Design and kinematic analysis of a new 3-DOF spherical parallel manipulator for a prosthetic wrist

Abstract

This paper presents a new three-degrees-of-freedom spherical parallel manipulator, which is designed to be used as a prosthetic wrist. The inverse position problem is solved and a closed form equation is obtained. Afterward, using the screw theory approach, the mobility analysis is performed to demonstrate that the proposed mechanism performs spherical motion. The velocity analysis is carried out by means of screw theory, and an input–output velocity equation is obtained. Furthermore, a preliminary virtual design of the mechanism is presented and the workspace and analytical static analysis is performed. Finally, a set of dynamic simulations are carried out to demonstrate the three movements (i.e., pronation–supination, flexion–extension, and ulnar–radial deviation) of the wrist, and the simulation results show that the proposed mechanism is capable of performing the full range of motion required for daily living and the required actuation torques are obtained for the future development.