AN ADAPTIVE FEEDFORWARD CONTROLLER FOR REJECTION OF PERIODIC DISTURBANCES

The issue of rejecting periodic disturbances arises in various applica tions dealing with rotating machinery. A novel adaptive feedforward co ntroller (AFC) design method for rejecting periodic disturbance is pro posed. It can be added to an existing feedback control system without altering the original closed loop characteristics, such as the stabili ty margin and transfer functions. An adaptive algorithm derived for th e proposed controller based on the steepest gradient descent method tu rns out to be identical to the popular delayed-x LMS algorithm. A numb er of computer simulations were carried out to demonstrate the salient features of the proposed AFC compared to the conventional one. The pr oposed method can be useful for control engineers in designing an adap tive feedforward controller for the rejection of the periodic disturba nces. (C) 1997 Academic Press Limited.