Global Practical Output Regulation of a Class of Nonlinear Systems by Output Feedback

In this paper we solve the global practical output regulation problem for a class of nonlinear systems by dynamic output feedback control. Unlike most of the existing results where the unmeasurable states in the nonlinear vector field can only grow linearly, we allow higher-order growth of unmeasurable states. The proposed controller makes the tracking error arbitrarily small and demonstrates nice properties such as robustness to the disturbances and universality to any continuously differentiable references.