Output Feedback Global Stabilization for a Class of Nonlinear Systems with Unmodelled Dynamics

We address the output feedback global stabilization problem for a class of nonlinear systems with both output and input driven unmodelled dynamics. The output-dependent nonlinearities are not assumed to satisfy usual growth conditions. The zero-dynamics are not necessarily linear. With the help of the small-gain results recently presented in (Jiang et al., Mathematics of Control, Signals and Systems 1994; 7: 95-120), we design a robust output-feedback nonlinear stabilizer guaranteeing the global asymptotic stability of the zero equilibrium of the closed-loop system.