Western Digital Technologies, Inc.

Alexander Babinski

Duc T Phan

Orhan Beker

Chuanwen Ji

Min Chen

Yanan Huang

Donald Joseph Brunnett

Raffi Codilian

Chun Sei Tsai

Jifang Tian

Tetsuo Ueda

Alain Chahwan

Young-Hoon Kim

Dean V Dang

Shinsuke Nakagawa

Colin W Morgan

David D Nguyen

Aswartha Narayana

Hien T Chu

Thao Hieu Banh

Shan Tang

Nathan J Santee

Hengchang Guo

Eugene Chun-Tsing Wu

Qixing Zheng

Yanbin Song

Zhenyu Zhang

Lu Feng

Alan M Fossen

Lingfei Zhou

Shang-Chen Wu

Jun Huang

A data storage device is disclosed comprising a first head actuated over a first disk surface, and a second head actuated over a second disk surface. During a first revolution of the disk surfaces, a first set of servo sectors are written to the first disk surface and a second set of servo sectors are written to the second disk surface, wherein the first set of servo sectors are circumferentially offset from the second set of servo sectors. During a second revolution of the disk surfaces, at least one of the servo sectors in the first set is read from the first disk surface and at least one of the servo sectors in the second set is read from the second disk surface to control a position of the first head over the first disk surface.

Data storage device bank writing servo sectors for interleaved servo control processing

A data storage device is disclosed comprising a head actuated over the disk. A first notch filter is calibrated at a first temperature, and a second notch filter is computed for a second temperature based on the first notch filter and a first delta temperature between the first temperature and the second temperature. The second notch filter is computed by transforming a continuous-time transfer function of the first notch filter adjusted by the first delta temperature into a discrete-time transfer function of the second notch filter.

Data storage device computing notch filters for multiple temperatures

An apparatus includes: a media; a head over the media; a read channel, coupled to the head, configured to extract data from the media; control circuitry, coupled to the read channel, configured to execute a read command; and wherein the read channel is further configured to: generate, based on extracting the data from the media, a data condition indicator, and provide, for use by the control circuitry, the data and the data condition indicator.

Electronic system with media scan mechanism and method of operation thereof

A disk drive is disclosed comprising a disk having a plurality of tracks, a head, and a voice coil motor (VCM) and a microactuator for actuating the head over the disk in response to a feed-forward compensation value. A sinusoidal disturbance is applied to the microactuator, and the resulting feed-forward compensation value is processed to characterize the microactuator.

Disk drive characterizing microactuator by injecting sinusoidal disturbance and evaluating feed-forward compensation values

An apparatus includes: a media; a head over the media; a primary-actuator coupled to the head; and control circuitry, coupled to the primary-actuator and a secondary-actuator, configured to limit a secondary-actuator slew rate.

Electronic system with actuator control mechanism and method of operation thereof

A disk drive is disclosed comprising a disk comprising a plurality of servo tracks, wherein each servo track comprises a plurality of servo sectors, and an actuator for actuating a head over the disk in response to an actuator control signal. The servo sectors are read to generate a first sequence of control samples x[k] at a sample frequency corresponding to a frequency of the servo sectors. A hybrid upsample filter is used to upsample by a factor of N the first sequence of control samples x[k] to generate a second sequence of control samples y[k], wherein the hybrid upsample filter provides a higher phase gain than a zero-order type upsample filter at frequencies less than one kilohertz, and approximately the same attenuation as a first-order type upsample filter around the sample frequency. The actuator control signal is generated in response to the second sequence of control samples y[k].

Disk drive servo control using hybrid upsample filter

A disk drive comprises a track follow control system having a plurality of selectable frequency modes, the track follow control system configured to receive a position error signal and to output a control signal based on the position error signal, wherein the control signal is used by a head assembly to position a head over a disk. The disk drive also comprises a state estimator configured to receive the control signal and a position signal indicating a position of the head, to estimate a disturbance based on the control signal and the position signal, and to output an estimated disturbance signal based on the estimated disturbance. The disk drive further comprises a disturbance evaluator configured to receive the estimated disturbance signal, and to select one of the frequency modes of the track follow control system based on the estimated disturbance signal.

Adaptive track follow control

A disk drive is disclosed comprising a disk including a plurality of servo tracks, wherein each servo track comprises a plurality of servo sectors. The disk drive further comprises an actuator for actuating a head over the disk in response to an actuator control signal. The servo sectors are read to generate a first sequence of control samples x[k] at a sample rate corresponding to a frequency of the servo sectors. The first sequence of control samples x[k] is upsampled by a factor of N to generate a second sequence of control samples y[k] according to: where &#x3b3; is a scalar greater than or equal to zero and less than one. The actuator control signal is generated in response to the second sequence of control samples y[k].

Disk drive upsampling servo control signal

A method is disclosed of operating a disk drive, the disk drive comprising a disk having a plurality of tracks, a head, and a closed loop servo system comprising a seek servo loop and a settle servo loop for actuating the head over the disk. The seek servo loop is used to seek the head toward a target track. When the head approaches the target track, the settle servo loop is used to settle the head on the target track in response to a reference signal generated in response to a system inversion of the settle servo loop.

Disk drive employing system inversion for tuning seek to settle servo loop

A disk drive is disclosed comprising a disk, a head, a voice coil motor (VCM) for actuating the head over the disk, and control circuitry comprising a notch filter for generating a VCM control signal, wherein a notch of the notch filter comprises a frequency, a width, and a depth. The notch filter is calibrated by initializing at least one of the width and the depth of the notch, measuring a quality metric of the notch filter, and increasing at least one of the width and the depth of the notch until the quality metric indicates good performance.

Disk drive calibrating VCM notch filter by increasing the width and/or the depth of the notch

A method of tuning a seek operation of a disk drive is disclosed, the disk drive comprising a disk, an actuator arm, a head coupled to a distal end of the actuator arm, a voice coil motor (VCM) for rotating the actuator arm about a pivot, and a closed loop servo system for generating a VCM control signal applied to the VCM. A function h is applied to the closed loop servo system and a corresponding output g of the closed loop servo system is measured. A reference signal is generated in response to a summation of a plurality of the function h, wherein each of the plurality of the function h is shifted by an offset and scaled by a coefficient, and the coefficients are generated in response to the measured output g.

Disk drive employing data-based basis function expansion for tuning seek servo loop

A disk drive comprising a first seek operating mode to move the actuator over a seek distance D in a seek time T, using a first seek profile for minimizing T, wherein for a first repetitive series of seeks over distance D a servo control system would require a delay time Tbetween seeks to control temperature rise in a VCM. A second seek operating mode to move the actuator over the seek distance D in a second seek time Tusing a second seek profile for limiting the temperature rise in the VCM, wherein for a second repetitive series of seeks over the seek distance D, a time average Tof the Tseek times is substantially less than T+T.

Growing community of inventors

Laguna Niguel, CA, United States of America

Alexander Babinski