A passive damper for the vibration modes of the head actuator in hard disk drives

As the track density of hard disk drives increases, further improvement in the performance of the read/write head positioning servo system is required. However, the servo performance is limited mainly by the inherent mechanical resonances of the head actuator. Passive damping has the potential to improve the head actuator dynamics. In this paper, a practical passive vibration damper is proposed that is very effective for damping the critical vibration modes of the head actuator. The experimental results from the application of this passive damper to two commercially available hard disk drives are presented. The measured data show that the tracking dynamics of the head actuator can be greatly improved by this passive damper. The vibration induced variation of the flying height is also significantly reduced.