Equipping the Baxter robot with human-inspired hand-clapping skills

Human friends and teammates commonly connect through handshakes, high fives, fist bumps, and other forms of hand-to-hand contact. As robots enter everyday human spaces, they will have the opportunity to join in such physical interactions, but few current robots are intended to touch humans. To begin investigating this topic, we sought to discover precisely how robots should move and react in hand-clapping games, which we define as interactions involving repeated hand-to-hand contacts between two agents. We conducted an experiment to observe seven pairs of people performing a variety of hand-clapping activities. Their recorded hand movements were accurately described by sinusoids that have a constant participant-specific maximum velocity across clapping tempos. Behaviorally, people struggled most with hand clapping at fast tempos, but they also smiled and laughed most often during fast trials. We used the human-human experiment findings to select, modify, and program a Rethink Robotics Baxter Research Robot to clap hands with a human partner. Preliminary tests have demonstrated that this robot can move like our participants and reliably detect human hand impacts through its wrist-mounted accelerometers, thereby exhibiting promise as a safe and engaging interaction partner.