Robust and nonfragile H∞ decentralized fuzzy model control method for nonlinear interconnected system with time delay

In general, due to the interactions among subsystems, it is difficult to design a decentralized controller for nonlinear interconnected systems. In this study, the model of nonlinear interconnected systems is studied via decentralized fuzzy control method with time delay and polytopic uncertainty. First, the nonlinear interconnected system is represented by an equivalent Takagi and Sugeno type fuzzy model. And the represented model can be rewritten as parameterized linear matrix inequalities (PLMIs), that is, LMIs whose coefficients are functions of a parameter confined to a compact set. We show that the resulting fuzzy controller guarantees the asymptotic stability and disturbance attenuation of the closed-loop system in spite of controller gain variations within a resulted polytopic region by example and simulations.