Seagate Technology Incorporated

ShuangQuan Min

KianKeong Ooi

MingZhong Ding

YangQuan Chen

Xiong Liu

WeiSung Lee

BengWee Quak

Ricky Wei Watt Yeo

Lihong Zhang

Qiang Bi

Beng Wee Quak

ChoonKiat Lim

Kian Keong Ooi

Chris Michael Woldemar

WingKong Chiang

Jack Ming Teng

KianSoon Yeo

Ricky WeiWatt Yeo

ChiapHeok Ang

KianKeon Ooi

WeiSoon Lee

Provided is an apparatus including a motor configured to rotate a rotating member at a rotational speed based on an applied current; and a controller configured to modify one or more operating parameters in response to determining whether a change in an environment has occurred based on the applied current.

Current-based environment determination

In a particular embodiment, a controller is adapted to control a spindle motor that controls rotation of at least one rotatable disc of a storage device. The controller is adapted to increase a spindle speed associated with the spindle motor to an unload spindle speed that is greater than an operating spindle speed during a ramp unload operation.

Variable spindle speed for ramp unload

Track closure errors written into servo sectors of an information track of a disc of a disc drive are resolved from a position control signal generated by a servo control circuit of a data storage device by steps comprising: determining a value for the track closure error from a position error signal, establishing a track closure profile based on the value of the track closure error, and injecting the track profile into the servo control circuit as a feed forward compensation input for the position error signal to resolve the track closure error from the position control signal.

Track closure error cancellation for a disc drive

For runout compensation in a data handling system, a servo feedback loop is configured to control a head position relative to a corresponding disc surface. Operation of the feedback loop is complicated by a repeatable error in the head position having energy at harmonics of the spindle rotation frequency. Also, the feedback loop has a gain with a frequency sensitivity in a target frequency range. A feedforward controller generates an output injected into the feedback loop based on an error-indicative input. This defines a feedforward closed-loop transfer function, between the loop output and the feedforward controller input. The feedforward controller prevents the frequency sensitivity from substantially varying the feedforward closed-loop transfer function gain and phase within the target frequency range, thus reducing computational burden.

Method and apparatus for feedforward repeatable runout compensation in a selected frequency range

Written-in runout due to vibration of the cage of a spindle motor of a disc drive is detected by identifying an initial cage frequency value of the motor. A written-in magnitude of successive servo burst closures, D(n ), is read over a plurality of tracks, and a maximum servo burst closure D(n ) is identified from the plurality of read servo bursts. A magnitude of the cage frequency at a servo sector n is calculated based on a difference between the read magnitudes of the servo burst closures at servo sectors n and n , and a phase of the cage frequency is calculated based on the magnitude of the written-in cage frequency at servo sector n . The profile, in the form of cage frequency, maximum servo burst closure magnitude, and initial phase, is stored in a memory or table for each of a plurality of radial zones of tracks. The profile is combined with a position error signal and applied to the controller in a feed forward scheme to adjust the position of the head based on the written-in runout.

Identification and cancellation of cage frequency in a hard disc drive

A method and apparatus for controlling acoustic noise generated by a seek operation in a disc drive by using a feedback control system to control the seek operation. The feedback control system is excited by a feed-forward signal during execution of the seek operation. An acoustic factor, which defines a seek operation noise level, is selected. The feed-forward signal is generated based, at least in part, upon the selected acoustic factor. The feed-forward signal has a first derivative having a maximum value. The selected acoustic factor is used to select the maximum value of the first derivative of the feed-forward signal.

Sinusoidal feed-forward seek with adaptive acoustic level constraint

A method of implementing an automatic acoustic management feature for a disc drive includes receiving an acoustic/performance compromising factor from a host, tuning disc drive performance by applying the factor to a control parameter to generate a modified control parameter, and executing a loop for controlling a disc drive operation using the modified control parameter. In another embodiment, a disc drive has a base, a rotatable disc, an actuator assembly with an arm for carrying a head in transducing relation to the disc in response to a control signal, a receiver for receiving an acoustic/performance compromising factor, and a controller that monitors the position of the arm and generates the control signal. The controller executes a seeking control loop having a control parameter modified by applying a compromising factor to the parameter to tune the acoustic performance of the drive.

Automatic acoustic management system for a disc drive

A disc drive device includes a base and a disc rotatably attached to the base. The disc drive also includes an actuator assembly rotatably attached to said base and a device for moving the actuator assembly. The actuator assembly includes an actuator arm and a transducer head in a transducing relationship with respect to the disc. The transducer is attached to the actuator arm. A method of screening disc drives for harmonic resonant frequencies includes sampling the position error signal at a track location in the disc drive, and determining the velocity of the position error signal from the sample of the position error signal. The velocity of the position error signal sample is divided by the position error signal to produce a quotient. The quotient is compared to a selected quotient threshold value to determine the type of a harmonic in the disc drive.

Method for harmonic frequency identification in a disc drive

Steps for isolating and correcting total written-in repeatable run-out error written into servo sectors of a disc drive include, determining a total repeatable run-out error value for each servo sector, isolating a repeatable error value component of the total written-in repeatable run-out error value for each servo sector, removing the repeatable error value component from total written-in repeatable run-out error value to provide a non-repeatable error value component of the total written-in repeatable run-out error value for each servo sector, providing both the repeatable and non-repeatable error value components to a processor for generation of compensation signals, and applying the compensation signals into a servo control circuit of control loop of the disc drive using compensation circuits to compensate for each component of the total written-in repeatable run-out error.

Repeatable run-out error compensation method for a disc drive

The magnitude and frequency of runout due to vibration of the cage of the spindle motor is detected. A plurality of servo patterns are written to a reference track having a clock pattern on the disc, and the plurality of servo patterns are then read over a plurality of revolutions of the disc using a clock head. The magnitude of position error of the clock head relative to the reference track is identified for each of the read servo patterns. The magnitude and frequency of runout due to cage vibration is identified from the position errors. Servo patterns are written to user tracks on the disc by identifying periods of low magnitude runout due to cage vibration, and writing the servo patterns to the user track during those periods of low magnitude runout.

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Singapore, Singapore

ShuangQuan Min