Geometric modeling method for cable assembly parameterized model

Abstract

The invention relates to the technical field of cable assemblies, in particular to a geometric modeling method for a cable assembly parameterized model. The method comprises the following steps: collecting a physical sample piece of a cable assembly, performing geometric measurement on a main cable and each branch cable, and generating a cable structure parameter set according to a measurement result; a main cable central axis is generated according to the main cable structure parameters, a vertical section circular ring is established on the main cable central axis, section scanning operation is executed in the corresponding branch cable direction by taking the circular ring as a starting point, and a branch cable cylinder is generated; performing section scanning by taking the central axis of the main cable as a path, and combining a main cable cylinder entity with each branch cable cylinder entity to generate a cable assembly three-dimensional geometry; according to the method, the cable assembly parameterized three-dimensional model is automatically generated through actual measurement data, accurate modeling, broken line correction and bent section processing of the main cable and the branch cable are achieved, and the modeling precision and the automation degree are improved.

Description

Technical Field

[0001] This invention relates to the field of cable assembly technology, and in particular to a geometric modeling method for parametric models of cable assemblies. Background Technology

[0002] Cable assemblies typically consist of a main cable and several branch cables, exhibiting complex shapes and limited space. Current technologies rely heavily on 2D drawings or simple 3D modeling for design, resulting in low modeling efficiency, insufficient accuracy, and difficulty in accurately representing the connection relationships between branch cables and the main cable. Complex bends and multi-branch structures make parametric and automated processing difficult with traditional CAD modeling methods, often requiring repeated manual adjustments during the design process and hindering the rapid generation of 3D models suitable for assembly analysis or virtual simulation. Furthermore, existing technologies lack systematic methods for handling the central axis and branch connection points of cable assemblies, making it difficult to accurately reproduce details such as cable bends, branch angles, and arc transitions in the 3D model, thus affecting assembly accuracy and subsequent virtual verification. Summary of the Invention

[0003] Therefore, it is necessary to provide a geometric modeling method for parametric models of cable assemblies to solve at least one of the above-mentioned technical problems.

[0004] To achieve the above objectives, a geometric modeling method for a parametric model of a cable assembly includes the following steps: Step S1: Collect physical samples of the cable assembly, perform geometric measurements on the main cable and each branch cable, and generate a set of cable structure parameters based on the measurement results; Step S2: Generate the central axis of the main cable based on the main cable structure parameters, establish a vertical cross-section ring on the central axis of the main cable, and perform a cross-section scanning operation along the corresponding branch cable direction with the ring as the starting point to generate the branch cable cylinder; Step S3: Perform a cross-sectional scan along the central axis of the main cable to generate a cylindrical solid of the main cable. Merge the cylindrical solid of the main cable with the cylindrical solids of each branch cable to generate a three-dimensional geometry of the cable assembly. Step S4: Detect the bending radius of each bending segment of the cable based on the three-dimensional geometry of the cable assembly. If it is less than the preset minimum bending radius, insert a straight transition segment at both ends of the bending segment, regenerate the main cable cylindrical entity, merge all branch entities, and construct a parametric model of the cable assembly.

[0005] The beneficial effects of this invention are as follows: Accurate structural parameters of the main cable and branch cables are obtained through geometric measurements of physical samples of the cable assembly. Based on these parameters, cylindrical geometric entities of the main cable's central axis and each branch cable are generated, achieving complete 3D modeling of the cable assembly. Precise measurements of the main cable along its axial direction and key positions of each branch cable obtain parameters such as cable outer diameter, length, and branch installation coordinates, ensuring the accuracy and completeness of the basic data for model generation. By generating a polygonal line along the main cable's central axis and correcting it with a circular transition, the geometric abrupt change caused by sharp angles in the polygonal line is resolved, allowing the cylindrical entities of each branch cable to extend smoothly along the axial direction. Simultaneously, branch cylinders are generated through vertical cross-sectional circular scanning, ensuring the connection accuracy and spatial consistency between the branch cables and the main cable. Further, a circular cross-sectional scan is performed along the corrected main cable's central axis to generate the main cable's cylindrical entity, which is then merged with the branch cylinders to form a complete 3D geometry of the cable assembly. This achieves unified modeling of the trunk and branches, ensuring the geometric continuity and topological integrity of the overall structure. Based on the detection of the bending radius of each bending segment of the cable, a straight transition segment is inserted for bending segments with an actual radius smaller than the preset minimum value. The axis after insertion is smoothed, which effectively eliminates local stress concentration or spatial collision problems caused by excessive bending. On this basis, the main cable cylindrical entity is regenerated and merged with all branch entities to form a parametric model, achieving high precision, controllability, and repeatability in the design, simulation, and assembly of cable assemblies. Overall, this method, through logical and data closed loops between steps, makes the 3D modeling process of cable assemblies highly automated, accurate, and structurally consistent. It also supports the modeling of cable assemblies with different geometries and complex wiring, providing reliable technical support and data foundation for subsequent structural analysis, spatial wiring optimization, and virtual assembly. Attached Figure Description

[0006] Figure 1 This is a flowchart illustrating the steps of a geometric modeling method for a parametric model of a cable assembly. Figure 2 This is a schematic diagram of the geometric structure of the cable assembly; Figure 3 This is a cross-sectional view of the cable assembly structure; The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0007] The technical method of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0008] Furthermore, the accompanying drawings are merely illustrative of the invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor methods and / or microcontroller methods.

[0009] It should be understood that although the terms "first," "second," etc., may be used herein to describe various units, these units should not be limited by these terms. These terms are used merely to distinguish one unit from another. For example, without departing from the scope of the exemplary embodiments, a first unit may be referred to as a second unit, and similarly, a second unit may be referred to as a first unit. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0010] To achieve the above objectives, please refer to Figures 1 to 3 A geometric modeling method for parametric models of cable assemblies includes the following steps: Step S1: Collect physical samples of the cable assembly, perform geometric measurements on the main cable and each branch cable, and generate a set of cable structure parameters based on the measurement results; Step S2: Generate the central axis of the main cable based on the main cable structure parameters, establish a vertical cross-section ring on the central axis of the main cable, and perform a cross-section scanning operation along the corresponding branch cable direction with the ring as the starting point to generate the branch cable cylinder; Step S3: Perform a cross-sectional scan along the central axis of the main cable to generate a cylindrical solid of the main cable. Merge the cylindrical solid of the main cable with the cylindrical solids of each branch cable to generate a three-dimensional geometry of the cable assembly. Step S4: Detect the bending radius of each bending segment of the cable based on the three-dimensional geometry of the cable assembly. If it is less than the preset minimum bending radius, insert a straight transition segment at both ends of the bending segment, regenerate the main cable cylindrical entity, merge all branch entities, and construct a parametric model of the cable assembly.

[0011] In one embodiment, geometric measurements are performed on the main cable and branch cable samples of the cable assembly. Specifically, a coordinate measuring machine (HEXAGONGLOBALS09.15.08) is used to perform point cloud scanning on the geometric shape of the cable, with a measurement point spacing of 0.5 mm and an accuracy of ±0.01 mm. For the main cable, the outer diameter and curvature information are measured every 20 mm along the center direction; for each branch cable, the outer diameter, deflection angle, and spatial coordinates are measured every 10 mm from the joint to the free end. After the measurements are completed, the measurement point data are imported into the CAD environment, and the center point sequence is fitted using the least squares method to obtain the center coordinate set of each cable path. The measured parameters such as outer diameter, branch length, installation angle, and bending radius are then recorded to form a structural parameter set, which serves as the input basis for subsequent modeling.

[0012] A central axis is generated based on the main cable's structural parameters. Specifically, following the installation coordinate sequence recorded in the structural parameter set, center points are connected sequentially from the starting point to the ending point to generate the main cable's central path. For turning points where the angle between adjacent path segments is less than 45°, a circular arc with a radius 1.5 times the outer diameter is used for smooth replacement to avoid abrupt changes. Subsequently, a circular cross-section perpendicular to the path tangent is created on the main cable's central path, with a radius equal to half the main cable's outer diameter. Using this cross-section as the initial contour, a cross-section scanning operation is performed along the direction of each branch installation node, with a scanning step of 5mm, generating the corresponding branch cylindrical geometric entities. The generated branch entities are saved as independent geometric files and will be merged with the main cable entity later.

[0013] The main cable cylinder was generated using the corrected central axis of the main cable as the scanning path. During modeling, circular cross-sections were replicated along the central axis at intervals of 0.8 times the outer diameter, with each cross-section consisting of 48 discrete points. Quadrilateral meshes were generated for the sequential boundary points of adjacent cross-sections to form the sidewalls of the main cable. The total path length was approximately 1.2m, generating 60 cross-section replication positions, ultimately forming a main cable cylinder enclosed by the bottom, top, and sidewalls. The main cable cylinder and the entities of each branch cable were then merged using Boolean algorithm based on node coordinates to obtain the complete 3D geometry. The model error was verified to be less than 0.05mm, which meets the requirements for harness layout simulation.

[0014] A bending radius detection was performed on the generated 3D geometry. The detection method was as follows: equidistant point sets (5mm spacing) were taken along the central axis of the main cable, and the local radius of curvature was calculated between every three consecutive points. A minimum allowable bending radius of 10 times the outer diameter was set; when the detection result was below this threshold, the segment was recorded as an abnormal bending zone. For each abnormal bending zone, a straight transition segment with a length of twice the outer diameter was inserted at both ends, and the main cable axis was regenerated through spline fitting. The updated axis was reused for cross-sectional scanning to obtain the corrected main cable entity. Finally, the corrected main cable entity was merged back with each branch entity to form a parametric model, which can be used for subsequent constraint analysis and morphological updates.

[0015] In another embodiment, a laser scanner (FAROFocus S70) is used to acquire the overall point cloud data of the cable assembly, with a scanning resolution of 1 mm / pt. After scanning, the point cloud is aligned with the reference fixture coordinate system using an ICP iterative nearest-point algorithm. After noise filtering and redundant point trimming, the center point sequence of the main cable and the connection node positions of each branch cable are extracted from the aligned point cloud. The main cable is approximately 1200 mm long, with 5 branches, a minimum branch length of 120 mm, and a maximum branch length of 480 mm. All parameters are normalized and stored as a structural parameter set file to provide a consistent input format for subsequent geometric modeling. The central axis of the main cable is established using the modeling software CATIA V5. First, the structural parameter set file is imported into the software, and a script is called to automatically generate a polyline trajectory. The polyline trajectory contains 17 control nodes, with corners distributed at... to Between. For corners exceeding At nodes, the system automatically inserts a 10mm radius circular transition segment to ensure the continuity of the modeling curve. A cross-sectional ring is created every 25mm along the main cable axis, and a vertical circular cross-section is created at the node location with the tangent direction of each branch connector node as the normal. The radius of the ring is half the outer diameter of the branch. Each ring serves as the starting cross-section, and a linear scan is performed along the branch direction with a step size of 10mm to generate a cylindrical model of the branch cable. Automatic generation is achieved in SolidWorks using a self-programmed geometric modeling script. The program reads the main cable path point set and automatically creates a circular cross-section (6mm outer diameter) at the path start point, copies it along the path direction, and scans to form the main cable entity. Then, the Boolean operation module is called to merge the main cable entity with the five branch entities, with an execution time of approximately 1.2 seconds. The total number of facets in the generated 3D model of the cable assembly is [number missing]. The file size is approximately 4.5MB.

[0016] Assuming the main cable's outer diameter is 8mm and the scanning interval is 4mm, two areas with bending radii less than 40mm were detected. The system automatically inserted a 16mm long straight transition segment at the corresponding position and regenerated the main cable cylinder. After updating the model, the cross-sectional consistency check showed that the outer diameter error of each segment was controlled within ±0.02mm, meeting the assembly simulation accuracy requirements.

[0017] Of particular importance, step S1 includes: Use a coordinate measuring machine to fix the physical sample of the cable assembly, and mark measurement points at fixed intervals along the main cable axis from the start point to the end point. Perform an outer diameter measurement at each marked point, record the local outer diameter value of the main cable, and take the average as the standard outer diameter of the main cable; For each branch cable, measure the outer diameter and protrusion length segment by segment from the root of the connector to the end, and record the branch number and corresponding parameters; A global coordinate system is established on the main cable with the starting point as the origin. The three-dimensional installation coordinates of the center of each branch joint are recorded one by one, and all measurement data are integrated into a structural parameter set.

[0018] In one embodiment, a coordinate measuring machine (CMM) is first used to fix the physical sample of the cable assembly on the measuring table, ensuring that the sample does not shift during the measurement process. Measurement markers are set at 5cm intervals along the main cable axis from the starting point to the ending point. The outer diameter of each marker is measured, and the measured local outer diameter value is recorded. The average of the outer diameter data from all marker points is used to obtain the standard outer diameter value of the main cable. Subsequently, for each branch cable, measurements are performed in segments at 10cm intervals from the joint root to the end, recording the outer diameter and branch extension length of each segment, and labeling the branch number. The data is then compiled into a branch cable parameter table. A global coordinate system is established on the main cable with the starting point as the origin, and the three-dimensional installation coordinates of the center positions of each branch joint are recorded sequentially. Finally, the outer diameter, length, and coordinates of the starting and ending points of the broken line axis of the main cable, as well as the number, length, outer diameter, and three-dimensional installation coordinates of each branch cable, are integrated to generate a complete cable structure parameter set.

[0019] In another embodiment, a similar coordinate measuring machine (CMM) is used to fix the physical sample of the cable assembly. Measurement points are set every 7 cm along the main cable axis from the starting point to the ending point, and the local outer diameter of the main cable is measured and recorded. The measured data are averaged to obtain the standard outer diameter value. For each branch cable, the outer diameter and extension length are measured every 8 cm from the joint root to the end, and the corresponding branch number and measurement parameters are recorded. A global coordinate system is established on the main cable, with the starting point as the origin, and the three-dimensional center coordinates of all branch joints are recorded one by one. The measurement results of the main cable and branch cables are integrated to form a structural parameter set, which is used for subsequent center axis generation, polyline correction, and three-dimensional geometric modeling.

[0020] Preferably, step S2 includes: Read the installation coordinates of the main cable structure parameters, and connect the center points sequentially from the start point to the end point of the main cable according to the coordinate order to generate a polygonal line of the main cable center axis; Traverse any three adjacent points in the polyline, calculate the angle between the two segments, and when the angle is less than the preset angle threshold, insert an arc transition segment at the midpoint to replace the original two straight segments and complete the polyline correction. After the polyline correction is completed, each branch joint installation point is used as a reference node to extract the tangent direction of the main cable's central axis at the node position, and the branch generation direction is determined. With the tangent direction as the normal, establish a vertical circular section at the installation point, and take the radius of the circular section as the outer diameter of the branch cable; A straight path is generated by extending the branch length recorded in the parameter set from the center of the circular ring along the branch direction; Starting with the circular ring as the cross section, perform a cross section scan operation along a straight path to generate a cylindrical solid for the branch cable.

[0021] In one embodiment, the installation coordinate sequence in the main cable structure parameter file is read. The coordinates of each installation point are arranged in the installation order, including the starting point, several intermediate points, and the ending point. Based on the coordinate sequence, adjacent coordinate points are connected sequentially to generate a central axis polyline representing the geometric path of the main cable. The polyline is formed by connecting several line segments end to end, used to characterize the initial spatial direction of the main cable. Geometric continuity correction is performed on the polyline. Traversing any three adjacent points in the polyline, the line segments formed by the three points are used as calculation objects, and the direction vectors of the line segments are calculated and the included angle is calculated. When the included angle is less than a preset angle threshold, it is determined that there is a sharp turn. At this time, an arc transition segment is constructed at the intermediate point, replacing the original two straight lines with an arc, so that the polyline achieves a continuous transition in the tangential direction at this point. The radius of the arc is set according to a multiple of the outer diameter of the main cable, for example, 1.5 to 2 times the outer diameter of the main cable, to balance curvature smoothness and space occupation. After correction, the polyline segment and the arc segment are reassembled to form a continuous and smooth central axis of the main cable.

[0022] After the main cable's centerline is corrected, the coordinates of the branch connector's installation points are read. Using each installation point as a reference node, the tangent direction at that node is calculated on the main cable's centerline. This tangent direction serves as the reference direction for branch generation, ensuring that the branch cable maintains a reasonable spatial connection with the main cable at the connection point.

[0023] Subsequently, at each branch node, a circular cross-section perpendicular to the main cable axis is established with the tangent direction as the normal. The circular cross-section is centered at the branch installation point, with a radius equal to half the outer diameter of the branch cable, used to define the initial geometric boundaries of the branch cable. After determining the circular cross-section, the branch length recorded in the parameter set is extended along the branch direction to generate the corresponding straight path. The direction of the branch path maintains a specific angular relationship with the tangent direction of the main cable; the angle value can be preset according to the assembly process, for example, when the left and right branches are symmetrically arranged, the angle values ​​are respectively set to... .

[0024] Finally, using the circular ring as the starting section, a section scanning operation is performed along the straight path to gradually generate the cylindrical entity of the branch cable. During the scanning process, the section orientation remains consistent with the path normal to ensure a smooth and continuous cylindrical surface. The generated cylindrical entity is tangent to the central axis of the main cable at the installation point, forming a complete branch connection structure.

[0025] After the above steps, the central axis of the main cable achieves spatial continuity and smoothness, the connection position of the geometry of each branch cable with the main cable is accurate, and the length and direction of the branches conform to the parameter set settings. It can be directly used for subsequent assembly simulation, interference verification and cable layout optimization calculation.

[0026] Preferably, reading the installation coordinates of the main cable structure parameters and connecting the center points sequentially from the start to the end of the main cable according to the coordinate order to generate a broken line of the main cable's central axis includes: Extract the three-dimensional coordinates of the starting point of the main cable from the structural parameter set and mark it as the path starting point; The center coordinates of each branch joint are read sequentially from smallest to largest, based on the number recorded in the parameter set. Starting from the path's starting point, take the coordinates of the current point and the center point of the next junction in sequence to generate a straight line segment between the two points, and calculate the length of the straight line segment. Record the starting point coordinates, ending point coordinates, and length parameters of each straight line segment, and store them in the axis list in the order of generation to generate the main cable center axis polyline.

[0027] In one embodiment, the three-dimensional coordinates of the main cable's starting point are read from the structural parameter set and marked as the path's starting point. Following the order of the branch connector numbers in the parameter set, the center three-dimensional coordinates of each connector are extracted sequentially from smallest to largest. The starting point is connected to the center point of the first connector to generate the first straight line segment, and the starting point, ending point, and length of the straight line segment are recorded. Subsequently, straight line segments are generated sequentially by connecting the current connector's center point to the next connector's center point. The length of each straight line segment is calculated, and the starting point, ending point, and length information are sequentially stored in the axis list to form a preliminary polyline. By traversing the axis list, a three-dimensional polyline path covering the entire length of the main cable can be generated. Each polyline segment is precisely aligned according to the actual measured coordinates, ensuring that the polyline geometry is consistent with the actual cable. Finally, the generated polyline is used as the initial representation of the main cable's central axis for subsequent polyline correction and branch generation.

[0028] In another embodiment, assume the coordinates of the starting point of the main cable are... Branch connectors are numbered sequentially. First, read the three-dimensional coordinates of each connector corresponding to its number sequence. Starting point Starting from the polyline's starting point, the coordinates of each connector are sequentially connected to form a set of straight line segments. For each straight line segment, its vector length is calculated, and the starting and ending coordinates, along with the length value, are stored in the central axis list. After sequentially connecting all the straight line segments, a central axis polyline covering the entire length of the main cable is obtained. Its spatial distribution accurately reflects the actual installation direction and geometry of the main cable and can be directly used for subsequent polyline correction and branch cylinder generation.

[0029] Preferably, the process involves iterating through any three adjacent points in the polyline, calculating the angle between the preceding and following segments, and inserting an arc transition segment at the midpoint when the angle is less than a preset angle threshold, replacing the original two straight segments. Take out three adjacent center points from the broken line of the main cable center axis in sequence, and record them as the previous path point, the path turning point and the next path point; Calculate the angle between the vector from the previous path point to the path turning point and the vector from the path turning point to the next path point. When the angle is less than a preset angle threshold, mark the path turning point as a point to be processed. Read the outer diameter parameters of the main cable corresponding to the point to be processed, and calculate the radius of the arc; At the turning point of the path, construct an arc transition segment based on the arc radius, with the starting point of the arc connecting to the previous path point and the ending point connecting to the next path point. Remove the two straight lines from the previous path point to the path turning point and from the path turning point to the next path point, and replace them with arc transition segments to generate the corrected main cable centerline.

[0030] In one embodiment, three adjacent points are sequentially extracted from the broken line of the main cable's central axis and denoted as the previous path point, the path turning point, and the next path point, respectively. First, the angle between the two straight lines before and after the path turning point is calculated. When the angle is less than a preset threshold (e.g., 30°), the path turning point is marked as a point to be processed. Then, the outer diameter parameter of the main cable corresponding to this point is read, and the radius of the arc transition segment is determined using this outer diameter. An arc is created at the path turning point, connecting the starting point of the arc to the previous path point and the ending point to the next path point, ensuring a smooth transition between the arc and the two straight lines in direction. After constructing the arc, the original two straight lines are removed, and the arc is used to replace them to generate the corrected central axis. All three-point combinations in the broken line are traversed sequentially to complete the correction of the entire main cable's broken line, ensuring a smooth and continuous arc transition at the corners.

[0031] In another embodiment, it is assumed that the main cable polygon consists of a starting point and path points in numbered order. Three-point combinations are processed sequentially, and the included angle is calculated. When the included angle is less than a preset threshold, the path inflection point is marked as an arc processing point. The corresponding outer diameter of this point is read, and the arc radius is determined according to an empirical coefficient. An arc is drawn at the path inflection point, connecting the starting point of the arc to the previous point and the ending point to the next point, ensuring a smooth transition of the arc in three-dimensional space. The original two straight lines are deleted and replaced with arc segments, and the center axis list is updated. After traversing all three-point combinations, a corrected main cable center axis polygon is formed, which can be directly used for subsequent branch cylinder generation and main cable cylinder modeling.

[0032] Preferably, calculating the angle between the vector from the previous path point to the path turning point and the vector from the path turning point to the next path point, and marking the path turning point as a point to be processed when the angle value is less than a preset angle threshold includes: Read the 3D coordinates of the previous path point, the path turning point, and the next path point. Subtract the coordinates of the path turning point from the coordinates of the previous path point to obtain the inbound vector. Subtract the coordinates of the path turning point from the coordinates of the next path point to obtain the outbound vector. Calculate the lengths of the incoming and outgoing vectors, and then calculate the dot product of the two vectors. Divide the dot product by the product of the lengths of the two vectors to obtain the cosine of the included angle. Perform an inverse cosine operation on the cosine value of the included angle to obtain the included angle. Set the preset included angle threshold to 30°. When the calculated included angle is less than the threshold, mark the corresponding path turning point as a point to be processed.

[0033] In one embodiment, three points are sequentially extracted from the broken line of the main cable's central axis before correction: the previous path point, the path turning point, and the next path point. First, the three-dimensional coordinates of these three points are read. An ingress vector is formed between the path turning point and the previous point, and an outgress vector is formed between the path turning point and the next point. The spatial angle between the ingress and outgress vectors is calculated, and a preset threshold of 30 degrees is set. When the calculated angle is less than the threshold, the path turning point is marked as a point to be processed, so that a circular transition segment can be inserted later. By sequentially traversing all adjacent three-point combinations in the broken line, all broken line corner points requiring smooth transitions are marked.

[0034] In another embodiment, it is assumed that the polyline consists of path points arranged in numerical order. Three points are sequentially combined, their 3D coordinates are read, and the angle is determined based on the spatial positions of points before and after the path turning point. When the angle is less than a preset threshold, the path turning point is recorded as a point to be processed. After all markings are completed, they can be used for subsequent arc transition segment construction and polyline correction operations. The entire process ensures a smooth transition of the central axis at the polyline turning points while maintaining the precise spatial position of each path point.

[0035] Preferably, at the turning point of the path, an arc transition segment is constructed based on the arc radius, with the starting point of the arc connecting to the previous path point and the ending point connecting to the next path point, including: The spatial coordinates of the previous path point and the next path point determine the arc plane. The vector direction from the previous path point to the path inflection point is taken as the starting tangential direction of the arc. The vector direction from the path inflection point to the next path point is taken as the ending tangential direction of the arc. Draw an arc path in the arc plane with the turning point of the path as the center and the arc radius as the radius. The starting point of the arc is connected to the previous path point, and the ending point is connected to the next path point. Calculate the arc length between the start and end points of the arc, and construct the arc transition segment.

[0036] In one embodiment, for a marked turning point in the path to be processed, the three-dimensional coordinates of the point and its adjacent path points before and after it are first read. The plane containing the arc is determined by the two points before and after it, and the turning point is taken as the center of the arc. The direction from the previous point to the turning point is taken as the starting tangent of the arc, and the direction from the turning point to the next point is taken as the ending tangent of the arc. Based on the center and the pre-calculated arc radius, the arc path is drawn in the arc plane, connecting the starting point of the arc to the previous point and the ending point of the arc to the next point. After drawing, the arc length of the arc path is calculated, and the corresponding arc transition segment is generated. The two straight line segments in the original polyline are replaced with the arc segment, thereby obtaining a smooth central axis polyline.

[0037] In another embodiment, for each turning point of the path to be processed, the three-dimensional coordinate values ​​of the turning point and its two adjacent points are read sequentially, and an arc plane is established with the turning point as the center. After determining the starting and ending tangential directions, an arc path is drawn based on the arc radius, ensuring that the preceding and following path points are precisely aligned with the starting and ending points of the arc. Subsequently, the drawn arc path is sampled at equal intervals to generate a point set, and this point set is used to replace the corresponding two straight lines of the original polyline, achieving a smooth transition of the polyline. By processing all the turning points in the polyline one by one, the smoothing of the entire main cable's central axis is completed.

[0038] Preferably, the process of generating a branch cable cylindrical entity by performing a cross-section scan operation along a straight path, starting with a circular ring as the initial cross-section, includes: Read the set of vertical annular section points of the current branch and mark them as the starting section; Read the coordinates of the start and end points of the straight path of the branch; The total length is calculated based on the difference between the coordinates of the starting point and the ending point of the path. A fixed step size is set, and the step size is accumulated along the path direction starting from the starting point to generate a sequence of scan position points. Copy the initial cross-section point set sequentially to each scan position point, and adjust the path direction to the cross-section normal direction; For the same-order boundary points of two adjacent scanning positions, generate a connecting mesh surface, traverse all adjacent positions and corresponding points to form the cylindrical side mesh; Copy the starting section point set as the bottom surface, copy the end scan position point set as the top surface, and connect them to form a closed contour. Merge the bottom, top, and side meshes into a closed solid to generate a complete branch cable cylindrical solid.

[0039] In one embodiment, the set of vertical circular cross-section points established at the installation point of the current branch cable is first read and marked as the starting cross-section. Then, the three-dimensional coordinates of the start and end points of the branch's straight path are read, and the spatial distance from the start to the end point is calculated as the total scan length. Positions are accumulated along the path direction with a fixed step size (e.g., 0.5 times the outer diameter) to generate a series of scan position points. The starting cross-section point set is copied to each scan position point, and the cross-section normal is adjusted according to the path direction to ensure the cross-section is always perpendicular to the path direction. Sequential boundary points of adjacent scan positions are connected sequentially to form a quadrilateral mesh on the side, generating the side surface of the branch cable segment by segment. The starting cross-section is copied as the bottom surface, and the end scan position point set is copied as the top surface, and connected to the side mesh to construct a closed contour. Finally, the bottom, top, and side meshes are merged to obtain a complete cylindrical solid of the branch cable.

[0040] In another embodiment, for each branch cable, the point set of the circular cross-section at the installation point is first read and marked as the starting cross-section. After reading the coordinates of the start and end points of the straight path, the area between the start and end points is evenly divided into several scanning positions at fixed intervals. The starting cross-section point set is copied according to the scanning positions, and the normal direction of each cross-section is updated according to the path direction. Next, the corresponding boundary points of every two adjacent scanning positions are connected to form a continuous side mesh, and the bottom and top surfaces are constructed for the starting and end cross-sections, respectively. The bottom, top, and side meshes are integrated to generate a closed branch cylinder solid. This operation is repeated for all branches to ensure that the cylinder of each branch cable correctly corresponds to the main cable structure and can be used for subsequent 3D modeling and parametric analysis.

[0041] Preferably, step S3 includes: Read the corrected center axis of the main cable as the scanning path; Extract the outer diameter of the main cable from the set of structural parameters, and establish a circular cross-section at the starting point of the path with the outer diameter as the diameter. Copy the circular cross-section at fixed intervals along the entire length of the central axis, and connect the corresponding points of adjacent cross-sections to generate the main cable cylindrical entity; Merge the main cable cylindrical entity with all branch cable cylindrical entities to generate a complete three-dimensional geometry of the cable assembly.

[0042] In one embodiment, the central axis of the main cable, after being corrected by polylines, is first read as the scan path. The outer diameter data of the main cable is extracted from the cable structure parameter set, and this outer diameter is used as the diameter to create a circular cross-section at the starting point of the path. Then, the circular cross-section is copied along the entire length of the central axis at fixed intervals (e.g., 0.8 times the outer diameter). The normal of each cross-section is updated according to the tangential direction of the path, ensuring that the cross-section is always perpendicular to the axis direction. Next, the corresponding boundary points of adjacent cross-sections are connected sequentially to generate the side mesh of the main cable cylinder, and the bottom and top surfaces are constructed at the starting and ending points to form a closed cylindrical solid. Finally, the generated main cable cylinder is merged with the branch cable cylinder solids to obtain the complete three-dimensional geometry of the cable assembly.

[0043] In another embodiment, after reading the corrected central axis of the main cable, a circular cross-section is first established at the outer diameter of the path starting point, and the cross-section is uniformly discretized into multiple boundary points. Along the axis, the circular cross-section is copied to each scanning position at fixed intervals, and the cross-section normal is adjusted according to the local tangent. Then, each pair of adjacent cross-section points is connected to form a side mesh, and the starting cross-section is copied as the bottom surface and the ending cross-section as the top surface, merging with the side mesh to form a closed cylinder. After the main cable cylinder is generated, it is merged with all the generated branch cable cylinder entities to form a complete three-dimensional geometry of the cable assembly, used for subsequent parametric modeling and simulation analysis.

[0044] Please refer to [link / reference needed] for further information. Figure 2 The main cable cylindrical entity is generated by cross-sectional scanning along the central axis of the main cable. Its visible braided texture represents the shielding structure of the actual cable, and the multiple small cylinders arranged in a ring inside correspond to the geometric arrangement of the multi-core conductors. Each branch cable cylindrical entity extends from the branch point of the main cable, and its end is a plug shape as the branch endpoint. By performing a geometric merging operation on the aforementioned main cable cylindrical entities and each branch cable cylindrical entity, the complete three-dimensional geometry of the cable assembly is finally obtained as shown in the figure.

[0045] Preferably, extracting the outer diameter of the main cable from the structural parameter set and establishing a circular cross-section at the starting point of the path using the outer diameter as the diameter includes: Read the outer diameter value of the main cable from the structural parameter set and mark it as the diameter value; Take the starting point coordinates of the first segment of the main cable's central axis as the center of the cross section; Establish a local coordinate system with the direction of the first path segment as the normal, and draw a circular outline within the local coordinate system with the center as the origin and the radius as half of the outer diameter; The circular outline is uniformly discretized into multiple boundary points, which are then connected in a clockwise order. Transform the coordinates of all boundary points to the global coordinate system to generate a circular cross section at the starting point of the path.

[0046] In one embodiment, the outer diameter of the main cable is first read from the cable structure parameter set and marked as the cross-sectional diameter value. Then, the starting coordinates of the first segment of the main cable's central axis are taken as the cross-sectional center. A local coordinate system is established with the path direction of the first segment as the normal, and a circular outline is drawn within this local coordinate system with the cross-sectional center as the origin and a radius equal to half the outer diameter. The circular outline is uniformly discretized into several boundary points, which are then connected sequentially in a clockwise order to form a closed outline. Finally, the coordinates of all boundary points are transformed to the global coordinate system, generating the circular cross-section at the path's starting point.

[0047] In another embodiment, the outer diameter of the main cable is also read from the structural parameter set and used as the cross-sectional diameter. Using the starting point of the first segment of the central axis as the center, a reference coordinate system is established in the local coordinate system with the normal direction aligned with the path direction. Then, a circular outline is drawn with the center as the center and a radius equal to half the outer diameter. Multiple boundary points are uniformly sampled on the outline, and these points are connected in a clockwise order to form a complete closed cross-section. The coordinates of this cross-section are then transformed into the global coordinate system, completing the generation of the circular cross-section at the path's starting point, providing the basic data for subsequent replication along the axis and the construction of the cylinder.

[0048] Preferably, replicating circular cross-sections at fixed intervals along the entire length of the central axis, and connecting corresponding points of adjacent cross-sections to generate the main cable cylindrical entity includes: Read the total length of all path segments along the central axis of the main cable, and set a fixed copy interval of 0.8 times the outer diameter; Starting from the path origin, the interval distance is accumulated segment by segment along the axis to generate the cross-section replication position; For each copy location, calculate the local path tangent and update the cross-section normal, then copy the starting circular cross-section point set to that location; Connect the same-order boundary points of two adjacent copied positions in point order to generate a lateral quadrilateral mesh; Close the end section at the end of the path, merge all side meshes and end faces to generate the main cable cylindrical solid.

[0049] In one embodiment, the total length of all path segments along the corrected central axis of the main cable is first read, and the cross-section replication interval is set to 0.8 times the outer diameter of the main cable. Starting from the path's origin, the replication interval is accumulated segment by segment along the central axis, generating each cross-section replication position sequentially. At each replication position, the local path tangential direction is calculated and used as the cross-section normal direction to replicate the starting circular cross-section point set. Subsequently, the sequential boundary points of adjacent replication positions are connected in order to form a quadrilateral mesh on the cylindrical side surface. Upon reaching the path's end point, the end cross-section is closed and merged with all side meshes to generate a complete cylindrical main cable entity.

[0050] In another embodiment, the total length of the main cable's central axis is also read, and the cross-section replication step size is set to 0.8 times the outer diameter. Starting from the axis origin, the step size is accumulated along the path direction to determine all cross-section replication points. For each replication point, the cross-section normal is calculated based on the local path direction, and the first cross-section circular boundary point set is replicated to that location. Side meshes are generated sequentially for the corresponding boundary points of two adjacent replication locations. The path endpoint cross-section is used as the end closing surface, and the starting point, end point, and all side meshes are merged to form a closed main cable cylinder, providing a foundation for the connection of branch cylinders and the construction of the overall three-dimensional geometry.

[0051] Of particular importance, step S4 includes: Traverse all path segments along the central axis of the main cable and identify continuous arc segments as curved segments; Calculate the distance between the center of the circle and the axis point for each curved segment, and take the average value as the actual bending radius; Read the outer diameter of the main cable from the structural parameter set and multiply it by 3 to get the preset minimum bending radius; If the actual bending radius is less than the preset minimum value, a straight transition section with a length of twice the outer diameter of the main cable will be inserted on the outer side of each end of the arc. Perform three smoothing processes on the center axis after the inserted transition segment to generate a continuous smooth path; The main cable cylindrical entity is regenerated by sweeping along the smooth path and merged with all branch cylindrical entities to construct a parametric model of the cable assembly.

[0052] In one embodiment, firstly, all path segments along the central axis of the main cable are traversed, and continuous arc segments are identified and marked as curved segments. For each curved segment, the distance from the center of the arc to each point on the axis is calculated point by point, and the average of all distances is taken as the actual bending radius of the curved segment. Subsequently, the outer diameter value of the main cable is read from the structural parameter set and multiplied by 3 to obtain the preset minimum bending radius. For curved segments whose actual bending radius is less than the preset value, straight transition segments with a length twice the outer diameter of the main cable are inserted on the outer sides of both ends of the arc to ensure a smooth bending transition. The central axis after inserting the straight transition segments is smoothed three times, and each time the average calculation is performed on adjacent points along the axis direction to generate a continuous smooth path. Finally, the circular cross-section sweep is re-executed based on the smoothed path to generate the main cable cylindrical entity, which is then merged with the cylindrical entities of all branch cables to construct the completed parametric model of the cable assembly.

[0053] In another embodiment, the central axis of the main cable is traversed, and continuous arc segments with a length greater than 5 cm are identified as curved segments. For each curved segment, the distance from the center to all axis points is calculated, and the average of these distances is taken as the actual bending radius. The outer diameter of the main cable is read and multiplied by 3 to obtain the minimum bending radius threshold. If the actual radius of a curved segment is less than the threshold, a straight transition segment with a length twice the outer diameter is inserted at both ends of the arc. After inserting the transition segment, the central axis is smoothed three times, and each time the coordinates of the current point and the two adjacent points are averaged to eliminate sharp inflection points and form a continuous smooth path. Finally, the circular cross-section is swept along the smooth path to generate the main cable cylindrical entity, which is then merged with the branch cylindrical entities to complete the construction of the parametric model of the cable assembly.

[0054] Please refer to [link / reference needed] for further information. Figure 3 The left side shows the complete external shape of the cable, while the middle section is magnified to expose the internal structure. The right side shows three independently insulated cores branching off from the main cable, visually presenting the physical form of the branch cables. This figure represents the solid structure of the cable assembly to be modeled. The complete shape on the left corresponds to the three-dimensional geometry of the cable assembly generated by geometric modeling. The middle sectional view reveals the arrangement of the multi-core conductors and the insulation shielding layer structure inside the main cable, providing parameter basis for geometric measurement. The branch structure on the right is based on the outer diameter parameters of the branch cables. A vertical circular section is established at the central axis node of the main cable, and a section scan is performed along the branch direction to generate the direct physical basis of the branch cable cylinder. This bifurcated connection structure merges the main cable cylinder with the cylinders of each branch cable.

[0055] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.

Claims

1. A geometric modeling method for parametric models of cable assemblies, characterized in that, Includes the following steps: Step S1: Collect physical samples of the cable assembly, perform geometric measurements on the main cable and each branch cable, and generate a set of cable structure parameters based on the measurement results; Step S2: Generate the central axis of the main cable based on the main cable structure parameters, establish a vertical cross-section ring on the central axis of the main cable, and perform a cross-section scanning operation along the corresponding branch cable direction with the ring as the starting point to generate the branch cable cylinder; Step S3: Perform a cross-sectional scan along the central axis of the main cable to generate a cylindrical solid of the main cable. Merge the cylindrical solid of the main cable with the cylindrical solids of each branch cable to generate a three-dimensional geometry of the cable assembly. Step S4: Detect the bending radius of each bending segment of the cable based on the three-dimensional geometry of the cable assembly. If it is less than the preset minimum bending radius, insert a straight transition segment at both ends of the bending segment, regenerate the main cable cylindrical entity, merge all branch entities, and construct a parametric model of the cable assembly.

2. The geometric modeling method for parametric models of cable assemblies according to claim 1, characterized in that, Step S2 includes: Read the installation coordinates of the main cable structure parameters, and connect the center points sequentially from the start point to the end point of the main cable according to the coordinate order to generate a polygonal line of the main cable center axis; Traverse any three adjacent points in the polyline, calculate the angle between the two segments, and when the angle is less than the preset angle threshold, insert an arc transition segment at the midpoint to replace the original two straight segments and complete the polyline correction. After the polyline correction is completed, each branch joint installation point is used as a reference node to extract the tangent direction of the main cable's central axis at the node position, and the branch generation direction is determined. With the tangent direction as the normal, establish a vertical circular section at the installation point, and take the radius of the circular section as the outer diameter of the branch cable; A straight path is generated by extending the branch length recorded in the parameter set from the center of the circular ring along the branch direction; Starting with the circular ring as the cross section, perform a cross section scan operation along a straight path to generate a cylindrical solid for the branch cable.

3. The geometric modeling method for parametric models of cable assemblies according to claim 2, characterized in that, Read the installation coordinates of the main cable structure parameters, and connect the center points sequentially from the start to the end of the main cable according to the coordinate order to generate a polygonal line of the main cable's central axis, including: Extract the three-dimensional coordinates of the starting point of the main cable from the structural parameter set and mark it as the path starting point; The center coordinates of each branch joint are read sequentially from smallest to largest, based on the number recorded in the parameter set. Starting from the path's starting point, take the coordinates of the current point and the center point of the next junction in sequence to generate a straight line segment between the two points, and calculate the length of the straight line segment. Record the starting point coordinates, ending point coordinates, and length parameters of each straight line segment, and store them in the axis list in the order of generation to generate the main cable center axis polyline.

4. The geometric modeling method for parametric models of cable assemblies according to claim 2, characterized in that, Traverse any three adjacent points in the polyline, calculate the angle between the preceding and following segments, and when the angle is less than a preset angle threshold, insert an arc transition segment at the midpoint to replace the original two straight segments, including: Take out three adjacent center points from the broken line of the main cable center axis in sequence, and record them as the previous path point, the path turning point and the next path point; Calculate the angle between the vector from the previous path point to the path turning point and the vector from the path turning point to the next path point. When the angle is less than a preset angle threshold, mark the path turning point as a point to be processed. Read the outer diameter parameters of the main cable corresponding to the point to be processed, and calculate the radius of the arc; At the turning point of the path, construct an arc transition segment based on the arc radius, with the starting point of the arc connecting to the previous path point and the ending point connecting to the next path point. Remove the two straight lines from the previous path point to the path turning point and from the path turning point to the next path point, and replace them with arc transition segments to generate the corrected main cable centerline.

5. The geometric modeling method for parametric models of cable assemblies according to claim 4, characterized in that, Calculate the angle between the vector from the previous path point to the path inflection point and the vector from the path inflection point to the next path point. When the angle is less than a preset angle threshold, mark the path inflection point as a point to be processed, including: Read the 3D coordinates of the previous path point, the path turning point, and the next path point. Subtract the coordinates of the path turning point from the coordinates of the previous path point to obtain the inbound vector. Subtract the coordinates of the path turning point from the coordinates of the next path point to obtain the outbound vector. Calculate the lengths of the incoming and outgoing vectors, and then calculate the dot product of the two vectors. Divide the dot product by the product of the lengths of the two vectors to obtain the cosine of the included angle. Perform an inverse cosine operation on the cosine value of the included angle to obtain the included angle. Set the preset included angle threshold to 30°. When the calculated included angle is less than the threshold, mark the corresponding path turning point as a point to be processed.

6. The geometric modeling method for parametric models of cable assemblies according to claim 4, characterized in that, At the turning points of the path, construct an arc transition segment based on the arc radius. The starting point of the arc connects to the previous path point, and the ending point connects to the next path point. This includes: The spatial coordinates of the previous path point and the next path point determine the arc plane. The vector direction from the previous path point to the path inflection point is taken as the starting tangential direction of the arc. The vector direction from the path inflection point to the next path point is taken as the ending tangential direction of the arc. Draw an arc path in the arc plane with the turning point of the path as the center and the arc radius as the radius. The starting point of the arc is connected to the previous path point, and the ending point is connected to the next path point. Calculate the arc length between the start and end points of the arc, and construct the arc transition segment.

7. The geometric modeling method for parametric models of cable assemblies according to claim 2, characterized in that, Starting with the circular ring as the initial cross-section, a cross-section scan operation is performed along a straight path to generate a branch cable cylindrical solid, including: Read the set of vertical annular section points of the current branch and mark them as the starting section; Read the coordinates of the start and end points of the straight path of the branch; The total length is calculated based on the difference between the coordinates of the starting point and the ending point of the path. A fixed step size is set, and the step size is accumulated along the path direction starting from the starting point to generate a sequence of scan position points. Copy the initial cross-section point set sequentially to each scan position point, and adjust the path direction to the cross-section normal direction; For the same-order boundary points of two adjacent scanning positions, generate a connecting mesh surface, traverse all adjacent positions and corresponding points to form the cylindrical side mesh; Copy the starting section point set as the bottom surface, copy the end scan position point set as the top surface, and connect them to form a closed contour. Merge the bottom, top, and side meshes into a closed solid to generate a complete branch cable cylindrical solid.

8. The geometric modeling method for parametric models of cable assemblies according to claim 1, characterized in that, Step S3 includes: Read the corrected center axis of the main cable as the scanning path; Extract the outer diameter of the main cable from the set of structural parameters, and establish a circular cross-section at the starting point of the path with the outer diameter as the diameter. Copy the circular cross-section at fixed intervals along the entire length of the central axis, and connect the corresponding points of adjacent cross-sections to generate the main cable cylindrical entity; Merge the main cable cylindrical entity with all branch cable cylindrical entities to generate a complete three-dimensional geometry of the cable assembly.

9. The geometric modeling method for parametric models of cable assemblies according to claim 8, characterized in that, Extract the outer diameter of the main cable from the structural parameter set, and establish a circular cross-section at the starting point of the path using the outer diameter as the diameter, including: Read the outer diameter value of the main cable from the structural parameter set and mark it as the diameter value; Take the starting point coordinates of the first segment of the main cable's central axis as the center of the cross section; Establish a local coordinate system with the direction of the first path segment as the normal, and draw a circular outline within the local coordinate system with the center as the origin and the radius as half of the outer diameter; The circular outline is uniformly discretized into multiple boundary points, which are then connected in a clockwise order. Transform the coordinates of all boundary points to the global coordinate system to generate a circular cross section at the starting point of the path.

10. The geometric modeling method for parametric models of cable assemblies according to claim 8, characterized in that, Copy circular cross-sections at fixed intervals along the entire length of the central axis, and connect corresponding points of adjacent cross-sections to generate the main cable cylindrical entity, including: Read the total length of all path segments along the central axis of the main cable, and set a fixed copy interval of 0.8 times the outer diameter; Starting from the path origin, the interval distance is accumulated segment by segment along the axis to generate the cross-section replication position; For each copy location, calculate the local path tangent and update the cross-section normal, then copy the starting circular cross-section point set to that location; Connect the same-order boundary points of two adjacent copied positions in point order to generate a lateral quadrilateral mesh; Close the end section at the end of the path, merge all side meshes and end faces to generate the main cable cylindrical solid.

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