Input-to-state stabilization of linear systems with quantized feedback

We consider the problem of achieving input-to-state stability (ISS) with respect to external disturbances for control systems with linear dynamics and quantized state measurements. Quantizers considered in this paper take finitely many values and have an adjustable "zoom" parameter. Building on an approach applied previously to systems with no disturbances, we develop a control methodology that counteracts an unknown disturbance by switching repeatedly between "zooming out" and "zooming in". Two specific control strategies that yield ISS are presented. The first one is implemented in continuous time, while the second one incorporates time sampling. We discover that in the presence of disturbances, time-sampling implementation requires an additional modification which has not been considered in previous work.