A New Design of Plug-In Adaptive Controller for Rejection of Periodic Disturbances

A new adaptive controller for rejecting periodic disturbances is proposed. The controller is constructed in a plug-in manner, i.e., it can be added to an existed feedback control system without altering the original closed-loop configuration. It is shown that the controller can reject disturbances at selected frequencies independently. Furthermore the proposed design method of the plug-in adaptive controller is based on linear control theory although the closed loop system includes the adaptive algorithm as nonlinear operator.