Multiphysics Simulation of an Electrostatics-Rotary MEMS Stepper Motor

Abstract

This paper shows the multiphysics simulation process of a rotary MEMS stepper motor with electrostatic actuation, where the solid mechanics, electrostatics, and moving mesh simulations through COMSOL are considered in a time-dependent study. The rotary MEMS motor comprises the aluminum structural layer from a 0.5μm CMOS technology used for integrated circuit fabrication. Both the rotor and the stator are immersed in a dielectric; for this reason, the simulation requires a moving mesh to model the electrical characteristics of the medium. A mesh convergence study is conducted to ensure the accuracy and mesh independence of the results. The simulation also considers the frequency of the stator electrodes alternating signal and the frequency response of the rotor to define the solver time stepping. Through this simulation, it was possible to verify that the micrometric electrostatic actuator has an angular displacement with a linear trend, which allows the proposed design to be verified.