Settling judgment method for positioning control device, positioning control device and disk apparatus

A positioning control device, comprising:

• a positioning control block for performing position control of an object according to a position error between a target position and a current position;
• and
• a settling judgment block which calculates a judgment value from said position error using a predetermined judgment formula, judges whether said judgment value is less than a slice value to judge said settlement, said slice value being determined such that each maximum value of maximum amplitude ratios for each frequency of a cyclic disturbance, which are ratios between a maximum value of said cyclic disturbance and the maximum amplitude value of said judgment value for each frequency of a cyclic disturbance measured when said cyclic disturbance is applied, is contained within a predetermined positioning accuracy,
• wherein said settling judgment block judges whether a number of samples, of which said judgment value is less than said slice value, continue for a number of samples which is set such that the maximum value of said maximum amplitude ratios is contained within said predetermined positioning accuracy.

A disk apparatus comprising:

• a head for at least reading data on a disk;
• an actuator for moving said head over the disk;
• a positioning control block for performing position control of said head according to a position error between a target position and a current position;
• and
• a settling judgment block which calculates a judgment value from said position error using a predetermined judgment formula, judges whether said judgment value is less than a slice value to judge said settlement, said slice value being determined such that each maximum value of maximum amplitude ratios for each frequency of a cyclic disturbance, which are ratios between a maximum value of said cyclic disturbance and the maximum amplitude value of said judgment value for each frequency of a cyclic disturbance measured when said cyclic disturbance is applied, is contained within a predetermined positioning accuracy,
• wherein said settling judgment block judges whether a number of samples, of which said judgment value is less than said slice value, continue for a number of samples which is set such that the maximum value of said maximum amplitude ratios is contained within said predetermined positioning accuracy.