Unified Inverse Dynamics of Variable Topologies of a Metamorphic Parallel Mechanism Using Screw Theory

This paper presents the topology variation of a 3(rT)PS metamorphic parallel mechanism which can change its mobility from 3 to 6. The reconfiguration stems from a reconfigurable (rT)PS limb of which the two phases can be unified by taking one as a special case of the other. Based on this, unified inverse kinematics is solved and a unified dynamics modeling is built using screw theory which naturally represents the geometric constraint and actuation forces in the same manner. The obtained modeling covers all the topologies of the parallel mechanism. A numerical example demonstrates the theoretical results which provide basis for this metamorphic parallel robot with applications in reconfiguration-required environment.