Adaptive Base Casting Dynamics Estimator with Compensation for Base Casting Motion in Direct-Access Storage Devices
Original Publication Date: 1996-Jul-01
Included in the Prior Art Database: 2005-Mar-31
In many disk files, digital head positioning systems are used both to move the read/write elements from track to track and to keep the elements close to the track center once they arrive on track. Typically, the plant model used in the digital servo includes only the dynamics of the power amplifier and Voice Coil Motor (VCM) (1 and 2). In the past, this was adequate because the force-to-mass ratios were sufficiently small. Fig. 1 illustrates that peak acceleration of the Head/Disk Assembly (HDA) base casting has increased an order of magnitude, with a concomitant increase in base casting motion.