Robust output asymptotic stabilizability and smooth control design

The problem of strong output asymptotic stabilization of uncertain nonlinear systems is studied. It is shown that the class of uncertain systems with nonvanishing uncertainty is not stabilizable under any continuous control and that, for a cascaded systems, strong output asymptotic stabilization calls for smoothness of both system dynamics and robust control. Smoothness of robust control can be pursued by a new design which is based on bounding functions on both uncertainty´s magnitude and the rate of change. Better performance under the new uniformly continuous robust control is demonstrated