Design and analysis of MEMS piezoresistive rectangular paddle microcantilever based wind speed sensor

摘要

This paper presents design, simulation and finite element analysis of a wind speed sensor based on MEMS piezoresistive microcantilever. The design is based on the drag force of the wind flow on any structure and employs four piezoresistors in Wheatstone bridge configuration to provide an electrical readout. Two basic structures, diaphragm and cantilever, are designed and simulated for the wind speed range 0-35 m/s using Coventorware 2012. As the magnitude of the force exerted by the wind with a speed of 35 m/s is very small, enhancement in the sensitivity of the sensors involved is a priority and can be achieved by structural variation of the cantilever. The optimized diaphragm structure provides a sensitivity of 0.31007mV/(m/s)V. This is increased to 0.41612mV/(m/s)V when utilizing a simple cantilever structure. The piezoresistors are also optimized by varying their dimensions so as to provide maximum sensitivity of 0.47843mV/(m/s)V. The cantilever structure is optimized for maximum sensitivity by introducing a rectangular paddle at the free end. The optimized sensor is simulated for the range wind speed 0-35 m/s and provides a sensitivity of 1.3156mV/(m/s)V. MEMS based piezoresistive wind speed sensor has advantages of having a small size, low power consumption and good sensitivity over wide range of operation.