Design And Research Of Launch Platform For Decoupling 3 - RRR Spherical Mechanism

Spherical mechanism is widely used, as its many advantages. The research object of this paper is decoupled 3-RRR spherical parallel mechanism launch platform.According to the design requirements of the launch platform, the configuration design of the spherical mechanism is carried out, the coordinate systems are established and the structure parameters are defined based on the structural characteristics.Using spherical analytic method, the positive and inverse position solution of the mechanism are derived. The first order influence coefficient matrix is established,and the relationship between input and output is obtained.Spherical crank-spherical slider mechanism is added in the third chain to increase the maximum turning angle, the design of unloading structure to improve torque of the branched chain members, then according to the theory of mechanism interference, the virtual prototype of launch platform is built by using the layered assembly method in Pro/E. Finally, the transmission dynamics model of mechanism single chain is established, the formula of load torque and equivalent moment of inertia are derived, the transfer function of single chain system is obtained, and its stability and errors are analyzed.The dynamic and static bearing characteristics of the launch platform were defined, the distribution of the static bearing characteristics in space and the dynamic load performance of the dynamic platform around the three axis were analyzed, and the influence of the parameters on the load characteristics was analyzed. Finally, according to the principle of the integration of small displacement, the stiffness matrix of the mechanism is established, the spatial distribution of angular displacement stiffness is analyzed, a basis for the structural optimization is put forward.