UGAS of nonlinear time-varying systems: a delta-persistency of excitation approach (original) (raw)

We study the problem of stability analysis for certain nonlinear systems. Our contributions are new tools to guarantee uniform global asymptotic stability (UGAS) of nonlinear time-varying (NLTV) systems. Firstly, we provide new de nitions of persistency of excitation (PE). In particular, we g i v e here a new de nition of uniform -PE (u -PE) which, though conceptually equivalent to the original one introduced 7], is mathematically less conservative. We also provide with some properties of -PE pairs and contribute with a result which establishes UGAS of NLTV systems under u -PE.