A method for robust regulation of non-mimimum-phase linear systems

The paper discusses a new method for the design of output regulators for a class of nonlinear systems characterized by a possibly unstable zero dynamics. In the case of linear systems, the method is always applicable if controlled plant has a (multiple) zero at the origin and all other zeros with negative real part. If the plant has zeros with positive real part, the method is applicable if the frequencies which characterize the harmonic components of the exogenous input exceed a minimal value determined by the gain needed to solve an auxiliary stabilization problem.