Perfect Tracking Control System with Prediction State Observer for Next-Generation Optical Disks

Recently, the capacity of optical disk recording systems has been increasing. Optical disk drive systems must realize high-precision tracking control. For this purpose, we previously proposed a tracking control system that is composed of both a robust feedback controller and a zero-phase-error feedforward tracking controller. The proposed feedforward tracking control system effectively suppresses the tracking error caused by track eccentricity. However, it is sometimes difficult for conventional feedforward tracking control systems to realize higher precision in their tracking control. Hence, in this paper we propose a new perfect tracking control (PTC) system with a prediction state observer for next-generation optical disks. The experimental results confirm that the proposed system suppresses the tracking error at a disk rotation speed of 8000 rpm. Therefore, the proposed system realizes high-precision tracking control.