Title :
Identification of contributors to HDD servo errors by measuring PES only
Author :
Yang, Hyun Seok ; Jeong, Jun ; Park, Cheol Hoon ; Park, Young-Pil
Author_Institution :
CISD, Yonsei Univ., Seoul, South Korea
fDate :
3/1/2001 12:00:00 AM
Abstract :
In this paper, disturbances, the source of TMR being the barrier to high track density of HDD are analyzed quantitatively using PES only without extra sensors. Disturbances are separated into RRO and NRRO, then, NRRO is separated into input torque disturbance, output disturbance, and noise. The effect of each disturbance on PES is compared. It is shown that PES NRRO measured in open-loop and in closed-loop can be used to calculate sensitivity transfer function. Using separated disturbances, PSD of PES RRO and NRRO are predicted for various gain levels in track following servo, and they are compared with PSD of PES measured in experiments. We propose that this can be used to predict servo performance accurately. Also addressed are some discussions on the differences between this work and the former contributing work
Keywords :
disc drives; hard discs; position control; servomechanisms; torque; transfer functions; HDD servo errors; NRRO; PES; RRO; closed-loop measurement; gain levels; input torque disturbance; noise; nonrepeatable run-out; open-loop measurement; output disturbance; position error signal; repeatable run-out; sensitivity transfer function; separated disturbances; track density; track following servo; Acoustical engineering; Density measurement; Gain measurement; Hardware; Noise measurement; Predictive models; Rail to rail outputs; Servomechanisms; Torque; Transfer functions;
Journal_Title :
Magnetics, IEEE Transactions on
