ADAPTIVE ROBUST-CONTROL OF NONLINEAR UNCERTAIN SYSTEMS

The robust stabilization problem is studied for nonlinear uncertain sy stems. The nominal system is input-output linearizable. The uncertaint y is assumed to be either generalized matching or mismatched. The cont rol design combines differential geometric feedback linearization with the deterministic approach, in which no statistical property of the u ncertainty is assumed and used. The only information on the uncertaint y, which is needed for the design, is its possible bound. The bound, h owever, may be unknown; and the (non-adaptive) robust control design b ased on this information may not be feasible. Adaptive schemes are the n adopted to track the bound. Two adaptive robust schemes for the gene ralized matching and mismatched nonlinear uncertain systems, respectiv ely, are given. A systematic design procedure to deal with mismatched uncertainties is also presented. The adaptive control schemes construc ted can be used to replace the previous (nonadaptive) robust controlle rs in pragmatic applications.