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Disturbance suppression beyond Nyquist frequency in hard disk drives

Takenori Atsumi
2010 Mechatronics (Oxford)  
In conventional hard disk drives, a control system compensates for vibration in which the frequency is higher than the Nyquist frequency by using a multi-rate filter that decreases the gain above the Nyquist  ...  When the method was applied to the head-positioning system of a hard disk drive, the experimental results showed that the control system suppressed disturbances above the Nyquist frequency.  ...  The control system in conventional hard disk drives compensates for these vibrations by using a multi-rate filter that decreases the gain above the Nyquist frequency [Weaver et al. (1995) ].  ... 
doi:10.1016/j.mechatronics.2009.06.002 fatcat:4qhc7fcjp5cwzbx353mjhqnipy

Track-following Control Using Resonant Filter in Hard Disk Drives

Takenori Atsumi, Atsushi Okuyama, Masahito Kobayashi
2007 American Control Conference (ACC)  
With this method, the control engineers can easily design and implement a controller to suppress the disturbances in head-positioning systems at a specific frequency by adding digital filters.  ...  Our experimental results show that the proposed method can greatly suppress the nonrepeatable runout and repeatable runout above the servo bandwidth.  ...  In head-positioning control of hard disk drives, the control system can decrease the vibrations at frequencies within the servo bandwidth.  ... 
doi:10.1109/acc.2007.4282597 dblp:conf/acc/AtsumiOK07 fatcat:zlh7nu5d2zc7zcsgqwu5gil5zm

Track-Following Control Using Resonant Filter in Hard Disk Drives

Takenori Atsumi, Atsushi Okuyama, Masahito Kobayashi
2007 IEEE/ASME transactions on mechatronics  
With this method, the control engineers can easily design and implement a controller to suppress the disturbances in head-positioning systems at a specific frequency by adding digital filters.  ...  Our experimental results show that the proposed method can greatly suppress the nonrepeatable runout and repeatable runout above the servo bandwidth.  ...  In head-positioning control of hard disk drives, the control system can decrease the vibrations at frequencies within the servo bandwidth.  ... 
doi:10.1109/tmech.2007.901944 fatcat:72agi2ut55frjgth5o6ay6qprq

HDD Servo Control Technologies - What we have done and where we should go -

Takashi Yamaguchi, Takenori Atsumi
2008 IFAC Proceedings Volumes  
Since 1986 when digital servo was introduced in mass production HDDs, various kinds of control theories have been applied to HDD servo system, and the performances had improved dramatically.  ...  been required in HDD servo system to achieve the capacity increase.  ...  HARD DISK DRIVE Hard disk drive (HDD) Figure 2.1 shows a photo of HDD.  ... 
doi:10.3182/20080706-5-kr-1001.00141 fatcat:dh6ri6t42zfftdx764lt43i54u

Vibration control with thin-film-coil actuator for head-positioning system in hard disk drives

Takenori ATSUMI, Kenji SUZUKI, Shigeo NAKAMURA, Mutsuro OHTA
2015 Journal of Advanced Mechanical Design, Systems, and Manufacturing  
because it can be easily excited by operational vibrations of other hard disk drives in a datastorage server.  ...  In a head-positioning system of hard disk drives, various mechanical resonances may degrade performance or stability of the control system.  ...  system in hard disk drives actuator for moving a suspension of the HSA, and the third stage is the film actuator to control the torsional mode of the HSA.  ... 
doi:10.1299/jamdsm.2015jamdsm0010 fatcat:227q4usxpvd4hbnl43kda332oe

Head-Positioning Control Using Virtual Resonant Modes in a Hard Disk Drive

Takenori ATSUMI
2007 Journal of Advanced Mechanical Design, Systems, and Manufacturing  
In conventional control systems in hard disk drives, it is difficult to compensate for disturbances above the primary mechanical resonance.  ...  In this paper, a design method that uses a virtual resonant mode in head-positioning systems of hard disk drives was developed.  ...  In the head-positioning control of hard disk drives, the control system can decrease the vibrations at frequencies within the servo bandwidth.  ... 
doi:10.1299/jamdsm.1.408 fatcat:4f3wjsl6qbhopm6h5yb54cibbe

Enhanced Vibration Suppression in Hard Disk Drives Using Instrumented Suspensions

Sarah Felix, Jianbin Nie, Roberto Horowitz
2009 IEEE transactions on magnetics  
This paper summarizes work that has been completed to evaluate the use of high-resolution thin-film strain sensors for vibration suppression in hard disk drives (HDDs).  ...  Index Terms-2 control, hard disk drive servos, multisensor systems, piezoelectric thin films.  ...  ACKNOWLEDGMENT This work was supported in part by the National Science Foundation under Grant CMS-0428917, the Information Storage Industry Consortium, and the Computer Mechanics Laboratory, University  ... 
doi:10.1109/tmag.2009.2029635 fatcat:cal7v66li5amjd3zzsl45un2ea

Unobservable Settling Vibration on Head-Positioning Control in Hard Disk Drives

Takenori Atsumi, William C. Messner
2011 IFAC Proceedings Volumes  
In this paper, we study the unobserved vibrations of the head in hard disk drives which may lead to destruction of user data.  ...  These phenomena are confirmed through the experiments using the actual head-positioning system of the hard disk drive.  ...  INTRODUCTION In a head-positioning system of a hard disk drive (HDD), the controlled variable is a head-position signal, which is generated by reading special magnetic patterns embedded in the disks.  ... 
doi:10.3182/20110828-6-it-1002.01000 fatcat:27777i5crjg2zbaqyeewr4hcne

A Design Method of a Full Closed Loop Sampled Servo Control for Hard Disk Drive

Takashi YAMAGUCHI, Takenori ATSUMI
2008 SICE Journal of Control Measurement and System Integration  
A servo control of hard disk drive (HDD) achieves 3-4 ms fast access and nanoscale positioning accuracy.  ...  of feedback control to have better sensitivity, and multi-rate filter design to suppress disturbances above the Nyquist frequency.  ...  This means that the control system can suppress the vibrations above the Nyquist frequency. The effectiveness is also verified in experiment [23] .  ... 
doi:10.9746/jcmsi.1.242 fatcat:kdjyj2o2qbdg3lp4fbeqtor65m

Dual-stage servo systems and vibration compensation in computer hard disk drives

Roberto Horowitz, Yunfeng Li, Kenn Oldham, Stanley Kon, Xinghui Huang
2007 Control Engineering Practice  
The second is the instrumentation of disk drive suspensions with vibration sensing strain gages, in order to enhance airflow-induced suspension vibration suppression in hard disk drives.  ...  This paper discusses two mechatronic innovations in magnetic hard disk drive servo systems, which may have to be deployed in the near future, in order to sustain the continuing 60% annual increase in storage  ...  INTRODUCTION Since the first hard disk drive (HDD) was invented in 1950s by IBM, disk drives' storage density has been following Moore's law, doubling roughly every 18 months.  ... 
doi:10.1016/j.conengprac.2006.09.003 fatcat:pecdup4asjbz3epzzqo45oqjwu

Frequency Separation based Adaptive Feedforward Control for Rejecting Wideband Vibration with Application to Hard Disk Drives [article]

Jinwen Pan, Zhi Chen, Yong Wang, Roberto Horowitz
2020 arXiv   pre-print
In this paper, a frequency separation based adaptive feedforward control algorithm is developed with the ability to identify the plant and do compensation region by region.  ...  In each subband, the corresponding subband signal acts as the feedforward signal and only the frequency response of system in that region needs to be identified, thus a pretty low order model can be expected  ...  ACKNOWLEDGEMENTS Financial support for this study was provided by a grant from the Advanced Storage Technology Consortium (ASTC).  ... 
arXiv:2012.05049v1 fatcat:apydykrc4jgizimz5eieqiy75e

Emerging Technology for Head-Positioning System in HDDs

Takenori Atsumi
2016 IEEJ Journal of Industry Applications  
The recent rapid growth of the information industry has strongly increased the demand for large-capacity hard disk drives (HDDs).  ...  This paper introduces two examples of emerging technologies for future HDDs: "Vibration Control with Thin-Film-Coil Actuator" and "High-Bandwidth Control with Thermal Actuator".  ...  In the data-storage drives, a hard disk drive (HDD) is the most widely used device, and the positioning accuracy of magnetic heads in the HDD must be improved to meet this increasing demand for the larger  ... 
doi:10.1541/ieejjia.5.117 fatcat:kakufx24zjastl4i3wyqsgwe6a

Loop-shaping controller design with the RBode plot for hard disk drives

T Atsumi, W C Messner
2010 Proceedings of the 2010 American Control Conference  
The controller for the head positioning system of a hard disk drive must have both high performance and high robustness.  ...  The design results for a benchmark hard disk drive problem show the usefulness of proposed method.  ...  INTRODUCTION Hard disk drives (HDD) are inexpensive mass-production products and are used in a range of environments.  ... 
doi:10.1109/acc.2010.5531303 fatcat:2hidrnfxz5gsxo6biuz4mdj7f4

Estimation Method of Unobservable Oscillations in Sampled-Data Positioning Systems

Takenori Atsumi
2017 IEEJ Journal of Industry Applications  
To demonstrate the use of the proposed indexes, unobservable magnitudes of oscillations are analyzed for a head-positioning control system in a hard disk drive.  ...  For example, a control input in the sampled-data control system can easily excite transient vibrations of mechanical resonances around the sampling frequency.  ...  For example, in the head-positioning control system of hard disk drives (HDDs), the unobservable head-position may cause destruction of user's data in HDDs (7)- (10) .  ... 
doi:10.1541/ieejjia.6.199 fatcat:7ubjsjyys5f5nkanld7d5qluc4

Stable Peak Filtering Method to Reject High Frequency Disturbance in Hard Disk Drives

Fan HONG, Chunling DU
2010 Journal of Advanced Mechanical Design, Systems, and Manufacturing  
In this paper, novel solutions are provided for designing the disturbance filter when there are significant plant dynamics within the bandwidth of the filter.  ...  The resulting closed-loop systems can provide large gain attenuation at the resonance frequency, and thus have more disturbance rejection capability.  ...  Introduction The requirement for areal density in hard disk drive (HDD) industry has been kept increasing due to the continuing demand for higher storage capacity (1) , (2) .  ... 
doi:10.1299/jamdsm.4.119 fatcat:gkl4tzb5ijehhjhupl6cxo3o2q
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