Stabilization of discrete-time linear systems subject to input saturation and multiple unknown constant delays

In this technical note, we study the semi-global stabilization of general linear discrete-time critically unstable systems subject to input sat- uration and multiple unknown input delays. Based on a simple frequency- domain stability criterion, we find upper bounds for delays that are in- versely proportional to the argument of open-loop eigenvalues on the unit circle. For delays satisfying these upper bounds, linear low-gain state and fi- nite dimensional dynamic measurement feedbacks are constructed to solve the semi-global stabilization problems.