Development of a Robot Finger Module with Multi-directional Passive Compliance

In this paper, we describe the development of a human-sized 3DOF finger module for human-care services, having multi-directional passive compliance and the ability to estimate external torque. In order to achieve the above characteristics, silicone gum cushions (SGC) are used at the finger-tip and the MP joint (metacarpal-phalangeal joint). These SGCs have a hollow shape and deform easily. The elastic deformation of SGC enables the robot to react softly to the external forces exerted from multiple directions. Furthermore, these forces can be inferred by measuring the pressure in the SGC's hollow. The basic characteristics of the module's passive compliance and its accuracy in sensing external forces are examined through several experiments. In addition, in order to confirm the possible application of this finger to a human-care services, we executed an experiment that simulates the motion of wiping a human body, taking advantage of the system's merits