Method and apparatus for controlling spindle speed to compensate for drag in a disk drive system

摘要

Control system/method for controlling disk spindle motor speed in a disk drive system using transducers riding or flying upon the disks, with a viscous substance between the disks and the transducers thereby exerting a load upon the spindle motor, the load having a non-uniform profile from the disk inner diameter to the outer diameter where the load at any location across the disk is a function of the medium upon which the transducers ride or fly above the disks, the location itself and the physical environment being experienced by the medium at any given instant of time. The control system provides speed control data that defines the power applied to the spindle motor to maintain a desired motor speed as a function of the presently selected track address and a controller that provides and selects for a presently selected track address the speed control data to the spindle control system to maintain the spindle motor speed at the specified speed. The method comprises the steps of: a) generating speed data for maintaining the spindle motor at a specified speed as a function of the track addressed by the disk drive system; b) storing the speed data in a first memory table in the disk drive system; c) retrieving the stored speed data for the track presently being addressed by the disk drive system; and d) providing the retrieved speed data to the speed controller for controlling the spindle motor speed.