Positive observer based tracking controller design for Takagi-Sugeno systems

This paper presents a new methodology of designing a positive observer based-tracking controller for Takagi-Sugeno systems with unmeasurable premise variables. For that, a positive Takagi-Sugeno observer is developed in order to estimate the system states and to guarantee the nonnegativity of the estimates at each time. Convergence conditions are established in order to guarantee the convergence of the state error. These conditions are given in Linear Matrix Inequalities (LMIs) formulation which makes possible to obtain the gains of the fuzzy controller and observer considered. Finally, simulation results show the effectiveness of the proposed positive observer.