Optimising Dynamic Behaviour of Electrostatically Actuated MEMS Contact Switch

摘要

The reliability of the electrostatically actuated MEMS contact switches is known to be significantly undermined by the unstable dynamic behaviour of devices. High impact forces, bouncing at the contact and oscillations upon release result in substantial mechanical damage to the contacts and the switch compromising the functionality of the switch and reducing its lifetime. Certain effects become more pronounced, such as stiction causing 'fail-to-open' malfunctions, resistance increases leading to degraded performance, as well as fracture. To address the issue of the dynamic instability of the switch behaviour this work employs Finite Element Analysis (FEA), linear and nonlinear system identification techniques and optimal control theory to study the dynamic performance of the switch and optimise (soften) its dynamic behaviour by establishing an actuation input voltage that substantially reduces or eliminates the instabilities.