ROBUST ADAPTIVE CONTROLLER WITH ZERO RESIDUAL TRACKING ERRORS.

Abstract

The adaptive control of a plant whose dominant part has a transfer function with relative degree n*** equals 1 has been considered in the presence of parasitics and disturbances. A new adaptive law is proposed which guarantees the existence of a large region of attraction from which all signals converge to a small residual set provided the adaptive gains and the magnitude and frequencies of the reference input signal are small compared to the 'speed' of parasitics. In contrast to the adaptive law used by the author previously, the new law guarantees smaller residual tracking errors, which reduce to zero when the parasitics become infinitely fast and the disturbances disappear, provided that a certain design parameter is properly chosen.