Robust control of strict- and output-feedback systems with input unmodeled dynamics

Applies dynamic nonlinear damping to two classes of nonlinear systems: the strict-feedback systems where unmodeled dynamics affect all the “virtual inputs,” and the output-feedback systems where the input unmodeled dynamics prevent the design of an exponentially converging observer. For both classes of systems the authors achieve global asymptotic stability when the unmodeled dynamics are “small”