Patent ID: 6154340
Filing Date: 2000-11-28
Classification: G11B

Abstract:
In a disk drive system having a disk, an actuator arm assembly with a head and a ramp interface, a ramp positioned in proximity to said disk to receive said ramp interface, and a voice coil motor for controlling movement of the actuator arm assembly, a method for loading the head onto the disk, comprising steps of:(a) creating an essentially frictionless load of said actuator arm assembly by applying an alternating current to the voice coil motor;(b) applying, to the voice coil motor, an offset current that increases according to a predetermined function of time such that the voice coil motor moves the actuator arm assembly to exit the ramp at a predetermined velocity, where said predetermined function of time is a constant times time and is based on said predetermined velocity, where said predetermined function of time is determined prior to performing steps (a) and (b); and(c) sampling a velocity of the actuator arm assembly as the actuator arm assembly moves to exit the ramp, including:(i) sampling a first potential difference across the voice coil motor when said applied alternating current basses through zero from a positive to a negative amplitude to obtain a first sample;(ii) sampling a second potential difference across the voice coil motor when said applied alternating current passes through zero from a negative to a positive amplitude to obtain a second sample; and(iii) summing said first sample and said second sample.