Geometrical approach for the workspace of 6-DOF parallel manipulators

Since parallel manipulators have relatively small workspace when compared to serial manipulators, it is important to determine the workspace in the design stage. However, due to the complexity of the closed-loop chain mechanism, the determination of the workspace is difficult. In this paper, a fully geometrical method for the determination of the workspace of 6-DOF parallel manipulators is presented using the concept of a 4-bar linkage. The reachable and dexterous workspace can be determined from the proposed algorithm. In order to evaluate the workspace, each leg is considered as an open chain, and two kinematic constraints-position and mechanism constraints-are developed. The proposed method is verified by simulation.