Research status and development trend of micro-mechanical resonance accelerometer

The micro-mechanical resonance accelerometer(MMRA) is used to measure the acceleration by detecting the change of resonant frequency of the sensitive element．This kind of sensor has become one of the important development direction of micro-sensors because it has many advantages such as frequency signal output，high stability, sensitivity and precision．This paper describes the key technologies, difficulties and corresponding solutions, development trends of MMRA. The key technologies include mechanical structure, excitation and detection methods, and methods of changing the resonator stiffness. The three mechanical structures of the resonator and the asymmetry caused by the error of the micro-lever process are analyzed; according to the piezoelectric properties of the resonators materials, MMRA can be divided into piezoelectric MMRA and non-piezoelectric MMRA, piezoelectric MMRA employs piezoelectric excitation/piezoelectric detection and non-piezoelectric are mainly electrostatic excitation/capacitance detection; there are two main methods to change the stiffness of the resonator: axial stress method and electrostatic stiffness method, whose principles and scopes are analyzed and compared. Development of MMRA mainly includes four technical difficulties: mechanical coupling, temperature characteristics, process error, assembly and packaging, and the corresponding solutions are given. Integration, static stiffness, new materials, multi-axis and higher performance will be the main development trends for MMRA in the future.