Kinetostatic Analysis of 4-R(CRR) Parallel Manipulator with Overconstraints via Reciprocal-Screw Theory

Abstract

The paper proposes a new approach based on reciprocal screw theory to analyze kinetostatics of lower-mobility parallel mechanisms with overconstraints and static indeterminacy. For force analysis of parallel mechanisms, the main reactions should be solved firstly, and then all other constraint reactions are easy to be obtained. The approach can remarkably reduce the number of unknowns and keep the number of simultaneous equilibrium equations not more than six each time. For static indeterminacy, it also needs to set some complementary equations. All active forces and constraint reactions of the kinematic pairs can be simultaneously obtained by analyzing the equilibrium of everybody one by one. A 4-R(CRR) parallel manipulator with collinear-force static indeterminacy is taken to introduce the method, which indicates that the method is simple and effective.