基于模拟内插法的振梁加速度计测频方法  

Frequency Measurement of Vibrating Beam Accelerometer Based on Analog Interpolation Method

作　　者：张雅宁 仇斌 王晓东[1] 袁文辉 张国鹏 ZHANG Yaning;QIU Bin;WANG Xiaodong;YUAN Wenhui;ZHANG Guopeng(Beijing Institute of Aerospace Control Devices,Beijing 100039)

机构地区：[1]北京航天控制仪器研究所,北京100039

出　　处：《导航与控制》2024年第3期62-72,46,I0002,共13页Navigation and Control

摘　　要：针对现有应用于振梁加速度计后端的小型化测频电路的精度不高问题,提出了一种利用模拟器件搭载实现准确测频的模拟内插法,本实验采用FPGA和模拟器件配合完成待测信号的测量和数据流水线式的处理及运算;实验中使用等周期法和模拟内插法分别测量标准信号源的输出、振梁加速度计的输出。实验结果显示,模拟内插测频法明显优于等周期测频法:使用标准信号源做输入时,平均波动对比等周期法的结果由0.63 mHz降至0.012 mHz,稳定精度提升了52.5倍;当测量振梁加速度计的输出时,平均波动对比等周期法的结果由2.5 mHz降至0.98 mHz,稳定精度提升了2.6倍,将系统时钟的频率由22.1184 MHz提升至150 MHz继续进行测试,稳定精度进一步提升了2.7倍,对结果采用递推平均滤波处理后平均波动达到0.11 mHz。基于模拟内插法的振梁加速度计测频方法的实验结果表明,利用硬件来控制计数时间可以提高测频精度,应用于设备或者箭体上均可实现,且在精度上有很大的优化空间。Aiming at the existing miniaturised frequency measurement circuit applied to the back-end of the vibrating beam accelerometer with low accuracy,an analogue interpolation method using analogue devices piggybacking to achieve accurate frequency measurement is proposed,and this experiment adopts the FPGA and analogue devices to cooperate to complete the measurement of the signal to be measured and the data pipelined processing and arithmetic.The output of the standard signal source and the output of the vibrating beam accelerometer are measured using the isoperiodic method and the analogue interpolation method,respectively.The experimental results show that the analogue interpolation frequency measurement method is significantly better than the isoperiodic frequency measurement method:when using a standard signal source as the input,the average fluctuation amount compared to the isoperiodic method is reduced from 0.63 mHz to 0.012 mHz,and the stabilisation accuracy is improved by 52.5 times.When measuring the output of the vibrating beam accelerometer,the average fluctuation compared to the results of the equal period method is reduced from 2.5 mHz to 0.98 mHz,and the stability accuracy is improved by 2.6 times,the frequency of the system clock is increased from 22.1184 MHz to 150 MHz to continue the test,and the stability accuracy is further improved by 2.7 times,and the results are applied recursive average filtering process to achieve an average fluctuation of 0.11 mHz.The experimental results of the frequency measurement method of the vibrating beam accelerometer based on the simulated interpolation method show that the frequency measurement accuracy can be improved by using the hardware to control the counting time,which can be achieved by applying it to the device or the arrow,and there is a lot of room for optimisation in terms of accuracy.

关 键 词：模拟内插法 测频电路 振梁加速度计 

分 类 号：V19[航空宇航科学与技术—人机与环境工程]