Patent ID: 7576943

Claim:
A disk drive, comprising: a controlled object including; an actuator, a head for performing a seek operation by being driven by the actuator, and a circuit for extracting a head position signal from information read by the head from a recording medium, and a control part including; a signal generator for generating an operation signal to the actuator to make an error signal made by a difference between a target position and a head position indicated by the head position signal coming from the circuit as 0, a phase compensator for stabilizing transfer characteristics of the controlled object by inputting the error signal, a resonance filter, configured as a band-pass filter, connected in series to the phase compensator via a time-variable gain adjuster, and an adder for adding an output of the resonance filter and an output of the phase compensator, wherein a gain of the time-variable gain adjuster is 0 during the seek operation of the head, becomes a specified value larger than 1 when the seek operation is about to end, and becomes 1 by gradation after remaining at the specified value for a predetermined length of time.