Rotational vibration detection using a velocity sense coil

Details Rotational vibration detection using a velocity sense coil Rotational vibration detection using a velocity sense coil

1999-04-05

2000-07-11

Loomis, Paul

Dynamic magnetic information storage or retrieval

Automatic control of a recorder mechanism

Controlling the head

360 60, G11B 5596

Patent

active

060881852

ABSTRACT:
An apparatus and method for detecting rotational vibration applied to a disc drive having a rotary actuator adjacent a rotatable disc. The actuator supports a head adjacent a recording surface of the disc and an actuator coil in a magnetic field of a magnetic circuit of a voice coil motor. A second, velocity sense coil is further coupled to the actuator and immersed in the magnetic field of the magnetic circuit, with the velocity sense coil being electrically isolated from the actuator coil. Rotational vibration is detected in relation to a sense voltage induced across the velocity sense coil as the magnetic circuit is moved relative to the velocity sense coil. A data transfer operation between the head and a host device is interrupted when the magnitude of the rotational vibration exceeds a specified magnitude. A servo circuit applies current to the actuator coil to position the head relative to the disc recording surface in relation to servo information transduced by the head, as well as in relation to the sensed voltage from the velocity sense coil.

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