Improvement of Convergence for Adaptive Feed-Forward Cancellation Using Variable Gains in a Head Positioning System of Hard Disk Drives

Abstract

We present an enhanced adaptive feed-forward cancellation (AFC) with variable gains to be used in the head positioning control system of a hard disk drive (HDD). The variable gains can help to improve the convergence characteristic of the enhanced AFC after the track seeking control. Therefore, the proposed enhanced AFC can improve the transient response of the head positioning after the track seeking control. The track seeking simulation results from HDDs showed that the proposed control method compensated for the disturbances caused by the repeatable run-out (RRO) and airflowinduced vibration immediately after the track seeking control.

Keywords

• hard disk drive
• repeatable run-out
• non-repeatable run-out
• adaptive feed-forward cancellation
• transient response