Strict Lyapunov functions for time-varying systems with persistency of excitation

Mohamed Maghenem (1) , Antonio Loria (1)

1 L2S - Laboratoire des signaux et systèmes

We study the stability of the origin for a class of linear time-varying systems with a drift that may be divided in two parts. Under the action of the first, a function of the trajectories is guaranteed to converge to zero; under the action of the second, the solutions are restricted to a periodic orbit. Hence, by assumption, the system's trajectories are bounded. Our main results focus on two generic case studies that are motivated by common nonlinear control problems: model-reference adaptive control, control of nonholonomic systems, tracking control problems, to name a few. Then, based on the standing assumption that the system's dynamics is persistently excited, we construct a time-dependent Lyapunov function that has a negative definite derivative. Our main statements may be regarded as off-the-shelf tools of analysis for linear and nonlinear time-varying systems.

Mots clés: Linear time-varying systems; adaptive control; persistency of excitation

Domaines: Automatique

Mohamed Maghenem, Antonio Loria. Strict Lyapunov functions for time-varying systems with persistency of excitation. Automatica, 2017, 78, pp.274-279. ⟨10.1016/j.automatica.2016.12.029⟩. ⟨hal-01744598⟩