Stability analysis and observer-based controllers design for T-S fuzzy positive systems.

This paper investigates the stability analysis and observer-based controllers design for T-S fuzzy positive systems. A fuzzy copositive Lyapunov function is first proposed to analyze the stability of the T-S fuzzy positive systems via linear programming. In terms of the property of the fuzzy membership functions, the fuzzy copositive Lyapunov function is employed to derive the less conservative stability conditions. Then, the line-integral Lyapunov function is presented for the stability analysis. The time-derivatives of the membership functions do not appear in the stability analysis of the T-S fuzzy positive systems, therefore, the proposed stability conditions are more relaxed than those of the conventional Lyapunov function approaches. Based on the obtained stability conditions, observer-based control schemes are designed such that the resultant closed-loop systems are both stable and positive. Finally, two examples are provided to validate the effectiveness of the results proposed in this paper. (C) 2017 Published by Elsevier B.V.