Relaxed sufficient conditions for the stability of continuous and discrete-time linear time-varying systems

This paper states new sufficient conditions for the uniform asymptotic stability of linear time-varying (LTV) systems. The approach proposed derives and uses the notion of perturbed frozen time (PFT) form that can be associated to any LTV system. Exploiting the Bellman-Gronwall lemma, relaxed stability conditions are then stated in terms of "average" parameter variations. Numerical comparisons with other methods are reported.