Modeling and Characterization of a Novel in-Plane Dual-Axis MEMS Accelerometers Based on Self-Support Piezoresistive Beam

Herein, a novel in-plane dual-axis micro-electromechanical system piezoresistive accelerometer was proposed based on theoretical and simulation analyses. Its self-support piezoresistive beam (SPB) possessed the features of force amplification and axial deformation to obtain high sensitivity. To clarify the influence of structural dimensions on the performance of the accelerometer and the pure axial-deformation condition of the SPB, a theoretical model was established to analyze mechanical behavior. The theoretical results were in well accordance with the simulation ones, displaying a maximum relative error of less than 10%. The theoretical and simulation results suggested that the accelerometer with thin and long support/hinge beams possesses a higher sensitivity but a lower frequency. However, the sensitivity and natural frequency increased simultaneously before the distance between SPB and support beam D reached a certain value. The simulated longitudinal stress of SPB achieved the average value of 32.473 MPa, and the first-order natural frequency was nearly 13.6 kHz. Furthermore, the fabricated accelerometer was tested in a simple packaging case. The experimental results demonstrated that the proposed accelerometer had a measuring sensitivity of 0.198 mV/g/V with a maximum non-linearity of 1.00% FS and a resonant frequency of 12.93 kHz. The cross sensitivities were 11.93 and 15.97 it V/g/5V in the y and z axes, respectively, which were 1.21% and 1.61% of the prime-axis sensitivity. The zero offset with varying temperatures was 0.00296%/degrees C, and the zero drift in the long-term static stability test was 0.02 mV. All the results above revealed the promising application potential of the proposed accelerometer in vibration detection in the high-speed rotating spindle of machine tools.