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公开(公告)号：JPH1027442A
公开(公告)日：1998-01-27
申请号：JP1809497
申请日：1997-01-31
Applicant: IBM
Inventor： MUCHUTANBII SURIIJAYANTA , ARN SHARMA , HIEN DANGU , SUZUKI HIROYUKI
Abstract: PROBLEM TO BE SOLVED: To provide a direct access storage device a high track density and low power consumption at low cost by controlling a servo system by using a corrected position error signal obtained by subtracting filtered data from a position error signal. SOLUTION: A direct access storage device(DASD) 32 includes a disk 34 and, when the disk 34 is rotated by a spindle motor 40, the disk 34 interacts with the head 36 of the end part of an actuator 38. A repeating runout component is stored in the reserve data zone of the disk 34 during manufacturing and read in a RAM 42 during power up. The repeating runout component of a RAM base is subtracted from a position error correcting signal(PES) in a next track-following mode.
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公开(公告)号：JPH11112289A
公开(公告)日：1999-04-23
申请号：JP26203597
申请日：1997-09-26
Applicant: IBM
Inventor： KAGAMI NAOYUKI , TOKIZONO AKIRA , HIEN FUU DAN , ARN SHARMA , MUTUTANBII SURIIJAYANTA
Abstract: PROBLEM TO BE SOLVED: To prevent filter output from becoming discontinuous at the time of switching a filter characteristic by setting the output value of a delay means with an initial value setting means at the time of changing a filter coefficient by the setting of a coefficient setting means. SOLUTION: The hardware state machine(SM) 29 of a hardware sequencer(SA) 23 calculates respective parameters and judges an operation mode. The SM 29 compares the mode of previous execution, which is held in an inner variable or the like, with a present mode. When the mode is changed, the parameters of the filter characteristics for the respective operation modes, which are stored, are set and the initial value of the inner variable is set. When the filter characteristic is changed, the filter coefficient of the digital filter suddenly changes. Thus, the filter output becomes discontinuous when the inner variable (delay value) until previous time is used as it is. A value Uss obtained by multiplying a value Css estimated to be control output at the time of switching the filter and the gain together is obtained and the delay value is set.
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公开(公告)号：JP2000137960A
公开(公告)日：2000-05-16
申请号：JP30892398
申请日：1998-10-29
Applicant: IBM
Inventor： KAGAMI NAOYUKI , TOKIZONO AKIRA , MUTUTANBII SURIIJAYANTA , SAKAI TATSUYA , YONEDA ISAO , HIEN FUU DAN , ARN SHARMA
Abstract: PROBLEM TO BE SOLVED: To effectively perform disturbance suppression, mechanical resonance suppression by providing plural filter means and constituting the filter means in multistage with a parallel or serial form for a position control output with instructions of an MPU when an actuator is position controlled. SOLUTION: A servo control part SV 21 receives a signal from a servo pattern of a magnetic disk 1 to process it, and generates a servo signal output DACOUT moving a head arm 3 through a hardware sequencer SA 23 to send it to a voice coil motor VCM drive part 6. The SA 23 consists of plural digital filters, and sets arrangement of respective digital filters for the servo signal output DACOUT based on the instructions from the MPU 40. For instance, peak filters are arranged serially, and a peak is given to an output gain at a required frequency. Or, notch filters are arranged parallel, and the output gain suppressing the mechanical resonance is obtained.
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公开(公告)号：JP2000048509A
公开(公告)日：2000-02-18
申请号：JP20168399
申请日：1999-07-15
Applicant: IBM
Inventor： SURI MUSHUZAMBI SURIIJAYANZA , ARN SHARMA , HEIN HUGH DAN , KAGAMI NAOYUKI , NAKAGAWA YUZO , TOKIZONO AKIRA , YONEDA ISAO
Abstract: PROBLEM TO BE SOLVED: To compensate for vibration that is encountered in a disk drive by first detecting a governing vibration frequency and then executing a two-step algorithm for constituting an optimum servo feedback solution. SOLUTION: A detection filter for scanning a positional signal over the frequency range of vibration is composed while a data storage is operating, amplitude related to frequency is recorded, it is judged whether the recorded amplitude exceeds a specific threshold or not, the corresponding frequency of vibration is detected accordingly, and the frequency of vibration is detected. A correction filter using a plurality of filter coefficients being determined as the function of the detection frequency of vibration is constituted, and the influence of the detection frequency of vibration for the positional signal is reduced. External and internal vibrations are targeted as vibration. When the correction filter is repeatedly involved, the filter state vector as initial filter conditions is refreshed periodically in response to output from the correction filter.
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