Robustness of a simple indirect continuous time adaptive controller in the presence of bounded disturbances

A new result on the robustness of an indirect continuous adaptive controller using just estimator projection is reported. It is shown that, for arbitrarily bounded disturbances, global stability is ensured without any assumption on signals. Moreover, the robust adaptive controller can still retain the properties that earlier unmodified conventional adaptive controllers have when there is no disturbance. The a priori knowledge for the implementation of the simple adaptive controller is the (large) ranges of unknown parameters in the nominal system model