Decentralized output feedback control of large-scale nonlinear systems interconnected by unmeasurable states

This paper studies the problem of global decentralized control by output feedback for large-scale uncertain systems whose subsystems are interconnected not only by their outputs but also by their immeasurable states. We show that under a linear growth condition, there is a decentralized output feedback controller rendering the closed-loop systems globally exponentially stable. This is accomplished by extending the output feedback domination design (C. Qian and W. Lin, 2002) that only needs little information of the nonlinear systems. A time-varying output feedback controller is also constructed for the large-scale systems with unknown parameters.