Design of a feedforward control system considering dead time for optical disc systems

Abstract

Recently, the data size of digital content has increased. In order to cope, manufacturers have tried to increase capacity by narrowing the track pitch of digital storage media. In addition, recent advancements in technology have resulted in a new optical disc that has a rotation speed of over 15,000 rpm. Considering all these factors, a high-precision pick-up control system is needed for optical discs. In this study, a feedforward control system using an error prediction mechanism to effectively suppress periodic components is implemented. However, the feedforward control system of a conventional pick-up control system does not consider the dead time delay component. This paper proposes a zero phase error tracking feedforward control system that does consider it. The propose control system is designed and implemented for a test system, the ODU-1000 for Blu-ray Disc, implanted in a digital signal processor (DSP). The results of experiments confirm that the propose system is practical and effective.