A novel non-vacuum packaged triaxial accelerometer with differential dual-axis resonantors and torsional elements.

Tri-axis MEMS accelerometers are used in a wide range of applications such as health monitoring, industrial electronics and navigation guidance due to their low cost, high performance and integration. At this stage, the main structure of commercial products of triaxial accelerometers is the integration of three single-axis capacitive accelerometers. However, many reports have shown that resonant accelerometers can achieve better performance than capacitive accelerometers. In this paper, a novel triaxial accelerometer include a dual-axis resonantors and two torsional elements is proposed. The prototype was fabricated using MEMS processing technology and had a footprint of 10.8 mm × 10.8 mm. A non-vacuum package is adopted to guarantee the stability of the torsional accelerometers included. As a result, a low Q value is obtained for each part included. The effect of low Q is analyzed and its control circuit is optimized to obtain excellent stability. Finally, the triaxial accelerometer prototype was tested to evalute its performance, the Q value of each resonantors is lower than 100, the cross-axis coupling coefficient is below than 0.5%, the nonlinearity is belower than 0.053% at a range of ± 10 g and the bias instability at each axis is 5.7 μg, 4.8 μg and 73 μg respectively (X, Y and Z aixs). [ABSTRACT FROM AUTHOR]