Patents by Inventor Naoyuki Kagami
Naoyuki Kagami has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 11043243Abstract: A data storage device is disclosed wherein an elevator actuator is controlled to move a head along an axial dimension toward a first disk surface of a first disk while processing a proximity signal generated by a proximity sensor. A first actuator position is detected when the actuator arm is proximate the first disk surface of the first disk based on the proximity signal.Type: GrantFiled: August 17, 2020Date of Patent: June 22, 2021Assignee: Western Digital Technologies, Inc.Inventors: Kexiu Liu, Kuang-Yang Tu, Jenghung Chen, Naoyuki Kagami, Gaku Ikedo
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Patent number: 10996740Abstract: The present disclosure generally relates to an electronic circuit and method of operating thereof to back up write cache data on DDR memory in data storage devices during an emergency power off (EPO). The method involves using a power management integrated circuit (PMIC), a combo driver and one MOSFET for regulator output. The method involves detecting a voltage value that is below a predetermined threshold value, retracting a write head away from a hard disk drive (HDD), backing up data, and then resetting the HDD after the backup is complete. The backing up and retraction may occur in parallel or in sequence. The method utilizes the spindle back-electromotive force (BEMF) power to have sufficient power to make the backup. If the power from the spindle BEMF is too low, then the retraction is suspended and a high impedance is present to lighten the load until the BEMF recovers before the power on reset. As such, the back-up data is not reset and volatized by a lack of power.Type: GrantFiled: March 26, 2020Date of Patent: May 4, 2021Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.Inventors: Hiroki Watanabe, Gaku Ikedo, Naoyuki Kagami, James Jinshi Ng, Brian Kenneth Tanner
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Publication number: 20200381016Abstract: A data storage device is disclosed wherein an elevator actuator is controlled to move a head along an axial dimension toward a first disk surface of a first disk while processing a proximity signal generated by a proximity sensor. A first actuator position is detected when the actuator arm is proximate the first disk surface of the first disk based on the proximity signal.Type: ApplicationFiled: August 17, 2020Publication date: December 3, 2020Inventors: Kexiu Liu, Kuang-Yang Tu, Jenghung Chen, Naoyuki Kagami, Gaku Ikedo
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Publication number: 20200225733Abstract: The present disclosure generally relates to an electronic circuit and method of operating thereof to back up write cache data on DDR memory in data storage devices during an emergency power off (EPO). The method involves using a power management integrated circuit (PMIC), a combo driver and one MOSFET for regulator output. The method involves detecting a voltage value that is below a predetermined threshold value, retracting a write head away from a hard disk drive (HDD), backing up data, and then resetting the HDD after the backup is complete. The backing up and retraction may occur in parallel or in sequence. The method utilizes the spindle back-electromotive force (BEMF) power to have sufficient power to make the backup. If the power from the spindle BEMF is too low, then the retraction is suspended and a high impedance is present to lighten the load until the BEMF recovers before the power on reset. As such, the back-up data is not reset and volatized by a lack of power.Type: ApplicationFiled: March 26, 2020Publication date: July 16, 2020Inventors: Hiroki WATANABE, Gaku IKEDO, Naoyuki KAGAMI, James Jinshi NG, Brian Kenneth TANNER
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Patent number: 10635158Abstract: The present disclosure generally relates to an electronic circuit and method of operating thereof to back up write cache data on DDR memory in data storage devices during an emergency power off (EPO). The method involves using a power management integrated circuit (PMIC), a combo driver and one MOSFET for regulator output. The method involves detecting a voltage value that is below a predetermined threshold value, retracting a write head away from a hard disk drive (HDD), backing up data, and then resetting the HDD after the backup is complete. The backing up and retraction may occur in parallel or in sequence. The method utilizes the spindle back-electromotive force (BEMF) power to have sufficient power to make the backup. If the power from the spindle BEMF is too low, then the retraction is suspended and a high impedance is present to lighten the load until the BEMF recovers before the power on reset. As such, the back-up data is not reset and volatized by a lack of power.Type: GrantFiled: April 24, 2017Date of Patent: April 28, 2020Assignee: Western Digital Technologies, Inc.Inventors: Hiroki Watanabe, Gaku Ikedo, Naoyuki Kagami, James Jinshi Ng, Brian Kenneth Tanner
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Patent number: 7035034Abstract: A hard disk device includes a servo control unit that constitutes a servo loop for a head seek for performing read/write of data from/to a recording medium, a correction signal generation unit for generating a correction signal for correcting a control by the servo control unit based on an output of a predetermined sensor, and a correction signal control unit for estimating an effect of supplying the correction signal to the servo loop and for controlling whether or not the correction signal is to be supplied to the servo loop in response to a result of the estimation. Moreover, the gain of the sensor is dynamically controlled in response to the above estimation result.Type: GrantFiled: May 21, 2003Date of Patent: April 25, 2006Assignee: International Business Machines CorporationInventors: Tetsuo Semba, Naoyuki Kagami, Akira Tokizono, Gaku Ikedo
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Patent number: 7019921Abstract: A method and apparatus for use with a rotating storage device. The rotating storage device includes a storage medium driven to rotate, a head for reading and writing information on the storage medium and a ramped loading mechanism in which the head is stored. In accordance with the method of the present invention, the head is loaded from the ramped loading mechanism onto the storage medium. Next, determining whether or not a write operation on said storage medium is performed within a predetermined amount of time after loading said head on said storage medium and in response to said determination, setting a verification flag to indicate a data verification is required immediately after said write operation.Type: GrantFiled: January 8, 2004Date of Patent: March 28, 2006Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Naoyuki Kagami, Masayuki Kanamaru, Shunichiroh Ohta, Akira Tokizono, Toshihiko Tsunokawa
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Patent number: 6961202Abstract: A data storage device includes an enclosure case and a circuit board attached to an outer surface of the enclosure case, the enclosure case containing a spindle motor and a circular movement actuator, the spindle motor being for rotating a storage medium, the circular movement actuator being for controlling a position of a read and write head for reading data from the storage medium and for writing data to the storage medium, the circuit board having an interface cable connector at one end portion thereof for establishing a connection to a host. The circuit board is located between the interface cable connector and the spindle motor, and is attached to the enclosure case by use of a plurality of fastening members. An acceleration sensor is attached to the circuit board next to the fastening members for detecting vibrations applied to the data storage device in a rotation direction in a plane along the circuit board.Type: GrantFiled: April 23, 2003Date of Patent: November 1, 2005Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Gaku Ikedo, Mirei Hosono, Yoshitaka Kakizaki, Naoyuki Kagami
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Patent number: 6937422Abstract: An apparatus and method of controlling an actuator of a data storage device detect and/or correct narrowband mechanical excitations such as due to spindle bearing defects through sensing and/or rejecting disturbance frequencies associated with such narrowband mechanical excitations in an actuator control signal generated by a data storage device controller. A narrowband filter may be used to reject, from an actuator control signal generated by a data storage device controller, a disturbance frequency associated with a spindle bearing defect in a data storage device, and disposed in proximity to a zero crossover frequency associated with the data storage device controller. In addition, a peak filter disposed in a control loop of a data storage device controller may be configured to detect a spindle bearing defect in a data storage device by detecting an amplitude of a control signal in the control loop in proximity to a disturbance frequency associated with the spindle bearing defect.Type: GrantFiled: November 7, 2002Date of Patent: August 30, 2005Assignee: Hitachi Global Technologies Netherlands B.V.Inventors: Hien Phu Dang, Mirei Hosono, Naoyuki Kagami, Kenji Okada, Arun Sharma, Gordon James Smith, Sri M. Sri-Jayantha
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Patent number: 6937408Abstract: In addition to the conventional test pattern writing in a center of each track and inspection of burst patterns (A and B patterns) through a writing test in a SAT, there is also performed a test pattern data writing test, which is done at each boundary between tracks. With this additional test, it is possible to accurately inspect both C and D burst patterns that are sensitive to a PES signal at each boundary between tracks.Type: GrantFiled: February 27, 2002Date of Patent: August 30, 2005Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Ryoheita Hattori, Naoyuki Kagami, Tetesuya Kokubo, Nobuya Matsubara, Kaoru Umemura
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Patent number: 6831809Abstract: A control arrangement having a feedforward system and a feedback system, a control model for generating reference position data from a feedforward control signal is separated into an original control model and a compensation filter. Gain of the feedforward control signal is compensated by a gain compensation circuit to form a feedforward control signal after compensation. The reference position data is input to a feedback controller, and a feedback control signal and feedforward control signal are input to a control object. Coefficients of the compensation filter and the gain compensation circuit are compensated on the basis of a head position trajectory obtained by actual seek operation.Type: GrantFiled: February 27, 2002Date of Patent: December 14, 2004Assignee: International Business Machines CorporationInventors: Naoyuki Kagami, Kenji Okada, Tetsuo Semba, Akira Tokizono, Hiroshi Uchida, Akinori Yuba
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Publication number: 20040179288Abstract: A method and apparatus for use with a rotating storage device. The rotating storage device includes a storage medium driven to rotate, a head for reading and writing information on the storage medium and a ramped loading mechanism in which the head is stored. In accordance with the method of the present invention, the head is loaded from the ramped loading mechanism onto the storage medium. Next, location information stored in said storage medium via said head is read. A location of the head is then retained for a predetermined period above a track of a region other than a valid storage region of said storage medium after successfully reading the location information.Type: ApplicationFiled: January 8, 2004Publication date: September 16, 2004Applicant: International Business Machines CorporationInventors: Naoyuki Kagami, Masayuki Kanamaru, Shunichiroh Ohta, Akira Tokizono, Toshihiko Tsunokawa
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Patent number: 6754019Abstract: An improved system and method for implementing a rotary memory device, including a host system and a disk-shaped memory medium storing position information, or a servo address mark (SAM). If a head fails to read a valid SAM, a dummy SAM is generated to prevent an arm with a read/write head from entering a neutral state. If the normal state cannot be restored within a fixed number of intervals, the system goes into the emergency brake control mode. In this emergency brake control mode, the direction of the head is determined, and the VCM current is applied in such a way drive the arm in the opposite direction. Damage to the magnetic medium and subsequent data loss problems are reduced because the velocity of the head is reduced to a safe level.Type: GrantFiled: July 3, 2001Date of Patent: June 22, 2004Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Akira Tokizono, Naoyuki Kagami, Hiroshi Uchida, Takashi Kuroda
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Publication number: 20040090698Abstract: An apparatus and method of controlling an actuator of a data storage device detect and/or correct narrowband mechanical excitations such as due to spindle bearing defects through sensing and/or rejecting disturbance frequencies associated with such narrowband mechanical excitations in an actuator control signal generated by a data storage device controller. A narrowband filter may be used to reject, from an actuator control signal generated by a data storage device controller, a disturbance frequency associated with a spindle bearing defect in a data storage device, and disposed in proximity to a zero crossover frequency associated with the data storage device controller. In addition, a peak filter disposed in a control loop of a data storage device controller may be configured to detect a spindle bearing defect in a data storage device by detecting an amplitude of a control signal in the control loop in proximity to a disturbance frequency associated with the spindle bearing defect.Type: ApplicationFiled: November 7, 2002Publication date: May 13, 2004Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Hien Phu Dang, Mirei Hosono, Naoyuki Kagami, Kenji Okada, Arun Sharma, Gordon James Smith, Sri M. Sri-Jayantha
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Patent number: 6707634Abstract: A method and apparatus for use with a rotating storage device. The rotating storage device includes a storage medium driven to rotate, a head for reading and writing information on the storage medium and a ramped loading mechanism in which the head is stored. In accordance with the method of the present invention, the head is loaded from the ramped loading mechanism onto the storage medium. Next, location information stored in the storage medium via the head is read. A location of the head is then retained for a predetermined period above a track of a region other than a valid storage region of the storage medium after successfully reading the location information.Type: GrantFiled: September 10, 2001Date of Patent: March 16, 2004Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Naoyuki Kagami, Masayuki Kanamaru, Shunichiroh Ohta, Akira Tokizono, Toshihiko Tsunokawa
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Patent number: 6690537Abstract: A read/write head servo control system for data recording devices, wherein a method of compensating initial values is utilized to generate a control signal to move the head from an initial position to a target position. The method estimates and stores multiple position compensation values. A first control signal moves the head from an initial position to a target position. Head position values are sampled as the head moves. Head position deviation values are calculated for the sampled position values. The head position values are utilized to select a set of estimated position compensation values. These values are in turn utilized to generate a second control signal, which is then utilized to control the position of the head.Type: GrantFiled: July 13, 2001Date of Patent: February 10, 2004Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Naoyuki Kagami, Akira Tokizono, Hiroshi Uchida
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Patent number: 6678109Abstract: A disk drive, a servo controller, and a controller which have realized high-degree control by lightening processing load to a microprocessor unit (MPU) without increasing cost is disclosed. An analog/digital (AD) converter (ADC) performs the AD conversions of the regenerated levels A, B, C, and D of burst patterns supplied from a channel and retains the converted levels in an ADC register. A servo assist (SA) computes parameters, such as the position error of a head, independently of an MPU, based on the regenerated levels of the burst patterns retained in the ADC register and an instruction from the MPU retained in a SRAM. Based on the computed parameters, the SA computes servo data (DACOUT) for driving a voice coil motor and supplies the servo data to the DAC section of a VCM driver section through a SIO.Type: GrantFiled: August 13, 1998Date of Patent: January 13, 2004Assignee: Hitachi Global TechnologiesInventors: Naoyuki Kagami, Masayuki Murakami, Yuzo Nakagawa, Tatsuya Sakai
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Publication number: 20040001280Abstract: A data storage device includes an enclosure case and a circuit board attached to an outer surface of the enclosure case, the enclosure case containing a spindle motor and a circular movement actuator, the spindle motor being for rotating a storage medium, the circular movement actuator being for controlling a position of a read and write head for reading data from the storage medium and for writing data to the storage medium, the circuit board having an interface cable connector at one end portion thereof for establishing a connection to a host. The circuit board is located between the interface cable connector and the spindle motor, and is attached to the enclosure case by use of a plurality of fastening members. An acceleration sensor is attached to the circuit board next to the fastening members for detecting vibrations applied to the data storage device in a rotation direction in a plane along the circuit board.Type: ApplicationFiled: April 23, 2003Publication date: January 1, 2004Applicant: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Gaku Ikedo, Mirei Hosono, Yoshitaka Kakizaki, Naoyuki Kagami
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Publication number: 20030231423Abstract: A hard disk device includes a servo control unit that constitutes a servo loop for a head seek for performing read/write of data from/to a recording medium, a correction signal generation unit for generating a correction signal for correcting a control by the servo control unit based on an output of a predetermined sensor, and a correction signal control unit for estimating an effect of supplying the correction signal to the servo loop and for controlling whether or not the correction signal is to be supplied to the servo loop in response to a result of the estimation. Moreover, the gain of the sensor is dynamically controlled in response to the above estimation result.Type: ApplicationFiled: May 21, 2003Publication date: December 18, 2003Inventors: Tetsuo Semba, Naoyuki Kagami, Akira Tokizono, Gaku Ikedo
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Patent number: 6614613Abstract: An active control mechanism and method for stabilizing a servo-controlled actuator system such as an actuator system in a data recording disk drive by compensating the vibrational modes of the actuator's arm assembly. The control mechanism has a sensing arrangement which can include one or more individual sensors attached to the actuator at locations where they generate signals in phase with the vibrational modes, and especially with all the low-frequency major vibrational modes, of the arm assembly. A control mechanism derives from the signals an adjustment signal consisting of three corrective terms—a stiffening correction, an active damping correction, and an inertia correction by a phase correction. Furthermore, high-frequency out-of-phase modes can be stabilized by appropriately shifting the phase of the signals. The adjustment signal is used in the feedback control loop to stabilize the actuator system.Type: GrantFiled: March 16, 2000Date of Patent: September 2, 2003Assignee: International Business Machines CorporationInventors: Fu-Ying Huang, Naoyuki Kagami, Tetsuo Semba, Eiji Soga, Shingo Tsuda