Stabilization for Feedforward Systems with Delay in the Input

We solve a family of uniform global asymptotic stabilization problems for time varying feedforward systems with a delayed input. Our solution relies on a time-varying change of coordinates and Lyapunov-Krasovskii functionals. It applies under any given constant delay, and provides controllers of arbitrarily small amplitude. We also prove input-to-state stability with respect to additive disturbances on the controllers under certain bounds on the disturbances. We demonstrate our work using a tracking problem for a model that is suitable for high level formation flight of unmanned air vehicles.