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

IPC: G11B21/10 ,  G11B5/55 ,  G11B5/56 ,  G11B19/28 ,  H03H17/02 ,  G11B19/247

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.

公开(公告)号：JPH0547125A

公开(公告)日：1993-02-26

申请号：JP32832391

申请日：1991-11-18

Applicant: IBM

Inventor： ARAI KOICHI ,  HIEN FUU DAN ,  NAKAGAWA YUZO ,  HARU HIYARUMAA OTSUTESEN ,  ARUN SHIYARUMA ,  MUTOUTANBII SURIIJIYAYANTA

IPC: G11B21/10

Abstract: PURPOSE: To cope with variation in the resonance frequency of an actuator. CONSTITUTION: Under the control a microprocessor 33, a switch 50 is so set as to exclude a filter 48 and a sine wave of variable frequency from a sine wave generator 54 is supplied to a driving circuit 34 to drive an actuator including a suspension 28 and an arm 29 which support a head 14. The microprocessor 44 analyzes a position error signal obtained from a decoder 22 at this time to determine the resonance frequency of the actuator, and constitutes the filter 48 so that the determined resonance frequency is excluded. Then the switch 50 is so set as to supply a signal for driving to the driving circuit 34 through the filter 48.

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

IPC: G11B5/55 ,  G05B15/02 ,  G11B5/596 ,  G11B21/08 ,  G11B21/10 ,  H03H17/02 ,  H03H17/04 ,  G11B19/00

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.