Progress in the development of a multifunctional hand prosthesis

A new experimental hand prosthesis design is presented that differs from that of conventional prostheses. With the objective of addressing consumers´ requirements, functionality was increased and cosmetic appearance became more natural. By integrating a hydraulic system with 8 small fluidic actuators at the digit joints, different important grasping patterns of everyday life can be performed. These are: power grasp, hook grasp, precision grasp, lateral pinch, and a posture to operate a keyboard with the extended index. As a result of multi-articulation and the inherent compliancy of the actuators, objects can be grasped adaptively. Moreover, a vibrotactile feedback system makes the prosthesis controllable without visual attention. For a more natural appearance, the hand is covered by a cosmetic silicone rubber glove. The hands are designed for performing activities of everyday life, including office work. The new hand design can help closing the gap between purely cosmetic hands and functional hands.