Alleviation of residual oscillations in electrostatically actuated variable-width microbeams using a feedforward control strategy

作者：Godara R K; Joglekar M M^*

来源：Microsystem Technologies, 2017, 23(10): 4441-4457.

DOI：10.1007/s00542-016-3211-x

This article presents a feedforward control strategy for alleviating the residual oscillations in electrostatically driven nonprismatic microbeams. The two prevalently employed microbeam configurations (fixed-free and fixed-fixed) are analyzed in this work. The governing differential equation is first developed taking into account the effects of electrostatic nonlinearity, viscous energy dissipation, moderately large beam-deflections, and the fringing-fields. Modal superposition method with full-order electrostatic nonlinearity is then used to solve the equation of motion numerically. The mass-normalized mode shapes of the respective nonprismatic configuration are extracted using the differential transform method. Response of the microbeams driven by a multi-step voltage waveform is investigated highlighting the presence of residual oscillations about the anticipated equilibrium positions. A feed-forward control strategy is proposed to alleviate the effect of such residual oscillations; thereby achieving fast switching between the successive equilibrium configurations. Efficacy of the proposed control technique is demonstrated by controlling the motion over various user-defined equilibrium sequences. A parametric study involving variations in the taper parameter is performed to bring out the utility of using nonprismatic geometries in place of conventional prismatic beams. Additionally, an impact of higher vibration modes on the performance of the proposed control strategy is investigated. The present work can find its potential use in the development of open-loop controllers to be used in microelectromechanical systems involving beam-type actuators.

• 出版日期2017-10