ROBUST INDIRECT ADAPTIVE-CONTROL OF TIME-VARYING PLANTS WITH UNMODELED DYNAMICS AND DISTURBANCES

It is shown that indirect pole-zero placement adaptive controllers are robust for systems with time-varying parameters as well as unmodeled dynamics and disturbances. A parameter estimator with projection is us ed. No special signal normalization is employed to ensure robustness. The nominal system parameters need only be bounded, and their variatio ns need only be small in an average sense. This allows them to Vary sl owly with time, as well as to take large jumps occasionally. The adapt ive controllers can also simultaneously tolerate small unmodeled dynam ics, as well as bounded disturbances, with no restriction on the magni tude of the bound.