3 Hz/g and a resolution of 167.8 ��g [16]. The micromechanical silicon resonant accelerometer prototype developed by Chongqing University in 2010 has a sensitivity of approximately 55.03 Hz/g and a resolution of approximately 182 ��g [17]. Nanjing University of Science and Technology studied the temperature influence mechanism of the micromechanical silicon resonant accelerometer. An improved structure restraining thermal stress and a temperature compensation measure based on electrostatic stiffness was proposed. After the accelerometer is electrically pre-heated for 10 min, the bias stability of the prototype is 100 ��g, and the bias repeatability is 286 ��g. The scale factor stability is 51 ppm, and the scale factor repeatability is 2.7335 �� 10?3. The temperature coefficient of the resonator is 42 Hz/��C [18].

The China Academy of Aerospace Electronics Technology launched a micromechanical silicon resonant accelerometer prototype in 2013 with an unloaded resonant frequency of approximately 17 kHz and a scale factor of approximately 220 Hz/g. In the range of ?40�C+70 ��C, the temperature coefficient of the resonant frequency is ?71.5 �� 10?6/��C. The bias stability approaches 42.5 ��g within 1.5 h [19].The domestic SOG technique is currently adopted by most research institutions for fabricating micromechanical silicon resonant accelerometers. In this technique, the anodic bonding process is used to form a tight silicon-oxygen bond to adhere the silicon wafer and the glass wafer together.

Because of the mismatching thermal expansion coefficients of silicon and glass, thermal stress will be produced during the fabrication, packaging and use of the accelerometer. This thermal stress will seriously affect the accelerometer performance. In this study, the structure of the micromechanical silicon resonant accelerometer is optimized to reduce the temperature influence on the accelerometer. Thus, the closed-loop drive circuit is designed based on the phase-locked loop. A performance test is also performed on the developed prototype.2.?Structural Design of Micromechanical Silicon Resonant Entinostat AccelerometerA structural diagram of the micromechanical silicon resonant accelerometer is shown in Figure 1. The accelerometer is designed with a perfectly symmetrical differential structure.Figure 1.Structural diagram of the micromechanical silicon resonant accelerometer.Two identical double-ended tuning forks (DETFs) serve as the stress-sensitive resonators. The two DETFs are symmetrically arranged and connected by the proof mass, which converts the acceleration into an inertial force, which is later magnified by leverage before being transmitted to the resonators.