Optimal filtering to improve performance in hard disk drives: simulation results

The analysis in this paper demonstrates how resonances limit control system bandwidth in hard disk drives and how optimal filtering can extend the bandwidth. In a hard disk drive, resonances do not limit performance by their oscillation amplitude but rather by limiting bandwidth via stability margin constraints. With a reduced bandwidth, the control system cannot provide enough disturbance rejection to achieve a desired level of performance, which is often measured in track density. This paper will address these issues and demonstrate how optimal filtering can improve hard disk drive performance.