Aerodynamic Pressure Fluctuations Associated With Flow-Induced Vibration of the Head Gimbals Assembly Inside a Hard Disk Drive

Min, Hequn; Huang, Xiaoyang; Zhang, Qide

doi:10.1109/tmag.2011.2169419

Cited by 11 publications

(8 citation statements)

References 20 publications

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“…The distance between two adjacent tracks (track pitch) is about 100 nm in current HDDs. Positioning the READ/WRITE head precisely over a track is a considerable challenge because of the wideband disturbances in the system, such as spindle runout, slider vibration, and thermal drift and windage [2], and the servo bandwidth that is limited by the mechanical characteristics of the actuators [3]. The bit error rate increases if the head cannot follow the data track during the reading process; the head will miswrite or erase other tracks if it is not located on the right track during the writing process.…”

Section: Hard Disk Drive Servo System Based Onmentioning

confidence: 99%

Hard Disk Drive Servo System Based on Field-Programmable Gate Arrays

Xiong

Bogy

2014

IEEE Trans. Ind. Electron.

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Servo systems are essential components of current magnetic storage hard disk drives (HDDs). In this paper, we demonstrate a novel servo scheme using a field-programmable gate array (FPGA). Adjacent magnetic tracks with two different frequencies are recorded on the magnetic disk and are used as servo tracks to encode the position information. A discrete Fourier transform is employed to decode the magnetic head position and to obtain the position error signal (PES). The PES is defined in terms of the difference of the magnitudes of the two frequencies. The relationship between the displacement and the PES is obtained by offline calibration. A real-time signal acquisition and processing system using a commercial FPGA, analog-to-digital converter chips, and digital-to-analog converter chips is built to do the high-speed spectrum analysis and generate the PES. The PES is transmitted to a laboratory virtual instrument engineering workbench (LabVIEW) real-time control target to implement the control algorithm. The computed control output from the real-time control target is amplified to drive a piezoelectric stage, which moves the magnetic head along the radial direction to compensate for the position error. A simple repetitive and proportional-integral-derivative control algorithm is implemented for head positioning and to verify this new servo scheme in this paper. With the controller, most of the major disturbances, such as the harmonics of the spindle runout, have been effectively attenuated compared with an open-loop control scheme.Index Terms-Field-programmable gate arrays (FPGAs), hard disks, servo systems.

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Section: Hard Disk Drive Servo System Based Onmentioning

confidence: 99%

Hard Disk Drive Servo System Based on Field-Programmable Gate Arrays

Xiong

Bogy

2014

IEEE Trans. Ind. Electron.

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“…Vibration of a head gimbals assembly (HGA) induced by high speed circumferential airflows in working hard disk drives (HDDs) limits the positioning accuracy of slider magnetic head on the HGA tip, and is therefore receiving much attention associated with the development of high magnetic storage density in disks, such as 10 Tb/in 2 . Aerodynamic pressure fluctuation around the HGA plays an important role in the flow-induced vibration (FIV) on the HGA [1]. Passive methods such as modification on the HDD inner structures have proved to be difficult for the fine control on this issue [2].…”

Section: Introductionmentioning

confidence: 99%

Feedback Control of Flow-Induced Vibrations on Head Gimbals Assembly Inside Hard Disk Drives

Xiao

Min

Zhang

2013

Fluid-Structure-Sound Interactions and Control

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“…High speed flows in working hard disk drives (HDDs) can induce off-track vibration of a head gimbals assembly (HGA), which limits positioning accuracy of the slider magnetic head on the tip of the HGA for the future 10 Tb/in 2 magnetic storage density. Passive methods such as HDD interior geometry modifications have been applied to control such HGA flow-induced vibration, but seem hard for further fine control to meet the super-high slider positioning accuracy demand in swift growth of storage density [1,2]. Active control methods may be good alternative for this bottleneck.…”

Section: Introductionmentioning

confidence: 99%