Optimal Design and Redundancy Resolution of a Novel Robotic Two-Fingered Exoskeleton

This article deals with the optimal design and redundancy resolution of a seven DOF robotic two-fingered hand exoskeleton intended for rehabilitation purposes. The exoskeleton is designed to track the human digit motion accurately. As the human digit joint cannot be modeled by single revolute joint due to instantaneously varying center of rotation, a 4-bar mechanism is employed to model each phalanx of a finger. Optimal 4-bar linkages are designed by minimizing the error between the Cartesian trajectories of the human phalanx and those of the coupler points in respective 4-bar mechanisms. It is demonstrated that the designed 4-bar based exoskeleton can track the human digit motion accurately. Performance analysis of the developed device has been carried out by resolving its kinematic redundancy during a fine object translation motion by instantaneously optimizing manipulability measure.