Pull-in Characteristic Analysis Of Electrostatic Micro-actuators

Micro Electro Mechanical System (MEMS) is usually composed of micro-sensors, micro- actuators, the units of information and the units of communication or interface. As a movable part, the indicators of micro-actuators, including the size of its range of motion, the level of efficiency and the reliability, determine the property of the system. Micro-actuator is the most important aspect of MEMS, which are given a high priority by scholars from various countries.The electrostatic driver mode is used most widely, which can generate great driving force, but the driving force is nonlinear, thus leading to the pull-in instability phenomenon. Two important parameters of the pull-in phenomenon are pull-in point and pull-in voltage, which are the key factors to study the pull-in phenomenon. So it is very important for the study of pull-in phenomenon to obtain precise pull-in point and pull-in voltage. Pull-in phenomenon has advantages and disadvantages, but we can make full use of pull-in phenomenon flexibly once making sure the pull-in point. Therefore, whether in theory or in practical applications, the precise pull-in point is very necessary.Firstly, this paper introduces the mechanism of static pull-in phenomenon and dynamic pull-in phenomenon of parallel plate and torsion micro-actuators without considering the fringing fields. According to the Runge-Kutta, the simulations without the edge effects are obtained, which are the motion of parallel plate and torsion micro-actuators in the step signal and the modulation signal. Secondly, based on the study of the pull-in phenomenon without the fringing fields of electrostatic micro-actuators, the pull-in phenomenon of considering the edge effects of electrostatic micro-actuators has been studied and attention is focused on the dynamic pull-in phenomenon. The simulations of considering the fringing fields are obtained, which are the motion of parallel plate and torsion micro-actuators in the step signal and the modulation signal, and comparisons are taken with the simulations of the motion of parallel plate and torsion micro-actuators without the fringing fields. At last, ANSYS software is used to model and analysis parallel plate and torsion micro-actuators. The simulation results of static pull-in are obtained.