On detuned model reference adaptive control: Robustness improvement via high gain design

In this paper an adaptive algorithm that attempts to match a reference model at low frequencies, but not at high frequencies, (i.e. detuned model reference adaptive controller (DMRAC)) is studied. The DMRAC is implemented combining an adaptive observer-like controller with a non-adaptive high gain design. The observer controller structure insures good disturbance rejection properties and the high gain controller is included to enhance robustness to unmodeled dynamics. Guidelines are given for the choice of a design parameter to carry the former tradeoff. A complete global stability analysis is given.