Method for identifying and analyzing general three-dimensional pipe tool path

Abstract

The invention discloses a method for identifying and analyzing a universal three-dimensional pipe tool path, which comprises the following steps of: acquiring file information of a model to be identified, and analyzing by applying a corresponding file analyzer to obtain a geometric data model in a file according to different file types; repairing and removing abnormal data based on the geometric data model; rotating the repaired geometric data model until the stretching direction is a Y stretching direction; acquiring an end face of the geometric data model; analyzing the end face data to obtain corresponding pipe features; and obtaining processing data of the pipe based on the pipe characteristics. According to the method for recognizing and automatically correcting the three-dimensional pipe model based on the end face features, the pipe introduction process is optimized, manual intervention is reduced, and the recognition accuracy and efficiency of the pipe model are improved.

Description

Technical Field

[0001] The present invention relates to the field of laser numerical control processing, and in particular to a method for identifying and analyzing a universal three-dimensional pipe tool path. Background Art

[0002] With the rapid development of the intelligent manufacturing industry, parts processing is becoming more complex and customized, and the direct import of 3D models for processing has become the mainstream method. Common formats in the industry include STEP and IGES. The model information obtained from these common formats only contains the model's geometric information. In actual processing, relying solely on the model's geometric information cannot meet the requirements of pipe cutting. Further analysis or repair of the file data and feature recognition are required to obtain the information required for pipe cutting. Summary of the Invention

[0003] The object of the present invention is to provide a method for identifying and analyzing universal three-dimensional pipe tool paths, which reduces manual intervention and improves processing efficiency and accuracy.

[0004] The object of the present invention is achieved through the following technical solution: A method for identifying and parsing a universal three-dimensional pipe tool path, comprising the following steps: A. Obtain file information of the model to be identified, wherein, for different file types, apply corresponding file parsers to parse and obtain the geometric data model in the file; B. Repairing and removing abnormal data based on the geometric data model; C. Rotate the repaired geometric data model so that the stretching direction is the Y stretching direction; D. Obtain the end face of the geometric data model; E. Analyze the end face data to obtain the corresponding pipe characteristics; F. Based on the pipe characteristics, obtain the processing data of the pipe.

[0005] A further improvement of the present invention is that step B is specifically as follows: b1. Screen the 3D data model at the surface level and collect surfaces that are of a size that can be processed; b2. Repair the geometric structure of the above-mentioned surfaces, including geometric discontinuities, missing 2D and 3D space curves, and geometric discontinuities such as small gaps or degenerate surfaces. b3. Repair the topological structure of the above-mentioned surface, including unclosed edges, inconsistent orientations, and other topological structure repairs; b4. Standardize the geometric structure and topological results, and optimize the surface parameters.

[0006] A further improvement of the present invention is that step C is specifically as follows: c1. Convert the 3D data structure into a data structure based on boundary representation, and perform mesh discretization on the data structure using an incremental algorithm to obtain a triangulated mesh. c2. Calculate an oriented bounding box for the discretized data, rotate the oriented bounding box according to the difference between the three axis directions of the oriented bounding box and the axis directions of the standard coordinate system, and then translate the three-dimensional model to the standard origin position.

[0007] A further improvement of the present invention is that step D is specifically as follows: d1. Calculate an axis-aligned bounding box for the three-dimensional data model obtained in step C, and find the end face of the axis-aligned bounding box in the Y-axis direction; d2. Perform an intersection operation between the three-dimensional data model and the end face to find the end face of the three-dimensional data model.

[0008] A further improvement of the present invention is that: Step E specifically comprises: analyzing the shapes of the inner and outer rings according to the surface formed by projecting the end face onto the XOZ plane to obtain the tube type information corresponding to the current tube.

[0009] A further improvement of the present invention is that step F specifically comprises: searching for a processing surface related to the end face according to the topological structure of the three-dimensional data model to obtain processing data of the pipe.

[0010] The beneficial effects of the present invention are as follows: the present invention proposes a method for geometrically repairing a three-dimensional pipe model and performing a universal pipe identification method based on end face features, which optimizes the pipe import process, reduces manual intervention, and improves the accuracy and efficiency of pipe model identification. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a flow chart of the present invention.

[0012] Figure 2 This is the original model diagram of channel steel.

[0013] Figure 3 yes Figure 2 The processing model diagram generated by the present invention is transformed into the Y stretching direction after identification and analysis.

[0014] Figure 4 yes Figure 2 The interface effect diagram generated by the present invention is transformed into the Y stretching direction after identification and analysis.

[0015] Figure 5 It is the original model of square tube.

[0016] Figure 6 yes Figure 5 The processing data model diagram generated by the present invention is converted to the Y stretching direction after identification and analysis.

[0017] Figure 7 yes Figure 5 The interface effect diagram generated by the present invention is transformed into the Y stretching direction after identification and analysis.

[0018] Figure 8 It is an interface effect diagram generated by converting the angle steel into the Y-stretching direction after identification and analysis by the present invention.

[0019] Figure 9 It is an interface effect diagram generated when a round tube is identified and analyzed by the present invention and then turned to the Y stretching direction. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The elements and features described in one embodiment of the present invention may be combined with the elements and features shown in one or more other embodiments. It should be noted that for the purpose of clarity, the representation and description of components and processes that are not related to the present invention and are known to those of ordinary skill in the art are omitted in the description. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0021] The present invention proposes a method for identifying and analyzing universal three-dimensional pipe tool paths. Figure 1 The method flow chart of the present invention comprises the following steps: A. Obtain the file information of the model to be identified.

[0022] B. Repair and remove abnormal data based on the geometric data model.

[0023] C. Rotate the repaired geometric data model so that the stretching direction is the Y stretching direction.

[0024] D. Obtain the end face of the geometric data model.

[0025] E. Analyze the end face data to obtain the corresponding pipe characteristics.

[0026] F. Based on the pipe characteristics, obtain the processing data of the pipe.

[0027] Specifically, when executing step A, you can perform the following steps: Use the third-party library OpenCascade to parse the file, adapt different file parsers according to different file types, and output the three-dimensional data model in the file.

[0028] Optional, taking the igs file parser as an example: The hierarchical entity records of the IGES file are deconstructed by the format parser and discretized into a set of geometric primitives and topological relationships. Then the type converter is started to reparameterize the geometric description in the neutral format into the kernel's mathematical objects to generate a qualified parametric geometric structure.

[0029] At the same time, the hierarchical topological structure composed of complex-solid-shell-surface-ring-edge-vertex is used to disassemble the topological data of each level, reconstruct the topological constraint unit, and construct a strict hierarchical topological structure based on the BREP representation theory.

[0030] Specifically, when executing step B, you can perform the following steps: b1. Traverse the surface level in the topological structure based on the obtained 3D data model, delete the surfaces that cannot be processed in the topological structure, and rebuild the topological constraints.

[0031] b2. Graphics repair Specifically, when executing step C, you can perform the following steps: c1. Discretize the faces in the 3D model into triangular meshes using the Bowyer-Watson algorithm.

[0032] c1.1. Traverse all faces of the 3D model, collect all edges on each face, and record the topological relationships between edges and faces. Update the deflection value of the edge and calculate the discrete points of the edge based on the deflection value, and calculate the 2D data of the discrete points.

[0033] According to the topological relationship between face, ring, edge and point, the discrete points on the edge of the ring with the same position are merged.

[0034] c1.2. The basic idea of ​​the Bowyer-Watson algorithm is to construct a super triangle, insert new scattered points into the current triangle mesh, and reconnect triangles that do not satisfy the Delaunay property until all points are inserted and the Delaunay triangle mesh is correctly constructed.

[0035] (i) Traverse each face and calculate the axial bounding box of the two-dimensional discrete point set on the face. According to the maximum and minimum values ​​of the axial bounding box in the X and Y directions, a super triangle containing all the two-dimensional point sets is obtained.

[0036] (ii) Sort the 2D discrete point set on the face and construct three triangles using the first point after sorting and the three edges of the super triangle. Traverse the 2D discrete point set and determine for each point whether it is inside the triangle. If so, construct three triangles using the three edges of the triangle and the current point and add them to the triangle mesh. If the point is on the edge of a triangle, delete the corresponding triangle. If the circumcircle of more than one triangle contains the point, delete the triangles corresponding to those circumcircles and then add the point to the triangle mesh.

[0037] (iii) Place the triangulated network data into the corresponding surface data.

[0038] c2. Calculate the oriented bounding box c2.1 Construct point cloud data of the 3D model. The point cloud data includes points at the topological level of the 3D model, vertices of triangles after discretization of the triangular mesh of the face, and calculation of the projection extreme points of the point set in multiple directions.

[0039] C2.2 traverses the extreme point set, selects three extreme points, calculates the normal vectors and edge vectors of the plane where the three extreme points are located, uses them as candidate directions for the bounding box, projects the point cloud onto these directions, calculates the size of the bounding box, and selects the bounding box with the smallest volume or surface area from the traversal results.

[0040] c3. Adjust the three-dimensional data structure to coincide the center position of the oriented bounding box of the three-dimensional data structure with the origin position of the standard coordinate system, find the direction of the longest side of the oriented bounding box of the three-dimensional model, and use this direction as a reference to calculate the quaternion composed of the vector in the X direction of the oriented bounding box and the vector in the X direction of the standard coordinate system. Apply the transformation represented by the quaternion based on the Y-axis of the oriented bounding box. At this time, the X direction of the oriented bounding box is completely aligned with the X direction of the standard coordinate system, but the Y direction may still not be in the Y direction of the standard coordinate system. Perform the same operation on the vector in the Y direction of the oriented bounding box and the vector in the Y direction of the standard coordinate system. The Y direction of the oriented bounding box is completely aligned with the Y direction of the standard coordinate system. At this time, the Z direction of the oriented bounding box is automatically aligned with the Z direction of the standard coordinate system.

[0041] Optionally, for a stretched body model, when it contains special surfaces, the direction of the longest side of the oriented bounding box may not completely coincide with the stretching direction. In this case, you can perform the following steps: c3.1 traverses all faces of the 3D model and collects all faces whose features are spline surfaces, rotation surfaces, cylindrical surfaces, and extruded surfaces. It traverses the collected faces again and collects faces whose normal vectors at the center points are perpendicular to the direction of the longest side of the bounding box. It determines whether these faces have closed outer contours and finds the face with the largest outer contour as the reference face.

[0042] C3.2 Calculate isoparametric curves in the U and V directions for the reference surface c3.3 Traverse the edge level of the largest ring on the reference surface to determine whether the edge coincides with an isoparametric curve in the U direction or an isoparametric curve in the V direction. If the two curves coincide, determine whether the midpoints of the curves coincide. If so, collect the curve. Simultaneously, search for the longest edge in the ring whose midpoint tangent is approximately in the same direction as the longest side of the oriented bounding box.

[0043] C3.4 evaluates the edges that coincide with the isoparametric curves. If they approximate the direction of the longest side of the oriented bounding box, the model is fine-tuned based on the angle between the tangent of the edge's midpoint and the stretching direction, using the normal to the stretching direction as the axis. If no edge on the current ring coincides with the isoparametric curve, adjustments are made based on the edge on the ring that coincides with the longest side of the oriented bounding box.

[0044] Specifically, when executing step D, the following steps may be performed: d1. Calculate the axis-aligned bounding box for the rotated 3D model, convert the six faces of the axis-aligned bounding box into topological faces, and retain the faces whose normals are parallel to the stretching direction.

[0045] d2. Try to find a face in the 3D model whose normal is completely parallel to the stretching direction. If it exists, continue to determine whether other features of the face meet the end face features. If other features do not meet the requirements, continue searching.

[0046] d3. When executing step d2, the end face may not be located on the surface whose surface normal is parallel to the stretching direction, and the end face may not be found. At this time, the face calculated in step d1 is translated toward the midpoint of the three-dimensional model to calculate whether the cross-section generated by the face and the three-dimensional model meets the end face characteristics. If not, continue to translate the face calculated in step d1 toward the midpoint of the three-dimensional model until an end face that meets the characteristics is found.

[0047] Specifically, when executing step E, the following steps may be performed: e1. Determine the internal and external relationship of the ring on the end face. Based on the topological relationship between points, edges, and surfaces, the side surface connected to the internal and external contours on the end face can be obtained, and the corresponding relationship between the external contour of the end face and the side surface can be recorded.

[0048] Optionally, if there are hollow surfaces on the upper surface of the tube that cannot be found through the topological relationship between edges and faces, the following process can be used: Filter hollow faces. Hollow faces do not share edges with other faces. By collecting the edges on the known end faces and the side surfaces connected to the end faces, and then collecting the faces to which the edges belong, for non-hollow faces, generally one edge will belong to two faces. Then continue to look for uncollected shared edges on the collected edges. Repeat this process until all non-hollow faces are collected. Exclude all non-hollow faces from the faces of the 3D model, and the remaining ones are the non-hollow face set.

[0049] Traverse all hollow surfaces and determine the relationship between the outer contour of each hollow surface and the outer contour of the end face in the XOZ plane. When the relationship between the two graphics is a containment relationship, record the hollow surface and the projected outer contour. For hollow surfaces not associated with the outer contour, try to determine the relationship with the projected inner contour. The determination principle is the same as that of the outer contour. At this point, all pipe features have been collected.

[0050] e2. The pipe feature data includes the pipe processing data. There are two types of pipe processing data: one is the cutting data for dividing the pipe into several parts, and the other is the intersection data of the intersection graphics on the pipe body.

[0051] e2.1. The ring on the side surface associated with the outer contour of the end face is judged to determine the internal and external relationship on the surface where the ring is located. When the side surface is the hollow surface screened out in step e1, the outer contour of the hollow surface is the intersecting processing data. When a ring exists on the non-hollow surface and the ring is the inner contour, the collected graphics are intersecting processing data.

[0052] e2.2. Collect cutting data from the outer contour of the non-hollow surface, traverse the edges on the ring, and collect graphics into the cutting data when the edges are non-shared edges.

[0053] The above technical means can be used to identify the general three-dimensional model and turn it to the Y stretching direction. Figure 2 The original tensile direction of the three-dimensional model of the standard T-shaped steel is the X-axis direction. The present invention can correctly identify and convert it to the Y-axis direction as shown in the attached figure. Figure 3 ; Attached Figure 4 The original tensile direction of the three-dimensional model of the channel steel is the X-axis direction. Through the present invention, it can be correctly identified and turned to the Y-axis direction as shown in the attached figure. Figure 5 ; Attached Figure 6 The original stretching direction of the three-dimensional model of the rectangular tube is not in the XYZ direction. The present invention can correctly identify and convert it to the Y stretching direction as shown in the attached figure. Figure 7 The present invention can identify and analyze other standard tubes, non-standard tube types, and special-shaped tubes, and convert the stretching direction to the Y direction.

[0054] Finally, it should be noted that although the present invention and its advantages have been described in detail above, it should be understood that various changes, substitutions, and modifications may be made without departing from the spirit and scope of the present invention as defined by the appended claims. Moreover, the scope of the present invention is not limited to the specific embodiments of the processes, devices, means, methods, and steps described in the specification. A person of ordinary skill in the art will readily understand from the disclosure of the present invention that existing and future developed processes, devices, means, methods, or steps that perform substantially the same functions or achieve substantially the same results as the corresponding embodiments described herein may be used in accordance with the present invention. Therefore, the appended claims are intended to include within their scope such processes, devices, means, methods, or steps.

Claims

1. A method for identifying and parsing universal three-dimensional pipe tool paths, characterized by: The following steps are involved: A. Obtain file information of the model to be identified, wherein, for different file types, apply corresponding file parsers to parse and obtain the geometric data model in the file; B. Repairing and removing abnormal data based on the geometric data model; C. Rotate the repaired geometric data model so that the stretching direction is the Y stretching direction; D. Obtain the end face of the geometric data model; E. Analyze the end face data to obtain the corresponding pipe characteristics; F. Based on the pipe characteristics, obtain the processing data of the pipe.

2. The method for identifying and analyzing universal three-dimensional pipe tool paths according to claim 1, characterized in that: Step B is as follows: b1. Screen the 3D data model at the surface level and collect surfaces that are of a size that can be processed; b2. Repair the geometric structure of the above-mentioned surfaces, including geometric discontinuities, missing 2D and 3D space curves, and geometric discontinuities such as small gaps or degenerate surfaces. b3. Repair the topological structure of the above-mentioned surface, including unclosed edges, inconsistent orientations, and other topological structure repairs; b4. Standardize the geometric structure and topological results, and optimize the surface parameters.

3. The method for identifying and analyzing universal three-dimensional pipe tool paths according to claim 1, characterized in that: Step C is as follows: c1. Convert the 3D data structure into a data structure based on boundary representation, and perform mesh discretization on the data structure using an incremental algorithm to obtain a triangulated mesh. c2. Calculate an oriented bounding box for the discretized data, rotate the oriented bounding box according to the difference between the three axis directions of the oriented bounding box and the axis directions of the standard coordinate system, and then translate the three-dimensional model to the standard origin position.

4. The method for identifying and analyzing universal three-dimensional pipe tool paths according to claim 1, characterized in that: Step D is as follows: d1. Calculate an axis-aligned bounding box for the three-dimensional data model obtained in step C, and find the end face of the axis-aligned bounding box in the Y-axis direction; d2. Perform an intersection operation between the three-dimensional data model and the end face to find the end face of the three-dimensional data model.

5. The method for identifying and analyzing universal three-dimensional pipe tool paths according to claim 1, characterized in that: The step E is specifically as follows: The shapes of the inner and outer rings are analyzed based on the surface formed by projecting the end face onto the XOZ plane to obtain the pipe type information corresponding to the current pipe.

6. The method for identifying and analyzing universal three-dimensional pipe tool paths according to claim 1, characterized in that: The step F is specifically as follows: According to the topological structure of the three-dimensional data model, the processing surface related to the end face is found to obtain the processing data of the pipe.

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