Research On Influence Factors Of Capacitive Accelerometer Performance

Capacitive accelerometers are widely used in various fields such as seismic monitoring,aerospace,defense,and communications,and are currently the hot topics in the inertial instrument industry.In seismic monitoring,capacitive accelerometers are mainly used in strong earthquake observation stations.They have advantages such as large dynamic range,high precision,and good linearity.Although the performance of the capacitive accelerometer is constantly improving,there are still many deficiencies.In the actual use process,it is very vulnerable to the effects of the manufacturing process,the ambient temperature,and the fatigue loss,especially the influence of the ambient temperature.Significant.This topic aims to study the influencing factors of capacitive accelerometer performance,and focuses on the structural design,simulation optimization and performance testing of capacitive accelerometers,and conducts related research on the capacitive accelerometer system and its influencing factors.In this paper,the detection method and structure of the pin capacitance accelerometer are firstly studied,the working principle is analyzed,the theoretical model of the sensitive structure is established,and the transfer function formulas in various states are deduced.The main performance parameters of the capacitive accelerometer are calculated,and the influencing factors of the bias error are analyzed in depth.Then,based on the force-displacement method and the resonant frequency method,ANSYS finite element simulation software was used to simulate and verify the accuracy of the beam in the working mode,and the sensitivity of the model was analyzed based on the working mode of the accelerometer model.The influence of ANSYS thermo-mechanical stress on accelerometer performance was simulated and analyzed,and the vertical offset of the elastic element at different temperatures was obtained.Combined with the relationship between the capacitor plate and the elastic element,the temperature change and the displacement data of the capacitor plate were obtained..Secondly,in order to reduce the influence of temperature change on the capacitive sensor,a temperature compensation circuit based on parasitic resistance was constructed.The feasibility of temperature compensation was initially verified in theory,and a temperature compensation circuit based on parasitic resistance was designed.Finally,a capacitive accelerometer test system was established to test and analyze the accelerometer performance indicators.By comparing the difference between the theoretical value and the analytical test value,the correctness of the theoretical design is verified.At the same time,it is verified that the performance of the capacitive accelerometer reaches the design requirements.