Robust Output Feedback Control for a Class of Nonlinear Systems with Input Unmodeled Dynamics

The robust global stabilization problem of a class of uncertain nonlinear systems with input unmodeled dynamics is considered using output feedback,where the uncertain nonlinear terms satisfy a far more relaxed condition than the existing triangular-type condition.Under the assumption that the input unmodeled dynamics is minimum-phase and of relative degree zero,a dynamic output compensator is explicitly constructed based on the nonseparation principle.An example illustrates the usefulness of the proposed method.