Abstract
We consider the absolute stability of discrete-time Lurie systems subjected to time-invariant uncertainties. Robust versions of frequency-domain criteria of absolute stability are formulated when the linear part is uncertain. Both parametric and nonparametric cases are considered. New forms of representing the uncertainty which are better suited for the problem under consideration are proposed. The case of fixed-but-unknown time-delay is also studied, and an efficient algorithm is presented for finding the maximum delay while retaining the absolute stability. Examples are given to illustrate the results obtained.
