Study On Dynamic Pull-in Phenomenon Of Magnetic Micro-actuators

As the core of MEMS, micro-actuators are composed with signal processing circuits andcontrol circuits. Both the two circuits finish some operation together. As an important characteristicof micro-actuators, Pull-in phenomenon draws more attention. In practice applications, Pull-inphenomenon can be used as micro-switch. It is very important to derive the Pull-in parameters forusing of Pull-in phenomenon. Magnetic micro-actuators have some particular advantages. Such as,it can provid both attractive force and repulsive force. Compared with static micro actuators,magnetic micro-actuators can provid larger driving force.Working voltages compatible with IC isalso an advantage of magnetic micro-actuators. Base on these characteristics, it’s very necessary toresearch the Pull-in phenomenon of magnetic micro-actuator.Two of the most common models of magnetic micro-actuator are parallel model and multilevelmeander model. In this paper, the dynamic Pull-in phenomenon and parameters of the two modelsare studied.For the parallel magnetic actuator, this paper gives a brief description of static Pull-inphenomenon, and simulates this phenomenon using the direct coupling method of ANSYS. Themechanism of dynamic Pull-in phenomenon is introduced in this paper. On the base of energyconservation principle, the Pull-in parameters under different conditions are deduced. The effects ofother structural parameters on dynamic Pull-in parameters are analyzed. The results prove thatelectricity and magnetism can be compared when ignoring the core reluctance. Under the conditionof considering the core reluctance, the dynamic Pull-in parameters have a linear relationship withthe length of core. When considering the leakage reluctance, the bigger of initial distance thegreater influence on the dynamic Pull-in parameters, and the parameters coincide well with FEMresults.For the multilevel meander model, this paper also deduces and compares the Pull-in parameterunder different conditions base on the principle of energy conservation. Also, the effects of otherstructural parameters on dynamic Pull-in parameters are analyzed.