Modeling and analysis of the squeezed film damping effect on electrostatic microactuators

Abstract

In this article the modeling aspects of an electrostatic microactuator with squeezed thin film damping effects are presented. The actuator is composed of a microcapacitor whose one plate is clamped on the ground while the other plate is floating on the air with the aid of an external supporting spring. Its highly nonlinear dynamic model is linearized at various operating points. Variations of the gap between the plates and the air pressure of the system are examined in order to find possible changes in the bifurcation points or other characteristics of the system. Significant conclusions for the case of the bifurcation point have been drawn and simulation studies substantiate the presented results.

Slide film damping in microelectromechanical system devices

“…[1][2][3] It has been confirmed by many experiments that the gas behaviors have great effects on the dynamic characteristics that work at an external environment with some certain gas pressures, such as micromachined accelerometers, microgyroscopes, micromirrors and micromotors. 2,[4][5][6][7][8][9] The mechanisms of fluid damping that were received by moving elements of MEMS devices can be mainly divided into two categories: [9][10][11] squeeze film damping and slide film damping. The squeeze film damping occurs when two parallel plates are in relative perpendicular motion.…”

“…1–3 It has been confirmed by many experiments that the gas behaviors have great effects on the dynamic characteristics that work at an external environment with some certain gas pressures, such as micromachined accelerometers, microgyroscopes, micromirrors and micromotors. 2,4–9…”

“…Viscous energy dissipation in the fluid between the two plates becomes a representative damping mechanism in laterally driven microdevices. 5,9 Over the past two decades, the squeeze film damping in MEMS devices has been studied extensively, 1–4,6–24 while less attention on slide film damping. 5,9,25–31 In 2007, Baoa and Yang 17 and Pratap et al 18 have presented a much comprehensive overview about squeeze film air damping in MEMS devices.…”