Functional observer–controller method for unmeasured premise variables Takagi-Sugeno systems with external disturbance

Abstract

A functional observer–controller design problem of Takagi-Sugeno fuzzy systems with unmeasured premise variables and external disturbance is investigated in this paper. First, robust state feedback controller is designed based on a relaxed fuzzy Lyapunov approach. With an estimation membership functions of transformation technique, a fuzzy functional observer is introduced to estimate the unmeasured premise variables and system control input. By using a robust separation principle, the observer and controller errors system is proved to be stable and robust to external disturbance. Finally, the estimation and control effects of the proposed method are verified through several engineering examples.