Patent ID: 8488268

Claim:
A disk device including a control object constituted by an actuator, a head for executing a seek operation while driven by said actuator and a circuit for taking out a head position signal from information read out by said head from an information recording medium, and a control unit for generating an operation signal for said actuator so that an error signal as a difference between a target position of said head and a head position represented by said head position signal from said circuit becomes 0, wherein: said control unit has a servo compensator for stabilizing transfer characteristics of said control object by using said error signal as an input, a variable gain device A the gain of which varies with the head position, a resonance filter using an output of said variable gain device A as its input and a variable gain device B using an output of said resonance filter as its input; the gain of said variable gain device A is an inverse number of the gain of said variable gain device B; an input signal to said variable gain device A is made 0 during the seek operation of said head and is said error signal near the end of the seek operation; and a signal as the sum of the output signal of said variable gain device B using the output signal of said resonance filter as its input signal and the output signal of said servo compensator is used as the input signal given to said actuator.