Robust global stabilization with input unmodeled dynamics: an ISS small-gain approach

Addresses the global asymptotic stabilization of nonlinear systems in the presence of unmodeled dynamics appearing at the input. The unmodeled dynamics are restricted to be minimum-phase and relative degree zero. On the basis of nonlinear small-gain arguments, we design a static feedback control law to achieve global asymptotic stabilization. In the absence of full state information an observer-based control design is developed