Inverse Kinematics and Dynamics of the 3-RRS Parallel Platform

This paper presents the fomulation of the inverse kinematics and dvnamics of the1 3-RRS parallel platform with three degrees of freedom. For inverse kinematics, The position analysis is f irs f ly performed. Then the differential motion constraint vquations of the movable platform are established, based on which the velocity and acceleration formulae of leg actuators are derived. In inverse dynamic analysis, the parallel platform is decomposed into two parts through parting the three spherical joints, and the forces acting on the parted joints are determined according to the moment (and forre) equilibrium’s of the legs and the movable platform Subsequently, the analytic expressions of the driving moments of the leg actuators are derived by means of the moment equilibrium’s of the ltpgs. Although only the 3RRS parallel platform is analyzed in this papeq the presented method and process can also be upplied to other less DOFparallel platform.