Development of Optimized Adaptive Feed-Forward Cancellation with Damping Function for Head Positioning System in Hard Disk Drives

This paper presents an adaptive feed-forward cancellation (AFC) technique with a damping function based on optimized AFC. The proposed AFC includes a mechanical resonance characteristic as an internal model that is realized by using the damping function and that achieves the best performance in the frequency domain. This makes it possible to apply the proposed AFC to suppress not only repeatable run-out (RRO) but also non-repeatable run-out (NRRO) of the head positioning system in hard disk drives. Simulation results showed that the proposed AFC can suppress NRRO such as disk flutter vibration and that the stability of the feedback loop was improved by the damping function.