Method and apparatus reducing off track head motion due to disk vibration in a hard disk drive using configuration of the disk drive servo controller
First Claim
1. A mechanism controlling a voice coil, comprising:
- means for reducing a gain of a PES within a disk vibration frequency range;
wherein said disk vibration frequency range includes frequencies between at least 1000 Herz and at most 3000 Herz; and
means for increasing said gain of said PES within a lower frequency range;
wherein said lower frequency range includes frequencies between at least 16 Herz and at most 800 Herz;
wherein said voice coil drives an actuator arm positioning a head gimbal assembly for a read-write head communicatively accessing a track on a rotating disk surface to generate said PES;
wherein said PES is a function of said head gimbal assembly responding to mechanical vibrations in said rotating disk surface by providing said read-write head with radial motion toward said track;
wherein said head gimbal assembly, comprises;
means for moving said slider parallel to said disk surface toward said track, when said disk surface is flat, by an actuator arm moving said slider by a lever action through a principal axis with said slider aligned at a bias angle;
means for radially moving said slider toward said track when said disk surface is bent, by said lever action through said principal axis at said bias angle causing said slider to move radially toward said track, when said disk surface is bent.
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Accused Products
Abstract
An improved and distinctive servo-controller scheme resulting in an overall improvement in PES performance, particularly when applied to hard disk drives employing the invention'"'"'s TMR reduction mechanisms. The servo-controllers trade off gain in the disk vibration frequency range, in favor of, increased rejection of low frequency disturbances. This leads to the lowest PES statistics, when applied to hard disk drives with the TMR reduction mechanisms of the invention.
Improved head gimbal assemblies reducing TMR (Track Mis-Registration) in a hard disk drive are provided. These head gimbal assemblies are as mechanically simple as contemporary head gimbal assemblies, support parallel flying sliders over flat disk surfaces, and reduce TMR induced by disk vibration. They are easier to build, more reliable, and cost less to make, than other known approaches at comparable track densities and rotational rates. The improved head gimbal assemblies include three sets of mechanisms moving the slider parallel the disk surface, when the disk surface is flat, and radially moving the slider toward the track, when the disk surface is bent. The first and third mechanisms as well as the second and third mechanisms can be used together in a head gimbal assembly.
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Citations
18 Claims
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1. A mechanism controlling a voice coil, comprising:
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means for reducing a gain of a PES within a disk vibration frequency range;
wherein said disk vibration frequency range includes frequencies between at least 1000 Herz and at most 3000 Herz; and
means for increasing said gain of said PES within a lower frequency range;
wherein said lower frequency range includes frequencies between at least 16 Herz and at most 800 Herz;
wherein said voice coil drives an actuator arm positioning a head gimbal assembly for a read-write head communicatively accessing a track on a rotating disk surface to generate said PES;
wherein said PES is a function of said head gimbal assembly responding to mechanical vibrations in said rotating disk surface by providing said read-write head with radial motion toward said track;
wherein said head gimbal assembly, comprises;
means for moving said slider parallel to said disk surface toward said track, when said disk surface is flat, by an actuator arm moving said slider by a lever action through a principal axis with said slider aligned at a bias angle;
means for radially moving said slider toward said track when said disk surface is bent, by said lever action through said principal axis at said bias angle causing said slider to move radially toward said track, when said disk surface is bent. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of controlling a voice coil in a hard disk drive, comprising the steps of:
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reducing a gain of a PES within a disk vibration frequency range;
wherein said disk vibration frequency range includes frequencies between at least 1000 Herz and at most 3000 Herz; and
increasing said gain of said PES within a lower frequency range;
wherein said lower frequency range includes frequencies between at least 20 Herz and at most 800 Herz;
said head gimbal assembly responding to mechanical vibrations in said rotating disk surface by providing said read-write head with radial motion toward said track, further comprising the steps of;
moving said slider parallel to said disk surface toward said track, when said disk surface is flat, by an actuator arm moving said slider by a lever action through a principal axis with said slider aligned at a bias angle, further comprising one of the steps of;
said actuator arm moving, through a flexure, said slider mounted to said flexure at a second bias angle to said principal axis; and
moving said actuator arm by a level action through a principal axis with said slider parallel said disk surface and flexibly mounted by said flexure at said second bias angle to said actuator arm; and
radially moving said slider toward said track when said disk surface is bent, by said lever action through said principal axis at said bias angle causing said slider to move radially toward said track, when said disk surface is bent, further comprising one of the steps of;
said flexure responding as said disk surface is bent, through said second bias angle, causing said slider to move radially toward said track; and
said flexure responding as said disk surface is bent through said second bias angle causing said slider to radially move toward said track;
wherein said voice coil drives an actuator arm positioning said head gimbal assembly for a read-write head communicatively accessing a track on a said rotating disk surface to generate said PES; and
wherein said PES is a function of said head gimbal assembly responding to mechanical vibrations in said rotating disk surface by providing said read-write head with radial motion toward said track. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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Specification