Physical Human-Robot Interaction Through Hugs with CASTOR Robot

Hugs play an essential role in social bonding between people. This study evaluates the hug interactions with a robot identifying the perception. Four hug release methods in adults were applied, a short-time hug, a long-time hug, a touch-controlled hug, and a pressure-controlled hug. The social robot CASTOR was integrated into this study, a modification was made in its arms to perform the hugging action, and a pressure sensor in its upper back. 12 adults (5 females and 7 males) participated in the study. Results showed that the perception of friendliness comparing the short-time hug and the pressure-controlled hug had differences (p = 0.036), making the pressure-controlled hug more friendly. In the case of natural perception, the touch-controlled hug was more natural comparing with the short-time hug (p = 0.047). This study presents the feasibility of implementing CASTOR in hugging interactions.