Adaptive fuzzy control of operation space constrained exoskeletons under unmodelled dynamics

In this paper, we present adaptive fuzzy tracking an exoskeletons that operates in a constrained region of the task space. The exoskeleton enables a human forearm to track any continuous desired trajectory within the constrained range, in the presence of parametric/functional uncertainties, unmodelled dynamics including actuator dynamics, and/or disturbances from the environment. Barrier Composite Energy Function (BCEF) scheme with a novel Barrier Lyapunov Function is proposed to facilitate the analysis of state tracking error convergence without the end-effector ever transgressing the constrained region. Adaptive scheme of fuzzy approximation controller to compensate for functional uncertainties in the dynamic model of human and exoskeleton, and unknown disturbances from the environment. The proposed adaptive control performance is validated through actual experiments.