Dynamic Model of Exoskeleton Based on Pneumatic Muscle Actuators and Experiment Verification

Abstract

To assist the elderly people and the patients with neurologic injuries for rehabilitation, the robot-assisted therapy is one of the most remarkable methods for this purpose. In this paper, we developed an exoskeleton based on Pneumatic Muscle Actuators (PMAs). By describing characteristics of human walking, a novel design was proposed to improve the walking comfort of the wearer. In addition, the dynamics of the exoskeleton were analyzed and divided into three parts: the modeling of PMAs, antagonistic configuration of PMAs and the mechanical structure of exoskeletons. The dynamics of the exoskeleton was established according the three parts. Furthermore, a model-free control strategy was utilized to get the exoskeleton properly controlled, which is called Proxy-based Sliding Mode Control. The validity of the exoskeleton model was verified through the comparisons of the simulations and corresponding experiments.