Distributed control design with robustness to small time delays

Recent results by the authors have shown how to construct a class of structured controllers for large scale spatially interconnected systems via linear matrix inequalities. These controllers guarantee that the closed loop interconnected system is well-posed, stable and has H_∞ norm less than unity. Of paramount importance in the control of interconnected systems is the requirement that the stability and performance of the controlled system be robust to arbitrarily small communication delays between subsystems; this amounts to a continuity property. In this paper, it is shown how to realize the structured controllers obtained from the linear matrix inequalities in order to ensure this continuity property for the closed loop system.