Performance analysis of Super Twisting Sliding Mode Controller in Lower Extremity Exoskeleton

Abstract

Lower extremity exoskeleton is a kind of wearable robot and is used both in medial and industrial applications for different purposes. In medical field it is used as a therapeutic equipment and in industry especially in defence, to carry heavy loads. This paper deals with how effectively the load carrying exoskeleton can track the motion of the wearer and how much load it can carry over from the wearer. Non Linear model for Hip, Knee and the ankle of the exoskeleton have been modeled by including uncertainties. Super twisting control algorithm is designed and simulated for Multi Input Multi Output (MIMO) exoskeleton system model. The Controller performance is analyzed by introducing external disturbances and parameter variations.