Decentralized Adaptive Control in the Presence of Multiparameter Singular Perturbations and Bounded Disturbances

The adaptive control of interconnected systems whose subsystems possess slow and fast modes is investigated in the presence of external disturbances. Local filters are introduced to filter the local outputs and an approach is developed for stabilization and tracking using decentralized adaptive controllers. The effects of disturbances, unmodeled interconnections and fast parasitics are examined. In the absence of parasitics all signals converge to a residual set which contains the equilibrium for exact regulation and tracking. The size of this set depends on design parameters, the magnitude of disturbances, the size of interconnections and the characteristics of the reference input signal. In the presence of parasitics global stability properties are no longer guaranteed, but a region of attraction exists from which all signals converge to a residual set.