Patent ID: 8873189

Claim:
A magnetic disk device comprising: a magnetic disk; a magnetic head provided to the magnetic disk; a fine-movement actuator configured to allow a fine movement of the magnetic head; a coarse-movement actuator configured to allow a coarse movement of the magnetic head; a movement position controller configured to control a movement position of the magnetic head by driving the fine-movement actuator and the coarse-movement actuator; a disturbance vibration detector configured to detect a disturbance vibration component with respect to the control of the movement position of the magnetic head; and a disturbance compensation module configured to correct the movement position so as to suppress the disturbance vibration component detected by the disturbance vibration detector, wherein the movement position controller comprises: a fine-movement controller configured to finely control the movement position of the magnetic head by performing a drive control of the fine-movement actuator based on an error position between a target position and a detected position of the magnetic head; a coarse-movement controller configured to coarsely control the movement position of the magnetic head by performing a drive control of the coarse-movement actuator based on the error position between the target position and the detected position of the magnetic head; and an observer configured to correct the error position between the target position and the detected position of the magnetic head such that the drive control of the coarse-movement actuator is performed in cooperation with the drive control of the fine-movement actuator, wherein the disturbance compensation module comprises a fine disturbance compensation module configured to correct the movement position controlled by the fine-movement controller so as to suppress the disturbance vibration component detected by the disturbance vibration detector, wherein the fine disturbance compensation module comprises: a high-order filter configured to convert the disturbance vibration component into a position component; and a first amplifier configured to adjust an output gain of the high-order filter, wherein the disturbance compensation module comprises a coarse disturbance compensation module configured to correct the movement position controlled by the coarse-movement controller so as to suppress the disturbance vibration component detected by the disturbance vibration detector, and wherein the fine disturbance compensation module is configured to correct the movement position based on a high-frequency component of the disturbance vibration component, and the coarse disturbance compensation module is configured to correct the movement position based on a low-frequency component of the disturbance vibration component.