The Influence of Initial Parameters on the Operation of Microelectromechanical Systems

The study results of the operation features of two-electrode microelectromechanical systems (MEMS) with changing of interelectrode gap during startup are presented. The analysis has been carried out taking into account the constant force and electromechanical coupling in a nonlinear approximation for the elastic and electrostatic forces. It is shown that the operation of such MEMS is significantly affected not only by the initial state and parameters of the system, but also the rate of the applied electrical voltage change. For the case when the MEMS is excited by a voltage surge in the form of a step, analytical expressions have been derived enabling for arbitrary system parameters to obtain separatrices limiting the areas of initial conditions, where periodic oscillations will be established for the system. Analytical expressions have been obtained for calculation the magnitude of such oscillations. For zero initial conditions, it is shown that if the normalized constant force $F\gt-0.5$ the oscillations will be concentrated at positive displacements of the movable electrode. It was found that with a decrease of F from $F\gt0$ to $F=-0.5$, the oscillation range will decrease, and with a further decrease of F, this range will begin to increase, but already in the region of negative movable electrode displacement.