Design Of Digital Inclinometer Based On Quartz Vibrating Beam Accelerometer

With the development of manufacture and science,angle measurement is more and more widely applied in various fields such as industry and research.As industrial technology develops,the requirements for inclinometers are becoming crucial.The proposal of the"Made in China 2025"shows the trend for automation and intelligent development.The rapid development of micro-electromechanical systems(MEMS)technology has led to tremendous advances in performance,stability,power consumption,and volume of micro-inertial sensors,with quartz vibrating beam accelerometer(QVBA)as one of the typical representatives.QVBA is a type of acceleration sensor,utilizing the stress-frequency effect of the resonant beam and the inverse piezoelectric effect of the quartz,which allows digital output.Besides,it has the advantage of high precision,low cost,small volume,low power consumption,good temperature stability,harsh environment resistance,long-term reliability,wide range,and can be put into batch production.Therefore,it has promising prospects in all precision fields,including civil purposes,military purposes,aerospace and exploration.On demand of the actual engineering,QVBA serves as a tilt sensor,and an intelligent,automatic and miniaturized digital inclinometer is designed.The status quo analysis and the development trend of angle detection technology,inclination sensor,QVBA and angle meter is firstly summarized.The working principle,equivalent circuit and performance index of QVBA,as well as the relevant parameters of QVBA used in design are then discussed.This paper puts emphasis on the principle of angle measurement based on QVBA,and the relationship between angle detection and frequency measurement is derived.After analyzing,a full synchronization frequency measurement method based on phase coincidence detection is selected,evaluating the systematic error of a measuring instrument at the same time.In terms of the principle and the characteristics of angle measurement,an overall design scheme is proposed.Furthermore,the hardware design with modules is introduced,the software design is presented in terms of function classification,and the problems encountered are summarized.Finally,software and hardware joint adjustment,test verification are carried out.At the same time,the factors affecting the measurement accuracy are analyzed,and the improvement scheme is given.The experimental data demonstrates that the digital inclinometer can achieve measurement range of±90~o,and measurement accuracy of±0.01~o within±45~o tilt angle.