Active control of a two-stage active vibration isolation system with online secondary path modeling

A new adaptive active control strategy with online secondary path modeling is proposed and applied in two-stage active vibration isolation system. Compared with existing algorithms, the proposed method doesn´t need feeding extra noise to the secondary source. Instead, the facts that the FIR filters have coefficient vectors equivalent to impulse responses corresponding to the transfer functions of physical systems are utilized, and when the coefficients of the control filter are updated, the filter coefficient vectors are different at different iteration steps because of estimation errors. Furthermore, in the method, the modeling of the secondary path is relatively independent of the active noise control system, and the reference signal is used as the input for the system identification. Therefore, the unwanted disturbances between the operation of the ANC controller and the identification of the secondary path are eliminated completely, and the complexity of ANC system is greatly reduced. Active control simulations by using the proposed method are conducted, and the results show good vibration reduction and strong robust.