Servo method and device for controlling head position for a hard disk drive

摘要

A target PES value input from a controller and a value from a PES value calculator which corresponds to the displacement of a magnetic head are synthesized. A coefficient applicator applies a predetermined coefficient K1 to the above deviation (multiplication), and a variable coefficient applicator applies a coefficient Ka to the resulting value. The coefficient Ka is varied and set in the variable coefficient applicator in accordance with a value input from a table. The correspondence between the target PES value and the coefficient Ka used as a feedback coefficient for the PES value is stored in the table in advance so that the coefficient Ka is small when the PES value varies sharply and so that the coefficient Ka is large when the PES value is small. The variable coefficient applicator outputs, to a driver, a value to which the coefficient Ka has been applied in accordance with the value from the table.