Dynamics of parallel manipulators by means of screw theory

An approach to the dynamic analysis of parallel manipulators is presented. The proposed method, based on the theory of screws and on the principle of virtual work, allows a straightforward calculation of the actuator forces as a function of the external applied forces and the imposed trajectory. In order to show the generality of such a methodology, two case studies are developed, a 2-DOF parallel spherical mechanism and a Gough–Stewart platform.