Hitachi, Ltd.

Souichi Tohyama

Hiromu Hirai

Takashi Yamaguchi

Haruaki Otsuki

Yoosuke Hamada

A disk drive has a data recording medium disk, a head disposed facing a recording surface of the disk, for reading and writing data, a positioning mechanism for supporting and moving the head, a position detector for detecting the position of the head and outputting a position detection signal, and a control unit for processing the position detection signal and outputting a position control signal to the positioning mechanism. The control unit calculates a target acceleration signal for a given target track so as to make a turnaround frequency of a frequency component of the target acceleration signal coincident with a resonance frequency of the head positioning mechanism, calculates a target position for a head positioning operation in accordance with the target acceleration signal, calculates a position command value by inputting the target position signal to a model (inverse model) of an approximate inverse system to a position control system which includes the head positioning mechanism and the position detector, and outputs a position tracking error to the positioning mechanism, the position tracking error being the difference between the position command value and the position detection signal of the head.

Disk drive and method of controlling the same

Method and apparatus for control of positioning of a recording/playback head or other controlled object. When a controlled object reaches the vicinity of a target position, the control system is switched from operation as a velocity control system to operation as a position control system. By using state variables of the controlled object at that time, coefficients corresponding to the detected state variables are determined from characteristics of the controlled object which are determined in advance. By using the determined coefficient values, initial values upon start of position control of the position control system are set, and positioning control is then carried out.

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Ibaraki, Japan

Souichi Tohyama