Design And Characteristic Analysis Of Two Degree-of-freedom Parallel Deflection Platform

Compared with the series mechanism,the parallel mechanism has the advantages of compact structure,strong bearing capacity,small cumulative error,high precision,etc.,which has aroused wide interest of scholars at home and abroad,especially the analysis of the parallel mechanism with less degrees of freedom is a research hotspot.This paper takes the two-degreeof-freedom parallel deflection platform as the research object,and analyzes and researches its configuration design,kinematics,dynamics,static stiffness and error,and specifically includes the following work:1.Based on the principle of a spherical two-degree-of-freedom parallel mechanism,a parallel deflection platform is designed,which can deflection ±45° in both directions around the X and Y axes at the same time.The size specifications of each component were determined by interference detection method,and a three-dimensional model of the platform was established with the aid of three-dimensional software.Through the movement simulation of the deflection platform,the feasibility of the platform movement is verified.2.The kinematics analysis of the two-degree-of-freedom parallel deflection platform is carried out,and the position inverse equation and velocity Jacobian matrix of the platform are solved.According to the principle of virtual work,the generalized coordinates and generalized force of the platform are derived,combined with the pull The Grange equation obtained the dynamics equation of the platform,and used the simulation software to perform the kinematics and dynamics simulation analysis of the platform.The simulation results were compared with the theoretical values,and the kinematics model and dynamics of the platform were verified.The correctness of the model.3.The finite element model of the platform was established using ANSYS Workbench software,the stiffness of the platform under different poses was calculated,the law of stiffness changing with the pose was obtained,and the weak parts of the platform stiffness were found.The modal analysis of the platform was carried out,and the natural frequency and mode shape of the first six orders of the platform were determined.On this basis,the harmonic response analysis is carried out,and the change curve between the frequency and the frequency response value of the moving platform in the three directions and the sensitive frequency that the platform should avoid during operation are obtained.4.The error analysis of the platform is carried out.According to the principle of error independent action,the source error that affects the accuracy of the platform is analyzed and calculated by the mapping method,the instantaneous arm method and the total differential method.Through the error synthesis method,the platform is obtained around the X and Y axes.Deflection error limit in both directions.