A stable adaptive control design for discrete plants with unmodeled dynamics

This paper presents a simple model reference adaptive control (MRAC) design which maintains stability around the equilibrium of the tracking error in the presence of unmodelled dynamics. Only a weak "a priori" knowledge (namely, upper-bounds of the absolute values of the unmodeled parameters and orders of the unmodeled dynamics) is required for the implementation. The adaptive controller has an additional parameter to prevent the scheme against instability.