Output regulation for a class of nonlinear systems with unknown sinusoidal disturbances

A stabilizable nonlinear system in output feedback form subject to unknown sinusoidal disturbances generated by an unknown linear exosystem is considered: only an upper bound on the exosystem’s order is supposed to be known. A nonlinear output error feedback control is designed to achieve output regulation. An application to a mechanical system is presented to illustrate the effectiveness the proposed control technique.