Force Sensor-less Robust Tracking Servo System Suppressing Periodic Disturbance and Sudden Disturbance for Optical Disk System

Abstract

This paper proposes a new force sensor-less robust tracking servo system, which detects and suppresses both the periodic disturbance and the sudden disturbance without force sensor. The proposed system estimates both the periodic disturbance and the sudden disturbance by using a new sudden disturbance observer and the memory of tracking error. In the proposed system, the influence of sudden disturbance is suppressed by the proposed sudden disturbance observer. On the other hand, the influence of periodic disturbance is suppressed by means of ZPET feed-forward servo system, respectively. The experimental results point out that the proposed tracking servo system has a precise tracking response against both the periodic disturbance and the sudden disturbance.