Development of robot hand aiming at nursing care services to humans

This paper describes a multi-joint robot finger with soft compliant mechanism for safe and comfortable nursing-care services. In proposed mechanism, we utilize 2 different types of elastic elements at fingertip and MP joint (Metacarpa-Phalangeal Joint), respectively, so as to realize soft and stable contact with human body. At fingertip, a hemisphere shaped silicone gum cushion is mounted, while eight cylindrical cushions are placed between the motor and the link inside MP joint. These cushions deform easily and, as a result, absorb external forces exerted from multiple directions. Furthermore the amplitudes and the directions of applied forces can be estimated with the information of changes in the pressure of each cushion.We examined the fundamental characteristics and performance of this finger module through several experiments.