Decentralized output tracking via variable gain controllers using observers

In this paper, an asymptotic robust output tracking problem for a large-scale uncertain system is considered. The total system consists of N subsystems with state interactions, and each matrix of the subsystems includes time-invariant matched uncertainties. We propose a design method for variable gain robust decentralized controllers using observers and then give sufficient stabilizability conditions for a total system. A critical feature of the design is that information is not required for the upper bound of matched uncertainties in the system matrix, as well as the input matrix of each subsystem in the design process.