AFC with Initial Value Compensation for High Precision Positioning for Track-Seek Control in HDDs

In this paper, we proposed an adaptive feed-forward cancellation (AFC) with initial value compensation to improve performance of the magnetic head positioning system of hard disk drives (HDDs). In the track seek control in HDDs, the magnetic head moves from current position to target position. After completion of the movement, the magnetic head should be tracking the target signal as soon as possible. The proposed method can compensate for repeatable run-out called RRO in target signal immediately. The RRO can be observed as fundamental wave and harmonics in the head positioning system. The proposed method can set optimal initial values for every frequency component. In addition, the control system with the proposed method can provide adequate control scheme for different types of RRO known as synchronous RRO, and asynchronous RRO. The effectiveness has been verified in HDD benchmark problem for track-seek control in HDDs.