Harmonically-Driven Snapping of a Micromachined Bistable Mechanism With Ultra-Small Actuation Stroke

In this paper, we study the snapping action of a micromachined bistable mechanism harmonically driven with an ultra-small actuation stroke, which is realized through the mode amplification in a two-degrees-of-freedom (2-DOF) vibration system using an on-chip electrostatic actuator. The micromachined bistable mechanism is based on a curved beam configuration. The dynamic response of the device is theoretically predicted with the harmonic balance method. Further, to demonstrate this proposed study, a microelectromechanical systems (MEMS) prototype device is designed, fabricated, and tested. In experiments, the forward and backward state switching actions of the prototype device are realized with actuation stroke smaller than 0.4 μm, while the traveling distance between the two states is about 18 μm. To the best of our knowledge, we demonstrate for the first time the state switching of a cured beam bistable mechanism using harmonic driving in a 2-DOF vibration system. This paper has potential in applications including MEMS switches and MEMS filters.