So Toyama, Norihisa Yanagihara, S. Saegusa, Atsushi Saito
The seek speed of magneto-optical disk drives is greater than that of other optical disk drives. To design a high-speed seek servo system that will be an improvement over the traditional system, we must achieve following two goals. One is to drive the coarse-positioning actuator as fast as possible. The other is to restrain shift and vibration of the lens during the seek. We propose to apply two-degree-of-freedom (2-DOF) seek-velocity control and lens-shift restriction control. The 2-DOF seek-velocity control uses acceleration feedforward of the lens motion as well as target velocity signal of the lens velocity. This method can work the coarse actuator quickly. Further, the lens-shift restriction control uses the controlling input to cancel the inertial force that acts on the lens during the seek. By simulating this method, we discovered that such control systems provide the prospect of average seek time shorter than 19 ms.
{"title":"Fast Seek Servo Method Using Two-Degree-of-Freedom Control for Magneto-Optical Disk Drives","authors":"So Toyama, Norihisa Yanagihara, S. Saegusa, Atsushi Saito","doi":"10.1115/imece1997-0584","DOIUrl":"https://doi.org/10.1115/imece1997-0584","url":null,"abstract":"\u0000 The seek speed of magneto-optical disk drives is greater than that of other optical disk drives. To design a high-speed seek servo system that will be an improvement over the traditional system, we must achieve following two goals. One is to drive the coarse-positioning actuator as fast as possible. The other is to restrain shift and vibration of the lens during the seek. We propose to apply two-degree-of-freedom (2-DOF) seek-velocity control and lens-shift restriction control. The 2-DOF seek-velocity control uses acceleration feedforward of the lens motion as well as target velocity signal of the lens velocity. This method can work the coarse actuator quickly. Further, the lens-shift restriction control uses the controlling input to cancel the inertial force that acts on the lens during the seek. By simulating this method, we discovered that such control systems provide the prospect of average seek time shorter than 19 ms.","PeriodicalId":447413,"journal":{"name":"8th International Symposium on Information Storage and Processing Systems","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115156390","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}
Head stiction problems have driven the search for new actuator bearing greases. It is well known in the industry that heads gradually accumulate e organic products which lead to stiction seizures after the heads have landed on the disks. Actuator pivot bearings were lubricated by the test greases. Three grease types were tested: 1) mineral oil with a polyurea thickener, 2) polyolester oil with a polyurea thickener, and 3) perfluorinated polyether oil with a polytetrafluorethelyne thickener. Airborne particle count tests were performed on five files each to assess the grease effect on disk drive contamination levels. Particle counts for sizes 0.2, 0.5 and 1.0 micron were taken from accessing files. Differences in the generation rate of aerosolized grease were measured when the files were new and also after having been exercised 10, 20 and 60 million seeks. Cascade impaction of disk drive’s air stream was analyzed by time of flight secondary ion mass spectroscopy to confirm that the aerosol particles captured were from the grease. Files built with the perfluorinated polyether oil based grease had the lowest particle count. Files built with bearings lubricated by the mineral oil based grease had a moderate particle count. Files containing the polyol ester oil based grease had the highest particle count.
{"title":"Actuator Bearing Greases: Their Effect on Aerosol Contamination in Disk Drives","authors":"W. Prater, G. Stone","doi":"10.1115/imece1997-0583","DOIUrl":"https://doi.org/10.1115/imece1997-0583","url":null,"abstract":"\u0000 Head stiction problems have driven the search for new actuator bearing greases. It is well known in the industry that heads gradually accumulate e organic products which lead to stiction seizures after the heads have landed on the disks.\u0000 Actuator pivot bearings were lubricated by the test greases. Three grease types were tested: 1) mineral oil with a polyurea thickener, 2) polyolester oil with a polyurea thickener, and 3) perfluorinated polyether oil with a polytetrafluorethelyne thickener.\u0000 Airborne particle count tests were performed on five files each to assess the grease effect on disk drive contamination levels. Particle counts for sizes 0.2, 0.5 and 1.0 micron were taken from accessing files. Differences in the generation rate of aerosolized grease were measured when the files were new and also after having been exercised 10, 20 and 60 million seeks. Cascade impaction of disk drive’s air stream was analyzed by time of flight secondary ion mass spectroscopy to confirm that the aerosol particles captured were from the grease.\u0000 Files built with the perfluorinated polyether oil based grease had the lowest particle count. Files built with bearings lubricated by the mineral oil based grease had a moderate particle count. Files containing the polyol ester oil based grease had the highest particle count.","PeriodicalId":447413,"journal":{"name":"8th International Symposium on Information Storage and Processing Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130730800","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}
A theoretical analysis of the fluid mechanics of the air cushion of the air reversers used in web-handling systems is presented. A two-dimensional model of the air flow obtained by averaging the equations of conservation of mass and momentum over the clearance between the web and the reverser is solved numerically. The effect of the pressure holes in the surface of the air reverser are represented by nonlinear source terms in the modified Euler’s and mass conservation equations. The results of the numerical solution axe compared with a 1D analytical solution of these equations, an empirical formula and the one-dimensional air-jet theory developed for hovercraft. Conditions that maximize the air pressure supporting the web are analyzed and design guidelines are deduced.
{"title":"A Numerical Solution of the Euler’s Equations With Nonlinear Source Terms in Modeling the Fluid Dynamics of an Air Reverser","authors":"Sinan Müftü, T. Lewis, K. A. Cole","doi":"10.1115/imece1997-0580","DOIUrl":"https://doi.org/10.1115/imece1997-0580","url":null,"abstract":"\u0000 A theoretical analysis of the fluid mechanics of the air cushion of the air reversers used in web-handling systems is presented. A two-dimensional model of the air flow obtained by averaging the equations of conservation of mass and momentum over the clearance between the web and the reverser is solved numerically. The effect of the pressure holes in the surface of the air reverser are represented by nonlinear source terms in the modified Euler’s and mass conservation equations. The results of the numerical solution axe compared with a 1D analytical solution of these equations, an empirical formula and the one-dimensional air-jet theory developed for hovercraft. Conditions that maximize the air pressure supporting the web are analyzed and design guidelines are deduced.","PeriodicalId":447413,"journal":{"name":"8th International Symposium on Information Storage and Processing Systems","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125547939","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}
Yuko Kobayashi, Shunsuke Hattori, Yuji Suzuki, Yasuo Shima, M. Ukai
Sheet separating mechanisms are used in ATMs (automated teller machines) to separate bank notes. These mechanisms are composed of separate-gate-rollers. Sheets are separated when the overlap distance of the separate-gate-rollers is appropriate. We have found out by experiment that although the appropriate overlap distance range differs according to the configuration of the separate-gate-roller, the range of friction force between a bank note and the separate-gate-roller is equally 3 to 10N. Thus, we have examined a method to estimate the friction force by numerical analysis, using the ABAQUS nonlinear structural analysis program. Consequently, calculated friction forces were found to correspond to experimental friction forces quantitatively and qualitatively.
{"title":"Analysis of Contact Problems Between a Sheet and Separate-Gate-Rollers","authors":"Yuko Kobayashi, Shunsuke Hattori, Yuji Suzuki, Yasuo Shima, M. Ukai","doi":"10.1115/imece1997-0578","DOIUrl":"https://doi.org/10.1115/imece1997-0578","url":null,"abstract":"\u0000 Sheet separating mechanisms are used in ATMs (automated teller machines) to separate bank notes. These mechanisms are composed of separate-gate-rollers. Sheets are separated when the overlap distance of the separate-gate-rollers is appropriate. We have found out by experiment that although the appropriate overlap distance range differs according to the configuration of the separate-gate-roller, the range of friction force between a bank note and the separate-gate-roller is equally 3 to 10N. Thus, we have examined a method to estimate the friction force by numerical analysis, using the ABAQUS nonlinear structural analysis program. Consequently, calculated friction forces were found to correspond to experimental friction forces quantitatively and qualitatively.","PeriodicalId":447413,"journal":{"name":"8th International Symposium on Information Storage and Processing Systems","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128573575","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}
M. Okayama, Y. Nagasawa, Ryoichi Ichikawa, I. Utsumi
We study on roller overlapped type friction feeder in which the rotating feed roller and stationary gate roller are overlapped in a direction to the roller’s radius, to increase its rehability. The paper traction forces created by the feeder and the paper double feeding mechanism are also studied. It is found that the characteristics of the reaction forces between the two rollers and paper which is buckled in three dimensions, and paper traction forces depend upon the position at which a sheet of paper is delivered. It is also found that the paper traction forces increase in proportion to the number of sheets of paper which are fed into the roller overlapped mechanism. The ratio of the overlapped area of the double feeding sheets of paper depends upon the degree of force to deliver the second paper.
{"title":"Mechanism of Paper Feeding on the Roller Overlapped Friction Feeder","authors":"M. Okayama, Y. Nagasawa, Ryoichi Ichikawa, I. Utsumi","doi":"10.1115/imece1997-0579","DOIUrl":"https://doi.org/10.1115/imece1997-0579","url":null,"abstract":"\u0000 We study on roller overlapped type friction feeder in which the rotating feed roller and stationary gate roller are overlapped in a direction to the roller’s radius, to increase its rehability. The paper traction forces created by the feeder and the paper double feeding mechanism are also studied.\u0000 It is found that the characteristics of the reaction forces between the two rollers and paper which is buckled in three dimensions, and paper traction forces depend upon the position at which a sheet of paper is delivered. It is also found that the paper traction forces increase in proportion to the number of sheets of paper which are fed into the roller overlapped mechanism. The ratio of the overlapped area of the double feeding sheets of paper depends upon the degree of force to deliver the second paper.","PeriodicalId":447413,"journal":{"name":"8th International Symposium on Information Storage and Processing Systems","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126931577","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}
A disk drive servo code and synchronous writing scheme is described in this paper. The encoding and decoding of the servo code; the writing and detecting of the synchronous clock writing can be realized in this system. In this paper, a synchronous clock writing with variable frequency method is discussed. The mathematical analysis of the variable frequency clock writing, the system design, and the writing and detecting of the servo code are presented.
{"title":"Design of Servo Code and Synchronous Clock Writing Scheme on a High Capacity Disk Drive","authors":"Jing-li Zhou, Sheng-sheng Yu, Joseph T. Ma","doi":"10.1115/imece1997-0582","DOIUrl":"https://doi.org/10.1115/imece1997-0582","url":null,"abstract":"\u0000 A disk drive servo code and synchronous writing scheme is described in this paper. The encoding and decoding of the servo code; the writing and detecting of the synchronous clock writing can be realized in this system. In this paper, a synchronous clock writing with variable frequency method is discussed. The mathematical analysis of the variable frequency clock writing, the system design, and the writing and detecting of the servo code are presented.","PeriodicalId":447413,"journal":{"name":"8th International Symposium on Information Storage and Processing Systems","volume":"153 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121518535","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 : 1997-11-16DOI: 10.1142/9789812816610_0003
K. Ono, H. Maruyama
In this paper, we described an experimental study about the fundamental characteristics of the bouncing vibration of contact slider which is composed of a small stainless steel suspension and a glass or lead ball. The behavior of the contact slider was analyzed by using a laser doppler vibrometer. We found that the bouncing vibration was always low when the slider load was large, the coefficient of restitution was low and the suspension damping was high. For lead contact sliders that had a low coefficient of restitution, smaller mass can reduce the bouncing vibration more than the larger mass can. On the other hand, for glass sliders with a high coefficient of restitution, larger mass can reduce the bouncing vibration due to the increase in the inertia effect. Almost all of our experimental results agreed qualitatively with our analytical ones.
{"title":"An Experimental Study About the Bouncing Vibration of a Contact Slider","authors":"K. Ono, H. Maruyama","doi":"10.1142/9789812816610_0003","DOIUrl":"https://doi.org/10.1142/9789812816610_0003","url":null,"abstract":"\u0000 In this paper, we described an experimental study about the fundamental characteristics of the bouncing vibration of contact slider which is composed of a small stainless steel suspension and a glass or lead ball. The behavior of the contact slider was analyzed by using a laser doppler vibrometer. We found that the bouncing vibration was always low when the slider load was large, the coefficient of restitution was low and the suspension damping was high. For lead contact sliders that had a low coefficient of restitution, smaller mass can reduce the bouncing vibration more than the larger mass can. On the other hand, for glass sliders with a high coefficient of restitution, larger mass can reduce the bouncing vibration due to the increase in the inertia effect. Almost all of our experimental results agreed qualitatively with our analytical ones.","PeriodicalId":447413,"journal":{"name":"8th International Symposium on Information Storage and Processing Systems","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129580952","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}
This paper is to study free vibration of a rotating disk/spindle system with hydrodynamic bearings (HDB). The disk/spindle system consists of multiple circular disks clamped on a rigid spindle, which allows infinitesimal rigid-body translation and rotation (rocking). Also, the spindle is mounted on a stationary, flexible, cantilever shaft through two identical radial HDB and a thrust HDB. Equations of motion were first derived in terms of the rigid-body translation and rocking of the spindle, the shaft bending, and the disk vibration. Then an eigenvalue analysis was performed to obtain natural frequencies, modal damping factors, and mode shapes of the rotating disk/spindle system. For a special case of rigid shaft and decoupled translation/rocking spindle, one pair of transverse modes and two pairs of rocking modes were observed. For the transverse modes, the disk/spindle system whirls transversely as a rigid body at half of the rotational speed (i.e., half-speed whirl). In addition, the backward whirl is heavily damped while the forward whirl is lightly damped. The first pair of rocking modes is similar to those found in disk/spindle systems with ball bearings and is lightly damped. The second pair of rocking modes occurs at low frequency. One of these modes is lightly damped and has natural frequency very close to half of the rotational speed. For the general case of a flexible shaft and coupled translation/rocking motion, eight coupled modes were obtained. Three of them occur at the half-speed frequency. Compared with systems with rigid shaft, the other five modes have significantly lower natural frequencies because of the shaft flexibility.
{"title":"Free Vibration of a Rotating Disk/Spindle System With Hydrodynamic Bearings","authors":"T. Jintanawan, I. Shen","doi":"10.1115/imece1997-0581","DOIUrl":"https://doi.org/10.1115/imece1997-0581","url":null,"abstract":"\u0000 This paper is to study free vibration of a rotating disk/spindle system with hydrodynamic bearings (HDB). The disk/spindle system consists of multiple circular disks clamped on a rigid spindle, which allows infinitesimal rigid-body translation and rotation (rocking). Also, the spindle is mounted on a stationary, flexible, cantilever shaft through two identical radial HDB and a thrust HDB. Equations of motion were first derived in terms of the rigid-body translation and rocking of the spindle, the shaft bending, and the disk vibration. Then an eigenvalue analysis was performed to obtain natural frequencies, modal damping factors, and mode shapes of the rotating disk/spindle system. For a special case of rigid shaft and decoupled translation/rocking spindle, one pair of transverse modes and two pairs of rocking modes were observed. For the transverse modes, the disk/spindle system whirls transversely as a rigid body at half of the rotational speed (i.e., half-speed whirl). In addition, the backward whirl is heavily damped while the forward whirl is lightly damped. The first pair of rocking modes is similar to those found in disk/spindle systems with ball bearings and is lightly damped. The second pair of rocking modes occurs at low frequency. One of these modes is lightly damped and has natural frequency very close to half of the rotational speed. For the general case of a flexible shaft and coupled translation/rocking motion, eight coupled modes were obtained. Three of them occur at the half-speed frequency. Compared with systems with rigid shaft, the other five modes have significantly lower natural frequencies because of the shaft flexibility.","PeriodicalId":447413,"journal":{"name":"8th International Symposium on Information Storage and Processing Systems","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127523643","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：