Design Of Quartz Resonant Accelerometer Stimulation Oscillating Circuit And Temperature Compensation Technology

Quartz resonance accelerometer has the advantage of direct digital signal output,avoiding A/D conversion errors.It has becomes one of the research hotspots in the field of high-precision inertial navigation.In view of the difficulty of starting vibration of high impedance quartz vibrating beam,a silicon-based quartz resonant accelerometer is designed,and a high gain exciting circuit is designed for the high impedance quartz vibrating beam.The temperature compensation technology is studied for the temperature sensitivity of the heterogeneous silicon-based quartz resonant accelerometer.The working principle of the silicon-based quartz resonant accelerometer is analyzed,and the advantages of using the differential structure scheme are explained.The electrical characteristics of the quartz vibration beam of the sensitive element,the principle of double-gate oscillation circuit is used,and the high-gain excitation circuit is designed using the scheme of operational amplifier+double-gate.And designed and manufactured a high-gain Stimulation oscillating circuit PCB,and silicon-based quartz resonant accelerometer chip using an integrated package.Using the Agilent DSO5012A model oscilloscope and frequency meter to test the resonant system composed of the high-gain resonant circuit and the quartz vibration beam,the test results show that:designing the resonant system composed of the high-gain Stimulation oscillating circuit and the quartz vibration beam can output a standard square wave signal,The output frequency accuracy reaches 10^-5KHz,the frequency change after vibration is stable is less than 0.1Hz,and no overtone frequency appears.Aiming at the requirement of quartz resonant accelerometer output frequency measurement,a differential quartz resonant accelerometer frequency measurement system was designed based on the FPGA platform.The design scheme of FPGA+SPOC is adopted.In order to facilitate the software design of SPOC,a computer is used to control the accelerometer to increase the compatibility of the system.The system is tested,and the test results show that it can realize the simultaneous acquisition of the frequency of the dual beams of the accelerometer,and the acquisition accuracy can reach the order of 10^-8.The temperature output characteristics of silicon-based quartz resonant accelerometers were studied.According to the characteristics of MEMS devices,it was decided to use software compensation for temperature compensation of quartz resonant accelerometers.A temperature compensation model of silicon-based quartz resonant accelerometer was established by establishing data samples and using a fusion of common polynomial fitting and support vector machine algorithms.Finally,the effect of temperature compensation is verified.The experimental results show that the maximum absolute error is reduced from 0.2379/g before compensation to 0.0079/g after compensation,and the bias temperature coefficient is 2 orders of magnitude lower than that before compensation.The scale factor temperature After the coefficient compensation,it is an order of magnitude lower than before the compensation.The compensation effect is significant,which greatly reduces the interference of temperature changes on the output frequency of the accelerometer,which is of great significance to the research of quartz resonance accelerometer.