公开(公告)号：HK1022370A1

公开(公告)日：2000-08-04

申请号：HK00101233

申请日：2000-02-29

Applicant: IBM

Inventor： SRI SHARMA ARUN MUTHUTHAMBY SR ,  HIEN PHU DANG ,  NAOYUKI KAGAMI ,  YUZO NAKAGAWA ,  AKIRA TOKIZONO ,  ISAO YONEDA

IPC: G11B5/596 ,  G11B21/02 ,  G11B21/10 ,  G11B21/21 ,  G11B

Abstract: Methods and systems for detecting and correcting for undesirable vibrations impacting the servo systems in data storage devices. A detection technique is provided wherein a detection filter is configured to scan a position signal of the servo system across a range of frequencies, and, at each respective scanned frequency, record an amplitude associated therewith. The recorded amplitudes are examined to determine whether any exceed a threshold, thereby locating a peak frequency of the vibration. Using the detected peak frequency of the vibration, a corrective filter is configured to operate about the peak frequency of vibration, thereby reducing its impact on the position signal in the servo system. Optimum detection and correction filter structures are disclosed, as are techniques for addressing filter state vectors as initial conditions as the corrective filters are repeatedly engaged during successive settle-out and track follow cycles (between seeks), as are continuous adaptation techniques for changing vibration environments.

公开(公告)号：SG86330A1

公开(公告)日：2002-02-19

申请号：SG1998002745

申请日：1998-08-04

Applicant: IBM

Inventor： TATSUYA SAKAI ,  MASAYUKI MURAKAMI ,  NAOYUKI KAGAMI ,  YUZO NAKAGAWA

IPC: G11B21/10 ,  G11B5/596 ,  G11B5/00 ,  G11B19/02 ,  G11B19/00 ,  G11B5/09 ,  G11B5/55

Abstract: 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.

公开(公告)号：SG83772A1

公开(公告)日：2001-10-16

申请号：SG200000797

申请日：2000-02-14

Applicant: IBM

Inventor： KENJI KUROKI ,  THOMAS ROBERT ALBRECHT ,  FUMINORI SAI ,  YUZO NAKAGAWA ,  NOBUHISA KOIDE ,  MASASHI MURAI ,  KEISHI TAKAHASHI ,  TIMOTHY CLARK REILEY ,  ERNO H KLASSEN

IPC: G11B21/02 ,  G11B19/04 ,  G11B21/12 ,  H02P8/12 ,  G11B5/54

Abstract: A method and apparatus to provide a retract circuit that can correspond to the tendency toward miniaturization and low supply voltage. When drive supply voltage Vcc is applied, a retract circuit charges a retract condenser Cr with boosted voltage Vup, equal to three times Vcc, generated by a booster circuit. Then, if the drive supply voltage Vcc is cut off and a VCM driver stops, the retract circuit detects power-off with a power OFF sense circuit, and provides retract delay time by a retract delay circuit. Furthermore, when the retract delay time elapses after the drive power supply is turned off, the retract driver switches the switching circuits on, discharges the retract condenser, charged at the boosted voltage, supplies discharge current to a voice coil, and retracts the head assembly.