EQUILIBRIUM STRUCTURE OF A 1-DOF ELECTROSTATIC

Date

2007-11

Authors

Wickramasinghe, I.P.M
Dayawansa, W.P.
Berg, J.M.
Kawade, B.D.
Maithripala, D.H.S

Journal Title

Journal ISSN

Volume Title

Publisher

American Society of Mechanical Engineers

Abstract

Feedback control of electrostatic microelectromechanical systems (MEMS) is significantly complicated by the presence of parasitic surfaces. This note considers the stabilization of a onedegree- of-freedom (1-DOF) piston actuator with capacitivelycoupled parasitics. Previous work by the authors has shown how, in the absence of parasitics, any feasible equilibrium point of this system may be made globally asymptotically stable using passivity-based control. However if parasitics are present this nominal closed-loop system may be destabilized by capacitive coupling, through a phenomenon called charge pull-in. This note shows how the nominal controller formulation may be modified to eliminate multiple equilibria. If the movable electrode is completely screened from the parasitic electrode by the control electrode, the unique equilibrium is globally asymptotically stable. Otherwise, though the desired equilibrium is still unique, its region of attraction may be finite and the equilibrium may lose stability through a Hopf bifurcation.

Description

Keywords

Citation

Equilibrium Structure of a 1-DOF Electrostatic MEMS Model With Parasitics

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