High-bandwidth hard disk drive tracking using a moving-slider MEMS microactuator

A moving-slider microactuator that enables both high stroke and good linearity for high track pitch HDDs (hard disk drives) was investigated. A new microactuator design called a "bipolar microactuator" was proposed that maintains proper slider grounding. A new microactuator fabrication technique was developed that allows the bonding pads to be manufactured on the sidewall of the microactuator chip for easier assembly into an HDD. The microactuator was used to achieve an open loop servo bandwidth of 8 kHz at 80 kHz sampling rate in a server-class HDD. Higher bandwidths may be achieved with higher sampling rates. A description of the dual-stage control scheme is presented.