System-level Simulation And Experiment Of A Force-balanced Micro-acceleromete

Accelerometers based on MEMS technology have the advantages of small size,high integration,low power consumption,and high accuracy,and are widely used in fields such as aviation,aerospace,automotive,and consumer electronics.In response to the problem of long MEMS design and development cycles and low success rates in China,this paper uses a system-level modeling and simulation method to study and design a force-balanced micro-accelerometer using a comb capacitor structure,and a capacitance detection circuit based on negative feedback is provided to ensure measurement performance under certain process errors,shortening the product development cycle effectively.This paper conducts research on micro accelerometers from four aspects: theoretical analysis,structural design and simulation analysis,manufacturing process selection,and measurement and control circuits.Firstly,starting from the overall working principle of capacitive micro accelerometer,the selection of micro accelerometer structure and determination of size parameters are carried out;Then the three-dimensional model of the accelerometer was built in the Coventor MP software,and the finite element analysis was carried out using the Coventor Ware software.The results showed that the Natural frequency of the detection mode was 1441 Hz,the displacement sensitivity was 0.199μm/g,the detection direction stiffness was 37.424N/m,and the output differential capacitance within the range of±10g maintained a good linear relationship with the acceleration,which verified the feasibility of the structure;Subsequently,the manufacturing plan of the micro accelerometer was determined by comparing different processing techniques;Finally,by studying the principle of small capacitance detection,a closed-loop detection circuit based on electrostatic force feedback was designed.The complete measurement and control circuit consists of an output signal conditioning module,a collection module,and a power supply module.After integrating the micro accelerometer with the servo circuit,performance testing was conducted on the system.The accelerometer sensitivity was 24.87 m V/g,the range was ±55g,and the maximum nonlinear error was 0.285%.This performance indicator indicates that the system meets the requirements of common industrial applications.