Title: Robust model reference adaptive control for five-link robotic exoskeleton

Authors: Saim Ahmed

Addresses: Department of Mechatronics, Shaheed Zulfikar Ali Bhutto Institute of Science and Technology (SZABIST), Karachi, Pakistan

Abstract: In this paper, H_∞-based model reference adaptive control (MRAC) for controlling five-link lower limb robotic exoskeleton is developed during the single support phase with uncertainties and unknown external disturbances. Unlike classical MRAC, the presented scheme using H_∞ control and MRAC with adaptive error gain is proposed under uncertain parameter vector and external disturbance. For robustness, H_∞ method is applied to minimise the impact of perturbation. Moreover, robust asymptotic stability of the overall system is investigated by Barbalat Lemma selecting a suitable Lyapunov functional candidate. Finally, the efficacy of developed scheme is validated by a relevant example.

Keywords: adaptive control; H_∞ performance; asymptotic stability; robotic exoskeleton.

DOI: 10.1504/IJMIC.2021.123799

International Journal of Modelling, Identification and Control, 2021 Vol.39 No.4, pp.324 - 331

Received: 01 Feb 2021
Accepted: 04 Apr 2021
Published online: 04 Jul 2022 *

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