Optimization of MEMS Thermal Actuators and Microgrippers

This paper presents the different approaches to optimize the performance of MEMS (Micro Electro Mechanical Systems) electro-thermal actuators and also the application of thermal actuation for a micro gripper, The operating principle is based on the asymmetrical thermal expansion of the beams with different lengths and cross sections. By applying voltage (current) on different contact pads, different beams are heated, thereby the micro actuator can produce bilateral motion in plane or out-of-plane. The analysis of the bilateral motion is performed by varying different parameters like applied voltage, geometrical measurements of model, structural material, electrical and thermal conductivities of material used, coefficient of thermal expansion, the temperature and many more. Designing of different models and structures is presented and hence concluding the most optimum material, design, structure and size of the actuator by simulating using all the known parameters of the actuators. Designs are also simulated with respect to different electrical parameters like voltage and currents which play a vital role in deformation of the actuators. Polysilicon made structures show the best results with respect to displacement for the applied voltages. Electrothermal Microgrippers with low set back time have also been designed by using the technique of reversal of voltage to perform release action. Polysilicon based microgroppers exhibit excellent gripping action.