Bifurcation Approach to the Analysis of Multiple Flying Height States in Load/Unload Hard Disk Drive Systems

2005 ◽  
Author(s):  
Pyung Hwang ◽  
Polina V. Khan
Keyword(s):  
Hard Disk Drive ◽  
Hard Disk ◽  
Disk Drive ◽  
Numerical Continuation ◽  
Continuation Methods ◽  
Multiple Equilibrium ◽  
Flying Height ◽  
Drive Systems ◽  
The Relationship ◽  
Force Equilibrium

The application of numerical continuation methods to calculate suspension force-equilibrium position curve for hard disk drive sliders is proposed. The method efficiently detects multiple equilibrium positions. The relationship between suspension force offset and critical preload is found for the femto slider.

Bifurcation Analysis of the Load/Unload Systems With Multiple Flying Height States

2006 ◽  
Vol 128 (3) ◽  
pp. 665-669 ◽  
Author(s):  
Pyung Hwang ◽  
Polina V. Khan
Keyword(s):  
Disk Drive ◽  
Stability Diagram ◽  
Numerical Continuation ◽  
Continuation Methods ◽  
Flying Height ◽  
Air Bearing ◽  
Bearing Force ◽  
Characteristic Values ◽  
The Stability ◽  
The Relationship

The load/unload behavior of the hard disk drive slider is studied in terms of the air bearing static characteristics. The application of numerical continuation methods to calculate spacing diagrams is proposed. The algorithm that detects multiple flying height states and fold points is developed. The relationship between suspension force x-offset and critical preload is found for femto size sliders. The second fold corresponding to the critical preload for unloading is found in the negative air bearing force area. The range of x-offsets and preloads where bi-stable phenomenon exists is depicted on the stability diagram. The perturbation method is used to check the dynamic system characteristic values near the fold points and to determine the stability of the solution branches. The present procedure can be employed to study the multiple flying height states in the terms of any other pair of parameters besides the preload and x-offset.

Air Entrapment in Nanometer-Thick Lubricant Films and its Effect on Slider Flying Height in a Hard Disk Drive

2012 ◽  
Vol 47 (3) ◽  
pp. 349-355 ◽  
Author(s):  
B. Marchon ◽  
X. C. Guo ◽  
S. Canchi ◽  
R. H. Wang ◽  
N. Supper ◽  
...  
Keyword(s):  
Hard Disk Drive ◽  
Hard Disk ◽  
Disk Drive ◽  
Flying Height ◽  
Air Entrapment ◽  
Lubricant Films

Settling control with reference redesign for dual actuator hard disk drive systems

2004 ◽  
Vol 28 (2) ◽  
pp. 219-227 ◽  
Author(s):  
Jiagen Ding ◽  
Shang-Chen Wu ◽  
Masayoshi Tomizuka
Keyword(s):  
Hard Disk Drive ◽  
Hard Disk ◽  
Disk Drive ◽  
Drive Systems

Finite Element Analysis of the Coupled Journal and Thrust Bearing in a Computer Hard Disk Drive

2005 ◽  
Vol 128 (2) ◽  
pp. 335-340 ◽  
Author(s):  
G. H. Jang ◽  
S. H. Lee ◽  
H. W. Kim
Keyword(s):  
Finite Element ◽  
Hard Disk Drive ◽  
Thrust Bearing ◽  
Fluid Dynamic ◽  
Hard Disk ◽  
Disk Drive ◽  
Flying Height ◽  
Separate Analysis ◽  
Element Analysis ◽  
Thrust Bearings

This paper proposes a method to calculate the characteristics of a coupled fluid dynamic journal and thrust bearing of a hard disk drive (HDD) spindle motor. The governing equations for the journal and thrust bearings are the two-dimensional Reynolds equations in the θz and rθ planes, respectively. The finite element method is appropriately applied to analyze the coupled bearing under the conditions of the continuity of mass and pressure at the interface between the journal and thrust bearings. The pressure in the coupled bearing was calculated by applying the Reynolds boundary condition. The validity of this application was verified by comparing the analytical results of the flying height at various rotating speeds with experimental results. The characteristics of the coupled journal and thrust bearing were also investigated due to the Reynolds and Half-Sommerfeld boundary conditions and the coupled and separate analysis. This research demonstrates that the proposed method can accurately and realistically describe the coupled fluid dynamic bearing in a HDD system.

Improved Fabrication of an Integrated Electromagnetic Second Stage Microactuator for a Hard Disk Recording Head

2009 ◽  
Author(s):  
Henry Saalfeld ◽  
Dragan Dinulovic ◽  
Hans H. Gatzen
Keyword(s):  
Hard Disk Drive ◽  
Hard Disk ◽  
Disk Drive ◽  
Flying Height ◽  
Recording Head ◽  
Process Redesign ◽  
Second Stage ◽  
Recording Heads ◽  
Mems Technology ◽  
Micro Systems

Key mechanical requirements for advanced Hard Disk Drive (HDD) recording heads are a minimal flying height and a perfect track following. By applying Micro Electro-mechanical Micro Systems (MEMS) technology, a Slider with an Integrated Microactuator (SLIM) enabling both in a cost competitive way was created. This paper describes the fabrication process for the system’s electromagnetic microatuator and emphasizes the technology enhancements achieved after a process redesign.

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