Towards Semi-Autonomous and Soft-Robotics Enabled Upper-Limb Exoprosthetics: First Concepts and Robot-Based Emulation Prototype

Abstract

In this paper the first robot-based prototype of a semi-autonomous upper-limb exoprosthesis is introduced, unifying exoskeletons and prostheses [1]. A central goal of this work is to minimize unnecessary interaction forces on the residual limb by compensating gravity effects via a upper body grounded exoskeleton. Furthermore, the exoskeleton provides the residual limb's kinematic data that allows to design more intelligent coordinated control concepts. The soft-robotics design of a prototype consisting of a transhumeral prosthesis and a robot-based exoskeleton substitute is outlined. For this class of hybrid systems a human embodied dynamics model and semi-autonomous coordinated motion strategies are derived. Here, in contrast to established standard sequential strategies all joints are moved simultaneously according to a desired task. In combination with an app-based programming framework the strategy goals are set either user-based via kinesthetic teaching or autonomously via 3D visual perception. This enables the user to execute tasks faster and more intuitive. First experimental evaluations show promising performance with a healthy subject.