Reduced-order modeling of electrostatically-actuated micro-beams

This paper addresses the compact modeling of MEMS devices with nonlinear electromechanical forces. Ideally, the reduced-order model should only involve one or two generalized coordinates. We show that a projection method based on the first eigenmode of the linearized unactuated structure is a good choice in terms of simplicity and accuracy. To take into account the influence of distributed electrostatic forces, it is necessary to approximate the nonlinear force in terms of the reduced coordinate. It is shown that a Pad´e approximation of order 2 is very attractive in terms of accuracy and numerical efficiency.