Damping effect on precise track following for nano-motion actuator

In the near future magnetic recording system, it is prospected that the allowable tracking error must be less than 8.5 nm for a high areal density over 600 Gbit/in² for HDD (Hard Disk Drive). In such a small dimension of tracking, a servo system becomes required even for a spin-stand system to make stable tracking and evaluation to avoid influence of mechanical disturbance. We have introduced a nano-meter positioning actuator with a high servo bandwidth for a conventional spin-stand stage. The actuator was required a large working-distance over 10 mum and a high resonance frequency for a positioning resolution less than 0.5 nm. However, our designed and produced actuator had high peak amplitude that reached to about 40 dB at the resonance. We introduce a new damping mechanism for the precise positioner for the nano-meter positioning actuator for the spin-stand system. Since the damping mechanism reduces the resonance peak of amplitude down to 2.5%, the servo bandwidth can be expanded to fifteen times as large as damper-less system