Abstract: For the dexterous hands, some features such as many actuator elements, complex control system and high cost make them difficult to be widely applied in a short time. Underactuated multi-fingered hands have the advantage of less actuators, simpler control system. So they can greatly cut down the complexity and cost of the hands under conditions of ensuring enough flexibility of grasping. A novel design program of the underactuated multi-fingered hand which has a tendon-pulley transmission is proposed. Following that, mechanical structure of the underactuated multi-fingered hand is designed. The methods of the joint springs are discussed. Pulley element’s geometrical parameters which could affect the magnitude of the joint driving torque have a optimization analysis. Based on the analysis , an optimum design of the finger mechanism is proposed. Experimental study shows that the hand have a strong adaptive ability, and have a powerful grabing objects ability.

Key words: underactuation;tendon;multi-fingered hand