Lightweight three-dimensional assembly instruction generation method for complex product

Abstract

The invention discloses a lightweight three-dimensional assembly instruction generation method for a complex product, and the method specifically comprises the steps: 1, constructing a position-attitude matrix of a part, enabling the moving process of the part to form an assembly path corresponding to the part, enabling the assembly path to be dispersed into a plurality of points, enabling each point to be mapped to a key frame, and enabling the key frame to be a key frame; calculating motion resources of the current key frame and the previous key frame, associating the motion resources to the current frame, and recording a timestamp of the current frame; 2, generating a simulation control instruction; 3, establishing a model hierarchical management structure which comprises an entity layer, an annotation layer and an application layer, and associating the annotation layer with the assembly process; and step 4, integrating the assembly path, the annotation layer display logic and the simulation control script, and generating a lightweight three-dimensional assembly guidance file. According to the invention, the efficiency and quality of the assembly process can be obviously improved, and the high-standard requirement of the modern manufacturing industry is met.

Description

Technical Field

[0001] The invention belongs to the field of computer-aided design and manufacturing, and in particular relates to a lightweight three-dimensional assembly instruction generation method for complex products. Background Art

[0002] Product assembly is an important part of complex product manufacturing. Complex products have complex structures, a large number of parts, and compact spatial layouts. There are many assembly constraints in the assembly process, and many assembly operations are manual and irreversible. Many manufacturing companies use text-described two-dimensional (2D) assembly instructions and 2D assembly drawings at the assembly site. 2D assembly instructions cannot clearly and accurately describe the assembly path, assembly direction, and assembly space. Complex assembly processes require a lot of text descriptions.

[0003] At present, manufacturing enterprises have widely adopted 3D CAD systems for product design, and used 3D product models for assembly process planning and design. However, on-site assembly cannot benefit from 3D assembly planning information because 3D planning information cannot be integrated into work instructions. If you want to view 3D assembly planning information, you need expensive 3D CAD systems, graphics workstations, or virtual reality devices to display 3D planning information. Even so, 3D planning information is still independent of 2D assembly instructions. It is not convenient for workers to browse instruction information. Therefore, the gap in 3D information transmission between complex product assembly process planning and instruction release should be filled. In summary, a lightweight 3D assembly instruction release method for complex products is urgently needed. It aims to accurately guide the rapid completion of complex product assembly work, improve the efficiency and quality of the assembly process, and reduce the deployment cost of 3D assembly instructions. Summary of the invention

[0004] Purpose of the invention: In order to solve the problems existing in the above-mentioned prior art, the present invention provides a lightweight three-dimensional assembly instruction generation method for complex products.

[0005] Technical solution: The present invention provides a lightweight three-dimensional assembly instruction generation method for complex products, which specifically includes the following steps: Step 1: Construct the position-attitude matrix of the component, form the movement process of the component into an assembly path corresponding to the component, disperse the assembly path into several points, each point is mapped to a key frame, calculate the motion resources of the current key frame and the previous key frame based on the position-attitude matrix, associate the motion resources with the current key frame, and record the timestamp of the current key frame; the motion resources include rotation vector, translation vector and scaling; Step 2: Extract the start and end key frames of any assembly path in the assembly steps, generate simulation control instructions, and realize the association between the assembly path and the dynamic simulation; Step 3: Establish a hierarchical model management structure, including the entity layer, annotation layer, and application layer, and associate the annotation layer with the assembly process; Step 4: Integrate the assembly path, annotation layer display logic and simulation control script to generate lightweight 3D assembly guidance files.

[0006] Furthermore, the expression of the current position-posture matrix P of the component in step 1 is as follows: ; in, Represents the direction vectors of the i, j, k axes of the local coordinate system of the component on the X, Y, and Z axes of the world coordinate system; Indicates the position of the origin of the local coordinate system in the world coordinate system at the current moment; T represents transposition; Using transformation matrix Represents the movement process of a component from its current position to the next position: ; Among them, 1 is the i axis, 2 is the j axis, and 3 is the k axis. , , Respectively represent the rotation vectors of the i, j, and k axes of the component's local coordinate system on the X axis of the world coordinate system. , , Respectively represent the rotation vectors of the i, j, and k axes of the component's local coordinate system on the Y axis of the world coordinate system. , , Respectively represent the rotation vectors of the i, j, and k axes of the component's local coordinate system on the Z axis of the world coordinate system. Represents the translation vector of the component's local coordinate system in the world coordinate system.

[0007] Furthermore, the rotation vector includes the rotation angle and the normal vector to the rotation axis; the rotation angle The expression is as follows: ; Normal vector about the rotation axis The expression is as follows: ; The expression of the translation vector is: ; in, Represents the translation vector of two adjacent keyframes on the X axis in the world coordinate system. Represents the translation vector of two adjacent keyframes on the Y axis in the world coordinate system. Represents the translation vector of two adjacent keyframes on the Z axis in the world coordinate system.

[0008] Furthermore, step 2 is specifically as follows: Step 2.1: Obtain the parts included in the qth assembly step, q=1,2,…,Q; Q represents the total number of assembly steps of the rth assembly unit, r=1,2,…,R; R represents the total number of assembly units in the three-dimensional product; Step 2.2: According to the ID of the component or the ID of the assembly unit, obtain the first key frame in the assembly path of the first component and the last key frame in the assembly path of the last component in the qth assembly step; Step 2.3: Generate simulation control instructions for the qth assembly step based on the key frame : ; in, represents the qth assembly step; Indicates the timestamp corresponding to the first keyframe in the assembly path of the first component. Indicates the timestamp corresponding to the last key frame in the last component assembly path; Indicates simulation playback; For any assembly step, simulation operations are performed by generating and calling corresponding control instructions.

[0009] Further, the timestamp corresponding to the key frame is generated according to static scheduling, dynamic scheduling or resource allocation; The static scheduling is to calculate the time difference between two adjacent key frames according to the preset assembly steps and the time required to execute the motion resources, so as to obtain the timestamp of each key frame; The dynamic scheduling is to dynamically adjust the execution time and order of the parts according to the real-time feedback in the assembly process and the time required to execute the motion resources, so as to obtain the timestamp of each key frame; The resource allocation is to determine the time of each assembly path and the equipment executing the assembly path according to the equipment used for assembly involved in the assembly process and the time required for the equipment to execute related motion resources.

[0010] Furthermore, the entity layer in step 3 includes geometric information of the three-dimensional model, and the annotation layer is provided with assembly technical annotations, which include geometric dimensions and tolerances, roughness, process requirements and benchmarks. The assembly technical annotations of the annotation layer are directly displayed on the three-dimensional model and are directly managed as part of the three-dimensional model; the application layer supports assembly-oriented applications based on assembly technical annotations, including parts lists and tools.

[0011] Furthermore, the method also includes associating the assembly technology annotations in the annotation layer with the assembly process and the assembly duration through a temporal granularity method, and associating the assembly technology annotations with any granularity in the assembly process granularity.

[0012] Furthermore, step 4 is specifically as follows: Step 4.1: Use portable interactive document software to customize a three-dimensional assembly instruction template, which is a carrier of assembly instruction description data and a lightweight assembly process model; Step 4.2: Use digital manufacturing software to plan the assembly sequence of parts, design assembly paths, detect assembly collisions, and export assembly models and assembly planning XML files; Step 4.3: Use 3D technical publishing software to import assembly model and assembly planning XML file, edit and annotate assembly technical annotations; Step 4.4: Establish assembly technology annotation mapping information and generate timing granularity mapping XML file; Step 4.5: Use 3D technology publishing software to convert the assembly model with assembly technology annotations into a lightweight model, and use the custom function to publish it to the assembly instruction card template in PDF format to generate an initial 3D assembly instruction file; Step 4.6: Using the customization function of the portable interactive document software, the assembly planning XML file is imported into the initial 3D assembly instruction file to form structured process description information; Step 4.7: Generate assembly simulation interactive control script resources according to the relationship between assembly process and animation, merge the script resources into the PDF file, and associate the script resources with the interactive buttons in the PDF file; Step 4.8: Merge the timing granularity mapping XML file into the PDF file as an attachment file, and associate the display control logic script of the assembly technical annotation with the PDF file to generate a single complete assembly instruction PDF file.

[0013] Beneficial effects: The present invention calculates the motion resources of the assembly process of each component to obtain the assembly completion time of each component, and associates the assembly of components with dynamic simulation through control instructions, so that the assembly of components is visualized and easy to understand and control. At the same time, the present invention uses the accuracy, intuitiveness and clarity of the three-dimensional model to express assembly intentions and requirements, completes the assembly of complex products with high efficiency and high quality, and reduces the deployment cost of assembly instructions. This method can significantly improve the efficiency and quality of the assembly process and meet the high standards of modern manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A flow chart of a method provided by an embodiment of the present invention;

[0015] Figure 2 A schematic diagram of the mapping relationship between the assembly process and the lightweight model provided in an embodiment of the present invention;

[0016] Figure 3 A schematic diagram of a model layering framework provided by an embodiment of the present invention;

[0017] Figure 4 A logical technical framework diagram of the timing granularity method provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0019] The method of the present invention is as follows Figure 1 As shown, specifically:

[0020] S1, construct a position-pose matrix for generating an assembly path, decompose the assembly path into key frames, and record rotation, translation, scaling and time information;

[0021] S2, matching the starting point and end point of the assembly path with the key frame, generating control instructions, and realizing the association between the assembly path and the dynamic simulation;

[0022] S3. Establish a hierarchical model management structure, including entity layer, annotation layer and application layer, to achieve the association between assembly technology annotation and assembly process;

[0023] S4, propose a temporal granularity method to dynamically control the display of assembly technical annotations, and adjust the display and hiding of assembly technical annotations through complete time, time span and timestamp granularity;

[0024] S5. Integrate assembly path, annotation display logic and simulation control script to generate lightweight 3D assembly guidance files.

[0025] In this embodiment, S1 is specifically:

[0026] The position-pose matrix determines the position and pose of a component in three-dimensional space. It consists of a 4×4 matrix P:

[0027]

[0028] in, Represents the direction vectors of the i, j, k axes of the local coordinate system of the component on the X, Y, Z axes of the world coordinate system; Indicates the position of the origin of the local coordinate system in the world coordinate system at the current moment.

[0029] The movement process of a component from one assembly position to the next assembly position (including translation and rotation) is equal to the movement from the original position P to the new position The transformation process can be described by the following formula:

[0030]

[0031] As shown in the following formula, is a 4×4 transformation matrix:

[0032]

[0033] Among them, 1 is the i axis, 2 is the j axis, and 3 is the k axis. , , Respectively represent the rotation vectors of the i, j, and k axes of the component's local coordinate system on the X axis of the world coordinate system. , , Respectively represent the rotation vectors of the i, j, and k axes of the component's local coordinate system on the Y axis of the world coordinate system. , , Respectively represent the rotation vectors of the i, j, and k axes of the component's local coordinate system on the Z axis of the world coordinate system. Represents the translation vector of the component's local coordinate system in the world coordinate system.

[0034] After assembly process planning and simulation, such as Figure 2 As shown in the figure, the movement process of each component forms an assembly path. The assembly path is divided into multiple points. Each point is mapped to a key frame, which records the rotation, translation, scaling and time information from the previous moment to the current moment.

[0035] Therefore, the assembly motion Anim is expressed by the following formula:

[0036]

[0037] Indicates Assembly units, Indicates The motion resources associated with the assembly units are R, which represents the total number of assembly units. Each motion resource consists of multiple assembly paths, which are called trajectories in the lightweight model:

[0038]

[0039] in, Indicates assembly paths, and Q represents the total number of assembly paths in the assembly unit.

[0040] Each assembly path consists of a series of keyframes. Each keyframe records the rotation, translation, scaling and time information of the component from the previous moment to the current moment, which is expressed by the following formula:

[0041]

[0042] Indicates the time offset of the keyframe from the start time of the assembly. Represents the direction vector of the keyframe in the world coordinate system, expressed as follows:

[0043]

[0044] In the formula, represents the rotation angle, The normal vector representing the rotation axis;

[0045]

[0046]

[0047] D represents the translation vector:

[0048]

[0049]

[0050] in, Represents the translation vector of two adjacent keyframes on the X axis in the world coordinate system. Represents the translation vector of two adjacent keyframes on the Y axis in the world coordinate system. Represents the translation vector of two adjacent keyframes on the Z axis in the world coordinate system;

[0051] E is the scaling factor, expressed as follows:

[0052]

[0053]

[0054] Respectively represent the scaling ratio of two adjacent keyframes in the world coordinate system.

[0055] Specifically, each assembly unit involved in the assembly process has an original assembly position and a final assembly position. The key to generating control instructions is to match the original keyframe and the final keyframe in the motion resource with the start and end points of the assembly motion in the assembly process. The generation process is described as follows.

[0056] Step 1: According to the assembly sequence of parts, obtain the assembly steps of the assembly unit. Assume that the parts in assembly step q are ; U represents the total number of parts. q=1,2,…,Q; Q represents the total number of assembly steps of the rth assembly unit, r=1,2,…,R; R represents the total number of assembly units in the three-dimensional product;

[0057] Step 2: Obtain the relevant motion resources through the assembly unit ID or component ID, and obtain the starting key frame time of the first component assembly path and the ending key frame time of the last component assembly path in assembly step q. The first key frame time can be expressed as ,for The last key frame time of can be expressed as ;

[0058] Step 3: Generate simulation control instructions based on key frame time :

[0059]

[0060] in, represents the qth assembly step; Indicates that the simulation playback is executed within the specified time period;

[0061] For any assembly step, simulation operations are performed by generating and calling corresponding control instructions.

[0062] When generating control instructions, the time sequence of each component must be considered, that is, how to reasonably arrange the time sequence of each assembly unit according to the requirements of motion resources. and Time. Time scheduling can be based on the following methods:

[0063] Static scheduling: Allocate a fixed amount of time in advance to each component based on known assembly steps and the time required to execute motion resources.

[0064] Dynamic Scheduling: Dynamically adjust the execution time and order of assembly units based on real-time feedback during the assembly process. For example, the scheduling order may be adjusted based on the efficiency of assembly tools, the availability of robots, or the supply of parts.

[0065] Resource allocation: The assembly process may involve multiple devices (such as robots, conveyors, assembly stations, etc.), and the availability of these devices directly affects the execution time of each assembly step. The resource allocation strategy determines when and by which resource each assembly step is executed.

[0066] In this embodiment, in S3, a model hierarchical management structure is established, including an entity layer, an annotation layer, and an application layer, so as to realize the association between assembly technology annotations and assembly processes.

[0067] In order to make the model view meet the time-based management requirements of assembly technical annotations, such as Figure 3 As shown, this embodiment expands the lightweight assembly process model into three layers: a physical layer, an annotation layer, and an application layer, so as to associate assembly technology annotations with the assembly process.

[0068] The entity layer consists of the geometric information of the 3D model. The entity information is the core design data of the 3D model and is also the carrier of the assembly technical annotations. The entity information is not allowed to be changed during the manufacturing process, but the assembly technical annotation information can be added to the entity information. The annotation layer defines the assembly technical annotation information such as GD&T (geometric dimensioning and tolerance), roughness, process requirements, and benchmarks. The information in the annotation layer is directly displayed on the 3D model and is directly managed as part of the 3D model. The data in the annotation layer is the main content of the assembly process model. The application layer supports assembly-oriented applications based on assembly technical annotations. The structure of the application layer data includes parts lists, tools, etc. Generally speaking, the application layer data is the management information of the assembly instructions and is not directly displayed on the 3D model.

[0069] In S4, this embodiment proposes a time series granularity method to dynamically control the display of assembly technical annotations, and adjusts the display and hiding of assembly technical annotations through the granularity of complete time, time span and timestamp.

[0070] This embodiment proposes a temporal granularity method, which associates assembly technology annotations with assembly processes and assembly durations, and dynamically controls the display and hiding of assembly technology annotations according to the granularity. Figure 4 As shown in the figure, the assembly process granularity is divided into assembly sequence (pre-set sequence), assembly operation and assembly step (assembly according to the pre-set sequence), and the assembly technical annotation can be associated with any granularity. The assembly duration granularity is divided into three modes: full time, time span and timestamp:

[0071] Full temporal granularity: Rigging technique annotations are displayed throughout the entire rigging step, from the first keyframe to the last keyframe.

[0072] Time span granularity: Assembly technical annotations are displayed within a specific time range of the step, starting from a specified keyframe and ending at another keyframe.

[0073] Timestamp granularity: Assembly technology annotations are displayed only at specific points in time for a step, and simulation can be paused for observation.

[0074] Granular control of the display of assembly technical annotations is achieved through the keyframe logic of assembly simulation, ensuring the integration of dynamic management of assembly technical annotations with the assembly process.

[0075] In the embodiment, in S5, the assembly path, annotation display logic and simulation control script are integrated to generate a lightweight three-dimensional assembly guidance file.

[0076] (1) Use portable interactive document software to customize the 3D assembly instruction template, which is the carrier of assembly instruction description data and lightweight assembly process model.

[0077] (2) Use digital manufacturing software to plan the assembly sequence of parts, design assembly paths, detect assembly collisions, and export assembly models and assembly planning XML files.

[0078] (3) Use 3D technical publishing software to import assembly models and XML files, and edit and annotate assembly technical annotations.

[0079] (4) Use the custom function of the 3D technical publishing software to establish assembly technical annotation mapping information and generate a temporal granularity mapping XML file.

[0080] (5) Use 3D technology publishing software to convert the assembly model with assembly technology annotations into a lightweight model, and use customized functions to publish it into an assembly instruction card template in PDF format to generate an initial 3D assembly instruction file.

[0081] (6) Using the customization function of the portable interactive document software, the assembly planning XML file is imported into the initial 3D assembly instruction file to form structured process description information.

[0082] (7) Generate assembly simulation interactive control script resources based on the relationship between assembly process and animation, merge the control script into the PDF file, and associate the control script with the interactive buttons in the PDF file.

[0083] (8) Finally, the timing granularity mapping XML file is merged into the PDF file as an attachment file, and the annotated display control logic script is associated with the PDF file to generate a single complete assembly instruction PDF file.

[0084] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

Claims

1. A lightweight three-dimensional assembly instruction generation method for complex products, characterized in that: The specific steps include: Step 1: Construct the position-attitude matrix of the component, form the movement process of the component into an assembly path corresponding to the component, disperse the assembly path into several points, each point is mapped to a key frame, calculate the motion resources of the current key frame and the previous key frame based on the position-attitude matrix, associate the motion resources with the current key frame, and record the timestamp of the current key frame; the motion resources include rotation vector, translation vector and scaling; Step 2: Extract the start and end key frames of any assembly path in the assembly steps, generate simulation control instructions, and realize the association between the assembly path and the dynamic simulation; Step 3: Establish a hierarchical model management structure, including the entity layer, annotation layer, and application layer, and associate the annotation layer with the assembly process; Step 4: Integrate the assembly path, annotation layer display logic and simulation control script to generate lightweight 3D assembly guidance files.

2. A lightweight three-dimensional assembly instruction generation method for complex products according to claim 1, characterized in that: The expression of the current position-posture matrix P of the component in step 1 is as follows: ； in, Represents the direction vectors of the i, j, k axes of the local coordinate system of the component on the X, Y, and Z axes of the world coordinate system; Indicates the position of the origin of the local coordinate system in the world coordinate system at the current moment; T represents transposition; Using transformation matrix Represents the movement process of a component from its current position to the next position: ； Among them, 1 is the i axis, 2 is the j axis, and 3 is the k axis. , , Respectively represent the rotation vectors of the i, j, and k axes of the component's local coordinate system on the X axis of the world coordinate system. , , Respectively represent the rotation vectors of the i, j, and k axes of the component's local coordinate system on the Y axis of the world coordinate system. , , Respectively represent the rotation vectors of the i, j, and k axes of the local coordinate system of the component on the Z axis of the world coordinate system, Represents the translation vector of the component's local coordinate system in the world coordinate system.

3. A lightweight three-dimensional assembly instruction generation method for complex products according to claim 2, characterized in that: The rotation vector includes the rotation angle and the normal vector to the rotation axis; the rotation angle The expression is as follows: ； Normal vector about the rotation axis The expression is as follows: ； The expression of the translation vector is: ； in, Represents the translation vector of two adjacent keyframes on the X axis in the world coordinate system. Represents the translation vector of two adjacent keyframes on the Y axis in the world coordinate system. Represents the translation vector of two adjacent keyframes on the Z axis in the world coordinate system.

4. A lightweight three-dimensional assembly instruction generation method for complex products according to claim 1, characterized in that: Step 2 is as follows: Step 2.1: Obtain the parts included in the qth assembly step, q=1,2,…,Q; Q represents the total number of assembly steps of the rth assembly unit, r=1,2,…,R; R represents the total number of assembly units in the three-dimensional product; Step 2.2: According to the ID of the component or the ID of the assembly unit, obtain the first key frame in the assembly path of the first component and the last key frame in the assembly path of the last component in the qth assembly step; Step 2.3: Generate simulation control instructions for the qth assembly step based on the key frame : ； in, represents the qth assembly step; Indicates the timestamp corresponding to the first keyframe in the assembly path of the first component. Indicates the timestamp corresponding to the last key frame in the last component assembly path; Indicates simulation playback; For any assembly step, simulation operations are performed by generating and calling corresponding control instructions.

5. A lightweight three-dimensional assembly instruction generation method for complex products according to claim 1, characterized in that: The timestamps corresponding to the key frames are generated according to static scheduling, dynamic scheduling or resource allocation; The static scheduling is to calculate the time difference between two adjacent key frames according to the preset assembly steps and the time required to execute the motion resources, so as to obtain the timestamp of each key frame; The dynamic scheduling is to dynamically adjust the execution time and order of the parts according to the real-time feedback in the assembly process and the time required to execute the motion resources, so as to obtain the timestamp of each key frame; The resource allocation is to determine the time of each assembly path and the equipment executing the assembly path according to the equipment used for assembly involved in the assembly process and the time required for the equipment to execute related motion resources.

6. A lightweight three-dimensional assembly instruction generation method for complex products according to claim 1, characterized in that: The entity layer in step 3 includes the geometric information of the three-dimensional model, and the annotation layer is provided with assembly technical annotations, which include geometric dimensions and tolerances, roughness, process requirements and benchmarks. The assembly technical annotations of the annotation layer are directly displayed on the three-dimensional model and are directly managed as part of the three-dimensional model; the application layer supports assembly-oriented applications based on assembly technical annotations, including parts lists and tools.

7. A lightweight three-dimensional assembly instruction generation method for complex products according to claim 6, characterized in that: The method also includes associating the assembly technology annotation in the annotation layer with the assembly process and the assembly duration through a temporal granularity method, and associating the assembly technology annotation with any granularity in the assembly process granularity.

8. A lightweight three-dimensional assembly instruction generation method for complex products according to claim 6, characterized in that: Step 4 is as follows: Step 4.1: Use portable interactive document software to customize a three-dimensional assembly instruction template, which is a carrier of assembly instruction description data and a lightweight assembly process model; Step 4.2: Use digital manufacturing software to plan the assembly sequence of parts, design assembly paths, detect assembly collisions, and export assembly models and assembly planning XML files; Step 4.3: Use 3D technical publishing software to import assembly model and assembly planning XML file, edit and annotate assembly technical annotations; Step 4.4: Establish assembly technology annotation mapping information and generate timing granularity mapping XML file; Step 4.5: Use 3D technology publishing software to convert the assembly model with assembly technology annotations into a lightweight model, and use the custom function to publish it to the assembly instruction card template in PDF format to generate an initial 3D assembly instruction file; Step 4.6: Using the customization function of the portable interactive document software, the assembly planning XML file is imported into the initial 3D assembly instruction file to form structured process description information; Step 4.7: Generate assembly simulation interactive control script resources according to the relationship between assembly process and animation, merge the script resources into the PDF file, and associate the script resources with the interactive buttons in the PDF file; Step 4.8: Merge the timing granularity mapping XML file into the PDF file as an attachment file, and associate the display control logic script of the assembly technical annotation with the PDF file to generate a single complete assembly instruction PDF file.

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