equation, the two end planes of the lap-type pipe clamp are determined, thus obtaining the bevel position point cloud. The point cloud with the largest curvature at both ends of the bevel position point cloud is extracted as the weld point, and these points are connected to form the weld. This solves the problems of low efficiency and unstable quality in existing welding methods when welding non-standard or irregularly shaped workpieces. Attached Figure Description

[0050] Figure 1 This is a flowchart of a teach-free welding method for clamping workpiece lap joint pipe clamps according to an embodiment of the present invention;

[0051] Figure 2 This is an embodiment of the diagram showing the relative position between the overlapping pipe clamp and the workpiece in this invention.

[0052] Figure 3 This is a schematic diagram of the bevel location according to an embodiment of the present invention;

[0053] Figure 4 This is a schematic diagram of the weld point distribution according to an embodiment of the present invention;

[0054] Figure 5 This is a schematic diagram of the weld inspection method according to an embodiment of the present invention. Detailed Implementation

[0055] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0056] It should be noted that if the embodiments of the present invention involve directional indications, such as up, down, left, right, front, back, etc., these directional indications are only used to explain the relative positional relationships and movement of the components in a specific posture. If the specific posture changes, the directional indications will also change accordingly. Furthermore, if the embodiments of the present invention involve descriptions such as "first," "second," "S1," "S2," "step one," "step two," etc., these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance, or implicitly indicating the number of technical features indicated or the order of method execution. Those skilled in the art will understand that anything that does not violate the inventive concept and is within the scope of the present invention should be included in the protection scope of the present invention.

[0057] like Figure 1 As shown, the present invention provides a teach-free welding method for clamping workpieces using lap-type pipe clamps, the method comprising:

[0058] Step S1: Obtain the point cloud of the pipe clamp workpiece;

[0059] Specifically, it is optional, but not limited to, acquiring images of the workpiece being gripped by the pipe clamp using a data acquisition device to obtain point cloud data of both the pipe clamp and the workpiece, thus obtaining the point cloud of the pipe clamp and the workpiece.

[0060] More specifically, the acquisition device may be, but is not limited to, electronic devices such as cameras, optical scanners, smartphones, or tablets that can be used to capture still images or continuous video.

[0061] Preferred, optional, but not limited to:

[0062] S11: Obtain the initial workpiece point cloud;

[0063] S12: Filter the initial workpiece point cloud to obtain the filtered workpiece point cloud;

[0064] S13: Set a preset threshold to segment and filter the workpiece point cloud to obtain the pipe clamp workpiece point cloud.

[0065] Specifically, after acquiring the workpiece point cloud, the workpiece point cloud is filtered using a pass-through filtering and uniform downsampling method. Then, a region growing segmentation algorithm is used to segment the workpiece point cloud based on a preset smoothness threshold Th. smooth and curvature threshold Thcurvature The point cloud of the pipe clamp workpiece is obtained by segmenting and filtering the other point clouds of the workpiece point cloud and the pipe clamp workpiece point cloud.

[0066] Step S2: Based on the point cloud of the pipe clamp workpiece, determine the equation for clamping the workpiece, and segment the point cloud of the pipe clamp and the point cloud of the clamped workpiece.

[0067] Specifically, it is optional, but not limited to, determining the equations that the clamped workpiece must satisfy based on its characteristics. Points in the pipe clamp workpiece point cloud that satisfy the equations are taken as the clamped workpiece point cloud, and other point clouds are filtered to become the pipe clamp point cloud. The clamped workpiece can be, but is not limited to, cylindrical workpieces, quasi-cylindrical workpieces, workpieces with concave and convex surfaces, etc., and can be clamped by pipe clamps. The following explanation uses a cylindrical workpiece as an example.

[0068] Preferably, step S2 may include, but is not limited to:

[0069] S21: Set the workpiece model, and randomly select m points from the point cloud of the pipe clamp workpiece as assumed interior points, fit and determine the parameters of the workpiece model, and obtain the current workpiece equation;

[0070] Specifically, the workpiece model can be optionally, but is not limited to, defined based on the workpiece characteristics and the equations it needs to satisfy. For example, a cylindrical model is defined using the three-dimensional coordinates of the central axis of the cylinder, the direction vector of the axis, and the radius of the cylinder as parameters. More specifically, the parameters of this cylindrical model can be optionally, but are not limited to, defined as: (x,y,z,a,b,c,r), where c(x,y,z) is a three-dimensional coordinate on the central axis of the cylinder, u(a,b,c) represents the direction vector of the axis, and r is the radius of the cylinder. It is worth noting that the equations that the cylindrical model needs to satisfy and the parameters used are for illustrative purposes only and are not limited to this.

[0071] Specifically, it is optional, but not limited to, randomly selecting 8 points p from the point cloud of the pipe clamp workpiece. i Let i = 1, 2, ..., 8 be the current interior points, and let P ∈ {p1, p2, ..., p8} be the initial sample set of the cylindrical model. m}, m=8, substitute into the cylinder equation, and calculate the parameters of the cylinder model by randomly selecting 8 points. The formula for calculating a three-dimensional coordinate on the central axis of the cylinder is: The formula for calculating the axis direction vector is: The operation represents the modulo operation on a vector, p. i The distance between the cylinder and the axis is |p i -c-ru|, using the least squares method according to the formula Once the radius r is obtained, the coefficients of the current cylinder equation are obtained; then, for the current cylinder equation, the current number of interior points is 8, which is the currently assumed number of interior points.

[0072] S22: Determine the actual interior points based on the distance between each point in the point cloud of the pipe clamp workpiece and the current workpiece equation, and count the number of actual interior points;

[0073] Specifically, the existing distance calculation formula can be used, but is not limited to, to calculate the distance from each point in the pipe clamp workpiece point cloud to the current workpiece equation. If the distance from any point other than the assumed inner point to the current workpiece equation is less than the set distance threshold T1, it means that under this equation, the actual inner point in the pipe clamp workpiece point cloud that satisfies this equation should not be the assumed inner points. Therefore, the actual calculated inner point is taken as the actual inner point, and the number of the actual inner points is counted for subsequent equation update processes.

[0074] Preferably, step S22 may include, but is not limited to:

[0075] S221: Obtain the assumed number of points and the actual number of points, and determine whether the actual number of points is greater than the assumed number of points;

[0076] S222: If so, then use the actual interior points to fit and determine the parameters of the workpiece model to obtain the updated current workpiece equation;

[0077] Specifically, the m points selected in step S21 are recorded as assumed interior points, and the distance from each point in the pipe clamp workpiece point cloud to the current workpiece equation is calculated. All points whose distance is less than the set distance threshold T1 are counted as actual interior points. If the number of actual interior points is greater than the number of assumed interior points, the actual interior points are substituted into the cylinder equation to fit and calculate the parameters of the cylinder model, and the updated current cylinder equation is determined.

[0078] For example, assuming the point cloud of the pipe clamp workpiece includes 100 points, under this wheel distance calculation, 30 points are less than the set distance threshold to the cylinder equation. These 30 points are then identified as actual interior points, and the number of actual interior points is counted as 30. Then, the parameters of the cylinder model are calculated by fitting these 30 points, and the updated current cylinder equation is determined.

[0079] S223: Calculate the distance between each point in the point cloud of the pipe clamp workpiece and the updated current workpiece equation, determine the updated internal points, and count the number of updated internal points;

[0080] S224: Determine whether the updated number of interior points is greater than the actual number of interior points; if yes, then use the updated interior points as the actual interior points and return to step S222; otherwise, continue to step S23.

[0081] Specifically, calculate the distance from each point in the pipe clamp workpiece point cloud to the updated current workpiece equation. Count all points whose distance is less than the set distance threshold T1 as updated inner points. Determine whether the number of updated inner points is greater than the actual number of inner points. If the number of updated inner points is greater than the actual number of inner points, it means that the parameters of the cylinder equation are not accurate and many points belonging to the cylinder workpiece point cloud in the pipe clamp workpiece point cloud have been lost. In this case, the updated inner points should be used as the actual inner points, and the process should return to step S222. If the number of updated inner points is not greater than the actual number of inner points, then step S23 should be executed.

[0082] S23: If the actual number of interior points is less than the preset interior point threshold and the iteration termination condition has not been met, return to step S21; if the actual number of interior points is not less than the preset interior point threshold or the iteration termination condition has been met, execute step S24.

[0083] Specifically, setting the number of interior point thresholds T is optional, but not limited to... inlier As an iteration termination condition, when the actual number of interior points is not less than T inlier If the parameters of the workpiece equation are considered sufficiently accurate, then the actual number of interior points is less than the preset interior point threshold T. inlier If the result is negative, it indicates that the parameters of the workpiece equation are not accurate. The workpiece should be clamped and the number of interior points should be randomly selected again, and the workpiece equation should be refitted with the actual interior points.

[0084] Taking step S22 as an example, if it is determined that 30 of the 100 points are interior points, but the preset threshold number of interior points is 50, and there are no other iteration termination conditions, then return to step S21, randomly select 8 points from the pipe clamp point cloud again, fit and calculate the parameters of the workpiece model, and then iterate the actual number of interior points according to step S22 until step S24 is satisfied.

[0085] More specifically, suppose that after multiple iterations in step S23, the number of interior points consistently fails to meet the preset threshold T. inlier However, in order to improve computational efficiency and avoid the iteration from getting stuck in an infinite loop, it is possible, but not limited to, to pre-set the iteration termination condition, such as ending the iteration process early when the maximum number of iterations t is reached.

[0086] S24: Use the current workpiece equation as the equation for clamping the workpiece; use the current number of internal points as the point cloud for clamping the workpiece; use the point cloud other than the clamping point cloud in the pipe clamping workpiece point cloud as the pipe clamping point cloud.

[0087] Specifically, after the iteration is completed, the equation of the current workpiece determined in the last round is used as the equation for clamping the workpiece; and the current interior point is used as the point cloud for clamping the workpiece, while the rest are used as the point cloud for clamping the pipe.

[0088] More specifically, such as Figure 2As shown, if the pipe clamp holds multiple cylinders, then steps S21-S24 can be repeated. For each cylinder equation determined, the point cloud contained in that cylinder equation is filtered out until the remaining point cloud can no longer fit the cylinder equation. Then, the coefficients (x) of each cylinder equation are obtained. i ,y i ,z i ,a i ,b i ,c i ,r i ), i = 1, 2, ..., n, and the clamp point cloud.

[0089] Step S3: Determine the equation of the bevel plane based on the equation for clamping the workpiece;

[0090] S31: Determine the angle between the direction vectors of the axes of the workpiece equations of each pair of workpieces, and update the direction vector for clamping the workpieces based on the angle; specifically, optional, but not limited to, including:

[0091] S311: Calculate the angles between each pair of workpiece equation axis direction vectors obtained in step S2 in sequence;

[0092] Specifically, based on the n workpiece equations obtained in step S2, two direction vectors α = (a_n) are sequentially selected from the direction vectors of the workpiece equation axes. j ,b j ,c j ) and β=(a l ,b l ,c l ), calculate the included angle θ according to formula 1-1:

[0093]

[0094] Where j = 0, l = j + 1, and j + 1 is incremented for each calculation of the formula until j = n - 1.

[0095] S312: Determine if the included angle is greater than the set threshold. If so, reverse the direction vector of one of the workpiece equation axes; otherwise, leave it unchanged.

[0096] In a specific example, the threshold value should be set to 90°, i.e. This indicates that the direction vectors of the axes of equations of two adjacent workpieces are not consistent. However, due to the existence of errors, this threshold can be set to approximately 90°, but is not limited to such a setting. For example, it can be set arbitrarily between 85° and 95°.

[0097] For example, if ten workpiece equations are obtained from step S2, and the direction vectors of the axes of the ten workpiece equations are named A0 to A9 respectively, calculate the angle θ0 between A0 and A1. Let A1·(-1), if Then no action is taken. Then calculate the angle θ1 between A1 and A2. If... Let A2·(-1), and calculate the angle between every two vectors in all workpiece equations in sequence using this method, and unify the direction vectors of all workpiece clamping.

[0098] S32: Calculate the average value of the updated workpiece clamping direction vector to obtain the coefficients of the bevel equation, and then determine the bevel plane equation.

[0099] Specifically, after unifying the orientation of all clamped workpieces, the average value of the clamping orientation vector is calculated. Therefore, we can construct a bevel plane equation Ax + By + Cz + D = 0, where D is a constant term in the bevel plane equation. It is important to note that this plane equation and the parameters used are for illustrative purposes only and are not intended to be limiting.

[0100] Step S4: Based on the bevel plane equation and the pipe clamp point cloud, determine the two end planes of the pipe clamp, and obtain the bevel position point cloud based on the two end planes;

[0101] Specifically, step S4 may include, but is not limited to:

[0102] S41: Substitute the point cloud coordinates of the pipe clamp into the bevel plane equation to obtain the two end planes of the pipe clamp;

[0103] Specifically, based on the bevel plane equation from step S3, the coordinates of all point clouds of the overlapping pipe clamp are substituted into the bevel plane equation to obtain the maximum and minimum values ​​of the constant term D in the bevel plane equation. min D max Thus, two overlapping pipe clamp planes Ax+By+Cz+D are obtained. max =0 and Ax+By+Cz+D min =0, representing the planes at both ends of the overlapping workpiece.

[0104] S42: Extract all point clouds in the pipe clamp point cloud that are less than the distance threshold from both ends of the plane, and regard them as the bevel location point cloud; the distance threshold can be set arbitrarily by those skilled in the art.

[0105] For example, based on the planes representing the two ends of the overlapping workpiece obtained in step S41, the distance between all points in the overlapping pipe clamp point cloud and the planes at both ends of the overlapping workpiece is calculated. It is then determined whether the distance is less than a distance threshold T3. If it is less, the point cloud is extracted as... Figure 3 Point cloud at the slope location shown; distance threshold T3, preset by staff.

[0106] Step S5: Extract the point cloud with the largest curvature at both ends of the bevel location point cloud, use it as the weld point, and connect them to form the weld.

[0107] Specifically, step S5 may include, but is not limited to:

[0108] S51: Extract the point cloud coordinates at the two endpoints of each bevel as the initial position of the weld;

[0109] Specifically, it is optional, but not limited to, calculating the point cloud coordinates at the leftmost and rightmost endpoints of each bevel based on the plane equation obtained in step S3, as the initial position of the weld, or finding the point cloud coordinates at the endpoints at the left and right ends of the bevel plane from the point cloud coordinates of each point cloud of the overlapping pipe clamp, as the initial position of the weld; it is worth noting that the endpoints only mean the boundaries or edges at the left and right ends of the bevel position.

[0110] Preferably, if there are multiple parallel point cloud coordinates at the leftmost or rightmost end of the bevel, the average of the point cloud coordinates at each end is taken as the initial position of the weld.

[0111] S52: Based on the initial position of the weld, find the point cloud within the radius of the weld and calculate the characteristic value of each point cloud;

[0112] Specifically, based on two initial weld point clouds, each point cloud within the radius range of the two initial weld point clouds is selected. The three-dimensional coordinates of each point cloud are collected, the mean of all points is calculated, and a coordinate point in three-dimensional space is obtained. The difference between each point and the mean is calculated to obtain an initial difference matrix. The difference matrix is ​​then transposed and multiplied with the initial difference matrix to obtain a 3x3 covariance matrix. Eigenvalue decomposition is performed on the covariance matrix to obtain the eigenvalue λ of each point cloud. i1 ,λ i2 ,λ i3 , i = 1, 2, ... q, where q is the total number of point clouds.

[0113] S53: Calculate the curvature of each point cloud based on the characteristic value, find the point cloud with the largest curvature at the two ends of each bevel, and use it as the starting point point cloud and the ending point cloud of the weld, and connect them to form a weld.

[0114] For example, based on the eigenvalue λ obtained in step S52 i1 ,λ i2 ,λ i3 Calculate the curvature of each point cloud Using the center point of each bevel as the boundary, the point cloud is divided into a left bevel point cloud and a right bevel point cloud. From the left bevel point cloud and the right bevel point cloud of each bevel, the point cloud with the largest curvature k is selected as the weld point cloud. The two weld point clouds represent the starting point (x) of the welding position. 1,y 1 ,z 1 ) and endpoint (x) 2 ,y 2 ,z 2 ), forming a weld seam s = (x 1 ,y 1 ,z 1 ,x 2 ,y 2 ,z 2 From this, we can obtain m weld seams S={s1,s2,..,s m}

[0115] This embodiment presents a teach-free welding method for lap-type pipe clamps for gripping workpieces according to the present invention. The method calculates the gripping workpiece equation from the workpiece point cloud within the pipe clamp point cloud, determines the two end planes of the lap-type pipe clamp based on the gripping workpiece equation, and thus obtains the bevel position point cloud. The point cloud with the largest curvature at both ends of the bevel position point cloud is extracted as the weld point, and these points are connected to form the weld. This method solves the problems of low efficiency and unstable quality in existing welding methods when welding non-standard or irregularly shaped workpieces.

[0116] More preferably, the teach-free welding method for clamping workpiece lap joint pipe clamps of the present invention further includes:

[0117] Step S6: Perform anomaly inspection and screening on the weld to obtain the final weld result.

[0118] Specifically, since misidentification or omission may occur during actual operation, it is necessary to inspect and screen the welds obtained in step S5, identify the missed welds and remove abnormal welds to obtain the final accurate weld result, so as to avoid problems and reduce efficiency during final welding.

[0119] Preferably, step S6 may include, but is not limited to:

[0120] S61: Construct a straight line model based on the weld points distributed on both sides of the pipe clamp point cloud;

[0121] Specifically, such as Figure 4 As shown, the weld points are distributed on both sides of the pipe clamp, and the weld points on each side are distributed on a straight line. The straight line model is set as y = mx + b, where m is the slope of the straight line, b is the intercept of the straight line, and x and y are the coordinates of the points on the straight line. Substitute the weld points on both sides of the pipe clamp into the straight line model respectively to obtain the equation coefficients of the two straight line models.

[0122] Preferably, the linear model can also be represented as Where A, B, and C are the components of the direction vector of the line, (a,b,c) is the coordinates of a known point on the line, and (x,y,z) is the coordinates of any point on the line. It is worth noting that the equations that this line model needs to satisfy and the parameters used are for illustrative purposes only and are not intended to be limiting.

[0123] S62: Determine whether the distance between the weld seams on both sides and the corresponding straight line model is greater than the set threshold; if it is less than the threshold, it is a normal weld seam; if it is not less than the threshold, it is an abnormal weld seam.

[0124] Specifically, the distance between the center point of the weld and the corresponding straight line model is calculated, and a distance threshold is set. Welds with a distance less than the distance threshold are judged as normal welds, while welds with a distance greater than the distance threshold are abnormal welds, which need to be corrected and screened.

[0125] Preferably, the distances between the weld start point cloud and the weld end point cloud and the straight line model are calculated and averaged to serve as the distance between the weld and the corresponding straight line model.

[0126] More preferably, the distances between the weld start point cloud and the end point cloud and the corresponding straight line model are calculated separately, and it is determined whether they are greater than a preset distance threshold. If either one is greater than the distance threshold, the weld is identified as an abnormal weld.

[0127] For example, if a threshold of T is set, and there are 8 welds, then 6 of them are considered normal welds if the distance between them and the corresponding straight line model is less than T; the other 2 are considered abnormal welds if the distance between them and the corresponding straight line model is greater than T, and they need to be corrected and screened.

[0128] Preferably, after step S62, the method further includes:

[0129] S63: Project the abnormal weld onto the straight line model to obtain the corrected weld;

[0130] For example, such as Figure 5 As shown, after obtaining the abnormal weld, the abnormal weld is projected onto the corresponding straight line model and corrected to the correct welding position. The projection of the abnormal weld on the corresponding straight line model is the corrected weld.

[0131] S64: Determine whether the length of the corrected weld is within the set range. If so, update the abnormal weld with the corrected weld; otherwise, delete the abnormal weld.

[0132] For example, determine whether the corrected weld length is within the set weld length range [L] min ,L maxWithin the range [L], if the corrected weld length is within the range, the corrected weld length replaces the abnormal weld; if the corrected weld length is not within the range, the abnormal weld is directly deleted; length range [L] min ,L max [This is] preset by those skilled in the art.

[0133] Preferred options also include:

[0134] S65: Determine whether the distance between any two center points of the remaining welds is within the set distance threshold range. If it is less than the threshold, remove two welds; if it is greater than the threshold, there is a problem of missed identification, and the final weld result is obtained.

[0135] Specifically, after deleting all abnormal welds, it is determined whether the distance between the center points of the remaining welds is within the set distance threshold range [T]. x ,T y Within [the specified range], if the distance is less than the minimum threshold T x If the distance between two welds is greater than the maximum threshold T, then the two welds are considered abnormal and removed; y If there are missed identification issues between weld seams, the problem will be reported to technical personnel for manual welding to obtain the final weld seam result; threshold interval [T x ,T y [This is] preset by those skilled in the art.

[0136] On the other hand, the present invention also provides a computer storage medium storing executable program code; the executable program code is used to execute any of the above-mentioned teaching-free welding methods for clamping workpiece lap joint pipe clamps.

[0137] On the other hand, the present invention also provides a terminal device, including a memory and a processor; the memory stores program code that can be executed by the processor; the program code is used to execute any of the above-mentioned teaching-free welding methods for clamping workpiece lap joint pipe clamps.

[0138] For example, the program code can be divided into one or more modules / units, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the program code in the terminal device.

[0139] The terminal device can be a desktop computer, laptop, handheld computer, or cloud server, etc. The terminal device may include, but is not limited to, a processor and memory. Those skilled in the art will understand that the terminal device may also include input / output devices, network access devices, buses, etc.

[0140] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0141] The memory can be an internal storage unit of the terminal device, such as a hard drive or RAM. The memory can also be an external storage device of the terminal device, such as a plug-in hard drive, SmartMedia Card (SMC), Secure Digital (SD) card, or Flash Card. Furthermore, the memory can include both internal and external storage units of the terminal device. The memory is used to store the program code and other programs and data required by the terminal device. The memory can also be used to temporarily store data that has been output or will be output.

[0142] The technical functions and beneficial effects of the above-mentioned workpiece clamping lap joint pipe clamping no-teach welding method, apparatus, electronic equipment and storage medium are not repeated here. The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0143] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A teach-free welding method for clamping workpieces using lap-type pipe clamps, characterized in that, include: S1: Obtain the point cloud of the pipe clamp workpiece; S2: Based on the point cloud of the pipe clamp workpiece, determine the equation for clamping the workpiece, and segment the point cloud of the pipe clamp and the point cloud of the clamped workpiece. S3: Determine the bevel plane equation based on the equation of the workpiece clamping; including: S31: Determine the angle between the direction vectors of the axes of the workpiece equations of each pair, and update the direction vector of the workpiece clamping according to the angle; S32: Calculate the average value of the updated direction vector of the workpiece clamping to obtain the coefficients of the bevel equation, so as to determine the bevel plane equation. S4: Based on the bevel plane equation and the pipe clamp point cloud, determine the plane equations of both ends of the connecting pipe clamp, and obtain the bevel position point cloud based on the plane equations of both ends; including: substituting the coordinates of the pipe clamp point cloud into the bevel plane equation to obtain the planes of both ends of the pipe clamp; extracting all point clouds in the pipe clamp point cloud that are less than the distance threshold from the planes of both ends, and considering them as the bevel position point cloud. S5: Extract the point cloud with the largest curvature at both ends of the bevel position point cloud as the weld point, and connect them to form a weld; including: extracting the point cloud coordinate points at the left and right ends of each bevel as the initial position of the weld; based on the initial position of the weld, finding the point cloud within the weld radius range and calculating the characteristic value of each point cloud; calculating the curvature of each point cloud based on the characteristic value, finding the point cloud with the largest curvature at the two ends of each bevel as the weld start point cloud and weld end point cloud, and connecting them to form a weld.

2. The no-teachability welding method for clamping workpiece lap joint pipe clamps according to claim 1, characterized in that, The specific steps of step S1 include: Obtain the initial workpiece point cloud; The initial workpiece point cloud is filtered to obtain the filtered workpiece point cloud. A preset threshold is used to segment and filter the workpiece point cloud, resulting in the pipe clamp workpiece point cloud.

3. The no-teachability welding method for clamping workpieces using lap-type pipe clamps according to claim 1, characterized in that, The specific steps of step S2 include: S21: Set the workpiece model, and randomly select m points from the point cloud of the pipe clamp workpiece as assumed interior points, fit and determine the parameters of the workpiece model, and obtain the current workpiece equation; S22: Determine the actual interior points based on the distance between each point in the point cloud of the pipe clamp workpiece and the current workpiece equation, and count the number of actual interior points; S23: If the actual number of interior points is less than the preset interior point threshold and the iteration termination condition has not been met, return to step S21; if the actual number of interior points is not less than the preset interior point threshold or the iteration termination condition has been met, execute step S24. S24: Use the current workpiece equation as the equation for clamping the workpiece; use the actual internal points as the point cloud for clamping the workpiece; use the point cloud other than the clamping point cloud in the pipe clamp workpiece point cloud as the pipe clamp point cloud.

4. The no-teachability welding method for clamping workpieces using lap-type pipe clamps according to claim 3, characterized in that, The specific steps of step S22 include: S221: Obtain the assumed number of points and the actual number of points, and determine whether the actual number of points is greater than the assumed number of points; S222: If so, then use the actual interior points to fit and determine the parameters of the workpiece model to obtain the updated current workpiece equation; S223: Calculate the distance between each point in the point cloud of the pipe clamp workpiece and the updated current workpiece equation, determine the updated internal points, and count the number of updated internal points; S224: Determine whether the updated number of interior points is greater than the actual number of interior points; if yes, then use the updated interior points as the actual interior points and return to step S222; otherwise, continue to step S23.

5. The no-teachability welding method for clamping workpieces using lap-type pipe clamps according to claim 1, characterized in that, The specific steps of step S31 include: Calculate the angles between each pair of the workpiece equation axis direction vectors obtained in step S2 in sequence. Determine if the included angle is greater than a set threshold. If so, reverse the direction vector of one of the workpiece equation axes; otherwise, leave it unchanged.

6. The no-teachability welding method for clamping workpiece lap joint pipe clamps according to any one of claims 1-5, characterized in that, The method further includes: Construct a straight line model based on the weld points distributed on both sides of the pipe clamp point cloud; Determine whether the distance between the weld seam on both sides and the corresponding straight line model is greater than a set threshold; if it is less than the threshold, it is a normal weld seam; if it is not less than the threshold, it is an abnormal weld seam.

7. The no-teachability welding method for clamping workpiece lap joint pipe clamps according to claim 6, characterized in that, The method further includes: The abnormal weld is projected onto the linear model to obtain the corrected weld; Determine if the length of the corrected weld is within the set range. If so, update the abnormal weld with the corrected weld; otherwise, delete the abnormal weld.

8. The no-teachability welding method for clamping workpiece lap joint pipe clamps according to claim 7, characterized in that, The method further includes: Determine whether the distance between any two center points of the remaining welds is within a set distance threshold range. If it is less than the threshold, remove two welds; if it is greater than the threshold, there is a problem of missed identification, and the final weld result is obtained.

9. A computer storage medium, characterized in that, It stores executable program code; the executable program code is used to perform the teachless welding method for clamping workpiece lap joint pipe clamps as described in any one of claims 1-8.

10. A terminal device, characterized in that, It includes a memory and a processor; the memory stores program code that can be executed by the processor; the program code is used to execute the teachless welding method for clamping workpiece lap joint pipe clamps according to any one of claims 1-8.

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