Decentralized robust control for a class of large-scale nonlinear systems

Decentralized robust control for a class of large-scale nonlinear systems with strong nonlinear interconnections is considered. Large-scale nonlinear systems transformable to the extended decentralized strict feedback form are considered. Each subsystem contains asymptotically stable appended dynamics and it is allowed to enter into the chain of integrators affinely via unknown nonlinearities. The interconnections are assumed to be bounded by nonlinear functions of the states. The uncertainties in the subsystem include both unknown parameters and unstructured dynamics. A novel robust adaptive controller is designed to achieve robust stability in the presence of unknown parameters and unstructured dynamics. It is shown that global asymptotic regulation of partial states and global uniform boundedness of the remaining states are guaranteed utilizing partial state feedback. An illustrative example is provided to demonstrate the proposed control design methodology