Patent ID: 7646560

Claim:
A positioning control system comprising: a head moving unit configured to move a head for recording and reproducing of information on a disk on which information can be recorded; a position detecting unit configured to detect a position of the head at predetermined time intervals; an error detecting unit configured to detect a position error signal representing an error between a detected head position and a target position set in advance; a storage configured to store the detected position error signal in association with a detected timing of the head position; a disturbance detecting unit configured to detect a non-periodic disturbance generated in the head moving unit; a modifying unit configured to modify a first position error signal corresponding to a first head position detected in a first rotation period of the disk, on the basis of a second position error signal corresponding to a second head position detected one period length before the first head position; and a feedback controller configured to calculate a position control command according to a modified first position error signal and supplies the position control command to the head moving unit, wherein the modifying unit reduces an amplitude of the second position error signal and modifies the first position signal error on the basis of an amplitude-reduced second position error signal, when the non-periodic disturbance is detected in a second rotation period which is one period before the first rotation period and when a detection timing of the second head position is included in a predetermined time range with respect to a detection timing of the non-periodic disturbance.