Adaptive gain super twisting algorithm to control a knee exoskeleton disturbed by unknown bounds

Rakhtala, Seyed Mehdi

Abstract

Knee exoskeletons as wearable robots have been increasingly aimed to assist elderly and disabled people to increase their movement abilities through flexion/extension execution of the knee. In this paper, a robust controller was suggested for a new knee joint orthosis. The system is integrated with the orthosis and the human shank and has a nonlinear dynamic model. This paper presents a novel robust controller of an active orthosis for rehabilitation due to no prior knowledge on the dynamical model and unknown the flexion/extension movements as disturbances, an adaptive gain super-twisting algorithm is used to control the knee joint. It is needed to this strategy to cope with the nonlinear nature of the knee exoskeleton with disturbance and model uncertainties that is bounded with unknown bounds. The stability analysis was proven by the Lyapunov approach.

• Journal Article Type: Article
• Acceptance Date: Sep 12, 2020
• Online Publication Date: Sep 29, 2020
• Publication Date: Jun 30, 2021
• Deposit Date: Aug 15, 2023
• Journal: International Journal of Dynamics and Control
• Print ISSN: 2195-268X
• Electronic ISSN: 2195-2698
• Publisher: Springer Verlag
• Peer Reviewed: Peer Reviewed
• Volume: 9
• Issue: 2
• Pages: 711-726
• DOI: https://doi.org/10.1007/s40435-020-00686-z
• Public URL: https://uwe-repository.worktribe.com/output/11001547