Discrete-time multivariable robust model reference adaptive control based on Kp = LDS factorization: an input–output approach

SUMMARY

A direct scheme of robust model reference adaptive control is reinvestigated, in an input–output approach, for a large class of discrete-time multivariable systems with unmodeled dynamics and bounded disturbances. Compared with the existing results, in virtue of a high-frequency gain matrix factorization, the assumptions required in the scheme are further relaxed without overmuch complicating the controller structure, and a permissible range of the gain parameter in a modified adaptive algorithm is clearly specified. Moreover, paralleling the continuous-time theoretic framework, robust stability and robust tracking performance are analyzed by using the multivariable versions of some important technical lemmas, such as an exponentially weighted norm-relation lemma and two swapping lemmas. Copyright © 2012 John Wiley & Sons, Ltd.