Controle por Realimentação de Saída Baseado em Observador de Estado para Sistemas Fuzzy T-S Sujeitos a Restrições

Abstract

In this article we propose a numerical method to compute an observer-based output feedback controller for fuzzy Takagi-Sugeno (T-S) systems subject to state and control constraints, based on the theory of invariant sets. Sufficient conditions are established for a polyhedron defined in the augmented state space (state + estimation error) to be positively invariant in two cases: when the membership function associated with the fuzzy T-S model can be calculated directly from the measured output of the system or when it has to be calculated from the state estimated by the observer. From these conditions, a bilinear optimization problem is formulated for the simultaneous calculation of the gains of the controller and of a positively invariant polyhedron guaranteeing the satisfaction of the constraints. Two examples illustrate the effectiveness of the method.