Robust adaptive asymptotic tracking of nonlinear systems with additive disturbance

This paper deals with the tracking control of multi-input/multi-output nonlinear systems in the presence of additive disturbances and parametric uncertainties. For such systems, robust adaptive controllers usually cannot ensure asymptotic tracking or even regulation. In this work, under the assumption the disturbances are C2 with bounded time derivatives, we present a C0 robust adaptive control construction that guarantees the tracking error is asymptotically driven to zero. We address this problem for two classes of nth-order nonlinear systems: parametric strict-feedback systems and flat systems. Numerical examples illustrate the main results, including cases where the disturbances do not satisfy the aforementioned assumptions. I