Stabilization of a class of non-minimum phase nonlinear systems by dynamic output feedback

The paper deals with the problem of stabilization of nonlinear systems by dynamic output feedback. Let the system be a single input and single output system and have a relative degree. By using center manifold theory and the approximate stability theory, sufficient conditions for stabilization of nonlinear systems by dynamic output feedback are established. Roughly speaking, the main result is that if the zero dynamics is stabilizable according to the N-th order approximation, and the state feedback law is locally uniformly observable, then the nonlinear system is stabilizable by dynamic output feedback. An example of non-minimum phase nonlinear systems is presented to illustrate the utility of the result.