A Family of Symmetrical Lower‐Mobility Parallel Mechanisms with Spherical and Parallel Subchains

Abstract

Abstract This paper presents a new family of symmetrical lower‐mobility parallel mechanisms (PMs) with spherical and parallel subchains, which consists of two 5‐DOF (degrees of freedom) PMs, one 4‐DOF PM and five 3‐DOF PMs. The basic feature of this family is that each limb consists of five revolute pairs and can be constructed with two subchains, a 2R pointing subchain and a 3R parallel subchain, or a 3R spherical subchain and a 2R parallel subchain. Different geometrical arrangements of the limbs lead to different degrees of freedom. All the PMs of this family can be modularized easily due to the simple structure of the subchains. © 2003 Wiley Periodicals, Inc.