Gap metric robustness of adaptive controllers for a class of nonlinear systems

We consider the construction of adaptive controllers for a class of nonlinear systems which achieve non-zero robustness margins in the sense of the L^∞[0, ∞) gap metric. The gap perturbations may be more constrained for larger disturbances and for larger parametric uncertainties. The class of plants considered has nonlinearities within the span of the control and the nonlinearities have known polynomial growth.