Delay-range-dependent robust H∞ control for uncertain discrete stochastic fuzzy time-delay systems via relaxed LMIs

Through free-weighting matrix and relaxed LMI approach, this paper deals with the problem of robust H
_infin
control for uncertain discrete stochastic fuzzy systems with interval time-varying delays. The uncertainties are time-varying but norm-bounded. The purpose is to design a state feedback fuzzy controller such that the resulting closed-loop system is not only robustly stochastically stable but also with a disturbance attenuation level lambda. Based on Takagi-Sugeno (T-S) fuzzy model, a delay-dependent sufficient condition for the solvability of the problem is obtained by utilizing a proper Lyapunov functional.