A novel recursive filtering approach to estimate repeatable run-out(RRO) disturbance in HDD

Motivated by optimal filtering theories, we propose a first-order filtering algorithm to estimate repeatable run-out (RRO) disturbance from position error signal (PES). The new algorithm outperforms the conventional averaging algorithm and provides a faster convergence rate which is crucial to reduce manufacturing time in hard disk drive industry. Utilizing RRO estimation, RRO disturbance can be pre-compensated before it enters disk drive servo and therefore Track MisRegistration (TMR) is improved. Experimental results using a 2.5" Western Digital drive show that a 60% reduction in the RRO is achieved in eight revolutions