Analysis of physical human-robot interaction for motor learning with physical help

In this paper we investigate physical human-robot interaction (PHRI) as an important extension of traditional HRI research. The aim of this research is to develop a humanoid robot that can work in the same spaces as humans. We first propose a new control system that takes advantage of inherent joint flexibility. The control system is applied on a new humanoid robot called CB². In order to clarify the difference between successful and unsuccesful interaction, we conduct an experiment where a human subject has to help the CB² robot in its rising-up behavior. We also develop a new measure that reveals the difference between smooth and nonsmooth physical interactions. An analysis of the experimentpsilas data, based on the introduced measure, shows significant differences between experts and beginners in human-robot interaction. Consequently, we assume that this measure can be used in the evaluation method required for a motor learning system that uses physical help from a human helper.