Parts finite element analysis method, equipment and medium based on actual boundary constraints

Abstract

The present invention discloses a method, device and medium for finite element analysis of parts based on actual boundary constraints, and the method comprises the following steps: S1, establishing a finite element model of the parts to be optimized, and setting the material parameters of the model; S2, performing experimental measurement on the parts to be optimized, and obtaining the displacement of the actual constraint boundary of the parts to be optimized; S3, performing stress analysis according to the displacement of the model and the actual constraint boundary; S4, performing topological optimization on the parts to be optimized according to the displacement of the model and the actual constraint boundary, the working load and the stress analysis results; S5, repeating steps S2 and S3 according to the optimized parts, and judging whether the topological optimization achieves the expected effect. The present invention can perform topological optimization on the parts according to the displacement of the actual constraint boundary of the parts to be optimized and the stress analysis results, and verify whether the topological optimization achieves the expected effect through secondary experimental measurement and secondary stress analysis.

Description

Technical Field

[0001] The present invention belongs to the technical field of robot structure analysis, and in particular relates to a part finite element analysis method, equipment and medium based on actual boundary constraints. Background Art

[0002] In the robot structural design process, topology optimization will be performed without affecting the product usage requirements - based on the given load conditions, constraints and performance indicators, the material distribution is structurally optimized in a given area. Generally speaking, robots have many parts and complex structures, and topology optimization of the entire robot is time-consuming and inefficient. The traditional robot topology optimization method is to extract the robot components that need to be optimized, establish a finite element model of the corresponding structure, and then set the connection position with other parts of the robot as a fixed constraint based on the equivalent boundary conditions. Finite element stress analysis is performed according to the load, and finally the material distribution is determined from the design domain through the optimization algorithm to form a new robot structure.

[0003] In general, during topology optimization, fixed constraints are set for the parts where the robot components are connected, and some or all of the freedom constraints on the boundaries are set to zero. However, in actual robot working conditions, the connection boundaries are rarely fixed and will shift slightly depending on the load. The difference between the two will affect the stress distribution results obtained by the robot's finite element stress analysis, and the stress distribution on the boundary and its vicinity cannot be accurately calculated, thus affecting the subsequent fatigue analysis and topology optimization results. Summary of the invention

[0004] In order to overcome the above technical defects, the present invention provides a part finite element analysis method based on actual boundary constraints.

[0005] In order to solve the above problems, the present invention is implemented according to the following technical solutions:

[0006] A part finite element analysis method based on actual boundary constraints, the method comprising the following steps:

[0007] S1. Establish a finite element model of the component to be optimized and set the material parameters of the model;

[0008] S2. Conducting experimental measurements on the components to be optimized to obtain the displacement of the actual constraint boundaries of the components to be optimized;

[0009] S3. Perform stress analysis based on the displacement of the model and actual constraint boundaries;

[0010] S4. Perform topological optimization on the components to be optimized based on the model, displacement of the actual constraint boundary, working load and stress analysis results;

[0011] S5. Repeat steps S2 and S3 based on the optimized parts to determine whether the topology optimization achieves the expected effect.

[0012] Furthermore, in step S1, the steps are included:

[0013] Simplify the robot structure and determine the parts to be optimized;

[0014] According to the shape and size of the parts to be optimized, a finite element model of the parts to be optimized is established;

[0015] Set the finite element model material parameters according to the shape, size and properties of the component to be optimized.

[0016] Furthermore, in step S2, the following steps are also included:

[0017] When the robot is in the design stage or other situations, the parts are simulated in motion or experimentally measured with parts of similar structure.

[0018] Furthermore, in step S4, the steps are included:

[0019] Set the design domain and non-design domain;

[0020] Determine the optimization objective function and topology optimization constraints;

[0021] Optimization is performed based on the model, displacement of actual constraint boundaries, working load, stress analysis results, objective function and constraints.

[0022] Furthermore, in step S5, the following steps are included:

[0023] Based on the optimized components, experimental measurements are carried out to obtain the secondary displacement of the actual constraint boundary;

[0024] Calculation is performed based on the model, the secondary displacement of the actual constraint boundary and the load of the optimized components;

[0025] Compare the calculation results with the design requirements to determine whether the topology optimization achieves the expected results.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention discloses a finite element analysis method for parts based on actual boundary constraints. According to the displacement of the actual constraint boundary of the parts to be optimized and the stress analysis results, the parts are topologically optimized. Through secondary experimental measurement and secondary stress analysis, it is tested whether the topological optimization achieves the expected effect.

[0028] The present invention also discloses a device, characterized in that it comprises:

[0029] processor;

[0030] a memory for storing instructions executable by the processor;

[0031] The processor is configured to execute the instructions to implement the above method.

[0032] The present invention also discloses a computer-readable storage medium, which is characterized in that it is a computer-readable storage medium and stores a computer program, and the computer program implements the above method when it is executed. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings, wherein:

[0034] Figure 1 A flowchart of the method described in Example 1;

[0035] Figure 2 This is a schematic diagram of the structure of the device described in Example 2. DETAILED DESCRIPTION

[0036] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0037] Example 1

[0038] like Figure 1 This embodiment discloses a part finite element analysis method based on actual boundary constraints, the method comprising the following steps:

[0039] S1. Establish a finite element model of the parts to be optimized and set the material parameters of the model: Simplify the robot structure, divide the parts into different parts, determine the parts to be optimized, establish a finite element model of the parts to be optimized according to the shape and size of the parts to be optimized, import it into relevant stress analysis software, and set the material parameters of the finite element model.

[0040] S2. Conduct experimental measurements on the components to be optimized to obtain the displacement of the actual constraint boundaries of the components to be optimized: Install the displacement sensor near the connection between the components to be optimized and other components, move it under standard working conditions, and measure the displacement of the actual constraint boundaries of the components to be optimized through experiments.

[0041] S3. Perform stress analysis based on the finite element model of the component to be optimized and the displacement of the actual constraint boundary: import the displacement of the actual constraint boundary and the load condition of the component to be optimized into the software, perform stress analysis, and obtain stress analysis results (stress, strain, deformation, etc.).

[0042] S4. Perform topological optimization on the components to be optimized based on the finite element model of the components to be optimized, the displacement of the actual constraint boundaries, the working load and the stress analysis results: import the finite element model, the displacement of the actual constraint boundaries, the working load and the stress analysis results of the components to be optimized into the topological optimization process; select the design domain and the non-design domain. In general, the connection features of the parts (holes, slots, etc.) are retained as the non-design domain to reduce the boundary motion displacement deviation before and after optimization; according to the working condition design requirements, pre-set the optimization objective function (mass, flexibility, etc.) and the constraints of topological optimization; obtain the optimized components through the optimization algorithm, and export the component structure model for processing and manufacturing through the software processing program.

[0043] S5. Repeat steps S2 and S3 based on the optimized parts to determine whether the topology optimization has achieved the expected results: perform secondary experimental measurements and secondary stress analysis on the optimized parts to obtain the maximum stress and boundary displacement of the optimized structure. The staff will compare the maximum stress and boundary displacement of the optimized structure with the pre-set objective function and constraints to determine whether the design requirements are met.

[0044] Specifically, in step S2, when the robot is in the design stage or the displacement of the actual constraint boundary cannot be calculated due to other reasons, parts with similar structures are used to replace the parts to be optimized for experimental measurement, or motion simulation is performed on the parts to be optimized to obtain the displacement of the actual constraint boundary; when performing motion simulation, the motion simulation model should include the parts that are in contact with the parts to be optimized as much as possible.

[0045] Specifically, in step S5, when the design requirements are met, the optimized components are considered to be the obtained topology optimization results; when the design requirements are not met, it is considered that the actual topology optimization structure may not achieve the expected results and needs to be redesigned or modified.

[0046] In the above embodiment, it can also be used to perform fatigue analysis on parts and components to obtain fatigue life.

[0047] The following is an explanation of the specific process:

[0048] Substitute the robot's parts to be optimized and the parts related to the boundary constraints into the software to build a finite element model;

[0049] Set the material properties of the component to be optimized: yield stress is 250MPa, minimum tensile strength is 250MPa, elastic modulus is 2e+5MPa, Poisson's ratio is 0.3, and density is 7.85g / cm 3 , the parts to be optimized are directly load-bearing, and structural rigidity is selected in the initial design of the parts to be optimized;

[0050] Mesh the parts to be optimized: When the model is small and smooth, and there is no machine structure with comparative load, use the default mesh; if the mesh is sparse and the calculated stress analysis results are significantly different from the actual ones, the mesh should be refined for this area;

[0051] Use Solidworks software to simulate rigid body motion, simulate the motion process of parts according to actual constraints and working conditions, and measure the displacement of the actual constraint boundary of the parts to be optimized during the motion process (the displacement of the actual constraint boundary of the parts to be optimized of the real robot can also be obtained through experimental measurement);

[0052] According to the working load of the part to be optimized and the displacement of the actual constraint boundary of the part to be optimized obtained by measurement, stress analysis is performed to obtain the stress distribution of the part to be optimized based on the displacement of the actual constraint boundary;

[0053] According to the finite element model of the parts to be optimized, the displacement of the actual constraint boundary, the working load and the stress analysis results, the topology optimization of the parts to be optimized is carried out to further optimize the parts of the robot.

[0054] In the above embodiment, fatigue analysis can also be performed on the component according to the stress analysis result to obtain the fatigue life of the component.

[0055] When performing stress analysis, topology optimization and other related finite element analyses on robot parts in this embodiment, boundary displacement conditions based on actual parts are used to replace traditional fixed constraint boundaries as constraint conditions, and static analysis is used to approximately simulate the stress distribution under the entire robot working condition.

[0056] In view of the unsatisfactory topology optimization effect caused by differences in traditional constraint settings, this embodiment performs finite element stress analysis based on the displacement of the actual constraint boundary; according to the stress analysis results, topology optimization is performed on the maximum stress or actual boundary displacement constraint of the robot mechanism, and it is checked whether the optimized structural stress result meets the requirements.

[0057] Under the conditions of the same load and model structure, the displacement of the actual constraint boundary is measured experimentally to replace the traditional fixed constraint, which can obtain stress distribution results that are closer to the real parts. In particular, the stress generated by the robot due to vibration during the loading process can also be reflected. When the contact boundary between the part load and the part is far away, the calculated stress value at the boundary is much larger than the stress at the load, and the wear and fatigue of the corresponding actual part contact is more serious.

[0058] The actual constraint boundary stress is higher than the fixed boundary stress. The topology optimization based on the maximum stress constraint or the maximum displacement deformation constraint can retain the material near the boundary as much as possible, improve the stiffness of the high stress area, reduce the fatigue damage of the parts, and reduce the allocation of other low stress areas, making the material distribution more reasonable.

[0059] Example 2

[0060] like Figure 2 This embodiment discloses a device, including: a processor; a memory for storing processor executable instructions; wherein the processor is configured to execute instructions to implement the method described in Example 1.

[0061] Example 3

[0062] This embodiment discloses a computer-readable storage medium, which is a storage medium readable by a computer and stores a computer program. When the computer program is executed, the method in Embodiment 1 is implemented.

[0063] Optionally, the computer readable storage medium may include: a read-only memory (ROM), a random access memory (RAM), a solid state drive (SSD) or an optical disk, etc. Among them, the random access memory may include a resistance random access memory (ReRAM) and a dynamic random access memory (DRAM).

[0064] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Therefore, any modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A finite element analysis method for parts based on actual boundary constraints, characterized in that: The method comprises the following steps: S1. Establish a finite element model of the component to be optimized and set the material parameters of the model; S2. Conducting experimental measurements on the components to be optimized to obtain the displacement of the actual constraint boundaries of the components to be optimized; S3. Perform stress analysis based on the displacement of the model and actual constraint boundaries; S4. Perform topological optimization on the components to be optimized based on the model, displacement of the actual constraint boundary, working load and stress analysis results; S5. Repeat steps S2 and S3 based on the optimized parts to determine whether the topology optimization achieves the expected effect.

2. The method according to claim 1, characterized in that In step S1, the steps are included: Simplify the robot structure and determine the parts to be optimized; According to the shape and size of the parts to be optimized, a finite element model of the parts to be optimized is established; Set the finite element model material parameters based on the shape, size and properties of the component to be optimized, including yield stress, minimum tensile strength, elastic modulus and / or Poisson's ratio.

3. The method according to claim 1, characterized in that In step S2, the steps are also included: When the robot is in the design stage or other situations, the parts are simulated in motion or experimentally measured with parts of similar structure.

4. The method according to claim 1, characterized in that: In step S4, the steps are included: Set the design domain and non-design domain; Determine the optimization objective function and topology optimization constraints; Optimization is performed based on the model, displacement of actual constraint boundaries, working load, stress analysis results, objective function and constraints.

5. The method according to claim 1, characterized in that In step S5, the following steps are included: Based on the optimized components, experimental measurements are carried out to obtain the secondary displacement of the actual constraint boundary; Calculation is performed based on the model, the secondary displacement of the actual constraint boundary and the load of the optimized components; Compare the calculation results with the design requirements to determine whether the topology optimization achieves the expected results.

6. A device, characterized in that: include: processor; a memory for storing instructions executable by the processor; The processor is configured to execute the instructions to implement the method according to any one of claims 1 to 5.

7. A computer-readable storage medium, characterized in that: It is a computer-readable storage medium on which a computer program is stored. When the computer program is executed, the method according to any one of claims 1 to 5 is implemented.

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