ADAPTIVE CONTROL SYSTEM WITH EFFICIENTLY CONSTRAINED ADAPTATION

An adaptive control system implements a back-projection technique to limit adaptation of adaptive parameters in the system so that system actuators are not driven beyond desired physical limitations. When the optimal controller solution lies outside of a desired region in the parameter space, chosen in accordance with the physical limitations of the system, adaptation is back-projected onto or near a smooth convex surface defining the edge of the desired region. Adaptation is preferably normalized to improve adaptation convergence. Back-projection is preferably compensated in accordance with adaptation normalization to facilitate convergence. To lessen computational burdens, adaptation and/or back-projection is accomplished in accordance with a time-sharing technique in which orthogonal components are separately processed. The technique can be implemented in tonal control systems, and in systems capable of controlling non-periodic disturbances.