Research of nonlinear electromechanical and vibro-impact interactions in electrostatically driven microactuator

This paper provides results of dynamic numerical analysis of nonlinear electromechanical and vibro-impact interactions in electrically-actuated contact-type microactuator, which is a common component in such devices as microswitches. Mathematical modeling was performed by means of finite element method, representing microactuator as a 3D cantilever microstructure and taking into account influence of bending forces generated by electrostatic field, damping forces due to squeezed air-film in the gap as well as bouncing of the microactuator tip upon its contact with substrate. Electrostatic-structural simulations were performed in order to predict actuation (pull-in) voltages of fabricated microswitches as well as to study influence of various system parameters on the value of the voltage. Results of these simulations were compared with experimental findings obtained by using electrical probe measurements of fabricated microswitches. Numerical analysis of free impact vibrations was carried out and allowed determination of effect of ambient air pressure and intermolecular adhesive interactions on the phenomenon of contact bouncing.