On the design of observer-based fuzzy adaptive controller for nonlinear systems with unknown control gain sign

Abdesselem Boulkroune (1) , Mohammed M'Saad (2)

1 UMSBJ - Université Mohammed Seddik Benyahia [Jijel] | University of Jijel
2 Equipe Automatique - Laboratoire GREYC - UMR6072

In this paper, an observer-based fuzzy adaptive controller for nonlinear systems with unknown control gain sign is investigated. Because the system states are not available for measurement, a tracking-error observer is constructed. In this controller, the adaptive fuzzy system is used to approximate the unknown nonlinearities and the Nussbaum function is incorporated to deal with the unknown control direction (i.e. with the unknown control gain sign). The stability of the closed-loop system is proven using the strictly positive real (SPR) condition and Lyapunov theory. Finally, simulation results are given to verify the feasibility and effectiveness of the proposed controller.

Mots clés: Fuzzy system; Adaptive control; Observer; Nussbaum function; SPR condition; Nonlinear system

Domaines: Automatique; Automatique / Robotique

Abdesselem Boulkroune, Mohammed M'Saad. On the design of observer-based fuzzy adaptive controller for nonlinear systems with unknown control gain sign. Fuzzy Sets and Systems, 2012, 201, pp.Pages 71-85. ⟨10.1016/j.fss.2011.12.005⟩. ⟨hal-01061695⟩