Design and control of supernumerary robotic limbs

Abstract

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.Cataloged from PDF version of thesis.Includes bibliographical references (pages 175-181).Humans possess the remarkable ability to control their four natural limbs in a voluntary, accurate and independent manner. The simultaneous use of two or more limbs allows humans to learn and robustly perform a wide range of complex tasks. Since the use of multiple limbs enables humans to master advanced motor skills, it would be interesting to study whether having additional limbs would enable users to expand their skill set beyond its natural limits. Inspired by this vision, we propose a new form of human augmentation: a wearable robot that augments its user by providing him with an additional set of robotic limbs. We named this new device Supernumerary Robotic Limbs (SRL). However, humans have never had the possibility to control additional, powered limbs besides their natural arms and legs. The main theme of this thesis, besides realizing a prototype of the robot and proving its usefulness in realworld tasks, is demonstrating that humans can voluntarily control additional limbs as if they were a part of their own body. We realized a lightweight (3.5 kg), comfortable prototype of the SRL that can be easily worn by an unassisted user. Two robotic limbs can assist the user in both manufacturing and locomotion tasks. We created control strategies that take advantage of the independence of the robotic limbs, enabling them to provide optimal assistance in specific tasks such as weight support, body stabilization, using powered tools, sitting/standing and dynamic walking. Finally, we developed an EMG-based control interface that enables users to voluntarily control the motion of the robotic limbs, without interfering with the posture of the rest of the body. The new augmentation technology presented in this thesis opens up new possibilities in the field of wearable robotics. The voluntary control of additional robotic limbs falls within the range of motor skills that humans can learn, and enables the acquisition of a new set of complex skills that would not be achievable using only the natural body..by Federico Parietti.Ph. D