硅微谐振加速度计因具有小体积优势和高精度潜力，成为硅微惯性传感器研制的热点之一。频率信号的高精度采集和系统参数补偿是提高硅微谐振加速度计性能的重要手段之一。在分析硅微谐振加速度计工作机理的基础上，从双路差动频率信号的精确采集和系统误差参数补偿角度出发，分析了数据采集的原理，提出了一种高精度硅微谐振加速度计用数据采集与参数补偿方法。给出了设计思路和电路实现方法，讨论了误差来源与改进方法。所设计的数据采集系统针对中心频率18 kHz.，标度因数400 Hz/g，量程±20g的加速度计，数据更新周期200 ms下频率分辨率为0.0005 Hz，等效加速度分辨率达到1.25μg。测试表明，补偿后的硅微谐振加速度计，在全温（-40~+70℃）内，K0温度系数从262μg /℃降低到29.9μg/℃， K1变化量从4.18％降低到2.04‰，全量程非线性从7.16‰降低到0.128‰，系统参数满足设计指标。%The silicon resonant accelerometer (SRA) is one of research hotspots in inertial instruments for its small volume and potential of high-precision.Data acquisition and parameter compensation is one of the important ways to improve the performance of the SRA. Based on the analysis of the SRA’s working principle, a high-precision design of frequency signal acquisition and parameter compensation system is presented to improve the performance of the SRA. The design idea and implementing method are studied, and the error source and its depressing solution are discussed. The experiment results show that the system can acquire resolution with ±0.0005 Hz, corresponding to 1.25μg in 200 ms on condition that the resonant accelerometer has a normal frequency of 18 kHz, a scale factor of 400 Hz/g, and a measuring range of ± 20g. Within full temperature range of -40℃ to +70℃, the temperature coefficients of bias and scale factor drop to 29.9μg/℃ and 2.04‰ from 262μg/℃ and 4.18%, respectively, and the nonlinearity for full scale is decreased to 0.128‰ from 7.16‰.
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