COMPARATIVE STUDY OF NON-LINEAR CONTROLLERS FOR THE REGULATION OF THE PARAPLEGIC KNEE MOVEMENT USING FUNCTIONAL ELECTRICAL STIMULATION

Abstract

The non-idealities resulting from the excitation of the paraplegic quadriceps muscle by the functional electrical stimulation (FES) make the control problem challenging. Few works addressed the control of this highly non-linear behavior where the elaborated controllers are useless in the real world. To improve the controllers’ metrics available in the literature, we test others controllers which are the Double PID, the backstepping, the backstepping with an integral action and the super-twisting. For that, we first propose an in-depth study of the knee’s dynamic through which we explain the poorness of the paraplegic quadriceps response to the FES. As a result, we propose to control using derivative way instead of de-convolving approaches as proposed in the literature. Second, we implement the different controllers cited earlier. Finally, we compare the resulting metrics of each controller with those of literature and we conclude by identifying the best controller among the ones chosen in this study which presents a considerable improvement and advantages.