Pressure Variation Study in Human-Human and Human-Robot Handshakes: Impact of the Mood

With the development of compliant mechanisms and tactile skins, social robots are more inclined to physically interact with humans. Touch has been proved highly beneficial in interpersonal social interaction. This motivates social robots to exhibit affective touch abilities. However, most of the studies tackle the consequences and the perception of touch instead of how touching is performed. Understanding the touch manner enables to control robots in a more rich and natural way, but also to detect the intention of the user while touching the robot. This paper focuses on one specific social interaction based on touch, the handshake, and it analyses the pressure exerted by the participants depending on their mood. A corpus of daily repeated handshakes of 11 participants, during 16 days in Human-Human and Human-Robot interactions was produced. A handshake descriptor of 6 variables was computed and allowed to discriminate the participants' behavior. One of the variables (i.e., the maximum pressure on the fingers) enabled to discriminate the mood 'Bored' from the others.