Reliable stabilization with integral action in decentralized control systems

Reliable stabilization with integral action is studied in the linear, time-invariant, multi-input, multi-output, two-channel decentralized control system, where the plant is stable. The objective is to achieve closed-loop stability when both controllers act together and when each controller acts alone. Necessary and sufficient conditions are obtained for existence of block-diagonal decentralized controllers that ensure reliable stabilization and integral action. All decentralized controllers with integral action that provide reliable stabilization are characterized.