Robust control of linear systems in presence of input saturation and unmodelled dynamics

We give a necessary and sufficient condition for an internal model control structure to be robustly L/sub 2/ stable with respect to H/sub /spl infin// bounded model uncertainty and in presence of input saturation. This condition is used for the design of a controller that is the best H/sub /spl infin// approximation to "perfect" linear control among all controllers guaranteeing L/sub 2/ stability in the presence of actuator saturation.