Dynamic characteristics of a voice coil motor for a high performance disk drive

1989 ◽  
Vol 25 (4) ◽  
pp. 3073-3075 ◽  
Author(s):  
Y. Hirano ◽  
J. Naruse ◽  
R. Tsuchiyama
Keyword(s):  
Dynamic Characteristics ◽  
High Performance ◽  
Voice Coil Motor ◽  
Disk Drive

Comparative Finite Difference and Finite Element Analysis of the Dynamic Characteristics of a Load-Beam-Lumped-Mass Unit

2007 ◽  
Author(s):  
Mohammad Kazemi ◽  
Hossein Haj-Hariri
Keyword(s):  
Finite Element ◽  
Finite Difference ◽  
Cross Sections ◽  
Dynamic Characteristics ◽  
Disk Drive ◽  
Lumped Mass ◽  
Simplified Models ◽  
Element Analysis ◽  
Mass Unit ◽  
Load Beam

The dynamics of a load-beam-lumped-mass unit (LBLMU) in a disk drive is modeled using physically motivated simplifications. Models are developed for sway, bending and torsion modes of vibration assuming mode decoupling. A finite-difference scheme (FDS) is employed to discretize the governing equations for the three modes. The models are verified by comparing the modal results of simplified models with the results of full 3D finite element models (FEMs) for beams with rectangular and U-shaped cross sections. Then, the models are used to predict the natural frequencies of a LBLMU. It is revealed that the simplified models capture well the dynamic characteristics of a LBLMU while requiring much smaller computational resources.

Adaptive and Repetitive Control for Rejecting Repeatable and Non-Repeatable Runout in Rotating Devices

2007 ◽  
Author(s):  
Ne´stor O. Pe´rez Arancibia ◽  
Chi-Ying Lin ◽  
Tsu-Chin Tsao ◽  
James S. Gibson
Keyword(s):  
High Performance ◽  
Disk Drive ◽  
Minimum Variance ◽  
Experimental Results ◽  
Recursive Least Squares ◽  
Broad Bandwidth ◽  
Periodic Disturbances ◽  
Write Heads ◽  
Control Scheme ◽  
Control Schemes

This paper presents a control scheme for rejecting both repeatable and non-repeatable runout components of disturbances occurring in rotational devices. To exemplify this method, implementation and experimental results for track following control of a computer hard disk drive (HDD) read/write heads are presented. Aiming for high performance, the control design involves two steps. The first is the design and tuning of a recursive least-squares (RLS) based scheme intended to achieve minimum variance performance. The second step integrates repetitive and adaptive control schemes in a real-time implementation to compensate for variations and changes in the disturbance dynamics. The repetitive part of this controller targets specific periodic disturbances. The adaptive part compensates for broad bandwidth stochastic disturbances. The key element in this design is the formulation of an appropriate optimization problem, solvable recursively by applying recursive adaptive algorithms. Experimental results obtained from the implementation of this method in a commercial HDD demonstrates the effectiveness of this approach.

Numerical Modeling for the Characterization of Flow Excitation for the HDD Disk Vibration Control

2006 ◽  
Vol 110 ◽  
pp. 143-150
Author(s):  
Ja Choon Koo ◽  
Sean W. Kang ◽  
Y.S. Han ◽  
Yeon Sun Choi
Keyword(s):  
Data Storage ◽  
High Performance ◽  
Air Flow ◽  
Flow Analysis ◽  
Disk Drive ◽  
Squeeze Film ◽  
Hard Drives ◽  
Design Improvement ◽  
Disk Flutter

This article presents a modeling method for air flow analysis of a hard disk drive. Air flow excitation causes disk vibration that aggravates TMR budget of the design of modern high performance hard drives. And it is the most expensive budget consumer so that controlling of the flutter becomes the primary design issue of the data storage industry. In the presented work, air flow excitation forces are characterized by LES modeling and the results are verified with experiments. A squeeze-film-type disk damper is employed in the experiments and it is applied for a hardware design improvement for disk flutter reduction. LES and RANS are compared and alternately used in a calculation in order to minimize computational efforts.

Realization of a hard disk drive head servo-positioning system with a voltage-driven voice-coil motor

2003 ◽  
Vol 9 (4) ◽  
pp. 271-281 ◽  
Author(s):  
R. Oboe ◽  
F. Marcassa ◽  
P. Capretta ◽  
F. Chrappan Soldavini
Keyword(s):  
Hard Disk Drive ◽  
Voice Coil Motor ◽  
Hard Disk ◽  
Disk Drive ◽  
Positioning System

scholarly journals Strength and dynamic characteristics analyses of wound composite axial impeller

2012 ◽  
Vol 2 (1) ◽  
Author(s):  
Jifeng Wang ◽  
Jorge Olortegui-Yume ◽  
Norbert Müller
Keyword(s):  
Dynamic Characteristics ◽  
High Performance ◽  
Low Cost ◽  
Three Dimensional ◽  
Design Parameters ◽  
Modal Shape ◽  
Kevlar Fiber ◽  
Start Up ◽  
High Performance Composite ◽  
Wound Composite

AbstractA low cost, light weight, high performance composite material turbomachinery impeller with a uniquely designed blade patterns is analyzed. Such impellers can economically enable refrigeration plants to use water as a refrigerant (R718). A strength and dynamic characteristics analyses procedure is developed to assess the maximum stresses and natural frequencies of these wound composite axial impellers under operating loading conditions. Numerical simulation using FEM for two-dimensional and three-dimensional impellers was investigated. A commercially available software ANSYS is used for the finite element calculations. Analysis is done for different blade geometries and then suggestions are made for optimum design parameters. In order to avoid operating at resonance, which can make impellers suffer a significant reduction in the design life, the designer must calculate the natural frequency and modal shape of the impeller to analyze the dynamic characteristics. The results show that using composite Kevlar fiber/epoxy matrix enables the impeller to run at high tip speed and withstand the stresses, no critical speed will be matched during start-up and shut-down, and that mass imbalances of the impeller shall not pose a critical problem.

Numerical Analysis for Dynamic Characteristics of New Launcher with Coupled Rigid and Flexible Motion

2010 ◽  
Vol 34-35 ◽  
pp. 44-49 ◽  
Author(s):  
Ying Ze Wang
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Dynamic Characteristics ◽  
High Performance ◽  
Coupling Effect ◽  
The Other ◽  
Flexible Coupling ◽  
Simulation Based ◽  
Coupling Dynamic ◽  
Coupling Dynamic Model

This paper is concerned with an analysis of the dynamic characteristics of the high performance launcher—rarefaction wave gun(RAVEN) by numerical simulation. Based on its launch mechanism and launch structure, a rigid-flexible coupling dynamic model which considered the coupling effect between the flexible virbation of the launch barrel and the motion behaviors of the other parts of the RAVEN is established via a subsystems method. The actual motion of the projectile and inertial breech during the lauching are described by the interior ballistic equations of the RAVEN. The dynamic characterisitcs of RAVEN is illustrated by the numerical simulation about a small caliber launcher, and the interaction between launch barrel and the other parts is also studied.

Stability analysis in wound composite material axial impeller

2011 ◽  
Vol 226 (5) ◽  
pp. 1162-1172 ◽  
Author(s):  
J Wang ◽  
J Piechna ◽  
J A O Yume ◽  
N Müller
Keyword(s):  
Composite Material ◽  
Stability Analysis ◽  
Dynamic Characteristics ◽  
Composite Laminates ◽  
High Performance ◽  
Low Cost ◽  
Modal Shape ◽  
Element Analysis ◽  
Rotating Speed ◽  
Wound Composite

A stability analysis is developed to assess the stresses and dynamic characteristics of the wound composite material axial impeller under centrifugal force loading conditions. This procedure is based on finite element analysis (commercial software ABAQUS) results. A low-cost, light-weight, high-performance composite turbomachinery impeller with a uniquely designed blade patterns is evaluated. Understanding the stress–strain behaviour of fibre-reinforced composite laminates as it relates to ultimate failure and the ability to predict ultimate strength is critical in the design of safe and lightweight impellers. To determine failures, the maximum stress failure criterion is used. In order to avoid operating at resonance, which can make impellers suffer a significant reduction in the design life, the designer must calculate the natural frequency and modal shape of the impeller to analyse the dynamic characteristics. The results show that using composite Kevlar fibre/epoxy matrix enables the impeller to run at a rotating speed 2228 rad/s and withstand the stresses, no critical speed will be matched during start-up and shut-down, and that mass imbalances of the impeller shall not pose a critical problem.

Magnetic Recording Head Materials

MRS Bulletin ◽  
1996 ◽  
Vol 21 (9) ◽  
pp. 23-27 ◽  
Author(s):  
James A. Brug ◽  
Thomas C. Anthony ◽  
Janice H. Nickel
Keyword(s):  
Magnetic Recording ◽  
High Performance ◽  
Disk Drive ◽  
Information Storage ◽  
Disk Drives ◽  
Recording Heads ◽  
Tremendous Amount ◽  
The Media ◽  
Materials Used ◽  
Magnetic Recording Heads

The materials used in magnetic recording heads have recently received a tremendous amount of attention. This has been the result of a fortunate set of circumstances. Ever-increasing demands for information storage, especially for graphics-intensive applications, have necessitated unprecedented increases in disk-drive areal densities. Combined with this are recent discoveries in the area of magnetoresistive materials, enabling the design and fabrication of much more sensitive recording heads. The end result is a flurry of activity that has come to dominate the field of magnetics. This article will explore choices for magnetoresistive read head materials, with an emphasis on the materials challenges.The recording heads that are used in high-performance disk drives typically consist of separate magnetoresistive read and inductive write heads (see Figure 1) where previously a single inductive head performed both functions. Separation of the two heads allows each to be optimized for their individual function, an essential factor in enabling disk drives to contain gigabytes of storage. The write head is the simpler of the two, consisting of a U-shaped ferromagnet surrounding a set of coils. The ends of the ferromagnet are the magnetic poles defining the write gap. When current passes through the coils, a field bridges the gap, setting the orientation of the magnetization in the media. Information is stored by changing the polarity of the current in order to write a pattern of magnetic domains in the media. The materials used in write poles will be reviewed in the section, Write Head Materials.

H ∞ Control Design for Systems With Periodic Irregular Sampling Using Optimal H2 Reference Controllers

2013 ◽  
Author(s):  
Behrooz Shahsavari ◽  
Richard Conway ◽  
Ehsan Keikha ◽  
Fu Zhang ◽  
Roberto Horowitz
Keyword(s):  
Hard Disk Drive ◽  
Root Mean Square ◽  
Simulation Study ◽  
High Performance ◽  
Control Design ◽  
Disk Drive ◽  
Sampling Time ◽  
Irregular Sampling ◽  
Mean Square ◽  
Design Algorithm

This paper presents a novel robust H∞ control design for linear systems with periodic irregular sampling and regular actuation rates. A three-step design algorithm is developed to design a controller that achieves high robustness in terms of disk margin, and high performance in terms of root mean square (RMS) of 3σ-value of performance signal. The proposed method is exploited to design a track-following controller for a hard disk drive (HDD) with 30% sampling time irregularity. The simulation study presented in this paper shows the effectiveness of the proposed control design for high-order systems with large periods.

Experimental Characterization Techniques for High Performance Hard Disk Drive Ball Bearing Spindle Motors

1999 ◽  
Author(s):  
Andrew Chong ◽  
Lu Yi ◽  
S. X. Chen ◽  
Q. D. Zhang
Keyword(s):  
Hard Disk Drive ◽  
High Speed ◽  
High Performance ◽  
Ball Bearing ◽  
Hard Disk ◽  
Disk Drive ◽  
Spindle Motor ◽  
Hard Disks ◽  
Steel Balls ◽  
Test Requirements

Abstract The key task for the spindle motor in a hard disk drive is to provide stable, reliable and consistent turning power for many years to allow the hard drive to function properly. As hard disks become more advanced, virtually every component in them is required to do more & perform better, and the spindle motor is no exception. Increasing the rotational speed at which the platters spin means that the data can be read off the disk faster, and also reduces rotational latency, the time that the heads must wait for the correct sector number to come under the head. For this reason, there has been a push to increase the speed of the spindle motor. Since the launching of hydro-dynamic bearing spindle technology for high speed application will not be in due course, current ball bearing technology will still be around for a couple of years provided the spindle speed does not exceed around 15 Krpm. Therefore optimizing the steel balls in the spindle system is an alternative to deal with the ever-increasing performance requirements of the hard disk drive. To accomplish this, we have to understand the failure phenomenon in the spindle, thereby set test requirements to overcome the failure mechanism. These test requirements will help us to understand the performance characteristic and robustness of the spindle motor. In this paper, the test requirements is set according to modal, load and vibration methods to quantify the hard disk drive ball bearing spindle motor.

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