The fuzzy Lyapunov function-based relaxed stabilization of output-feedback fuzzy control systems under imperfect premise matching

This paper proposes the relaxed stabilization condition for the output-feedback Takagi-Sugeno (T-S) fuzzy control system. Most of previous papers have used the state-feedback fuzzy controller for the T-S fuzzy model based on parallel-distribution-compensation. However, the state-feedback fuzzy controller is sometimes difficult to be designed when some states are unavailable or inaccessible. This paper introduces the T-S fuzzy control method with the output-feedback fuzzy controller. Furthermore, to reduce the implementation costs caused by the complicated system membership functions, the output-feedback fuzzy controller is designed under the imperfect premise matching. However, the stabilization condition of the output-feedback fuzzy controller under the imperfect premise matching may be conservative. Therefore, for the relaxed condition, the fuzzy Lyapunov function is considered. Finally, the proposed approach is verified by the simulation.