Analysis of kinematics and reconfigurability of a spherical parallel manipulator

This paper presents the kinematic characterization of a 3-Cylindrical-Prismatic-Universal (3-CPU) parallel manipulator designed for motions of pure rotation. The machine has been conceived at the Polytechnic University of Marche, and recent studies have shown that its kinematic architecture can be exploited for the realization of reconfigurable machines with different kinds of motions (pure rotational, pure translational, and planar motions among others). The 3-CPU concept has been subject to further investigations for a deeper understanding of this peculiar behavior. After a brief introduction to these concepts, the paper faces the position and the differential kinematics of the 3-CPU spherical manipulator aiming at identifying workspace boundaries and its kinematic manipulability.