Fuzzy decentralized controller and observer design for nonlinear interconnected systems

In general, it is not easy to design a decentralized controller for nonlinear interconnected systems. In this study, the stability of nonlinear interconnected systems is studied via a fuzzy decentralized control method. First, the nonlinear interconnected systems are represented by an equivalent Takagi-Sugeno type fuzzy model. If the state variables are unavailable, a fuzzy observer-based state feedback controller is also proposed to solve the stability problem of nonlinear interconnected systems. A robust decentralized stabilization technique is proposed for each decentralized controller to override the effect of fuzzy approximation error and interconnection among subsystems. This design problem is equivalent to solving a linear matrix inequality problem.