US 12,462,837 B2
Magnetic disk device and method
Shoya Yamamoto, Saitama Saitama (JP); and Masafumi Iwashiro, Yokohama Kanagawa (JP)
Assigned to Kabushiki Kaisha Toshiba, Kawasaki (JP); and Toshiba Electronic Devices & Storage Corporation, Kawasaki (JP)
Filed by KABUSHIKI KAISHA TOSHIBA, Tokyo (JP); and TOSHIBA ELECTRONIC DEVICES & STORAGE CORPORATION, Tokyo (JP)
Filed on Sep. 10, 2024, as Appl. No. 18/830,381.
Claims priority of application No. 2024-031640 (JP), filed on Mar. 1, 2024.
Prior Publication US 2025/0279117 A1, Sep. 4, 2025
Int. Cl. G11B 5/596 (2006.01)
CPC G11B 5/59688 (2013.01) 20 Claims
OG exemplary drawing
 
1. A magnetic disk device comprising:
a magnetic disk;
a magnetic head configured to write and read data to and from the magnetic disk;
an actuator arm having the magnetic head at a distal end;
a motor configured to move the actuator arm to move the magnetic head in a radial direction of the magnetic disk;
a drive circuit configured to generate a first current that drives the motor by an amount according to an instruction value and supply the generated first current to the motor;
a first sensor configured to detect a predetermined physical quantity; and
a controller configured to:
detect a position of the magnetic head;
generate a first instruction value so as to reduce a deviation amount of the detected position of the magnetic head from a target position of the magnetic head;
correct the first instruction value by a first feedforward control based on a first detection value obtained by the first sensor;
input a second instruction value, which is a value obtained by correcting the first instruction value, to the drive circuit as the instruction value; and
execute a first operation in accordance with occurrence of a set event, the first operation being an operation of acquiring a first waveform that is a waveform of the deviation amount, acquiring from the first waveform a first frequency band that is a frequency band whose amplitude is greater than a first threshold, and adjusting a coefficient of a transfer function of the first feedforward control so as to suppress the first detection value in a second frequency band different from the first frequency band and output a correction amount for the first instruction value based on the first detection value in the first frequency band.