Global output regulation of a class of nonlinear systems with unknown exosystems

Deals with global output regulation of a class of nonlinear systems using output feedback. The disturbances generated from a unknown linear exosystem are completely compensated. The order of the exosystem is assumed known and the eigenvalues; are distinct. No other assumptions are needed in the control design. This means that the proposed control design is able to completely compensate the disturbances without knowing their amplitudes, frequencies and phases, as long as the number of different frequency components in the disturbances is known. A new formulation of state estimation is introduced to ensure the regulation is a global one with respect to state variables. An adaptive control technique is used to deal with uncertainty in a previously introduced formulation of exosystems. In the proposed control design, a number of control coefficients are made adaptive so that the regulation is global with respect to unknown frequencies in the disturbances