Finite Element Modeling And Vibration Characteristics Analysis Of Mechanical Arm

When the vehicle is running, it will be subjected to the ground surface roughness, engine running vibration caused by the load, so the vibration environment of low voltage electrical apparatus used in vehicle is very bad, which will affect the life and accuracy of low-voltage electrical appliances. Therefore, it is very important to carry out the research on the reliability and the reliability test of low voltage electrical apparatus under the condition of high speed and variable load in the vehicle.In this paper, the three axis positioning mechanical arm is used to detect the reliability of low voltage electrical apparatus in the vibration environment,which is often in the vibration environment. The complexity of the operating environment has resulted in the increase of structure failure factors, especially the vibration caused by the equipment and the vibration fatigue failure can seriously affect the structure safety. Therefore, it is necessary to analyze the vibration characteristics of the three axis positioning mechanical arm and understand the response of the arm in the vibration environment. This study is significant to develop the key technology of low voltage electrical apparatus reliability testing, and carry out reliability test of low voltage apparatus.At first, the basic content and application of the finite element method are described, and the function modules of the finite element software Workbench ANSYS and the process of the finite element analysis are introduced.Secondly, the 3D model of three axis mechanical arm is established with Solidworks, and the model is simplified and modified by using the general finite element software ANSYS Workbench; The mesh generation of finite element model which gets a high quality grid is obtained by using a variety of mesh generation methods; analyze the stress and displacement of the mechanical arm under all typical conditions, figure out the most unstable conditions of structure according to the stress and displacement value, which is the maximum, and check the strength of the mechanical arm.Thirdly, modal analysis, harmonic response analysis and random vibration analysis of the structure under the most unstable condition are carried out. Through modal analysis, the natural frequency and corresponding vibration modes of the structure are obtained; Through harmonic response analysis, simulate grab mechanism installation position force, and obtain the dynamic response of mechanical arm under external excitation; At the same time, carry out random vibration analysis by applying the vertical, horizontal and longitudinal random loads on mechanical arm baseboard, and obtain stress and displacements of the mechanical arm in the x, y and x directions, extract displacement power spectral density of grab mechanism installation position in the x, y and z directions.Finally, according to the vibration characteristics analysis of the mechanical arm, it is found that the amplitude of the frame and the screw in Z axis are relatively large. Therefore, the vibration characteristics of the mechanical arm frame and the Z axis screw are respectively analyzed; Besides, use tuned mass damper successfully reduce the vibration response of some frequency points, describe the working principle of tuned mass damper, and optimize the characteristic parameters of tuned mass damper by using displacement of grab mechanism installation position in first, second and fourth order modes as objective function, which provides a powerful basis for engineering application.