Robust controls for upper limb exoskeleton, real-time results

Abstract

This article shows the development of an exoskeleton for human joint. The exoskeleton proposed was developed for rehabilitating individuals who have suffered injuries at their shoulders, by rehabilitation exercises. The exoskeleton has special characteristics to deal with the 5 degrees of freedom of the human shoulder. The dynamic model results in the following form: [Formula: see text], where [Formula: see text] and [Formula: see text] are state’s vector, torque’s vector, a matrix function and a vector function, respectively. Therefore, we applied four different control laws, among which stand two robust controls (adaptive sliding modes and proportional–derivative with adaptive gravity compensation). The adaptive controller properties allow the exoskeleton to adapt to different humans with different parameters such as size, length, weight and so on that, in mathematical terms, is represented as a mechanical system with uncertainties.