Adaptive Learning Control Method for Optical Disk Drive Tracking Control

Abstract

In response to the recent demand for high-density recording on an optical disk, the industry is now “going narrow track”. We have developed an adaptive learing control method capable of changing its learning according to track correlation, thus making it possible to avoid unnecessary learning during equipment vibration to avoid the lack of stability that is a problem for learning control, and to increase follow-up ability. As a result we have confirmed that track-error can be reduced to the equivalent noise level (0.1μm) and that stabilized operation with repetitive learning control system is possible.