DOI: 10.1177/0959651812459604

pii.sagepub.com Observer-based HN control for Takagi– Sugeno fuzzy systems with uncertainty and disturbance Thai-Viet Dang and Wen-JuneWang This article is devoted to the design of a fuzzy-observer-based HN control for an uncertain Takagi–Sugeno fuzzy system with the existence of external disturbance and unavailable state variables. First, an augmented fuzzy model is built by integrating the system state with the output disturbance to create a new variable. Based on Lyapunov theory and linear matrix inequality tools, we derive sufficient conditions for the existence of the fuzzy-observer-based fuzzy controller guaranteeing a generalized HN performance level. A decoupled method is proposed in this study to transform the non-linear matrix inequality (nonlinear matrix inequality) conditions into some LMI forms. Finally, the procedure of the fuzzy-observer-based HN control design is summarized and the effectiveness is demonstrated with a practical example