Uniqueness domains and regions of feasible paths for cuspidal manipulators

This paper addresses the kinematics of cuspidal manipulators, i.e., nonredundant manipulators which can change posture without meeting a singularity. It focuses on the uniqueness domains and on the regions of feasible paths in the workspace. For cuspidal manipulators, the uniqueness domains are not the singularity-free regions of the joint space. It is shown that additional surfaces, called characteristic surfaces, separate the inverse kinematic solutions in the joint space. The uniqueness domains define the regions of feasible paths in the workspace. Joint limits are taken into account in this paper. This paper should help the reader better understand the kinematics of cuspidal manipulators.