The Reference Frame of Robotic Limbs Contributes to the Sense of Embodiment and Motor Control Process

Abstract

The robotic limbs using a body remapping approach often follow either the user’s reference frame 1) fixed outside the user’s body (Space frame), 2) centered on a user’s torso (Torso frame), or 3) centered on a user’s head (Head frame). In this study, we investigate the effect of the reference frame on the sense of embodiment and the user’s motor control process. We asked 12 participants to perform some point-to-point tasks with the virtual robotic limbs remapped to the participants’ feet. The virtual robotic limbs tip followed the participants’ feet and each reference frame condition (Space frame, Torso frame, and Head frame). As a result, the reaction time, the movement straightness, and the movement priority were significantly high rate in the Torso frame condition. The subjective score on the sense of embodiment showed that the reference frame condition contributed to the sense of embodiment.