A robotic hand for social interaction should be capable of comfortable touch with humans. However, it is difficult to mount skin, tactile sensors, and driving mechanism required for human contact, especially holding hands, on a slender finger. In addition, in order to unitize the hand for easy use with any robot and maintainability, the mechanism must be contained within the small space of the fingers and palms. In this paper, we propose a human-sized five-fingered robotic hand named WARABI Hand. It is covered with multi-layored rubber skin to realize human-like soft and pleasant feel. Force sensors on each finger link detect contact with humans and adjust gripping force. We conducted experiments in which a humanoid equipped with WARABI Hand grasped forearm, held hands, and interlocked fingers with a person. The performance for object grasping was also evaluated. We demonstrated that our proposed hand is useful for interaction with humans including receiving and handing over things.

Holding hands can give people a sense of security. In this study, we developed a five-fingered robotic hand that can hold hands with a person and a guidance system that uses the developed hand to hold hands with them. In this system, a robot remembers the location where people have taught it and guides people to that point. We conducted an experiment to evaluate the sense of security in guidance with hand-holding compared with guidance without hand-holding. Participants watched the videos on these two conditions and answered a questionnaire. The results confirmed that holding hands can lead to a sense of security.