Servo control design for a hard disk drive based on estimated head position at high sampling rates

Abstract

In this paper we use the ACORN estimator that generates estimates of the head position by processing servo burst and data sector measurements of the mean square error (MSE), to provide head position error measurements at high sampling rates during read. A high bandwidth controller is designed and tested on an actual disk drive. The effect of the higher sampling rate on the seek time and steady state performance is evaluated and compared. While our results show that the use of a higher sampling rate provides some improvement, the position of the resonance modes limits further increase in bandwidth that is now possible due to the higher sampling rate. Consequently the proposed method is expected to have additional benefits in future generations of disk drives where dual stage actuators will be used during read.