H-infinity controller design for uncertain multiple-time-delay systems

In this dissertation, H-infinity controller design for systems withmultiple uncertain time-delays is studied. In the H-infinity controllerdesign for these systems, since the nominal time-delays are takenoutside the generalized plant, the uncertainty block of the overallsystem may become non-causal. However, the H-infinity controller isdesigned by the small-gain theorem, which assumes the causality ofthe feedback interconnected subsystems. To alleviate thisdifficulty, the sufficient conditions are derived to satisfy thevalidity of the small-gain theorem for feedback interconnection ofnon-causal systems. Utilizing these results, an optimal H-infinity flowcontroller is designed for data-communication networks. Stable H-infinitycontroller design is also studied and different design approachesare presented. Furthermore, to satisfy one of the time-domainrequirements of the flow controller, sufficient conditions areintroduced to choose the free parameter in the structure of thedesigned controller.