A Robust Adaptive Controller For Linear Time-Invariant Plants With External Disturbances

We present a direct adaptive control algorithm which is robust with respect to external plant disturbances. In the presence of constant disturbances, or time-dependent disturbances which eventually approach a constant, this algorithm ensures that the tracking error approaches zero asymptotically. For general time-varying bounded distances, the (norm of the) tracking error will be asymptotically reduced to a sufficiently small number. Moreover, in the absence of disturbances, the algorithm guarantees zero tracking error.