Method of mobility calculation for a coupled mechanism based on independent motion shunting measurement

Abstract

An improved method based on screw theory for constraint and mobility analysis of complex coupled multi-loop mechanisms is proposed. The innovation is the proposition of motion shunting measure, by which the complex multi-loop coupled mechanisms can be split into several independent elements. The relative motion of the coupled-nod link in each element was analyzed and replaced by a generalized kinematic chain. The coupled mechanism was ultimately regarded as a common parallel mechanism. Limb twist systems and limb constraint systems of the equivalent parallel mechanism were analyzed and the characteristic of the output mobility was identified. With the proposed method, a typical Hoberman Switch-Pitch ball was analyzed, which shows the validity and simplification of the new method.