Robust Control of CD-ROM Drives using Multirate Disturbance Observer

Abstract

We have developed a disturbance suppression method for the focusing control system of CD-ROM drives. Our servo system consists of a stabilizing compensator and a disturbance observer called the "multirate distrubance observer". The control system performs multirate sampling using a digital signal processor because this enables it to overcome the limitation in sampling rate. It makes the sampling rate of the disturbance observer longer than that of the stabilizing compensator. We confirmed that this control system can reduce the focusing error caused by disc vibration.