Robust Feedforward Tracking Control Suppressing Harmonics Disturbance and DC Offset for Optical Disk Recording System

This paper proposes a new robust feedforward tracking control system suppressing tracking error including harmonics disturbance and DC offset for optical disk recording system. The proposed tracking control system consists of triple compensation loops of tracking error which are the robust feedback control loop, a new harmonics disturbance suppression loop based on Zero Phase Error Tracking(ZPET) feedforward control and a new additional DC offset compensation loop. The feedback controller is the most inner loop which is based on the high gain servo system. The harmonics disturbance suppression loop based on ZPET control is the middle loop which suppresses the influence of many periodic disturbances. The final outer loop is a new additional DC offset compensation loop which suppresses the DC offset caused by ZPET feedforward control. The experimental results point out that the proposed system well realizes the fine tracking performance for optical disk recording system.