SOME NEW RESULTS ON STABILITY ROBUSTNESS OF 2-DIMENSIONAL DISCRETE-SYSTEMS

In this paper, we study the problem of stability robustness of two-dim ensional discrete systems in a local state-space setting. Two methods are proposed for efficient numerical evaluation of the exact complex p erturbation bound nu. The first method combines Byers' bisection metho d with a three-point-pattern optimization technique to compute nu. The second method utilizes a direct optimization technique to find the bo und. In addition, a 2-D Lyapunov approach is proposed to obtain two lo wer bounds of nu, and numerical techniques for solving the constant 2- D Lyapunov equation involved are presented. The paper is concluded wit h an example illustrating the main results obtained.