Pub Date : 2004-08-16DOI: 10.1109/APMRC.2004.1521966
Jaeho Lee, Dongho Park, Dae-Young Lee, Jungho Hwang
As the flying height of a slider in a hard disk drive decreases, the head and disk are more likely to come in contact and to generate contamination particles. Since particle contamination can cause serious problems including thermal asperity, its removal is very important to increase storage capacity. When particles are generated in a HDD, particles could be charged by several charging mechanism and have few number of elementary charge. In this paper, size distributions of particles from HDD and amount of particle charge with some rotational speed variations are shown. Also, the average numbers of elementary charge are calculated from experimental data. Following analysis from SEM images of charged particles, we can confirm some trends of experimental results
{"title":"Investigation of nano-particle's size distributions and charging characteristics in operating HDD","authors":"Jaeho Lee, Dongho Park, Dae-Young Lee, Jungho Hwang","doi":"10.1109/APMRC.2004.1521966","DOIUrl":"https://doi.org/10.1109/APMRC.2004.1521966","url":null,"abstract":"As the flying height of a slider in a hard disk drive decreases, the head and disk are more likely to come in contact and to generate contamination particles. Since particle contamination can cause serious problems including thermal asperity, its removal is very important to increase storage capacity. When particles are generated in a HDD, particles could be charged by several charging mechanism and have few number of elementary charge. In this paper, size distributions of particles from HDD and amount of particle charge with some rotational speed variations are shown. Also, the average numbers of elementary charge are calculated from experimental data. Following analysis from SEM images of charged particles, we can confirm some trends of experimental results","PeriodicalId":445247,"journal":{"name":"APMRC 2004 Asia-Pacific Magnetic Recording Conference, 2004.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125879729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-08-16DOI: 10.1109/APMRC.2004.1521938
G. Jang, M.G. Kim
This paper presents a method to drive an HDD spindle motor at high speed with large starting torque by utilizing a bipolar-starting and unipolar-running algorithm. It proposes a novel inverter circuit to switch from bipolar to unipolar drive, or vice versa. It also develops a DSP-based BLDC motor controller not only to drive the BLDC motor with bipolar or unipolar method, but also to switch from one method to the other at any speed. And the effectiveness of the proposed method is also verified by using the developed controller experimentally
{"title":"A bipolar-starting and unipolar-running method to drive an HDD spindle motor at high speed with large starting torque","authors":"G. Jang, M.G. Kim","doi":"10.1109/APMRC.2004.1521938","DOIUrl":"https://doi.org/10.1109/APMRC.2004.1521938","url":null,"abstract":"This paper presents a method to drive an HDD spindle motor at high speed with large starting torque by utilizing a bipolar-starting and unipolar-running algorithm. It proposes a novel inverter circuit to switch from bipolar to unipolar drive, or vice versa. It also develops a DSP-based BLDC motor controller not only to drive the BLDC motor with bipolar or unipolar method, but also to switch from one method to the other at any speed. And the effectiveness of the proposed method is also verified by using the developed controller experimentally","PeriodicalId":445247,"journal":{"name":"APMRC 2004 Asia-Pacific Magnetic Recording Conference, 2004.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133686644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-08-16DOI: 10.1109/APMRC.2004.1521932
K. Fukuzawa, T. Shimuta, A. Nakada, H. Zhang, Y. Mitsuya
Controlling the kinetic behaviors of molecularly thin lubricant is a key technology for designing head-disk interfaces (HDIs) of hard disk drives (HDDs). Direct visualization of molecularly thin lubricant films is useful in investigating kinetic properties such as replenishment or retention of thin lubricant films. To meet this demand, we demonstrated that the ellipsometric microscope can provide real-time visualization with a sub-nm thickness resolution. In this paper, we present a method of measuring the thickness of the lubricant film. In this method, the phase difference between the lights reflected from the film-covered and uncovered regions of the disk is obtained from the polarizer angles; then the thickness is calculated from the phase difference. We verified the feasibility of the method theoretically and experimentally. Measurement error of less than 0.2 nm was experimentally achieved for molecularly thin lubricants. This method provides real-time and quantitative imaging of molecularly thin lubricants and can provide useful information for designing HDIs for high-density HDDs.
{"title":"Measurement of thickness of molecularly thin lubricant film by using ellipsometric microscopy","authors":"K. Fukuzawa, T. Shimuta, A. Nakada, H. Zhang, Y. Mitsuya","doi":"10.1109/APMRC.2004.1521932","DOIUrl":"https://doi.org/10.1109/APMRC.2004.1521932","url":null,"abstract":"Controlling the kinetic behaviors of molecularly thin lubricant is a key technology for designing head-disk interfaces (HDIs) of hard disk drives (HDDs). Direct visualization of molecularly thin lubricant films is useful in investigating kinetic properties such as replenishment or retention of thin lubricant films. To meet this demand, we demonstrated that the ellipsometric microscope can provide real-time visualization with a sub-nm thickness resolution. In this paper, we present a method of measuring the thickness of the lubricant film. In this method, the phase difference between the lights reflected from the film-covered and uncovered regions of the disk is obtained from the polarizer angles; then the thickness is calculated from the phase difference. We verified the feasibility of the method theoretically and experimentally. Measurement error of less than 0.2 nm was experimentally achieved for molecularly thin lubricants. This method provides real-time and quantitative imaging of molecularly thin lubricants and can provide useful information for designing HDIs for high-density HDDs.","PeriodicalId":445247,"journal":{"name":"APMRC 2004 Asia-Pacific Magnetic Recording Conference, 2004.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124824498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-08-16DOI: 10.1109/APMRC.2004.1521968
C. Bi, Q. Jiang, Taile Wei
The performance of two-phase spindle motor is analyzed, which is driven by constant voltage sensorless BLDC mode. In the motoring operation, the rotor positions are estimated by back EMF detecting and a digital filter is used to realize BLDC sensorless control. The two-phase BLDC motor is more robust in the starting and low speed operation, and can realize accurate speed control. Both the simulations and experiments show that the proposed drive mode is effective in driving spindle motors
{"title":"Analysis of two-phase spindle motor driven by sensorless BLDC mode","authors":"C. Bi, Q. Jiang, Taile Wei","doi":"10.1109/APMRC.2004.1521968","DOIUrl":"https://doi.org/10.1109/APMRC.2004.1521968","url":null,"abstract":"The performance of two-phase spindle motor is analyzed, which is driven by constant voltage sensorless BLDC mode. In the motoring operation, the rotor positions are estimated by back EMF detecting and a digital filter is used to realize BLDC sensorless control. The two-phase BLDC motor is more robust in the starting and low speed operation, and can realize accurate speed control. Both the simulations and experiments show that the proposed drive mode is effective in driving spindle motors","PeriodicalId":445247,"journal":{"name":"APMRC 2004 Asia-Pacific Magnetic Recording Conference, 2004.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126290698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-08-16DOI: 10.1109/APMRC.2004.1521930
Kyoung-Su Park, Jeong-il Chun, Yonghyun Lee, N. Park, Hyun-Seok Yang, Young-Pil Park
Load/unload dynamic characteristics are affected by various parameters; load/unload speed, disk rotating speed, disk vibration and so on. The effect of load/unload process on various parameters was investigated by the experiment. As a result of experiment, the load performance was found to be better for lower load speed and disk rpm. On the other hand, it was confirmed to be better for lower unload speed and higher disk rpm in unload process. Also, the effect of disk vibration was studied for load/unload process. The amplitude of disk vibration can affect in a relative ramp-disk gap and the disk vertical velocity affects in a relative slider-disk speed during load/unload process. As the results of 1000 unload cycles, the non-contact region was changed as the function of disk rotating speed. The non-contact region was smaller in a lower disk rpm. This paper proposes a new control system in order to improve the load/unload performance.
{"title":"Improvement of L/UL performance using load/unload mechanism control considering disk vibration characteristics","authors":"Kyoung-Su Park, Jeong-il Chun, Yonghyun Lee, N. Park, Hyun-Seok Yang, Young-Pil Park","doi":"10.1109/APMRC.2004.1521930","DOIUrl":"https://doi.org/10.1109/APMRC.2004.1521930","url":null,"abstract":"Load/unload dynamic characteristics are affected by various parameters; load/unload speed, disk rotating speed, disk vibration and so on. The effect of load/unload process on various parameters was investigated by the experiment. As a result of experiment, the load performance was found to be better for lower load speed and disk rpm. On the other hand, it was confirmed to be better for lower unload speed and higher disk rpm in unload process. Also, the effect of disk vibration was studied for load/unload process. The amplitude of disk vibration can affect in a relative ramp-disk gap and the disk vertical velocity affects in a relative slider-disk speed during load/unload process. As the results of 1000 unload cycles, the non-contact region was changed as the function of disk rotating speed. The non-contact region was smaller in a lower disk rpm. This paper proposes a new control system in order to improve the load/unload performance.","PeriodicalId":445247,"journal":{"name":"APMRC 2004 Asia-Pacific Magnetic Recording Conference, 2004.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131352856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-08-16DOI: 10.1109/APMRC.2004.1521925
T. Arisaka, T. Shimizu, T. Atsumi, H. Masuda, T. Yamaguchi
This research shows the new design concept of an actuator in hard disk drives. The actuator which has several higher-order mechanical resonance determine the stability and mechanical noise suppression ability of the servo control system. We presented the new design concept that higher resonance are made in-phase to the first major resonance. In this concept, all the resonance with high gain are in-phase but the out-phase resonance's gain are reduced. It is shown that the prototype actuator based on this concept can be compensated only by the compensator which is designed for the first major resonance.
{"title":"Development on in-phase actuator mechanism in hard disk drives papers","authors":"T. Arisaka, T. Shimizu, T. Atsumi, H. Masuda, T. Yamaguchi","doi":"10.1109/APMRC.2004.1521925","DOIUrl":"https://doi.org/10.1109/APMRC.2004.1521925","url":null,"abstract":"This research shows the new design concept of an actuator in hard disk drives. The actuator which has several higher-order mechanical resonance determine the stability and mechanical noise suppression ability of the servo control system. We presented the new design concept that higher resonance are made in-phase to the first major resonance. In this concept, all the resonance with high gain are in-phase but the out-phase resonance's gain are reduced. It is shown that the prototype actuator based on this concept can be compensated only by the compensator which is designed for the first major resonance.","PeriodicalId":445247,"journal":{"name":"APMRC 2004 Asia-Pacific Magnetic Recording Conference, 2004.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133617967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-08-16DOI: 10.1109/APMRC.2004.1521940
T. Asada, H. Saitou, D. Itou
This paper reports on the basic design of a Hydrodynamic bearing with an oil circulation mechanism that has the express function of eliminating bubbles that remain inside the bearing cavity that would otherwise adversely affect the disruption-free nature of the oil film in the bearing.[1]-[2].
{"title":"Design of hydrodynamic bearing for mobile HDDs","authors":"T. Asada, H. Saitou, D. Itou","doi":"10.1109/APMRC.2004.1521940","DOIUrl":"https://doi.org/10.1109/APMRC.2004.1521940","url":null,"abstract":"This paper reports on the basic design of a Hydrodynamic bearing with an oil circulation mechanism that has the express function of eliminating bubbles that remain inside the bearing cavity that would otherwise adversely affect the disruption-free nature of the oil film in the bearing.[1]-[2].","PeriodicalId":445247,"journal":{"name":"APMRC 2004 Asia-Pacific Magnetic Recording Conference, 2004.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126289436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-08-16DOI: 10.1109/APMRC.2004.1521942
Q. Jia, Fu-Cai Wang, Zhong-Feng Wang
In this paper, a new method to collect RRO disturbance data is proposed. The estimated RRO disturbance obtained from the proposed method will not be affected by the variation of the actuator model. Test results show that the servo tracking performance can be significantly improved by using the estimated disturbance to compensate the actual RRO disturbances
{"title":"New RRO data collection method for HDD","authors":"Q. Jia, Fu-Cai Wang, Zhong-Feng Wang","doi":"10.1109/APMRC.2004.1521942","DOIUrl":"https://doi.org/10.1109/APMRC.2004.1521942","url":null,"abstract":"In this paper, a new method to collect RRO disturbance data is proposed. The estimated RRO disturbance obtained from the proposed method will not be affected by the variation of the actuator model. Test results show that the servo tracking performance can be significantly improved by using the estimated disturbance to compensate the actual RRO disturbances","PeriodicalId":445247,"journal":{"name":"APMRC 2004 Asia-Pacific Magnetic Recording Conference, 2004.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121289311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-08-16DOI: 10.1109/APMRC.2004.1521954
J.T. Li, H. Long, Z.J. Liu
This paper presents an analytical solution of the write field distribution for perpendicular recording with effect of the soft underlayer taken into consideration. The solution is based on vector magnetic potential, and the analytical solutions obtained are in good agreement with numerical simulations. It is useful in the design phase of the perpendicular recording heads to investigate the characteristics of the writing field versus structure parameters
{"title":"Analytical write field prediction for perpendicular recording heads","authors":"J.T. Li, H. Long, Z.J. Liu","doi":"10.1109/APMRC.2004.1521954","DOIUrl":"https://doi.org/10.1109/APMRC.2004.1521954","url":null,"abstract":"This paper presents an analytical solution of the write field distribution for perpendicular recording with effect of the soft underlayer taken into consideration. The solution is based on vector magnetic potential, and the analytical solutions obtained are in good agreement with numerical simulations. It is useful in the design phase of the perpendicular recording heads to investigate the characteristics of the writing field versus structure parameters","PeriodicalId":445247,"journal":{"name":"APMRC 2004 Asia-Pacific Magnetic Recording Conference, 2004.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131702341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2004-08-16DOI: 10.1109/APMRC.2004.1521949
Hua Qian, Chunqi Wang, E. Ong, N. Guo
The objective of this work is to demonstrate an experimental methodology based on structural intensity technique to visualize energy flow in hard disk drives with a scanning laser Doppler vibrometer. Preliminary experimental results illustrate the feasibility of the proposed methodology to locate sources/sinks and chart energy flow paths in a hard disk drive.
{"title":"Visualizing energy flow in hard disk dives using structural intensity method","authors":"Hua Qian, Chunqi Wang, E. Ong, N. Guo","doi":"10.1109/APMRC.2004.1521949","DOIUrl":"https://doi.org/10.1109/APMRC.2004.1521949","url":null,"abstract":"The objective of this work is to demonstrate an experimental methodology based on structural intensity technique to visualize energy flow in hard disk drives with a scanning laser Doppler vibrometer. Preliminary experimental results illustrate the feasibility of the proposed methodology to locate sources/sinks and chart energy flow paths in a hard disk drive.","PeriodicalId":445247,"journal":{"name":"APMRC 2004 Asia-Pacific Magnetic Recording Conference, 2004.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2004-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129840891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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