Patent ID: 7019938

Claim:
A head positioning method for positioning a head with respect to a rotating disk by using an actuator, the actuator including a general adjustment actuator which has a voice coil motor and has a stroke covering the entire disk and a fine adjustment actuator which is interposed between the general adjustment actuator and the head and has a stroke smaller that that of the general adjustment actuator, the method comprising the steps of: generating a first driving signal for driving the general adjustment actuator and a second driving signal for driving the fine adjustment actuator; detecting a voltage generated in the voice coil motor due to the driving of the general adjustment actuator to generate a voltage signal which indicates the detected voltage value; estimating the position of the head displaced due to the driving of the general adjustment actuator based on the first driving signal and the voltage signal to generate a first head position estimation signal; estimating a displacement of the fine adjustment actuator based on the second driving signal to generate a displacement estimation signal; adding together the first head position estimation signal and the displacement estimation signal to generate a second head position estimation signal; generating from a target position signal which indicates a target position of the head and the second head position estimation signal, a position error estimation signal which indicates an error of the head with respect to the target position; and correcting the first driving signal and the second driving signal based on the position error estimation signal.