Stable MRAC design for discrete plants with unmodelled dynamics

The paper presents a model reference adaptive control (MRAC) design which maintains stability around the equilibrium of the tracking error in the presence of unmodelled dynamics. Only a slight a priori knowledge in terms of lower and upper bounds for the absolute values of the parameters and orders of the unmodelled dynamics is required. The key to achieving signal boundedness is to use an additional parameter in the adaptive controller which involves the use of the a priori knowledge concerning the unmodelled dynamics.