MODELING POSITION ERROR NONLINEARITY TO IMPROVE SERVO PERFORMANCE

摘要

The present invention relates to an apparatus and method for improving the servo performance of a disk drive (100). The disk drive includes a head 126 near the rotatable disk 106 where data is stored on a plurality of tracks 164. The servo circuit 144 controls the position of the head by generating actual (circular) position error signals (PES) 218 and 458, which are characterized by a general nonlinearity in a portion of the width of the selected track and which indicate the position of the head with respect to the selected track /RTI The servo circuit also generates a predicted PES 456 near the actual PES and controls the position of the head by adding the actual PES and the predicted PES 236. [ The servo circuit is operable to compare the predicted burst signals 350 and 370 closely to the actual burst signals 208 and 210 determined in the readback signals from the head when the head reads the servo burst patterns 176 on the disk And a burst signal generator 300 for generating a burst signal. The error value tables 302 and 304 provide improved signals approximating the actual burst signals by compensating for the asymmetric response of the head.