CAD Geometric Approach For Synthesis And Kinematic Analysis Of The 3-RPRU Spatial Parallel Manipulator

The 3-RPRU spatial parallel manipulator is a novel type mechanism among the spatial imperfect-DOF parallel mechanisms. The processes of calculating of its location and pose, velocity and acceleration are more significant, meaningful and difficult in the mechanism analysis. Therefore, the task of the thesis is to find the simple and convenient, shortcut, and high precision approach of the spatial imperfect-DOF parallel mechanisms analysis. In the dissertation, a novel computer aided geometry approach for type synthesis and analysis of new spatial 3-DOF parallel manipulators is put forward, and kinematics and transition characteristics of the 3-RPRU spatial parallel manipulator are studied by using the novel computer aided geometry approach and analytic approach respectively. (1)By using the geometric constraints and dimension driving techniques in CAD software, some 3-DOF spatial parallel simulation mechanisms are constructed. By the spatial structure theory and computer aided geometry approach the type analysis and synthesis of the mechanisms are made and thus the optimization and creation of the mechanisms are realized.(2)Based on the construction of the new type 3-DOF spatial parallel simulation manipulator, the forward and reverse position kinematics are analyzed; the velocity and acceleration of the mechanism are received by constructing simulation mechanism at some different positions and setting approaching time; the transition and kinematics characteristics of the simulation mechanism constructed are analyzed when kinematics simulating; based on the structure characteristics and the position forward kinematics analysis, the workspace point coordinates are output and the workspace is get by putting together the workspace drawings in the same position on the different sections.(3)By analytic approach the position, velocity, acceleration and workspace of the novel type 3-DOF spatial parallel mechanisms are analyzed. From the results of the analytic approach the computer aided geometry approach is testified right and available.Indicated from the results studied, the simulation mechanism get by CAD geometry approach is contradictable. The kinematics exchange of input and output is realized by the exchange of driving and driven dimensions. No need to setup complicate mathematics analytic equations, draw repeatedly and calculate a lot by using the CAD geometry approach and only need to change the structure parameters. The CAD geometry approach has become the useful tool for the kinematics analysis of the spatial parallel mechanism and a novel way to the manipulator research in the computer aided optimization design.