On Lyapunov-Krasovskii methods for event-based control of retarded systems with sampled-data measures, non-smooth feedback, and non-uniform sampling

An event-based controller is here proposed for nonlinear retarded systems. Main novelty with respect to the literature is given by the following facts which here hold contemporarily: 1) control Lyapunov-Krasovskii functionals are used; 2) non-smooth feedbacks are allowed; 3) only sampled-data measures of variables in finite dimensional spaces are necessary; 4) non-uniform sampling is allowed. Practical semiglobal stability is proved, with arbitrarily small final target ball of the origin, under suitably high sampling frequency.