Improvement of RRO using hybrid-type STW for hard disk drives

Inoue, Takahiro; Horisaki, Makoto; Seo, Yoshiho; Yamazaki, Shota

doi:10.1109/20.917652

Cited by 10 publications

(4 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this section, we deal with the 2-D stabilization problem, thus we only need to consider the model of (8) and (10) with w(i, j) = 0. Let (8) and (10) are equivalent to [3] x(i + 1, j + 1) = A 1 x(i, j + 1) + A 2 x(i + 1, j)…”

Section: -D Stabilization Controller Designmentioning

confidence: 99%

“…Servo bursts are conventionally written by costly dedicated servowriting equipment external to the disk drive, which uses a laser-guided push-pin mechanism to position write head on the disk surface until the servo burst information is written on the media of a head disk assembly (HDA) completely [1]. Recently a great deal of attention has been paid to the improvement on servo track writing [5], [8], [10], [13].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Two-dimensional Control of Self-servo Track Writing for Hard Disk Drives

Xie

Teoh

et al. 2006

2006 9th International Conference on Control, Automation, Robotics and Vision

View full text Add to dashboard Cite

Self-servo track writing (SSTW) process for hard disk drives (HDDs) is described by using a two-dimensional (2-D) model, with which the error propagation containment problem of the SSTW is formulated as 2-D stabilization problem, and the position error minimization problem is formulated as 2-D H2 control problem. The adopted 2-D controller is designed with easily implemented linear matrix inequality (LMI) approach. With the stored error information of previous track, the 2-D control scheme is realizable. The simulation results demonstrate that the error propagation is prevented by the 2-D control scheme and the positioning accuracy is remarkably improved by the 2-D H2 control scheme. Also, from the 2-D controller servo performance is evaluated in usually concerned 1-D sense.

show abstract

Section: -D Stabilization Controller Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Two-dimensional Control of Self-servo Track Writing for Hard Disk Drives

Xie

Teoh

et al. 2006

2006 9th International Conference on Control, Automation, Robotics and Vision

View full text Add to dashboard Cite

show abstract

“…Various methods have been proposed to improve the precision of STW [1]- [4], but none might be capable of handling smaller track pitches in the future. One reason is that these STW methods work with high-speed rotation; therefore, degraded precision caused by nonrepeatable runout (NRRO) of the rotation system, i.e., wind turbulence against the head, the suspension, and the disk is inevitable.…”

Section: Introductionmentioning

confidence: 99%

Magnetic Duplication for Precise Servo Writing on Magnetic Disks

et al. 2004

View full text Add to dashboard Cite

A servo pattern of a 20 Gbit in 2 level was directly duplicated on hard disks by using a magnetic duplication method, and the accuracy of the signal and the following performance on the duplicated servo pattern were evaluated. The phase servo pattern was composed of straight lines and was lithographically formed on a mastering disk. The period accuracy of the readback signal was very high. The repeatable position error for adjacent tracks in a prototype drive was measured, and the difference between two adjacent RPE trajectories was sufficiently small. The magnetic duplication method showed the possibility of precise servo-track writing for high-density hard disk drives.Index Terms-Magnetic duplication, phase servo pattern, repeatable position error (RPE), servo-track writing.

show abstract

“…On the other hand, hybrid-type servo track writer has also been introduced [37]. There are two main stages involved in the hybrid STW process.…”

Section: Fig 18 Shows a New Magnetic Contact Duplication Technologymentioning

confidence: 99%

High precision motion control for hard disk drive systems

Teoh¹

View full text Add to dashboard Cite

The demand for better servo control technology for hard disk drives (HDDs) never ceases. One important element for HDDs servo control is better precision for future drives with ultrahigh densities. As the track density increases, the amount of time required for the process of writing servo information onto the disks will also increase accordingly. However, the cost of production must be kept low. Since HDDs are manufactured in mass production, the servo control design for the voice coil motor (VCM) actuator has to be robust towards uncertainty. At the same time, the track misregistration (TMR) during track following has to be minimized. These two requirements can be formulated into a mixed H 2 /H ∞ control problem. Therefore, a new mixed H 2 /H ∞ control design via a linear matrix inequality (LMI) based approach is proposed. By an equivalent transformation of Lyapunov matrix inequality, additional slack variables are introduced to characterize both the H 2 and H ∞ performances. This offers additional degree of freedom in optimizing the mixed H 2 /H ∞ performance, and thus, resulting in equal or better performance than existing LMI based methods. It is generally difficult to attenuate high frequency disturbances of a system due to waterbed effect of the sensitivity function. However, attenuation of dominant narrow-band disturbances is possible. Therefore, a technique that combines a disturbance observer with a phase stabilized controller is proposed for rejection of narrow-band disturbances at two different frequencies, which are higher than the servo bandwidth. The phase stabilized controller is designed first to attenuate a high frequency disturbance. Then, the disturbance observer is added into the loop in order to reject another high frequency disturbance, without affecting the stability of the feedback control loop. Previous research has shown that the sensitivity function can be shaped such

show abstract

Improvement of RRO using hybrid-type STW for hard disk drives

Cited by 10 publications

References 4 publications

Two-dimensional Control of Self-servo Track Writing for Hard Disk Drives

Two-dimensional Control of Self-servo Track Writing for Hard Disk Drives

Magnetic Duplication for Precise Servo Writing on Magnetic Disks

High precision motion control for hard disk drive systems

Contact Info

Product

Resources

About