Microfabricated electrostatic actuators for hard disk drives

Abstract

A dual-stage servo system which utilizes a highbandwidth secondary actuator has been proposed for magnetic hard disk drives. Microfabricated actuators are promising candidates for this secondary actuator, since they offer the benefits of extremely small size and weight and may be batch fabricated for reduced production cost. This paper presents the design of an electrostatic microactuator which produces sufficient output force to move a 1.6-mg picoslider from a conventional disk drive at frequencies above 2 kHz. A linear second-order actuation model is developed and fit to experimental data. The prototype device is shown to have an open-loop resonance frequency of 532 Hz when loaded with the picoslider, and a dc-voltage-to-position gain of 0.12 m/V. A closed-loop bandwidth of 2.5 kHz is achieved using a simple proportional derivative controller.

Internal electrical phase inversion for FF-beam resonator arrays and tuning fork filters

“…14 shows the measurement results with variable DC-bias driving and demonstrates the linear relation of the squared frequency and squared voltage as predicted by the electrical spring softening effect [13] . Also simulation results of the crossover of tunable mode frequency and stable mode frequency are illustrated in Fig.…”

“…The filter bandwidth is voltage tunable employing the electrical spring softening effect [13] . The mechanical mode of the filter can then be represented in Fig.…”

Dual-stage servo systems and vibration compensation in computer hard disk drives

“…Therefore, current suspensions need to be re-designed to adopt this secondary actuator. Suitable driving forces in this approach include electrostatic, electromagnetic and piezoelectric Horsley, 1998;Koganezawa et al, 1997 the assembly task of placing the MA in between gimbal structure and slider, some researchers have proposed MAs that are either integrated with the gimbal structure (Muller, 2000) or the slider (Imamura et al, 1998).…”

Folding assembly of micro-actuators

“…Micro-actuators drive pumps and valves in micro-total analysis system (m-TAS) [5], and other micro-fluidic or small volume chemistry systems such as lab on a chip (LOC) system [6] and ink jet print heads [7], among others. The small form factor of micro-actuators lends them additional stiffness to weight ratios and high resonant frequencies [8], making them ideally suited for fast response precision tasks such as in atomic force microscope (AFM) cantilevers and highdensity data storage devices [9]. The majority of micro-actuators are independent units since there is generally no need to have volumetric assembly and the assembly of MEMS actuators would be very costly.…”