Effects of Motion Parameters on Acceptability of Human-Robot Patting Touch

Touch between people is essential for forming bonds and communicating emotions. However, it is currently missing in human-robot interactions due to issues with reliability and safety. As robotics transitions to home and service sectors, it is increasingly important to design guidelines and models for human-robot social touch. This paper aims to determine how variations in the motions a robot uses while patting the user’s forearm or shoulder affect perception and acceptance of the interaction. We conducted a study with N=10 participants using a Sawyer robot with a hand-like end-effector, varying the force, speed, location, and pause duration of the pat. Participants rated perceived safety, valence, arousal, and dominance of each pat condition. Using these results, we propose guidelines for creating interactions that feel safe and non-dominant using low-speed and low-force trajectories. These results will be useful in helping HRI designers create appropriate human-robot social touch interactions.