Acquisition of new body representation about extra robotic thumb by use of vestigial muscles

Abstract

Our research purpose is to improve the utility of wearable robotic devices such as an extra robotic limb or finger with the help of acquiring a new body representation. One of the challenging problems of the conventional robotic prosthesis or wearable systems is their difficulty in the coordination of multiple degrees of freedom. Newly acquired body representation of the wearable robotic extremities could be helpful for a user to control the device as if they were a part of user's body. This paper introduces a posterior auricular muscle to obtain a new body representation of an extra robotic thumb. The posterior auricular muscle is one of vestigial muscle which does not have any body representation, while a daily used muscle has already had a certain body representation related with its functionality. In this paper, we conduct an experiment to test our hypothesis that a new body representation can be more easily acquired with the use of vestigial muscles than that of the muscles used in daily basis for the control of the extra robotic thumb. We compare the operability of the extra robotic thumb in reaching experiments by the use of muscles with different functionalities.