Robust direct seek control for high-speed rotational optical disk drives

Abstract

This paper presents a new direct seek control scheme (SCS) that provides fast data access capability and robust performance for high-speed rotational optical disk drives (ODD). When a disk is rotated at a high speed to obtain fast data transfer in ODD, the magnitude and frequency of disturbances caused by eccentric rotation of the disk increase in proportion to the rotational speed of the disk. Such disturbances make it almost impossible for the conventional SCS to achieve stable and satisfactory seek performance. We analyze the problems that may arise when the conventional SCS are applied to high-speed rotational ODD and propose a new direct SCS that will solve such problems. In the proposed scheme, a seek control system is designed such that its performance is guaranteed for a set of plants with parameter perturbations. The performance of the proposed SCS are shown by experiments using a 24/spl times/CD-ROM drive.