Robust H_∞ control for uncertain systems with time-varying delay

Based on the quadratic stability theory, the problem of robust H_∞control for time-delay systems with time-varying uncertainties was dealt with by using the linear matrix inequality approach. A sufficient condition for the systems to be quadratically stable with an H_∞-norm bound γ was presented for all admissible uncertainties. By solving a linear matrix inequality, the H_∞ state feedback controller was obtained.