Design and Analysis of 3R2T and 3R3T Parallel Mechanisms With High Rotational Capability

A new nonrigid (or articulated) moving platform with passive joints is proposed to reduce the interference between limbs and the moving platform. Then several 3R2T and 3R3T parallel mechanisms are synthesized by use of the proposed moving platform and Lie group theory. Finally, the rotational capability of the synthesized parallel mechanisms is exemplified by the kinematic analysis of one 3R3T parallel mechanism.