Rotary recording apparatus and method of controlling the apparatus

A method of controlling a rotary recording apparatus including a rotary type recording medium on which information is recorded, a head for at least reading out information from the recording medium;

• a head drive for driving the head, a head position detector for outputting data on the current position of the head, and a controller for controlling the position of the head relative to the recording medium, said controller including a feedforward control signal generator for outputting a feedforward control signal in response to input of a target position of the head, a control model which outputs reference position data in response to input of the feedforward control signal, and a feedback controller which outputs a feedback control signal in response to input of the reference position data and negative feedback data, said controller controlling the position of the head to be in the target position by inputting the feedback control signal and the feedforward control signal to the head drive, by setting the negative feedback data to the current position data, and by inputting the difference between the reference position data and the negative feedback data to the feedback controller, said method comprising the steps of:
• setting the controller of the rotary recording apparatus in a compensation process state in which compensation is made for an input to the feedback controller as a bias force, and in which the negative feedback is shut off;
• inputting the target position in the compensation process state to obtain the reference position data and the current position data for each control cycle;
• and
• compensating the control model so that the sequence of the reference position data and the sequence of the current position coincide with each other.