Quadratically convex combination approach to stability of T-S fuzzy systems with time-varying delay

This paper develops a novel stability analysis method for Takagi-Sugeno (T-S) fuzzy systems with time-varying delay. New delay-dependent stability criteria in terms of linear matrix inequalities for time-varying delayed T-S fuzzy systems are derived by the newly proposed augmented Lyapunov-Krasovski (L-K) functional. This functional contains the cross terms of variables and quadratic terms multiplied by a higher degree scalar function. Different from previous results, our derivation applies the idea of second-order convex combination, and the property of quadratic convex function without resorting to the Jensen's inequality. Two numerical examples are provided to verify the effectiveness of the presented results.