Feedback stabilization of nonlinear systems with unknown control directions and time-delay

Abstract

© 2017 IEEE. Global stabilization by state feedback is investigated for a class of time-delay nonlinear systems with unknown control directions. A dynamic state feedback control scheme is developed to achieve asymptotic state regulation with global stability. The proposed dynamic compensator employs, on one hand, the idea of the Nussbaum-gain functions to mitigate the effects of unknown control directions, and the Riccati-like gain update laws to counteract the time-delay nonlinearity, on the other hand. The proof of the closed-loop stability and state regulation is based on a novel construction of Lyapunov-Krasovskii functionals that are crucial in dealing with unknown control directions and time-delay nonlinearity.