H-two/H-infinity fuzzy state feedback control based on fuzzy observer for nonlinear MIMO systems

The problem of mixed H-two/H-infinity fuzzy state feedback control for nonlinear systems is studied.A nonlinear plant is approximated by a Takagi-Sugeno fuzzy linear model using local linearization method.The system states are estimated by a fuzzy linear observer.The fuzzy state feedback suboptimal controller is achieved by minimizing the H-two control performance with a desired H-infinity disturbance rejection constraint.The optimization problem is transformed into two eigenvalue problems(EVP'S)-One for observer and the other for controller.The EVP'S can be solved very efficiently using the linear matrix inequality(LMI) optimization techniques;so it can simplify the design.The closed-loop system designed by the proposed method is locally quadratically stable at equilibrium and its disturbance rejection and dynamic performance are satiefying as well.