Semi-global Output Regulation of Nonlinear Systems with Nonlinear Exosystems

This paper studies the semi-global output regulation problem for a class of nonlinear systems in the normal form under disturbances generated from nonlinear exosystems. By using a circle criterion and high gain design technique, a new nonlinear internal model is proposed to deal with the nonlinearities of the exosystems and to generate the desired input term for output regulation. It is shown that the proposed partial-state feedback control method ensures the semi-global convergence of the regulated variable.