Simulation of Position Error Signal Degradation Due to Operational Vibration for Hard Disk Drives in a Storage Server Box

Eguchi, Takehiko

doi:10.1109/tmag.2009.2029646

Cited by 4 publications

(1 citation statement)

References 5 publications

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“…However, the mechanical characteristics limit the servo bandwidth, and the disturbances exist in a wide frequency range (Atsumi et al, 2006;Atsumi and Messner, 2012b). The positioning errors caused by external vibrations below 1 kHz are also critical issues for HDDs (Eguchi, 2009). As a result, the servo bandwidth of HDDs has to be increased with the increasing track density of HDDs.…”

Section: Introductionmentioning

confidence: 99%

Flying-height and tracking-position controls with thermal-positioning actuator in hard disk drives

Atsumi

2017

JAMDSM

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To improve positioning accuracy of a magnetic head in hard disk drives (HDDs), a triple-stage-actuator system was developed with a thermal-positioning actuator for a magnetic-head-positioning system. This positioning system has three types of actuators: a voice coil motor (VCM), piezoelectric (PZT) actuators, and the thermal-positioning actuator. In this system, a magnetic head has a heater located in a horizontal direction of read/write elements as the thermal positioning actuator. By using this structure, the control system can move the position of read/write elements of the magnetic head in a horizontal direction with thermal expansion induced by the heater with an electric current. The thermal-positioning actuator is good for control in high frequency range because it has little adverse effect caused by mechanical resonances. As a result, the triple-stage-actuator system enable us to improve the positioning accuracy during a track-following control from conventional dual-actuator systems. However, the thermal-positioning actuator causes flying-height fluctuations of the magnetic head that may lead to worsening of magnetic recording performances. In HDDs, the magnetic head has another heater located in a vertical direction of read/write elements in order to control flying height of the read/write elements. This control system is called thermal flying-height control system. To compensate for the flying-height fluctuations of the magnetic heads caused by the thermal-positioning actuator, this paper presents a magnetic-head-positioning system that employs a feedforward control scheme on the thermal flying-height control system. Simulation results showed that the proposed method was able to compensate for the flying-height fluctuations during the track-following control by about 90 %.

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Section: Introductionmentioning

confidence: 99%