Finite-time Control of an Actuated Orthosis Using Fast Terminal Sliding Mode
Résumé
This paper deals with the controller of an active orthosis for rehabilitation reasons of the knee joint. The dynamical model of the system, constituted of the shank and the orthosis is complex and is considered as unknown in the conception of the proposed controller. The full security protocol has been carefully applied and we have selected a healthy person for our experiments. The flexion/extension movements used for our experiments are of sinusoidal form and are generally applied by therapeutic doctors. The fast terminal sliding mode technique used in the proposed controller permits a finite time convergence towards zero of the tracking errors both in position and in velocity. The experimental results are satisfactory and prove clearly the effectiveness of the proposed approach. As the wearer used can develop a muscular effort, we have tested the two cases: resistive and assistive effort and we have obtained a good performance in both cases as has been proven in the stability analysis by the the Lyapunov approach.