On observer-based controller design for Sugeno systems with unmeasurable premise variables

This paper considers the design of observer-based controller for a class of continuous-time nonlinear systems presented by Takagi-Sugeno (T-S) model with unmeasurable premise variables. This T-S structure can represent a larger class of nonlinear systems as compared to the measurable premise variable case but its analysis is more complicated. To reduce the design complexity, a common output model for subsystems is employed by the use of local nonlinear rules. As a result, the proposed T-S structure reduces the number of rules in the Sugeno model as well as the analysis complexity. The proposed controller guarantees exponential convergence of states based on the fuzzy Lyapunov function analysis and Linear Matrix Inequality (LMI) formulation. Simulation results illustrate effectiveness of the proposed method.