Towards faster data access: Seek operations in MEMS-based storage devices

Even in the most advanced hard-disk drives (HDDs), data access is a slow process because of the relatively large mechanical structures, the one-dimensional actuation capability of the head, and the latency due to rotating disks. It is expected that MEMS-based storage devices with two-dimensional actuation capability could significantly improve the speed of data access. In this paper we demonstrate this experimentally with a MEMS-based probe-storage prototype using a micro-scanner that serves as the positioner for the storage medium. First the theoretically minimum achievable seek times are derived for the micro-scanner by approximating its dynamics with a damped harmonic oscillator model. Then the similarity of the time-optimal solution with that of the better studied double integral system is exploited to employ a proximate-time-optimal controller for the experimental studies. The experimental results demonstrate seek times of approximately 1.6 ms for seek operations of 50 μm.