Non-fragile H∞ output feedback control design for continuous-time fuzzy systems

•A non-fragile control design for nonlinear (TS) fuzzy system is studied.•Using a non-quadratic Lyapunov function, a less conservative condition is analyzed.•For an unmeasurable state, a non-fragile observer based controller is synthesized.•Some examples are provided to show the effectiveness of the proposed results.

In this paper, we investigate the problem of non-fragile H∞ fuzzy control design for continuous Takagi Sugeno (T-S) fuzzy systems with uncertainties, external disturbance and unmeasurable state variables. For the case of controller and observer gain additive variations, we propose a new solution of the fragility problem by developing the non-fragile design schemes ensuring the asymptotic stability and H∞ performance for the resulting closed loop systems. By considering a fuzzy Lyapunov function and by introducing slack variables, we propose the new sufficient stabilization conditions formulated in LMI constraints which can be easily solved using the convex optimization tools. The effectiveness the proposed results are illustrated through three numerical examples.