Dynamic Characteristics Analysis Of A Micro-machined Switch Consisting Of A Cantilever Beam

As an important driving force in Micro Electromechanical System (MEMS), the electrostatic force is widely applied to such microdevices as micromirror, microforceps and microswitch et al. Although some electrostatically driven MEMS produces have been commercialized, the related design theory cannot satisfy the devising demands yet. So the methods of trial and error, which resulted in low design ratio, are the primary technology reason which slows down the step of research and industrialization of the products. This work is focused on researching the dynamic characteristics of the microswitch and the pull-in phenomena. The research is based on Electromagnetism, Dynamics of Structures, and Finite Element Methods, with the aid of computer simulation. The results of the analysis will be a reference in future microswitch design and optimization. Two dynamic analysis models of microswitch are introduced. The corresponding numerical methods are used to solve the governing equations of the models, and the dynamic responses of microswitch are calculated with MATLAB simulation. The static characteristic and the vibratory characteristic are calculated with ANSYS software. The dynamic characteristic is simulated by ANSYS. The static pull-in voltage is compared with the dynamic pull-in voltage. The differences between the static analysis and the dynamic analysis are compared. The relationship between the dynamic pull-in voltage and the pull-in time is get from the dynamic analysis. The influences of the structural parameters on the microswitch performance are discussed in detail. The results reveal that the dynamic response period of micro-machined switch increases with increasing of applied voltage. The dynamic pull-in voltage is less than the static pull-in voltage. Specially, the dynamic pull-in voltage is not one and only, and the pull-in time decreases when the dynamic pull-in voltage increases. There is an excursion between the frequency of vibration and the natural frequency,what with the damping of air and the nonlinearity of electrostatic force.