ADAPTIVE ROBUST-CONTROL OF NONLINEAR UNCERTAIN SYSTEMS

The robust stabilization problem is studied for nonlinear uncertain systems. The nominal system is input-output linearizable. The uncertainty is assumed to be either generalized matching or mismatched. The control design combines differential geometric feedback linearization with the deterministic approach, in which no statistical property of the uncertainty is assumed and used. The only information on the uncertainty, which is needed for the design, is its possible bound. The bound, however, may be unknown; and the (non-adaptive) robust control design based on this information may not be feasible. Adaptive schemes are then adopted to track the bound. Two adaptive robust schemes for the generalized matching and mismatched nonlinear uncertain systems, respectively, are given. A systematic design procedure to deal with mismatched uncertainties is also presented. The adaptive control schemes constructed can be used to replace the previous (nonadaptive) robust controllers in pragmatic applications.