Improved results on robust H∞ control of uncertain discrete-time systems with time-varying delay
Improved Results on Robust H∞ Control of Uncertain Discrete-time Systems with Time-varying Delay

In this paper, the robust H ∞ control problem for uncertain discrete-time systems with time-varying state delay is considered. Based on the Lyapunov functional method, and by resorting to the new technique for estimating the upper bound of the difference of the Lyapunov functional, a new less conservative sufficient condition for the existence of a robust H ∞ controller is obtained. Moreover, the cone complementary linearisation procedure is employed to solve the nonconvex feasibility problem. Finally, several numerical examples are presented to show the effectiveness and less conservativeness of the proposed method. This work was supported by National Natural Science Foundation of China (No. 60850004). Yong-Gang Chen received his B. Sc. and M. Sc. degrees from the College of Mathematics and Information at Henan Normal University, Xinxiang, PRC, in 2003 and 2006, respectively. He is currently a faculty member of Henan Institute of Science and Technology, PRC. His research interests include time-delay systems, neural networks, and robust control. Wen-Lin Li received his M. Sc. degree from the Department of Mathematics at Shandong Normal University, Jinan, PRC, in 1982, and Ph.D. degree in automatic control engineering at Beihang University, Beijing, PRC, in 1993. He is currently a professor with the College of Mathematics and Information Science at Henan Normal University, PRC. His research interests include variable structure control, fuzzy control, time-delay systems, and chaos synchronization control.