Patent ID: 6940680

Claim:
A positioning control system situating head in a target position on a disk incorporated in a disk drive, comprising: a position error detector that detects a position error between a position of the head and the target position; a frequency detector that detects a characteristic frequency component included in the position error, using a Fourier transform; an estimator that estimates a frequency of a disturbance related to a target value variation based on a Fourier coefficient resulting from the Fourier transform, the estimator estimating a plurality of frequencies as candidates for the frequency of the disturbance and positioning control being executed for each frequency candidate estimated by the estimator, to estimate a position error for said each frequency candidate; and a controller that modifies the characteristic frequency component based on the frequency of the disturbance estimated by the estimator, and calculates a control correction value for suppressing the target value variation having the modified characteristic frequency component, wherein the controller selects one of the estimated frequency candidates which shows a minimum position error and uses the selected frequency candidate as the frequency detected by the frequency detector.