Research On Dynamic Model Of Sperical 2-DOF Overconstrained Parallel Manipulator

The spherical 2-DOF overconstrained parallel manipulator which has the advantages of higher bearing capacity, higher rigidity and fewer singularity in the working space. It can finish locating spherical point, so it has good development prospects. Therefore, this article takes the model machine as research object, and researches the kinematic analysis, the dynamics modeling and inertial parameters identification.The inverse position solution model of spherical 2-DOF overconstrained is established, and its speed Jacobin matrix is solved. The velocity and acceleration mapping model of each linkage to the end effector are obtained.The dynamic model of the spherical 2-DOF overconstrained parallel manipulator which contains electrical and mechanical subsystem is established by using the screw bond graph. Because of the existence of the passive overconstrained and active overconstrained. So there are 43 unknown variables need to be solved. In order to solve the problem of passive overconstrained, the supplementary equations of deformation compatibility are added. Aiming at the issue of active overconstrained, the method of driving force optimization is proposed. Finally, the complete dynamic model of the parallel manipulator is obtained.The partial velocity matrix and force(moment) matrix of key point are obtained. And then according to the principle of virtual work, the linear model of dynamic parameters is obtained. The exciting trajectory is designed by Fourier series which is modified by the quintic polynomial and optimized. And the exciting trajectories are planned. At last, the identification process is briefly introduced.The identification results are obtained by the experiments, and verified through an arbitrary trajectory.