Robust D-stability analysis for discrete-time time delay systems via stability radii

This paper considers uncertain discrete-time systems with multiple time delays. The parameter perturbations of concern are time invariant, unstructured or structured. Based on stability radii, stability robustness criteria are derived to keep the eigenvalues inside a disk. Examples show that the proposed results in this paper are less conservative than some of the existing results in the literature. In particular, cases of constrained input systems are addressed. Simulation results indicate that the stability robustness of the system with actuator saturations can be well characterized by the proposed scheme of analysis.