This paper newly proposes a multi-fingered robot hand with a common rotational axis shared by all base joints of finger. By focusing on a manipulation around such a particular axis, finger motion planning drastically becomes simple. In order to generate the common rotational axis, we introduce the dual turning mechanism where two and two other fingers can independently turn along the inner and the outer circles with the common center axis, respectively. Due to this mechanism, the developed hand is good at twisting motion based tasks, for example opening a cap from a bottle, within one hand, while it is generally hard for human or conventional robot hands to execute the same task quickly. We show a couple of experiments for confirming our basic idea.
