An Approach for Type Synthesis of Overconstrained 1T2R Parallel Mechanisms

This paper presents a simple and illustrative approach for type synthesis of a family of overconstrained parallel mechanisms having one translational and two rotational movement capability. This family features a spatial limb plus a member of a class of planar symmetrical linkages, connected by a revolute joint either with the machine frame at the base link or with the platform at the output link. Criteria for selecting suitable structures among numerous candidates are proposed by considering the realistic and practical requirements of reconfigurability, movement capability, component design rationality, etc. Exploiting the structures obtained and examined by the criteria proposed leads to a novel 5-DOF hybrid module named TriMule, which offers a lightweight, cost effective, and flexible design particularly suitable for configuring various robotized manufacturing cells.