Authors: T. Veijola, H. Kuisma and J. Lahdenperä
Affilation: Helsinki University of Technology, Finland
Pages: 218 - 221
Keywords: electrical equivalencies, gas-film damping, squeezed-film damping, accelerometer model, macro model, large-displacement model
A compact large-displacement model for a gas damped capacitive accelerometer is presented. The gas-film model has been derived from the modified nonlinear Reynolds equation, where the in uence of the gas rarefaction is included. The error due to the simplifications in the simple damping model has been compared with those of a finite-difference model. The compact model is constructed of electrical equivalent-circuit blocks consisting of nonlinear controlled current and charge sources. The measured capacitance-voltage characteristics and large-displacement transient responses of an accelerometer are compared with simulation results. The finite element comparisons and the measurements show that the compact model has sufficient accuracy even if the gap displacement is as large as 90 % of the static gap separation.