Sampled-Data H_∞ fuzzy observer for uncertain oscillating systems with immeasurable premise variables

This paper proposes a sampled-data H_∞ fuzzy observer technique for nonlinear uncertain oscillating systems that are represented by the Takagi-Sugeno fuzzy model. The observers are designed for two cases: a measurable premise variable and an immeasurable premise variable. The error system between the nonlinear uncertain system and the sampled-data observer is constructed. The H_∞ performance function for the oscillating system is defined and is guaranteed in the Lyapunov sense. Sufficient conditions for the H_∞ sampled-data fuzzy observer are given in terms of linear matrix inequalities. Finally, the feasibility of the proposed technique is shown using two simulation examples.