Rejection of repeatable runout for HDDs using adaptive filter

This paper describes designing a controller of a hard disk drive for rejecting repeatable runout. Position Error Signal (PES) consists of Repeatable Runout (RRO) and Non-Repeatable Runout (NRRO), NRRO is decomposed into its contributing component which are force disturbance, mechanical vibration, etc, in frequency domain. The result of the numerical analysis is shown that the RRO has great influence for PES of all disturbances. In this research, the adaptive filter was applied to reject the influence of RRO where the Filtered-X LMS algorithm was used in the adaptive filter. The experimental results showed the validity of the proposed controller design method.