Human Mimetic Forearm and Hand Design with a Radioulnar Joint and Flexible Machined Spring Finger for Human Skillful Motions

Humans have characteristic forearm and hand structures, and most of the previously developed humanoids are not equipped with them. The human forearm has a radioulnar structure composed of two long thin bones, and the human hand has flexibility to move to fit the object and strength to support the human body. Therefore, we develop a novel miniature bone-muscle module integrating bone and muscle structures, and realize the human radioulnar structure. In addition, we develop a novel finger, which is flexible and robust, by using machined springs. We integrate them and construct a forearm and hand system which imitates human joint structures, muscle arrangements, proportion, and weight. Using this forearm and hand system, we realize several human skillful motions.