A design method for automatically generating a three-dimensional part based on a path planning algorithm

Abstract

The application discloses a kind of design methods for automatically generating three-dimensional parts based on path planning algorithm, by constructing design environment, according to process requirement, path planning algorithm is constrained and calibrated, and abstract path generation algorithm suitable for three-dimensional part generation is obtained;Based on the algorithm, a kind of three-dimensional abstract path is obtained in three-dimensional design environment;According to installation requirement, the three-dimensional abstract path is optimized, and a kind of three-dimensional abstract path is optimized to abstract path set, and the abstract path set includes one or more abstract paths meeting process requirements;Through sketch generation algorithm, according to abstract path set, automatically generate two-dimensional sketch set;Full-constrained two-dimensional sketch set is obtained by automatically adding constraint on two-dimensional sketch set;According to modeling parameter, full-constrained two-dimensional sketch set is automatically modeled, and three-dimensional part is obtained.The application greatly improves the design efficiency of design personnel for mechanical parts through improved path planning algorithm and automatic generation of digital model.

Description

Technical Field

[0001] This invention relates to the field of mechanical design technology, and in particular to a design method for automatically generating three-dimensional parts based on a path planning algorithm. Background Technology

[0002] In the field of mechanical design, the design of commonly used connectors occupies a large portion of the design work time. In the past, the design process of connectors was almost always carried out by design engineers drawing sketches and extruding shapes using CAD software based on design rules and relevant work experience. Moreover, the design of connectors needs to consider many factors such as interference avoidance with surrounding parts, material cost, ease of processing and manufacturing, ease of installation, and structural rationality. This often requires design engineers to repeatedly think about and modify the design, which is both time-consuming and labor-intensive.

[0003] "A Method for Optimizing Structural Parameters of Mechanical Components" is a method for optimizing the structural parameters of mechanical components considering the influence of actual assembly boundary constraints. The method includes the following steps: Step 1: Establishing an overall assembly finite element model of the optimized mechanical component under actual working conditions. The overall assembly finite element model includes the optimized mechanical component and other mechanical components with assembly constraints related to it. Step 2: Defining the structural parameter optimization design variables of the optimized mechanical component, defining the optimization constraints of the structural design variables, and selecting optimization target performance evaluation indicators. The optimization target performance evaluation indicators include the structural mechanical properties of the optimized mechanical component under actual working conditions in the overall assembly finite element model. This patent aims to better evaluate the rationality of mechanical design results by optimizing mechanical design schemes through finite element analysis; however, it does not significantly improve design efficiency.

[0004] "Designing 3D Modeled Objects Representing Mechanical Structures" discloses a computer-implemented method for designing 3D modeled objects representing mechanical structures through user interaction with a feature-based CAD system. The 3D modeled objects represent mechanical structures, including structural members and corners, with corresponding structural members connected together at each corner. The method includes: creating structural member features, each representing a corresponding structural member of the mechanical structure; displaying a graphical representation of the mechanical structure to the user based on the structural member features; and creating corner features, each representing a corresponding corner of the mechanical structure. The creation of the corner features is performed automatically by the system, and the corner features can be edited by the user. This patent achieves rapid matching of structural members through predefined mechanical design components and angle features, and allows editing of the predefined structural members. While improving the efficiency of assembling overall assemblies from structural members, the modeling process of the structural members themselves does not improve efficiency, and the designed mechanical structures are limited. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a design method for automatically generating three-dimensional parts based on a path planning algorithm. Through the improved path planning algorithm and the automatic generation of digital models, the design efficiency of mechanical parts is greatly improved.

[0006] The objective of this invention is achieved through the following technical solutions.

[0007] A design method for automatically generating 3D parts based on a path planning algorithm, comprising the following steps: Design environment construction: Based on the input information of the design scenario, a design environment for generating 3D parts is constructed; the input information of the design scenario includes 3D digital model information, process requirements, installation requirements, machining requirements, and modeling parameters in the design scenario; Improve the path planning algorithm and optimize the corresponding path of the 3D part: Improve the path planning algorithm according to the process requirements, and generate a preliminary 3D path of the 3D part based on the improved path planning algorithm; constrain and calibrate the preliminary 3D path according to the processing requirements to obtain the optimized 3D path; split the optimized 3D path according to the installation requirements; obtain the optimized 3D path set, which includes one or more 3D paths that meet the process requirements. Automatic generation of part models: Based on the optimized 3D path set, a 2D sketch set is automatically generated using a sketch generation algorithm; constraints are automatically added to the 2D sketch set to obtain a fully constrained 2D sketch set; based on the modeling parameters, the fully constrained 2D sketch set is automatically modeled to obtain the 3D part.

[0008] The steps for building the design environment include: The design scenario input information includes existing 3D digital models of the workpiece and 3D digital models of multiple parts; Extract hole feature information from the 3D digital model of the part: including the number of holes, the axis coordinates of the holes, the normal vector and the radius; and combine the hole feature information of the same mounting surface to construct hole groups; each 3D part has different hole group information; Determine the start and end position information; Combine and build the design environment: The workpiece is cut out by forming a bounding box composed of the three-dimensional digital models of all parts; the cut-out workpiece and all parts are combined together to build the design environment.

[0009] The methods for determining the start position information and the end position information include the following two: Through user interaction: select a hole group of a certain part as the starting position information, and select a hole group of another part as the ending position information; Based on the different types and spatial distribution of parts, the system automatically determines the starting position information of the hole group of a certain part and the ending position information of the hole group of another part. The three-dimensional digital model information includes: the digital model information of the workpiece in the scene, and the three-dimensional digital model information of all parts; The process requirements include: safety distance requirements, path direction requirements, number of path turns requirements, and path angle requirements. The installation requirements include: requirements for adjustment direction, adjustment gap, and number of disassembly cycles; The processing requirements are: the surface flatness and roughness of the three-dimensional parts, which in turn requires a smooth path; The modeling parameter requirements are as follows: sketch parameters, constraint requirements, numerical optimization requirements, 3D shape parameters, and drilling parameters.

[0010] The path planning algorithm is the A*Star path planning algorithm, and the improvements to the A*Star path planning algorithm include: A 3D environment map is constructed based on the design environment, and the area where obstacles are located in the 3D environment map is expanded according to the safety distance requirements to obtain an optimized 3D map. The distance cost is calculated based on the starting position information and the six-directional search (±X, ±Y, ±Z) of the spatial coordinate system to obtain the distance cost of the ending position information. The position update direction of the A* star path planning algorithm is constrained and calibrated according to the path direction and path angle requirements to obtain the constrained A* star algorithm. Using the constrained A*star algorithm, directional selection of expansion points is performed in the 3D map, prioritizing exploration in the horizontal / vertical direction; feasible paths are determined by expanding step by step.

[0011] The steps for optimizing the initial path based on process requirements and manufacturing requirements include: Based on the surface flatness requirements of the 3D part, the generated feasible path is smoothed and constrained for calibration. Starting from the initial location information and ending at the final location information, multiple 3D paths are obtained through an improved path planning algorithm. Based on the required number of path turns, multiple abstract paths are compared and analyzed to obtain a suitable abstract path.

[0012] The steps for optimizing the 3D path based on installation requirements include: Determine the appropriate offset direction of the abstract path based on the requirements of the adjustment direction (x / y / z); The offset distance of the abstract path is determined according to the requirements of the adjustment gap. By using different offset distances, the automatic installation of gaskets of different thicknesses is achieved, thereby realizing the adjustment of the installation gap. Based on the required number of splits, the abstract path is copied, split, and offset in a defined offset direction and distance to obtain a set of optimized 3D paths that meet the installation requirements.

[0013] The automatic generation steps of the part's digital model include: The 3D path set for 3D optimization is expanded according to the sketch parameter requirements to obtain a 2D sketch set; Based on the numerical optimization requirements, the algorithm automatically rounds and optimizes all sketch size parameters in the two-dimensional sketch set to obtain an optimized two-dimensional sketch set. Based on the constraint requirements, the algorithm automatically adds constraints to the optimized 2D sketch set to obtain a fully constrained 2D sketch set; Based on the requirements of the three-dimensional shape parameters, the two-dimensional sketch outline set is used to perform three-dimensional modeling to obtain a preliminary three-dimensional part model set; Based on the drilling parameter requirements, holes are automatically drilled on the preliminary 3D part set to obtain an output 3D part model set.

[0014] The sketch parameters include: length requirements, width requirements, angle requirements, parallelism requirements, and perpendicularity requirements; the numerical optimization includes: after Boolean operations on the 2D sketch data, the algorithm automatically performs integer optimization on the sketch outline; the constraint requirements include: parallel constraints, perpendicular constraints, angle constraints, length constraints, and fixed constraints; the 3D shape parameters include: modeling methods are extrusion and rotation; extruded bodies include extrusion length and extrusion direction; rotated bodies include rotation direction and rotation angle; the drilling parameters include: drilling direction, number of holes, hole type, and hole depth.

[0015] Compared to existing technologies, the advantages of this invention are as follows: This invention is applicable to the generation of topological structures of mechanical structures, and geometric features such as dimensions, angles, and holes can be added and modified on this basis; This invention does not rely on finite element models and pre-set structural parameters of mechanical components, but directly generates paths to express the topological structure of mechanical components, and generates geometric shapes based on these topological structures. This invention can realize the automatic design of mechanical topological structures without manual intervention during the design process; This invention automatically generates topological structures through path planning algorithms, optimizes the topological structure for smooth transitions based on design rules, and automatically decomposes the topological structure based on processing requirements and industrial rules to obtain one or more reasonable topological structures. Based on the topological structure, sketches and shape features are automatically added to obtain new three-dimensional design structures. Attached Figure Description

[0016] Figure 1 This is a flowchart of the present invention.

[0017] Figure 2This is a flowchart of an embodiment of the present invention.

[0018] Figure 3 This is a system block diagram of an embodiment of the present invention.

[0019] Figure 4 This is a schematic diagram of step one of the embodiments of the present invention.

[0020] Figure 5 This is a schematic diagram of step two in an embodiment of the present invention.

[0021] Figure 6 This is a schematic diagram of the result captured in step two of the embodiments of the present invention.

[0022] Figure 7 This is a schematic diagram of step three in an embodiment of the present invention.

[0023] Figure 8 This is a schematic diagram of step four in an embodiment of the present invention.

[0024] Figure 9 This is a schematic diagram of step five in an embodiment of the present invention.

[0025] Figure 10 This is a schematic diagram of step six in an embodiment of the present invention.

[0026] Figure 11 This is a schematic diagram of step seven in an embodiment of the present invention.

[0027] Figure 12 This is a schematic diagram of step eight in an embodiment of the present invention. Detailed Implementation

[0028] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0029] like Figure 1 As shown, a design method for automatically generating 3D parts based on a path planning algorithm includes the following steps: Design environment construction: Based on the input information of the design scenario, a design environment for generating 3D parts is constructed; the input information of the design scenario includes 3D digital model information, process requirements, installation requirements, machining requirements, and modeling parameters in the design scenario; Improve the path planning algorithm and optimize the corresponding path of the 3D part: Improve the path planning algorithm according to the process requirements, and generate a preliminary 3D path of the 3D part based on the improved path planning algorithm; constrain and calibrate the preliminary 3D path according to the processing requirements to obtain the optimized 3D path; split the optimized 3D path according to the installation requirements; obtain the optimized 3D path set, which includes one or more 3D paths that meet the process requirements. Automatic generation of part models: Based on the optimized 3D path set, a 2D sketch set is automatically generated using a sketch generation algorithm; constraints are automatically added to the 2D sketch set to obtain a fully constrained 2D sketch set; based on the modeling parameters, the fully constrained 2D sketch set is automatically modeled to obtain the 3D part.

[0030] The steps for building the design environment include: The design scenario input information includes existing 3D digital models of the workpiece and 3D digital models of multiple parts; Extract hole feature information from the 3D digital model of the part: including the number of holes, the axis coordinates of the holes, the normal vector and the radius; and combine the hole feature information of the same mounting surface to construct hole groups; each 3D part has different hole group information; Determine the start and end position information; Combine and build the design environment: The workpiece is cut out by forming a bounding box composed of the three-dimensional digital models of all parts; the cut-out workpiece and all parts are combined together to build the design environment.

[0031] The methods for determining the start position information and the end position information include the following two: Through user interaction: select a hole group of a certain part as the starting position information, and select a hole group of another part as the ending position information; Based on the different types and spatial distribution of parts, the system automatically determines the starting position information of the hole group of a certain part and the ending position information of the hole group of another part. The three-dimensional digital model information includes: the digital model information of the workpiece in the scene, and the three-dimensional digital model information of all parts; The process requirements include: safety distance (distance between the surface of the part and the workpiece), path direction, number of path turns, and path angle. The installation requirements include: requirements for adjustment direction, adjustment gap, and number of disassembly cycles; The processing requirements are: the surface flatness and roughness of the three-dimensional parts, which in turn requires a smooth path; The modeling parameter requirements are as follows: sketch parameters, constraint requirements, numerical optimization requirements, 3D shape parameters, and drilling parameters.

[0032] The path planning algorithm is the A*Star path planning algorithm, and the improvements to the A*Star path planning algorithm include: A 3D environment map is constructed based on the design environment, and the area where obstacles are located in the 3D environment map is expanded according to the safety distance requirements to obtain an optimized 3D map. The distance cost is calculated based on the starting position information and the six-directional search (±X, ±Y, ±Z) of the spatial coordinate system to obtain the distance cost of the ending position information. The position update direction of the A* star path planning algorithm is constrained and calibrated according to the path direction and path angle requirements to obtain the constrained A* star algorithm. Using the constrained A*star algorithm, directional selection of expansion points is performed in the 3D map, prioritizing exploration in the horizontal / vertical direction; feasible paths are determined by expanding step by step.

[0033] The steps for optimizing the initial path based on process requirements and manufacturing requirements include: Based on the surface flatness requirements of the 3D part, the generated feasible path is smoothed and constrained for calibration. Starting from the initial location information and ending at the final location information, multiple 3D paths are obtained through an improved path planning algorithm. Based on the required number of path turns, multiple abstract paths are compared and analyzed to obtain a suitable abstract path.

[0034] The steps for optimizing the 3D path based on installation requirements include: Determine the appropriate offset direction of the abstract path based on the requirements of the adjustment direction (x / y / z); The offset distance of the abstract path is determined according to the requirements of the adjustment gap (3mm, 5mm, 8mm). By using different offset distances, the automatic installation of shims of different thicknesses is achieved, thereby realizing the adjustment of the installation gap. Based on the requirement of splitting times (1 / 2 / 3), the abstract path is copied, split, and offset in a determined offset direction and offset distance to obtain a set of 3D optimized 3D paths that meet the installation requirements.

[0035] The automatic generation steps of the part's digital model include: The 3D path set is expanded according to the sketch parameter requirements to obtain a 2D sketch set; Based on the numerical optimization requirements, the algorithm automatically rounds and optimizes all sketch size parameters in the two-dimensional sketch set to obtain an optimized two-dimensional sketch set. Based on the constraint requirements, the algorithm automatically adds constraints to the optimized 2D sketch set to obtain a fully constrained 2D sketch set; Based on the requirements of the three-dimensional shape parameters, the two-dimensional sketch outline set is used to perform three-dimensional modeling to obtain a preliminary three-dimensional part model set; Based on the drilling parameter requirements, holes are automatically drilled on the preliminary three-dimensional part set to obtain an output three-dimensional part model set.

[0036] The sketch parameters include: length requirements, width requirements, angle requirements, parallelism requirements, and perpendicularity requirements; the numerical optimization includes: after Boolean operations on the 2D sketch data, the algorithm automatically performs integer optimization on the sketch outline; the constraint requirements include: parallel constraints, perpendicular constraints, angle constraints, length constraints, and fixed constraints; the 3D shape parameters include: modeling methods are extrusion and rotation; extruded bodies include extrusion length and extrusion direction; rotated bodies include rotation direction and rotation angle; the drilling parameters include: drilling direction, number of holes, hole type, and hole depth. Example

[0037] A fixture part design for automatically generating topology: In the design process of the fixture unit, the fixture unit, as an assembly, mainly consists of several parts such as supports, cylinders, pressure blocks, and connecting blocks. The supports and pressure blocks can be standard parts, requiring only minor dimensional modifications. The cylinders, being purchased externally, also require minimal design work. The main design task lies in the design of the connecting blocks. As intermediate connecting components, the connecting blocks primarily achieve installation and connection through threaded holes and pin holes. Therefore, the implementation steps of the automatic topology design method are illustrated using the automatic design process of the connecting blocks. Figure 2 As shown.

[0038] like Figure 3 As shown in the system framework diagram of this embodiment, it includes an input acquisition module, a 3D environment creation module, a topology generation module, a topology optimization module, a topology processing module, and a 2D sketch.

[0039] Step 1: Obtain the starting and ending mounting surfaces corresponding to the topology; for example... Figure 4 As shown, the connecting block needs to connect the cylinder pressure arm and the support block to achieve the overall installation function. The lower surface of the cylinder pressure arm is selected as the starting installation surface, and the upper surface of the support block is selected as the ending installation surface.

[0040] Step 2: Based on the spatial relationship between the starting and ending mounting surfaces, and the workpiece's dimensional information, the overall three-dimensional information of the workpiece is as follows: Figure 5 As shown: Set a threshold, and within the threshold range, cut off the workpiece. The cutting result is as follows: Figure 6 As shown, Step 3: Based on the starting and ending mounting surfaces and the 3D environment to be avoided, a reasonable preliminary topology is obtained through path planning algorithms. Due to the diversity of spatial path search, the generated path may have some undulations and fluctuations, such as... Figure 7 As shown.

[0041] Step 4: Perform transition processing (including smoothing, angle standardization, etc.) on the initial topology according to mechanical design rules to obtain an optimized topology. This optimized topology is flatter and the angles are more standardized. Figure 8 As shown.

[0042] Step 5: Based on the business design rules, combine or split the optimized topology to obtain one or more topologies that meet the installation requirements, such as... Figure 9 As shown, a spatial topology is obtained. This topology is not easy to process in actual manufacturing. Therefore, it needs to be split into two independent topologies according to the processing requirements. It is also necessary to ensure that there is a certain connection between the two independent topologies so that they can be installed after the shape is generated. (Specific examples can be added to explain the splitting principle: adjustment in the X / Y / Z directions) Step Six: Based on the process requirements (part thickness, width, number of holes, etc.), calculate the topology that meets the installation requirements to obtain a two-dimensional sketch with reasonable dimensions, such as... Figure 10 As shown.

[0043] Step 7: Automatically add 2D constraints based on the dimensional information of the 2D sketch, such as... Figure 11 As shown; Step 8: Based on the 2D sketch information and business design rules (extrusion length, extrusion direction, etc.), automatically generate a 3D shape that meets the requirements, such as... Figure 12 As shown.

Claims

1. A design method for automatically generating three-dimensional parts based on a path planning algorithm, characterized in that... The steps include: Design environment construction: Based on the input information of the design scenario, a design environment for generating 3D parts is constructed; the input information of the design scenario includes 3D digital model information, process requirements, installation requirements, machining requirements, and modeling parameters in the design scenario; Improve the path planning algorithm and optimize the corresponding path of the 3D part: Improve the path planning algorithm according to the process requirements, and generate a preliminary 3D path of the 3D part based on the improved path planning algorithm; constrain and calibrate the preliminary 3D path according to the processing requirements to obtain the optimized 3D path; split the optimized 3D path according to the installation requirements; obtain the optimized 3D path set, which includes one or more 3D paths that meet the process requirements. Automatic generation of part models: Based on the optimized 3D path set, a 2D sketch set is automatically generated using a sketch generation algorithm; constraints are automatically added to the 2D sketch set to obtain a fully constrained 2D sketch set; based on the modeling parameters, the fully constrained 2D sketch set is automatically modeled to obtain the 3D part; The path planning algorithm is the A*Star path planning algorithm, and the improvements to the A*Star path planning algorithm include: A 3D environment map is constructed based on the design environment, and the area where obstacles are located in the 3D environment map is expanded according to the safety distance requirements to obtain an optimized 3D map. Calculate the distance cost value. Based on the starting position information and the six-directional search of the spatial coordinate system, calculate the distance cost value to the ending position information. The position update direction of the A* star path planning algorithm is constrained and calibrated according to the path direction and path angle requirements to obtain the constrained A* star algorithm. Using the constrained A*star algorithm, directional selection of expansion points is performed in the 3D map, prioritizing exploration in horizontal or vertical directions; feasible paths are determined by expanding step by step.

2. The design method for automatically generating three-dimensional parts based on a path planning algorithm according to claim 1, characterized in that, The steps for building the design environment include: The design scenario input information includes existing 3D digital models of the workpiece and 3D digital models of multiple parts; Extract hole feature information from the 3D digital model of the part: including the number of holes, the axis coordinates of the holes, the normal vector and the radius; and combine the hole feature information of the same mounting surface to construct hole groups; each 3D part has different hole group information; Determine the start and end position information; Combine and build the design environment: The workpiece is cut out by forming a bounding box composed of the three-dimensional digital models of all parts; the cut-out workpiece and all parts are combined together to build the design environment.

3. The design method for automatically generating three-dimensional parts based on a path planning algorithm according to claim 2, characterized in that, The methods for determining the start and end position information include the following two: Through user interaction: select a hole group of a certain part as the starting position information, and select a hole group of another part as the ending position information; Based on the different types and spatial distribution of parts, the system automatically determines the starting position information of the hole group of one part and the ending position information of the hole group of another part.

4. The design method for automatically generating three-dimensional parts based on a path planning algorithm according to claim 1, characterized in that, The steps for optimizing the initial path based on process requirements and manufacturing requirements include: Based on the surface flatness requirements of the 3D part, the generated feasible path is smoothed and constrained for calibration. Starting from the initial location information and ending at the final location information, multiple 3D paths are obtained through an improved path planning algorithm. Based on the required number of path turns, multiple 3D paths are compared and analyzed to obtain a suitable 3D path.

5. The design method for automatically generating three-dimensional parts based on a path planning algorithm according to claim 4, characterized in that, The steps for optimizing the 3D path based on installation requirements include: Determine the appropriate offset direction of the 3D path based on the requirements for adjusting the coordinate axis direction; The offset distance of the three-dimensional path is determined according to the requirements of the adjustment gap. By using different offset distances, the automatic installation of gaskets of different thicknesses is achieved, thereby realizing the adjustment of the installation gap. Based on the required number of splits, the 3D path is copied, split, and offset in a defined offset direction and distance to obtain a set of 3D paths that meet the installation requirements.

6. The design method for automatically generating three-dimensional parts based on a path planning algorithm according to claim 1, characterized in that, The three-dimensional digital model information includes: the digital model information of the workpiece in the scene, and the three-dimensional digital model information of all parts; The process requirements include: safety distance requirements, path direction requirements, number of path turns requirements, and path angle requirements. The installation requirements include: requirements for adjustment direction, requirements for adjustment gap, and requirements for the number of times the device can be disassembled. The processing requirements are: the surface flatness and roughness of the three-dimensional parts, which in turn requires a smooth path; The modeling parameters include: sketch parameter requirements, constraint requirements, numerical optimization requirements, 3D shape parameter requirements, and drilling parameter requirements. The optimized 3D path set is expanded according to the sketch parameter requirements to obtain a 2D sketch set; Based on the numerical optimization requirements, the algorithm automatically rounds and optimizes all sketch size parameters in the two-dimensional sketch set to obtain an optimized two-dimensional sketch set. Based on the constraint requirements, the algorithm automatically adds constraints to the optimized 2D sketch set to obtain a fully constrained 2D sketch set; Based on the requirements of the three-dimensional shape parameters, a three-dimensional model is created from the fully constrained two-dimensional sketch set to obtain a preliminary three-dimensional part model set; Based on the drilling parameter requirements, holes are automatically drilled on the preliminary three-dimensional part model set to obtain an output three-dimensional part model set; The sketch parameters include: length requirements, width requirements, angle requirements, parallelism requirements, and perpendicularity requirements; the numerical optimization includes: after Boolean operations on the 2D sketch data, the algorithm automatically performs integer optimization on the sketch contour parameters; the constraint requirements include: parallel constraints, perpendicular constraints, angle constraints, length constraints, and fixed constraints; the 3D shape parameters include: modeling methods are extrusion and rotation; extruded bodies include extrusion length and extrusion direction; rotated bodies include rotation direction and rotation angle; the drilling parameters include: drilling direction, number of holes, hole type, and hole depth.

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