title: Adaptive fuzzy output-feedback controller design for nonlinear time-delay systems with unknown control direction.
abstract: In this paper, the robust-control problem is investigated for a class of uncertain nonlinear time-delay systems via dynamic output-feedback approach. The considered system is in the strict-feedback form with unknown control direction. A full-order observer is constructed with the gains computed via linear matrix inequality at first. Then, with the bounds of uncertain functions known, we design the dynamic output-feedback controller such that the closed-loop system is asymptotically stable. Furthermore, when the bound functions of uncertainties are not available, the adaptive fuzzy-logic system is employed to approximate the uncertain function, and the corresponding output-feedback controller is designed. It is shown that the resulting closed-loop system is stable in the sense of semiglobal uniform ultimate boundedness. Finally, simulations are done to verify the feasibility and effectiveness of the obtained theoretical results.
authors.affiliation: Institute of Electrical Engineering, Yanshan University, Qinhuangdao City, China. cch@ysu.edu.cn
authors.forename: Chang-Chun
authors.initials: CC
authors.lastname: Hua
authors.forename: Qing-Guo
authors.initials: QG
authors.lastname: Wang
authors.forename: Xin-Ping
authors.initials: XP
authors.lastname: Guan