Samsung Electronics Co., Ltd.

Dong-Ho Oh

Young-Hoon Kim

Seong-Woo Kang

Yun-Sik Han

Myeong-Eop Kim

Jae-Won Kim

Tae-Yeon Hwang

Sang Hoon Chu

Tae Yeon Hwang

Frank Ivan Morris

Tho Pham

Momo K Boljanovic

Edward Aguilar

Haeng-Soo Lee

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 for 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. 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.

Method for reducing off track head motion due to disk vibration in a hard disk drive through the head gimbal assembly

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.

Method and apparatus reducing off track head motion due to disk vibration in a hard disk drive through the head gimbal assembly

The invention applies to servo controllers for at least the voice coil motor of a hard disk drive. Today, many control algorithms require 80 to 90 percent of the sampling period to complete their calculation of the next control, making computation time delay no longer negligible. The invention accommodates the transport delay, such as computation time delay, into the state estimator and into the whole control system. Experimental results using a commercial hard drive, as well as simulation results, show that the invention's method effectively improves the hard disk drive control system stability by increasing the phase margin and gain margin. The invention includes the method of operating the servo-controller, as well as the apparatus implementing that method. The invention also includes hard disk drives containing servo-controllers implementing the method, and program systems residing in accessibly coupled memory to a computer within the servo controller implementing the method.

Servo controller method and apparatus for high tracks per inch hard disk drives using a delay accomodating state estimator

The invention includes sliders provided with indented surfaces, reducing the roll center for head gimbal assemblies below the effective thickness of the slider. Head gimbal assemblies built with these sliders may reduce off-track displacements induced by disk vibration. The load beam gimbal may contact the indented surface, creating a slider roll center less than the slider thickness. Alternatively, the sliders may include a slider contact cover interfacing to the load beam forming the gimbal. The slider contact covers may couple with the slider through an indented surface located closer than the slider thickness. These may have a negative slider roll center. The invention includes actuator arms, actuator assemblies, and hard disk drives including these head gimbal assemblies. The invention includes making the invention's sliders, head gimbal assemblies, actuator arms, actuator assemblies, and hard disk drives. The invention includes the products of these processes.

Method and apparatus reducing off track head motion due to disk vibration in a hard disk drive

A servo writer that writes servo information onto a disk of a hard disk drive. The servo writer can write servo information onto a disk of a hard disk drive while the disk is within an inner chamber of a housing. The rotating disk creates a flow of fluid within the inner chamber. The disk is rotated during the servo writing process. The density of a fluid medium within the inner chamber is controlled by a medium control system so that the density of the medium is less than the density of air at one atmosphere. Lowering the density decreases the amplitude of vibrational forces created by the flow of fluid. Decreasing the amplitude reduces errors in the servo writing process. The density can be reduced by pulling a vacuum within the inner chamber. The density can also be reduced by filling the inner chamber with a gas such as helium that has a lower density than air.

Servo track writing for ultra-high TPI disk drive in low density medium condition

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

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. 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.

Method and apparatus reducing off-track head motion due to disk vibration in a disk drive through flexure mounting and/or non-symmetric hinging within the head gimbal assembly

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San Jose, CA, United States of America

Dong-Ho Oh