Research On The Key Method Of The Small-range High-precision Quartz Flexible Accelerometer

Gravity sensor is the core device of the strapdown aviation gravimeter,its precision will directly influence the measuring accuracy of airborne gravimeter.The Gravity sensor that used in our strapdown airborne gravimeter that developed independently by our laboratory is quartz flexible pendulum accelerometer,the technical maturity is higher,after appropriate screening and using precision temperature control system can basically meets the requirements of scalar gravity meter on gravity sensor.But the quartz flexible pendulum accelerometer is the products that designed in 60 s and 70 s last century,the range is larger,the control precision of the servo control loop simulation that adopted is low,and the attenuation of the magnetic properties of magnetic steel,such as the change of the structure stress factors can cause long-term drift of the accelerometer.In this paper,we study and analysis quartz flexible pendulum accelerometer’s basic structure and mathematical model,Error model and the concrete influence factors,the Accelerometer small range improvement design,Accelerometer precision improvement design of four aspects.Summarized as follows:1.Carry on the discussion of the quartz flexible pendulum accelerometer error sources of the result,relevant error model of the accelerometer is analyzed in detail.On the source of the accelerometer bias error and bias stability system is analyzed.In addition,Then from accelerometer header,servo circuit and the processing and assembling three aspects affecting the quartz flexible pendulum accelerometer performance of specific factors are analyzed.Through the analysis,to reduce the range of the accelerometer,The accelerometer can increase the current scale factor and the stiffness of the flexible beam.To improve the accuracy of accelerometer can through reduce the magnetic field of magnetic induction intensity and change the processing technology and assembly process.2.Discuss the quartz flexible pendulum accelerometer and the key technologies of small scale design.Using magnetic induction intensity,reduce work quality,increase the coil quality,reduce the effective length of coil and the stiffness of the flexible beam method reduced the range of the accelerometer.And gives the specific parameters of the accelerometer structure improved design.Respectively through theoretical calculation and ANSYS software simulation to improve the design is verified.Verification results show that the design of structural parameters conform to the requirements,plus or minus 2 g range indicator.3.Discuss the quartz flexible pendulum accelerometer and the key technologies of precision design.The two indicators of accelerometer precision mainly zero bias stability and scale factor,So according to the relevant analysis to improve the design accuracy.Design reduce swing component migration is the largest,flexible beam stiffness,rapid increases the sensitivity.Use of samarium cobalt Sm2Co17 as modified magnetic steel material,Stability is significantly higher than the aluminum nickel and cobalt.At the same time,this paper designs a pendulum machining method of etching step by step,can further reduce the surface roughness of the flexible beam.Suggest a deep reactive ion etching method,processing submicron and the following dimensions.After verification,the improved current scale factor can reach,comply with the design at the beginning of the proposed >5 mA/g the requirements of the indicators.Through from the side of the gravity field experiment proved the feasibility of the design of small-range High-precision solution.