DESIGN OF A MEMS PIEZOELECTRIC ACCELEROMETER

Abstract

The piezoelectric micro accelerometers have wide applications in the field of auto mobiles, inertial navigation and bio medical instrumentation. The main aim of our research is to develop a piezoelectric accelerometer that can measure body movements in assessing the neurological disorders like parkinsons disease. The most important specifications for medical applications are amplitude range +/-5g. resolution 10 -3g, bandwidth d.c.-50 Hz, off axis sensitivity < 5%, low drift and power consumption < 1mW. The accelerometer design employs a proof mass suspended by four beams. When the device is accelerated the mass moves relative to the anchor, the beams deflect causing the piezoelectric layers to deform and hence a charge is induced .The amount of charge generated depends upon the piezoelectric properties of PZT material, and many dimensional design considerations. This design is proved to get very high sensitivity, good frequency response. FEM simulations are performed by the CoventorWare® to investigate the device behavior. Displacement of the structure due to the applied acceleration of 1g has been simulated. Charge sensitivity is found to be 3.201X10-6 Col/g at the resonant frequency of 58Hz has been evaluated