Robust Decentralized Controller Design for Descriptor-type Systems with Distributed Time Delay

Robust decentralized controller design is considered for linear time-invariant large-scale descriptor-type systems with distributed time delay which are composed of overlapping subsystems. A robustness bound, that accounts for the interactions among the subsystems and for modeling uncertainties both in the subsystem models and the interactions, is derived using overlapping decompositions and expansions. A robust decentralized controller design approach using this bound is then proposed. Once the robustness bound is derived, the proposed approach is decoupled for each subsystem and, for each subsystem, it is based on a local nominal model, which is also derived using overlapping decompositions and expansions. Satisfying a simple condition, involving the derived robustness bound, however, guarantees the robust stability of the overall actual closed-loop system.