Stability of slow adaptation for non-SPR systems with disturbances

Sufficient conditions are given for the existence of a bounded uniformly asymptotically stable (u.a.s.) solution of the model reference adaptive control system. These conditions, which do not require any matching assumptions or knowledge of the order of the plant, provide an estimate of the region of attraction and a bound on the average squared tracking error for which the u.a.s. property of the solution is preserved.