By Nonmagnetic Sensing (e.g., Optical, Capacitive) Patents (Class 360/77.03)
  • Patent number: 11942123
    Abstract: In a disk drive that includes a magnetic head and a flexible printed circuit board (FPCB) coupled to an actuator for the magnetic head, a method of writing servo information includes: receiving a signal based on an electrical property of a material included in the FPCB, wherein the electrical property of the material changes as the actuator moves; determining a radial position of the magnetic head relative to a disk of the disk drive based on the signal; and controlling a radial velocity of the magnetic head relative to the disk of the disk drive based on the radial position.
    Type: Grant
    Filed: March 1, 2023
    Date of Patent: March 26, 2024
    Assignees: Kabushiki Kaisha Toshiba, Toshiba Electronic Devices & Storage Corporation
    Inventors: Gary W. Calfee, Rodney Ngai, Gabor Szita
  • Patent number: 11456014
    Abstract: Generating a hard disk drive (HDD) data track repeatable runout (RRO) compensation value for a target track involves querying at least one RRO table for a closest track to the target track external servo target (EST) and identifying an ESTx corresponding to the closest track, computing a first absolute value of the difference between the EST and the ESTx, and responsive to the first absolute value being less than an approximation threshold, setting the RRO compensation value for the target track to the RRO compensation value for the closest track. Else, querying the RRO table(s) for each adjacent track to the target track, computing the difference between the ESTs for the adjacent tracks, and responsive to the second absolute value being less than an interpolation threshold, determining an RRO compensation value for the target track based on RRO compensation values corresponding to the adjacent tracks.
    Type: Grant
    Filed: October 5, 2021
    Date of Patent: September 27, 2022
    Assignee: Western Digital Technologies, Inc.
    Inventors: Zaifeng Chen, Chuanwen Ji
  • Patent number: 11300426
    Abstract: An encoder includes a scale having a pattern to be detected, a detecting sensor outputting a signal corresponding to the pattern, a position calculator calculating a relative position between the scale and the detecting sensor based on the signal, a position data storage storing the calculated position data, and a position estimator estimating a relative position between the scale and the detecting sensor at a calculation-target time point based on the stored position data. The position estimator estimates the position at the calculation-target time point based on positions at first and second time points each preceding the calculation-target time point by a predetermined time. The position estimator processes position data in a first time width centered on the first time point and position data in a second time width centered on the second time point to calculate the positions at the first and second time points.
    Type: Grant
    Filed: February 14, 2019
    Date of Patent: April 12, 2022
    Assignee: DMG MORI CO., LTD.
    Inventors: Akira Kimura, Takashi Uchida
  • Patent number: 11199831
    Abstract: A computing system may include a data access engine and a toolpath adjustment engine. The data access engine may be configured to access a computer-aided design (CAD) model of a part design and a computer-aided manufacturing (CAM) setup for the part design. The CAM setup may include a nominal toolpath specified through the CAD model for performing a finishing operation for the part design. The data access engine may also be configured to obtain 3-dimensional (3D) scan data for a physical part manufactured from the part design. The toolpath adjustment engine may be configured to extract, from the 3D scan data, a manufactured geometry of the physical part manufactured from the part design and generate an adjusted toolpath for the physical part to account for the manufactured geometry extracted from the 3D scan data.
    Type: Grant
    Filed: June 11, 2019
    Date of Patent: December 14, 2021
    Assignee: Siemens Industry Software Ltd.
    Inventors: Sanjeev Srivastava, Sudipta Pathak, Erhan Arisoy, Gil Chen, Eduard Finaro, Suraj Ravi Musuvathy, Guannan Ren
  • Patent number: 11151043
    Abstract: Systems, apparatuses, and methods for predictive memory access are described. Memory control circuitry instructs a memory array to read a data block from or write the data block to a location targeted by a memory access request, determines memory access information including a data value correlation parameter determined based on data bits used to indicate a raw data value in the data block and/or an inter-demand delay correlation parameter determined based on a demand time of the memory access request, predicts that read access to another location in the memory array will subsequently be demanded by another memory access request based on the data value correlation parameter and/or the inter-demand delay correlation parameter, and instructs the memory array to output another data block stored at the other location to a different memory level that provides faster data access speed before the other memory access request is received.
    Type: Grant
    Filed: August 12, 2019
    Date of Patent: October 19, 2021
    Assignee: Micron Technology, Inc.
    Inventor: David Andrew Roberts
  • Patent number: 10996655
    Abstract: A numerical controller, which can handle information on a use tool, calculates the shape of a workpiece being machined, based on an input machining program, shape information of the use tool, shape information of a unmachined workpiece, and a tool trajectory, and sets, as a movable range of the tool, a range in which the tool never contacts the workpiece being machined, based on the calculated shape of the workpiece being machined, if manual operation is performed during machining.
    Type: Grant
    Filed: June 11, 2019
    Date of Patent: May 4, 2021
    Assignee: Fanuc Corporation
    Inventor: Kiwamu Saitou
  • Patent number: 10923442
    Abstract: A key based technique that targets obfuscation of critical circuit parameters of an analog circuit block by masking physical characteristics of a transistor (width and length) and the circuit parameters reliant upon these physical characteristics (i.e. circuit biasing conditions, phase noise profile, bandwidth, gain, noise figure, operating frequency, etc.). The proposed key based obfuscation technique targets the physical dimensions of the transistors used to set the optimal biasing conditions. The widths and/or lengths of a transistor are obfuscated and, based on an applied key sequence, provides a range of potential biasing points. Only when the correct key sequence is applied and certain transistor(s) are active, are the correct biasing conditions at the target node set.
    Type: Grant
    Filed: March 12, 2018
    Date of Patent: February 16, 2021
    Assignee: Drexel University
    Inventors: Ioannis Savidis, Vaibhav Venugopal Rao, Kyle Juretus
  • Patent number: 10739311
    Abstract: In a rail inspection system, a positional deviation can be detected with accuracy. The rail inspection system includes a first sensor unit which is disposed to face a rail for a vehicle, and includes at least one receiver coil and at least one oscillation coil which are arranged in an arrangement direction intersecting with a layout direction of the rail, an AC voltage source which applies AC voltage to the oscillation coil, and a displacement detection unit which detects a displacement between the rail and the first sensor unit based on an induced voltage of the receiver coil. The first sensor unit is configured such that, when the displacement is a first displacement, a first maximum value appears in the induced voltage, and when the displacement is a second displacement, a second maximum value of which a phase is reversed against the first maximum value appears in the induced voltage.
    Type: Grant
    Filed: June 9, 2017
    Date of Patent: August 11, 2020
    Assignee: HITACHI HIGH-TECH FINE SYSTEMS CORPORATION
    Inventors: Ryuzo Kawabata, Akihiko Kandori
  • Patent number: 10621116
    Abstract: An apparatus includes an inversion circuit configured to invert a data word, a first partial-inversion circuit configured to invert a first portion of the data word, a second partial-inversion circuit configured to invert a second portion of the data word, and an output selection circuit configured to compare: the data word, an output of the inversion circuit, an output of the first partial-inversion circuit, and an output of the second partial-inversion circuit with a prior data word, and to select an output according to respective numbers of changed bits from the prior data word.
    Type: Grant
    Filed: June 8, 2017
    Date of Patent: April 14, 2020
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventor: David Brief
  • Patent number: 10580444
    Abstract: A slider of a heat-assisted magnetic recording head comprises an air bearing surface and an optical waveguide configured to receive light from a laser source. The slider comprises a plurality of electrical bond pads including a first bond pad and a second bond pad. A first resistive sensor is configured to sense for spacing changes and contact between the slider and a magnetic recording medium at or near a first close point of the slider. A second resistive sensor is configured to sense for spacing changes and contact between the slider and the medium at or near a second close point of the slider. A bolometer is situated at a location within the slider that receives at least some of the light communicated along the optical waveguide. The first resistive sensor, the second resistive sensor, and the bolometer are coupled together and between the first and second bond pads.
    Type: Grant
    Filed: February 11, 2019
    Date of Patent: March 3, 2020
    Assignee: Seagate Technology LLC
    Inventors: Declan Macken, Jon Kartsen Klarqvist
  • Patent number: 10361645
    Abstract: A method for identifying an error state in a brushless direct current motor. For the purposes of this identification, an angle deviation between a shaft angle and a control angle is calculated and used to identify error states on the basis of characteristic patterns. This also works, in particular, for slowly-rotating or stationary brushless direct current motors and allows a clear reduction in the calculation capacities required, compared to the prior art.
    Type: Grant
    Filed: September 24, 2015
    Date of Patent: July 23, 2019
    Assignee: Continental Automotive GmbH
    Inventors: Christian Gunselmann, Frank Sader
  • Patent number: 10229706
    Abstract: A slider of a heat-assisted magnetic recording head comprises an air bearing surface and an optical waveguide configured to receive light from a laser source. The slider comprises a plurality of electrical bond pads including a first bond pad and a second bond pad. A first resistive sensor is configured to sense for spacing changes and contact between the slider and a magnetic recording medium at or near a first close point of the slider. A second resistive sensor is configured to sense for spacing changes and contact between the slider and the medium at or near a second close point of the slider. A bolometer is situated at a location within the slider that receives at least some of the light communicated along the optical waveguide. The first resistive sensor, the second resistive sensor, and the bolometer are coupled together and between the first and second bond pads.
    Type: Grant
    Filed: April 23, 2018
    Date of Patent: March 12, 2019
    Assignee: Seagate Technology LLC
    Inventors: Declan Macken, Jon Karsten Klarqvist
  • Patent number: 9972350
    Abstract: A slider of a heat-assisted magnetic recording head comprises an air bearing surface and an optical waveguide configured to receive light from a laser source. The slider comprises a plurality of electrical bond pads including a first bond pad and a second bond pad. A first resistive sensor is configured to sense for spacing changes and contact between the slider and a magnetic recording medium at or near a first close point of the slider. A second resistive sensor is configured to sense for spacing changes and contact between the slider and the medium at or near a second close point of the slider. A bolometer is situated at a location within the slider that receives at least some of the light communicated along the optical waveguide. The first resistive sensor, the second resistive sensor, and the bolometer are coupled together and between the first and second bond pads.
    Type: Grant
    Filed: August 16, 2017
    Date of Patent: May 15, 2018
    Assignee: SEAGATE TECHNOLOGY LLC
    Inventors: Declan Macken, Jon Karsten Klarqvist
  • Patent number: 9784756
    Abstract: A method of measuring feeding velocity of a web, on which a scale having pitches different from pitches of a mask are formed, is provided. The method includes: calculating a number of vibrations of a moiré image of light passing through the mask and the scale; calculating pitches of the scale of the fed web based on the calculated number of vibrations of the moiré image; averaging the pitches of the scale so that a change in a pitch between adjacent timings among the calculated pitches of the scale is minimized; extracting first signals corresponding to our phases for one pitch based on the averaged pitches of the scale; calculating two second signals for forming a Lissajous circle from the first signals; and calculating an angle of the Lissajous circle by the two second signals and then calculating the feeding velocity of the web by using the calculated angle.
    Type: Grant
    Filed: May 9, 2014
    Date of Patent: October 10, 2017
    Assignee: KOREA INSTITUTE OF MACHINERY & MATERIALS
    Inventors: Dongwoo Kang, Taik Min Lee, Seung-Hyun Lee, Young Man Choi, Deokkyun Yoon, Kwang-Young Kim, Jeongdai Jo
  • Patent number: 9692341
    Abstract: An apparatus for detecting speed of a motor is disclosed, the apparatus including an amplifier configured to amplify a two-phase sine-wave signal inputted from an encoder based on rotation of a motor; a first conversion unit configured to convert the two-phase sine-wave signal to a digital data; a second conversion unit configured to convert the two-phase sine-wave signal to a square-wave signal; a counter unit configured to accumulate by counting the square-wave signal; and a speed determination unit configured to determine a speed of the motor, by receiving the digital data from the first conversion unit and the accumulated count from the counter unit.
    Type: Grant
    Filed: March 5, 2015
    Date of Patent: June 27, 2017
    Assignee: LSIS CO., LTD.
    Inventor: Min Hun Chi
  • Patent number: 9666219
    Abstract: Determining quality metrics of a magnetic tape recording medium. A production module that includes a write element that writes magnetic transitions to the magnetic tape is substantially in constant physical engagement with the magnetic tape. A supplemental module that includes one or more read elements periodically physically engages the magnetic tape, and the read elements generate an electrical signal corresponding to transitions written to the magnetic recording medium by a write element. A computer receives information representative of the electrical signal and determines if a quality metric of the magnetic recording medium derived from the electrical signal is within a defined range. If the quality metric is not within the defined range, a defined action is performed by the computer.
    Type: Grant
    Filed: March 28, 2016
    Date of Patent: May 30, 2017
    Assignee: International Business Machines Corporation
    Inventors: Robert G. Biskeborn, Calvin S. Lo, Tak H. Wong, Xu Yan
  • Patent number: 9455656
    Abstract: A method of estimating the position of a rotor of an electric motor comprises producing an output signal indicative of motor position using a position sensor which comprises a detector and at least one encoder which rotates along with the rotor of the motor and includes a plurality of encoding regions, the output signal of the sensor varying in a stepwise fashion as the encoding regions move past the detector, and passing the output of the sensor through a smoothing algorithm to produce an estimated position signal, the algorithm being arranged to smooth the transition between the steps in the output of the sensor by causing the estimated position signal to lag behind the output of the sensor following a step change in the output of the sensor.
    Type: Grant
    Filed: November 27, 2013
    Date of Patent: September 27, 2016
    Assignee: TRW Limited
    Inventors: Christopher David Dixon, Robert James Huxford
  • Patent number: 9389101
    Abstract: A readhead control mechanism serves to control a readhead included in an optical encoder that measures a mechanical displacement between a fixed portion and a movable portion by reading out a gradation mark on a scale provided on the fixed portion, by using the readhead that is provided on the movable portion. The readhead mechanism includes a securing member that secures the readhead onto the movable portion, an actuator that is directly or indirectly secured onto the readhead to shift the readhead in an approaching direction or in a distancing direction, and an actuator controller that controls the actuator to maintain a constant distance between the readhead and the scale.
    Type: Grant
    Filed: March 20, 2013
    Date of Patent: July 12, 2016
    Assignee: Mitsubishi Electric Corporation
    Inventors: Yutaka Ezaki, Noboru Itoh
  • Patent number: 9330714
    Abstract: A supplemental module that includes one or more read elements periodically engages a magnetic recording medium, and the read elements generate an electrical signal corresponding to transitions written to the magnetic recording medium by a write element. A computer receives information representative of the electrical signal and determines if a quality metric of the magnetic recording medium derived from the electrical signal is within a defined range. If the quality metric is not within the defined range, a defined action is performed by the computer.
    Type: Grant
    Filed: August 5, 2015
    Date of Patent: May 3, 2016
    Assignee: International Business Machines Corporation
    Inventors: Robert G. Biskeborn, Calvin S. Lo, Tak H. Wong, Xu Yan
  • Patent number: 9131848
    Abstract: An optical probe is provided. The optical probe includes a lens extending along an axis between a first end and a second end. A spacer extends along the axis between a first end and a second end. The first end of the spacer is connected to the second end of the lens. A prism is connected to the second end of the spacer such that the prism is spaced apart from the lens by the spacer.
    Type: Grant
    Filed: August 1, 2013
    Date of Patent: September 15, 2015
    Assignee: NINEPOINT MEDICAL, INC.
    Inventor: Matthew A. Sinclair
  • Patent number: 8687943
    Abstract: The application manager 37 conducts “application signaling” when a first disc is replaced with a second disc. At this point, an application is continued if it is written in an application management table assigned to a Title played last on a first disc and also written in an application management table assigned to a Title to be played first on a second disc. On the other hand, an application is ended is it is written in the application management table assigned to the Title played last on the first disc but not written in the application management table assigned to the Title to be played first on the second disc.
    Type: Grant
    Filed: August 19, 2011
    Date of Patent: April 1, 2014
    Assignee: Panasonic Corporation
    Inventor: Wataru Ikeda
  • Patent number: 8456643
    Abstract: A method and system for determining a shape of a portion of an air-bearing surface (ABS) of a head residing on a slider are described. The ABS is configured to fly at a fly height from and with a velocity with respect to a disk during normal operating conditions. The method and system include driving at least one heater residing in the head while the slider is substantially at the normal operating conditions with respect to the disk and the fly height. The shape of the portion of the ABS changes in response to the heater(s) being driven. The method and system also include performing Doppler measurements on the slider while the heater is driven. The shape may then be determined based on the Doppler measurements.
    Type: Grant
    Filed: September 20, 2010
    Date of Patent: June 4, 2013
    Assignee: Western Digital (Fremont), LLC
    Inventors: Vijay Prabhakaran, Wuxing Gan, Ladislav R. Pust, David E. Fowler, Lanshi Zheng
  • Patent number: 8456976
    Abstract: There is disclosed herein a method and apparatus for centering a disk on a spindle, a spinstand and a method of testing with a spinstand. The method of centering includes attaching the disk to the spindle with a stick-slip clamp. A vector is determined by which the centre of the disk is displaced from the spindle axis and the vector is aligned with a movably mounted piezo actuator. A voltage is then applied to the piezo actuator to cause the piezo actuator to apply an impulse to the edge of the disk to cause the disk to slip in the clamp and reduce the displacement of the disk.
    Type: Grant
    Filed: January 4, 2012
    Date of Patent: June 4, 2013
    Assignee: Xyratex Technology Limited
    Inventors: Nicholas John Granger-Brown, Martin Siering
  • Patent number: 8437100
    Abstract: Systems and methods for flexure based shock and vibration sensor for head suspensions in hard disk drives. Specifically, this invention deals with operational shock and vibration management within a hard disk drive. In one implementation, the assembly includes a circuit embedded optical waveguide sensor that includes a flexible electrical circuit board with a configuration of either a single or multi layers of conductor traces, a thin flexure gimbal for carrying and flying a HDD slider, a consecutive sensing layer constructed by an optical core and by clad construction with a configuration of either a single core array or a plural core array, an optical loop formed by light input and an output core, optical grating disposed on the consecutive sensing layer forming an optical grating waveguide sensor, a light emitter for injecting light into the optical core, and a receiver receiving the output light from the optical core.
    Type: Grant
    Filed: April 18, 2012
    Date of Patent: May 7, 2013
    Assignee: Nitto Denko Corporation
    Inventors: Martin John McCaslin, Visit Thaveeprungsriporn, Szu-Han Hu
  • Patent number: 8437099
    Abstract: A hard disk drive includes a housing including a base member and a cover member, a spindle motor disposed in the housing, a data storage disk disposed on the spindle motor, an actuator disposed in the housing to move a read/write head to a position on the data storage disk, a clock signal providing unit disposed on the data storage disk to provide a clock signal of the data storage disk, a position signal providing unit disposed on the actuator to provide a position signal of the actuator, and first and second windows disposed in the housing to correspond to the clock signal providing unit and the position signal providing unit.
    Type: Grant
    Filed: April 29, 2009
    Date of Patent: May 7, 2013
    Assignee: Seagate Technology LLC
    Inventors: Kyung-ho Kim, Dong-ho Oh, Ha-yong Kim, Sung-joon Han, Kwang-jo Jung
  • Publication number: 20120194945
    Abstract: Cross-track deviation of a writer from a predetermined track on a recording medium is detected. A write current is adjusted based on the cross-track deviation of the writer from the predetermined track. The adjusted write current is applied to the writer to compensate for the cross-track deviation of the writer from the predetermined track.
    Type: Application
    Filed: February 2, 2011
    Publication date: August 2, 2012
    Applicant: Seagate Technology LLC
    Inventor: Kaizhong Gao
  • Publication number: 20120147495
    Abstract: A storage system includes a first buffer configured to store a first repeatable runout profile (RRP) for a sector of a rotating storage medium. A second buffer is configured to store a second RRP for the sector. A controller: controls a servo of the rotating storage medium based on the first RRP during a first revolution of the rotating storage medium; and learns the second RRP (i) while operating in a track-following mode, and (ii) during the first revolution. The controller ceases learning of the second RRP when one of (i) the controller is operating in a seek mode and (ii) the rotating storage medium is in an off-track state. Subsequent to the first revolution of the rotating storage medium and based on whether the learning of the second RRP was stopped during the first revolution, the controller replaces the first RRP with the second RRP in the first buffer.
    Type: Application
    Filed: February 20, 2012
    Publication date: June 14, 2012
    Inventors: Pantas Sutardja, Yuan Zheng, Yong Huang, Qiuliang Fu
  • Patent number: 8182705
    Abstract: A method for producing a thin film magnetic head including a magnetoresistive effect element (MR element) that has a magnetic sensor multi-layered film with a polygonal shape such that a vertex angle faces an air bearing surface (ABS) and a tip of the vertex angle is cut when the magnetic sensor multi-layered film is viewed from an X-Y plane that is parallel to a plane of a lower shield electrode layer includes a step for stopping a lapping process by using a measurement point in which a resistance value is steeply increased while the lapping face is gradually approaching the vertex angle of polygonal shape by lapping from the ABS side. Therefore, an excellent effect in which an ultra narrow track width that exceeds limits of photolithography technology can be securely and constantly formed is obtained.
    Type: Grant
    Filed: October 30, 2009
    Date of Patent: May 22, 2012
    Assignee: TDK Corporation
    Inventors: Kosuke Tanaka, Daisuke Miyauchi, Takumi Yanagisawa
  • Patent number: 8179629
    Abstract: Systems and methods for flexure based shock and vibration sensor for head suspensions in hard disk drives. Specifically, this invention deals with operational shock and vibration management within a hard disk drive. In one implementation, the assembly includes a circuit embedded optical waveguide sensor that includes a flexible electrical circuit board with a configuration of either a single or multi layers of conductor traces, a thin flexure gimbal for carrying and flying a HDD slider, a consecutive sensing layer constructed by an optical core and by clad construction with a configuration of either a single core array or a plural core array, an optical loop formed by light input and an output core, optical grating disposed on the consecutive sensing layer forming an optical grating waveguide sensor, a light emitter for injecting light into the optical core, and a receiver receiving the output light from the optical core.
    Type: Grant
    Filed: November 26, 2008
    Date of Patent: May 15, 2012
    Assignee: Nitto Denko Corporation
    Inventors: Martin John McCaslin, Visit Thaveeprungsriporn, Szu-Han Hu
  • Patent number: 8059518
    Abstract: Disclosed are a data storage apparatus, an assembling method thereof and an apparatus for generating a tracking position error signal capable of storing data using recording media formed with patterns for generating tracking position error signals to obviate errors that may be generated amidst storage of the data, wherein the patterns are formed for generating tracking position error signals on recording media before the recording media and storage are assembled to reduce the manufacturing cost and manufacturing process time.
    Type: Grant
    Filed: March 4, 2008
    Date of Patent: November 15, 2011
    Assignee: LG Electronics Inc.
    Inventors: Choong Woo Lee, Young Sik Kim, Jun Moon, Ji Young Jeong, Chung Choo Chung
  • Patent number: 8032007
    Abstract: The application manager 37 conducts “application signaling” when a first disc is replaced with a second disc. At this point, an application is continued if it is written in an application management table assigned to a Title played last on a first disc and also written in an application management table assigned to a Title to be played first on a second disc. On the other hand, an application is ended is it is written in the application management table assigned to the Title played last on the first disc but not written in the application management table assigned to the Title to be played first on the second disc.
    Type: Grant
    Filed: February 2, 2006
    Date of Patent: October 4, 2011
    Assignee: Panasonic Corporation
    Inventor: Wataru Ikeda
  • Publication number: 20100328812
    Abstract: According to one embodiment, a magnetic disk device includes a receiver, a storage module, a determining module, and a prescanner. The receiver receives a command from a host device. The storage module stores, with respect to each of divided areas formed by dividing the recording area of a recording medium into a plurality of areas, pre-scan control information indicating at least one of the receiving time and the number of receiving times. The receiving time indicates a time at which a write command is received. The number of receiving times indicates the number of times the write command is received within a predetermined period after the power is turned on. The determining module determines the order in which pre-scan is performed on the divided areas based on at least one of the receiving time and the number of receiving times. The prescanner pre-scans the divided areas in the determined order.
    Type: Application
    Filed: June 24, 2010
    Publication date: December 30, 2010
    Applicant: Toshiba Storage Device Corporation
    Inventors: Masamitsu OHHASHI, Michihiko UMEDA
  • Patent number: 7835106
    Abstract: A method of controlling the position of a read/write head relative to a disk in a test apparatus is disclosed. The test apparatus has a positioner for positioning the head. The positioner has a sensor to measure the actual position achieved by the positioner. The method includes generating a sensor signal measuring the actual position achieved by the positioner; generating a position error signal of the head relative to the disk detected at the head; high pass filtering the head position error signal and low pass filtering the sensor signal so that there is substantially no overlap in frequency between them; and, deriving a low frequency head error signal from the head position error signal corresponding to any drift of the head.
    Type: Grant
    Filed: June 25, 2007
    Date of Patent: November 16, 2010
    Assignee: Xyratex Technology Limited
    Inventor: Michael Alan Miles
  • Patent number: 7768738
    Abstract: Embodiments of mitigating the effects of disturbances of a disk drive are disclosed. One method includes sensing a position error signal of a transducer coupled to a surface of the disk drive, wherein the position error signal aids in control of an actuator of the disk drive. A first disturbance signal is generated by sensing a disturbance of a first sensor attached to the disk drive, wherein the first disturbance signal aids in control of the actuator. A second disturbance signal is generated by sensing a disturbance of a second sensor attached to the disk drive, wherein the second disturbance signal aids in control of the actuator. Effects of the disturbances on the position error signal are reduced by adaptively adjusting a gain of the first disturbance signal and a gain of the second disturbance signal.
    Type: Grant
    Filed: November 13, 2007
    Date of Patent: August 3, 2010
    Assignee: Sensor Platforms, Inc.
    Inventors: Daniel Yves Abramovitch, George Hsu
  • Patent number: 7760461
    Abstract: A disk drive is disclosed including a disk having a plurality of servo tracks. The servo tracks are banded together to form a plurality of servo track bands, and each servo sector comprises a fine track address that identifies one of the servo tracks. The disk drive further comprises a head attached to a distal end of an actuator arm operable to generate a read signal by reading the disk, and a mechanical position sensor operable to detect a coarse position of the actuator arm. The coarse position is processed to identify one of the servo track bands, and the read signal is processed to detect one of the fine track addresses, wherein the detected fine track address identifies a servo track within the identified servo track band. The identified servo track band is combined with the detected fine track address to generate a servo track address.
    Type: Grant
    Filed: November 24, 2008
    Date of Patent: July 20, 2010
    Assignee: Western Digital Technologies, Inc.
    Inventor: George J. Bennett
  • Patent number: 7701661
    Abstract: A disk drive is disclosed including a disk having a plurality of servo tracks. The servo tracks are banded together to form a plurality of servo track bands, and each servo sector comprises a fine track address that identifies one of the servo tracks. The disk drive further comprises a head attached to a distal end of an actuator arm operable to generate a read signal by reading the disk, and a mechanical position sensor operable to detect a coarse position of the actuator arm. The coarse position is processed to identify one of the servo track bands, and the read signal is processed to detect one of the fine track addresses, wherein the detected fine track address identifies a servo track within the identified servo track band. The identified servo track band is combined with the detected fine track address to generate a servo track address.
    Type: Grant
    Filed: November 24, 2008
    Date of Patent: April 20, 2010
    Assignee: Western Digital Technologies, Inc.
    Inventor: George J. Bennett
  • Patent number: 7697234
    Abstract: A rotation disturbance compensation control unit applies a compensation signal to a positioning control unit so as to cancel out rotation disturbance vibration components detected by using acceleration velocity sensors. At predetermined timing, a position error detection unit detects respective position errors of the case in which the rotation disturbance compensation control unit is turned on and the case in which it is turned off. A compensation control switching unit switches the rotation disturbance compensation control unit to be on if the position error of the case in which the compensation control of rotation disturbance is turned on is small and switches the compensation control switching unit to be off if the position error of the case in which the compensation control of rotation disturbance is turned off is small.
    Type: Grant
    Filed: February 20, 2008
    Date of Patent: April 13, 2010
    Assignee: Toshiba Storage Device Corporation
    Inventors: Yoshinari Higashino, Shigenori Yanagi
  • Publication number: 20100039727
    Abstract: A recording system for magnetic storage devices, including a beam column for generating a beam, a platform for moving a magnetic storage medium relative to the beam, and a signal generator for sequentially, or in a continuously alternating manner, deflecting the beam. In turn, the beam is directed according to displacement of dots on the extent of the magnetic storage medium such that dots of a plurality of dot groupings can be written to on the extent during a single pass of the beam column above the extent.
    Type: Application
    Filed: August 15, 2008
    Publication date: February 18, 2010
    Applicant: Seagate Technology LLC
    Inventors: David S. Kuo, Kim Y. Lee
  • Patent number: 7602577
    Abstract: A microactuator incorporated within an actuator assembly of a disk drive is used as a detection element for rapid off track events that may occur. Preferably, the microactuator employs one or more piezoelectric elements used for purposes of secondary actuation. Uncontrolled movement of the actuator across the disk results in the piezoelectric elements generating a voltage spike or signal that is analyzed to determine whether a rapid off track event has occurred. Rapid off track events are distinguished from other possible events, such as shock events. If a rapid off track event is detected, then remedial actions are taken to restore data integrity, to include executing restore commands such as rewriting selected data tracks. Dedicated piezoelectric elements may also be provided for detecting rapid off track events wherein these elements are not incorporated in the servo loop that controls positioning of the actuator.
    Type: Grant
    Filed: January 31, 2006
    Date of Patent: October 13, 2009
    Assignee: Seagate Technology LLC
    Inventors: Rickmer Kose, Erhard Schreck, Frank Obregon
  • Patent number: 7555947
    Abstract: An air pressure sensor capable of measuring air pressure highly accurately with a simple configuration is provided. The sensor includes: a sealed case with a sealed space formed therein; a first thin plate member which constitutes at least a part of the wall of the sealed case and deforms to allow the capacity of the sealed space to vary corresponding to changes in the outside air pressure; a first PZT which contacts the first thin plate member to thereby detect the natural frequency thereof; and a second thin plate member which has the same vibration characteristics as those of the first thin plate member and is provided outside the sealed case while contacting it; and a second PZT which has the same temperature characteristics as those of the first PZT and contacts the second thin plate member to thereby detect the natural frequency thereof.
    Type: Grant
    Filed: September 14, 2007
    Date of Patent: July 7, 2009
    Assignee: SAE Magnetics (H.K.) Ltd.
    Inventor: Tamon Kasajima
  • Patent number: 7529057
    Abstract: A control system including a filter module generates a filtered disturbance signal based on a disturbance signal and a transfer function of the filter module. A set point adjustment module generates an adjusted set point signal based on a set point signal and the filtered disturbance signal. A servo control module generates an error signal based on the adjusted set point signal and a position feedback signal. A filter adjustment module generates a filter adjustment signal based on the disturbance signal and the error signal. The filter adjustment signal adjusts the transfer function.
    Type: Grant
    Filed: September 8, 2008
    Date of Patent: May 5, 2009
    Assignee: Marvell International Ltd.
    Inventor: Pantas Sutardja
  • Patent number: 7495857
    Abstract: A disk drive is disclosed including a disk, an actuator arm, a head attached to a distal end of the actuator arm, a mechanical position sensor operable to generate a position signal representing a position of the head relative to the disk, and a voice coil motor for rotating the actuator arm about a pivot. The disk is rotated at a predetermined velocity, a control signal is generated in response to the position signal generated by the mechanical position sensor, and the control signal is applied to the voice coil motor in order to seek the head radially over the disk while writing a spiral track to the disk. The spiral track is then processed to maintain the head along a servo track while writing product servo sectors along the servo track.
    Type: Grant
    Filed: December 30, 2005
    Date of Patent: February 24, 2009
    Assignee: Western Digital Technologies, Inc.
    Inventor: George J. Bennett
  • Patent number: 7480116
    Abstract: A disk drive is disclosed including a disk having a plurality of servo tracks. The servo tracks are banded together to form a plurality of servo track bands, and each servo sector comprises a fine track address that identifies one of the servo tracks. The disk drive further comprises a head attached to a distal end of an actuator arm operable to generate a read signal by reading the disk, and a mechanical position sensor operable to detect a coarse position of the actuator arm. The coarse position is processed to identify one of the servo track bands, and the read signal is processed to detect one of the fine track addresses, wherein the detected fine track address identifies a servo track within the identified servo track band. The identified servo track band is combined with the detected fine track address to generate a servo track address.
    Type: Grant
    Filed: January 20, 2006
    Date of Patent: January 20, 2009
    Assignee: Western Digital Technologies, Inc.
    Inventor: George J. Bennett
  • Publication number: 20090002873
    Abstract: A sensing device for sensing installation position of a read head is assembled on the read head correspondingly to a scale and comprises at least three sensing elements and three signal generators. The three sensing elements are located on one end surface of the read head facing the scale to sense the distance between the read head and the scale. According to the different distance, the respective signal generators will send out different signals to inform the user if the read head is correctly installed, thus ensuring the precision of the installation, the sensing operation and movement of the read head.
    Type: Application
    Filed: June 27, 2007
    Publication date: January 1, 2009
    Inventor: Chih-Mao SHIAO
  • Patent number: 7468857
    Abstract: Disturbances to actuator control caused by external vibrations are corrected using feed-forward techniques that are selectively enabled or disabled based on signal values within a track follow loop. An increase in data integrity and reliability may be achieved by reducing off-track reads and writes caused by physical disturbances to disk drives during operation. Accelerometers detect external forces imparted on a disk and an acceleration feed-forward (AFF) signal is generated to compensate for disturbances to the location of a head caused by such external forces. Application of the AFF signal to an actuator may be based on whether signal values along the track follow loop exceed a certain threshold.
    Type: Grant
    Filed: February 9, 2007
    Date of Patent: December 23, 2008
    Assignee: Maxtor Corporation
    Inventors: Larry Hutsell, Dave Finamore, Farhad Navid
  • Patent number: 7450335
    Abstract: Methods and systems for reducing read/write head track misregistration are described. According to one embodiment, a first signal is received from a first capacitive sensor that faces a surface of a disk associated with a disk drive. A second signal is received from a second capacitive sensor that faces the surface of the disk. A determination is made as to whether the disk is being moved along its axis of rotation or whether the disk is tilting. Read/write head track misregistration is reduced based on the determination of whether the disk drive is being moved along an axis of rotation or whether the disk is tilting.
    Type: Grant
    Filed: August 9, 2006
    Date of Patent: November 11, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Toshiki Hirano, Tetsuo Semba, Matthew T. White
  • Publication number: 20080218897
    Abstract: Disclosed are a data storage apparatus, an assembling method thereof and an apparatus for generating a tracking position error signal capable of storing data using recording media formed with patterns for generating tracking position error signals to obviate errors that may be generated amidst storage of the data, wherein the patterns are formed for generating tracking position error signals on recording media before the recording media and storage are assembled to reduce the manufacturing cost and manufacturing process time.
    Type: Application
    Filed: March 4, 2008
    Publication date: September 11, 2008
    Inventors: Choong Woo Lee, Young Sik Kim, Jun Moon, Ji Young Jeong, Chung Choo Chung
  • Patent number: 7423833
    Abstract: A noise canceling system includes a signal generator module that generates a set point signal based on a desired position signal and a position feedback signal, a summation module that generates an output control signal based on the set point signal and a correction signal, and a filter module that generates the correction signal based on a disturbance signal and that minimizes a correlation between the disturbance signal and an error signal. The error signal represents a difference between the desired position signal and the position feedback signal.
    Type: Grant
    Filed: November 21, 2006
    Date of Patent: September 9, 2008
    Assignee: Marvell International Ltd.
    Inventor: Pantas Sutardja
  • Patent number: 7405896
    Abstract: A method and apparatus for detecting slider/disk fly-height modulation in a hard disk drive is provided. A slider is electrically isolating from an electrically grounded suspension. A signal line is coupled to the slider, the signal line for providing an alert signal when a modulation in fly-height between the slider and an electrically grounded disk of the hard disk drive occurs.
    Type: Grant
    Filed: April 26, 2006
    Date of Patent: July 29, 2008
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Toshiki Hirano, Ullal V. Nayak
  • Patent number: RE40975
    Abstract: A head suspension assembly including a load beam having a rigid region, a mounting region on a proximal end of the load beam, and a flexure on a distal end of the load beam. The flexure has a read/write head attachment region for supporting a read/write head on the distal end of the load beam. Deformation of the head suspension assembly displaces the head attachment region. A strain transducer circuit that acts as a strain gauge is mounted on the head suspension assembly. The resistance of the transducer circuit varies with strain in the circuit, which, in turn, varies with displacement of the read/write head. The magnitude of resistance change of the transducer circuit indicates the magnitude of head off-neutral motion.
    Type: Grant
    Filed: June 9, 2006
    Date of Patent: November 17, 2009
    Assignee: Hutchinson Technology Incorporated
    Inventors: Robert B. Evans, Todd A. Krinke