Decentralized output-feedback control of large-scale nonlinear systems based on high-gain multiple time scaling

A globally stabilizing decentralized output-feedback controller is proposed for a general class of nonlinear interconnected large-scale systems. The subsystem interconnections and the dynamics of each subsystem feature both parametric and functional uncertainty. The controller design is based on a general high-gain scaling technique that utilizes arbitrary powers (instead of requiring successive powers) of the high-gain parameter with the powers chosen to satisfy certain inequalities depending on system nonlinearities. The scaling induces a weak-Cascading Upper Diagonal Dominance (w-CUDD) structure on the dynamics and allows relaxation of the cascading dominance assumption on upper diagonal terms. Disturbance attenuation properties of the proposed decentralized controller are also investigated.