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| Number | Title | Issue Date |
| 8144421 | Radial position seek tuning for acoustic performance Examples of the present invention relate to reduction in acoustic noise by tuning seek characteristics of a servo controller, depending on a radial position of a head relative to a disk. The servo controller can provide compensation for acoustic resonance modes.... | 03/27/2012 |
| 8031429 | Multi-directional self servo-writing for a disk drive A method of self servo-writing servo information to a plurality of disk surfaces in a disk drive that includes writing servo information to a plurality of disk surfaces in a first direction, writing servo information to a plurality of disk surfaces in a second direc... | 10/04/2011 |
| 7826170 | Apparatus and method for adjusting a feed-forward signal for seek control during a seek operation A hard disk drive control module has a feed-forward signal input port communicatively coupled with a reference model. The hard disk drive control module has a tracking error signal input port communicatively coupled with a magnetic transducer of the hard disk drive.... | 11/02/2010 |
| 7729081 | On-line bias estimator in hard disk drives A hard disk drive with a circuit that provides a control signal to a voice coil motor to move a head across a disk of the drive. The drive includes a flex circuit that applies a bias force onto an actuator arm coupled to the head. The circuit includes a state estima... | 06/01/2010 |
| 7667922 | Estimation of bias force for data tracking in a disk drive Bias force changes in a disk drive, including transient bias changes, are predicted and/or estimated. Bias compensation or change in bias compensation is calculated based on drive operating parameters such as seek length. Calculation can correspond to a modeled rela... | 02/23/2010 |
| 7656607 | Disk drive comprising a servo accelerator employing a dual state variable memory A disk drive is disclosed operable to generate an actuator control signal for actuating a head over a disk. A memory address is used to read a first state k variable from a first state variable memory SVM1. The first state k variable is stored in a second sta... | 02/02/2010 |
| 7619850 | Magnetic disk apparatus and magnetic head control method A magnetic disk apparatus includes: a driving unit; and control part configured to control the driving unit. The control part includes: a position error feedback control system and a two-degree-of-freedom control system. The position error feedback control system ha... | 11/17/2009 |
| 7609474 | Seek control method, seek control device and disk device A seek control device controls the seek of a plant to prevent the position shift due to an error between a model for generating seek current and a model of the plant. When the seek trajectory is provided by seek trajectory generation for controlling the seek of a pl... | 10/27/2009 |
| 7595957 | Servo gain adjustment based on bias force error Apparatus and related methods are described for adjusting servo gain. In an exemplary apparatus, a circuit determines a bias force error that occurs between an estimated bias force and an actual bias force on an actuator during movement by a servo motor. The circuit... | 09/29/2009 |
| 7554761 | Open loop Ka calibration with low frequency compensation A method of calibrating an actuator controller is discussed. The method includes using an open loop seek operation and compensating for a low frequency response to reduce the velocity at the end of the open loop seek operation. ... | 06/30/2009 |
| 7499239 | Feedforward controller and methods for use therewith A controller includes a combining module that generates a total control signal for the drive device of a disk drive by combining a feedback control signal and a feedforward control signal. A feedback control module generates the feedback control signal in response t... | 03/03/2009 |
| 7489472 | High-order hybrid actuator controller A method of providing a control output by selecting a controller to an actuator is discussed. A first controller having an estimator-compensator architecture is selected if the actuator is in a settle stage. A second controller having an architecture other than that... | 02/10/2009 |
| 7440225 | Disk drive employing pivot friction compensation A disk drive is disclosed including a disk having a plurality of servo tracks, wherein each servo track comprises a plurality of servo sectors forming N servo wedges, and a wedge time period (WTP) occurs between each servo wedge. A VCM control signal is generated by... | 10/21/2008 |
| 7423838 | Servo control method and apparatus suitable for the same A servo control method of controlling a plant to track a reference trajectory with enhanced accuracy using a reference signal and its derivative signals, an apparatus and a recording medium suitable for same. The servo control method includes: determining a polynomi... | 09/09/2008 |
| 7420764 | Servo controller method and apparatus for high tracks per inch hard disk drives using a delay accomodating state estimator 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 long... | 09/02/2008 |
| 7411761 | Seek adaptation system in hard disk drives A hard disk drive with a voice coil motor circuit that provides a current to a voice coil motor to perform a seek routine in a seek time. The disk drive includes a temperature sensor to sense a temperature of the disk drive and a voltage sensor to sense the voltage ... | 08/12/2008 |
| 7394614 | Control method to reduce settle TMR in hard disk drives A hard disk drive with a circuit that provides a control signal to a voice coil motor to move a head across a disk of a drive. The circuit includes a state estimator that provides a plurality of state estimates and a disturbance estimator that provides a disturbance... | 07/01/2008 |
| 7394613 | Control device, disk device, and seek orbit generation method A waveform generator generates an acceleration orbit, a velocity orbit, and a position orbit from the seek time. Each orbits multiplied by respective gains, whereupon the orbits are synthesized by a first adder. The resulting composite orbit is multiplied by a seek ... | 07/01/2008 |
| 7379262 | Higher-order state estimator for low TMR in hard disk drives A hard disk drive with a servo circuit that provides a control signal to a voice coil motor to perform a servo to align a head with a disk track of the drive. The servo circuit includes a fifth order state estimator that provides five estimates that are used to crea... | 05/27/2008 |
| 7372660 | Disc storage system with adaptive PID control A disc drive controller circuit for an actuator receives reference data indicating a desired actuator position “θd”, error data indicating a difference “e” between the desired actuator position and a sensed actuator position “θ”, and adaptiv... | 05/13/2008 |
| 7372658 | Correction table creation method for head position control, head position control method and disk device A head position control system controls the position of the head by correcting the components synchronizing rotation of the disk from the head control amount, in which an adjusted gain to minimize the components synchronizing rotation after correction is theoretical... | 05/13/2008 |
| 7369369 | Bidirectional micropositioning recording head for a magnetic storage device A recording head for use in magnetic storage devices is disclosed. The recording head includes a transducer that is bi-directionally movable with respect to a magnetic medium surface of the magnetic storage medium, thereby enabling improved positioning of the transd... | 05/06/2008 |
| 7362538 | Torque constant correction method in multiple sinusoidal seek servo and disk drive using the same A disk drive control method and apparatus. In particular, a torque constant correction method and apparatus in a disk drive using a multiple sinusoidal seek servo scheme. The torque constant correction method includes: performing a test seek routine for torque const... | 04/22/2008 |
| 7359140 | Method and apparatus of acceleration-based track seeking servo control of disk drive A method and apparatus directed to acceleration-based track-seeking servo control of a disk drive, which minimize jerk generated at the start and end of track seeking, thereby reducing mechanical noise of the disc drive while shortening track-seek time. In the metho... | 04/15/2008 |
| 7359133 | Magnetic recording medium and drive apparatus therefor A flexible recording medium, which has a track width in the range of approximately 1-3 μm, capable of facilitating good tracking control. A magnetic pattern bearing servo signals is provided on the guard bands formed on both sides of a data track of a magnetic reco... | 04/15/2008 |
| 7349174 | Soft sensor for operating shock in a disc drive A method of preventing a write operation to a disc in a disc drive during a shock event without the use of a separate shock sensor comprises steps of monitoring an actuator voice coil motor (VCM) control plant output signal, generating an actuator voice coil motor (... | 03/25/2008 |
| 7349173 | Self-tuning settle controller in hard disk drives A hard disk drive with a voice coil motor controlled by a circuit. The circuit provides a driving current to the voice coil motor to move a head of the drive in a seek routine. The seek routine includes a settle mode that has an initial state and a velocity versus h... | 03/25/2008 |
| 7349171 | Method for measuring actuator velocity during self-servo-write A system comprises a positioning module, a frequency measuring module, a simulation module, and a control module. The positioning module positions an actuator arm adjacent to a track to read spirals that are prewritten using current of a predetermined frequency. The... | 03/25/2008 |
| 7342737 | Off track write protection using filtered position error signal Methods of filtering a position error signal (PES) indicative of a position of a transducer of a disk drive include obtaining sample position data for the transducer, eliminating selected data of the sample position data to provide a subset of the sample position da... | 03/11/2008 |
| 7333288 | Method and apparatus for single written-in Repeatable Run-Out correction function used in multi-stage actuation control of hard disk drive RRO corrector function is formulated to partition the contribution of micro-actuator control from the other voice coil assembly contributions. Single stage actuation is supported by zeroing the micro-actuator control queue, otherwise multi-stage actuation is support... | 02/19/2008 |
| 7333286 | Method of writing a reference servo signal of hard disk drive and apparatus suitable therefor In a method of writing a reference servo signal of a hard disk drive having a spiral reference servo signal that is referred to when writing a final servo signal is written while a head is moved across a disk for a predetermined time at a target movement velocity, a... | 02/19/2008 |
| 7330331 | Repeatable runout estimation in a noisy position error signal environment A system and method for estimating repeatable runout in a servo control system, such as a disc drive servo loop, is provided. The system includes a Kalman filter that is configured to receive position error signals from the servo control system and to estimate the r... | 02/12/2008 |
| 7330322 | Utilizing a combination of physical tracks and virtual tracks to store data on a data storage medium A data storage system and a method for storing data in a data storage system are provided. The data storage system includes a data storage medium that has at least one physical track that stores at least a portion of manufacturing process data, and virtual tracks th... | 02/12/2008 |
| 7327103 | Driver and method for control of voice coil motor in disk drive A driver for a voice coil motor in a disk drive includes a sensor that provides a sense current by sensing a coil current in the voice coil motor, a comparator that provides an error current by determining a difference between a command current and the sense current... | 02/05/2008 |
| 7328118 | Method of determining the mass unbalance of an actuator The present invention is a method of determining mass unbalance of an actuator mechanism in a system. The method includes calculating a center of gravity in first x and y components with respect to a first coordinate system of the actuator mechanism. The method also... | 02/05/2008 |
| 7315433 | Non-repeatable run out compensating apparatus and method and disc drive using the same An apparatus and method are provided for quickly and finely compensating for non-repeatable run out (NPRO) of a disc drive. The NPRO compensation control apparatus in a run out compensation apparatus of a system includes: a frequency estimator directly estimating a ... | 01/01/2008 |
| 7315430 | Servo controller in magnetic disk drive Embodiment of the invention inhibit an effect of repeatable runout errors without expanding servo data areas of the magnetic disk. With regard to low frequency components of positional information read by a magnetic head, which are substantially equivalent to a rota... | 01/01/2008 |
| 7307810 | Method of compensating for track address discontinuity across servo track writing boundary in hard disk drives A hard disk drive with a circuit that provides a current to a voice coil motor to move a head over a disk in a seek routine. The disk has track boundaries with discontinuities in track addresses. The circuit includes a state estimator that predicts a next state of t... | 12/11/2007 |
| 7304751 | Apparatus and method for automatically measuring characteristics of a hard disk drive carriage arm An apparatus and method for automatically measuring characteristics of a hard disk drive carriage arm. The method provides a first measuring device for automatically measuring a first side of a carriage arm. A second measuring device for automatically measuring a se... | 12/04/2007 |
| 7304817 | Jerk controlled seek system A hard disk drive that includes a voice coil motor controlled by a servo circuit. The servo circuit provides a sinusoidal driving signal that has two different harmonic frequencies. The dual harmonic waveform creates a voice coil motor jerk profile (derivative of ac... | 12/04/2007 |
