On the stability of linear systems with uncertain delay

This paper focuses on the stability of some class of delay systems including uncertainty in the delays. More precisely, we are interested in guaranteeing the stability of perturbed delay systems by assuming the stability of the nominal system. If the delay perturbation is constant, necessary and sufficient conditions axe derived in terms of generalized eigenvalue distribution of some (finite-dimensional) constant matrix pencil. If the delay perturbation is time-varying, some sufficient stability conditions are derived using ´exact´ Lyapunov-Krasovskii functionals.