The Nonlinear Design Of Micro Cantilever

Micro Electro Mechanical Systems, MEMS, is a class of systems that are physically small, with dimensions in the micron (10-6meters/micron) range. These systems have both electrical and mechanical components. Today, micro sensors have been the mainstream of the development of the sensors, because of their lower cost, smaller dimension, and higher performance. The most of the successful micro machined sensors adopt the construction of micro cantilevers. For example, the resonant pressure micro sensors, and the micro machined force-balance capacitive accelerometers. These micro cantilever-based sensors have been frequently used. So they have drawn more and more attention now.In this paper, the object to study is a micro cantilever which is driven by the electrostatic force. Firstly mathematic model of the micro cantilever structure is established by elastic mechanics analysis, during which small-displacement and large-displacement are both discussed. Also the direct current exiting voltage and alternating current exciting voltage are both discussed. Then we investigate the bifurcations of the conditions which have been mentioned above. Secondly, we investigate the nonlinear dynamics if the system by using the multiple method of scale, and discuss the stability of the steady-state solution. Then employing singularity theory, the transition variety and the bifurcate diagram are given on the plane of unfolding parameters. According to diagram, we get the condition to avoid jump phenomenon. Thirdly, we investigate the impact of the pull-in voltage on the nonlinear vibration detailedly, and get the relationship between the physical parameters and the pull-in voltage. In the end, we discuss the relationship between the parameters in the cure of amplitude-frequency and the physical parameters of the system, and optimize the parameters.The result indicate that we can take the way of augment the length, thickness of the micro cantilever, the initial gap, the damp of the system to increase the pull-in voltage. We have to optimize the physical parameters synthetically to largen the region of the resonance, minish the range of jumping and increase the amplitude.