Robust stability analysis of time-delay systems using parameter-plane and parameter-space methods

In this paper, parameter-plane and parameter-space methods are applied for robust stability analysis of time-delay systems expressed by time-domain models. The relations among the parameters in time-domain matrices and those in s-domain characteristic equations are analyzed. A general rule for choosing the desirable elements in matrices as parameters is proposed. The advantages of the methods are illustrated by examples, and comparisons with two other methods in the current literature are made.