Hitachi, Ltd.

Yoosuke Hamada

Hiromu Hirai

Isao Kobayashi

Haruaki Otsuki

Souichi Tohyama

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

When a move command (data indicating to move a movable unit from one position to a target position) is issued, a movable unit is displaced in response to the move command. A target trajectory which is an aggregation of target positions varying with time is determined such that a residual vibration of a structure at and after the stop of displacement of the movable unit is minimized. Target positions at various times during the displacement of the movable unit are generated based on the target trajectory. The target positions at various times are supplied to a control unit which feeds back an actual position of the movable unit and produces a drive signal which makes a difference from the target position zero. The drive signal is supplied to an actuator so that a drive force is transmitted from the actuator to the movable unit which follows a change in the target position. As a result, the movable unit is moved to the target position and the vibration at and after the stop of movement is suppressed.

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Ibaraki, Japan

Yoosuke Hamada