高精度电子分析天平参数估计与滤波

电子分析天平的传感器结构和测量电路比较复杂，不能够精确求出系统的传递函数。为了估计出系统的传递函数并提高测量数据的信噪比，先通过拉氏变换的方法估计了系统传递函数的阶数，推导了稳态下系统的状态方程，通过自回归方法估计系统参数并结合卡尔曼滤波的方法对测量结果滤波。试验通过离线数据估计出了方程参数和噪声强度，并验证了测量过程数据的平稳性，显著性水平低至0.001。参数估计加卡尔曼滤波混合方法与普遍采用的滑动窗口滤波法作了比较，新方法的平滑性和稳定性均有显著提高，测量标准差可达原有方法的30%,线性度可达6.7×10^-5,响应时间较原方法低至10%。4个样品的试验数据验证了该方法的可行性和有效性。

High-precision electronic analytical balance parameter estimation and filtering

The sensor structure and measurement circuit of electronic analytical balances are complex and cannot accurately calculate thetransfer function of the system. In order to estimate the transfer function of the system and improve the signal-to-noise ratio of themeasurement data, the order of the transfer function of the system is estimated by the method of Laplace transform, the equation of stateof the system under steady state is derived, and the method of estimating the system parameters by autoregressive method and combiningwith Kalman filtering is proposed to filter the measurement data. Through the experimental estimation of equation parameters and noiseintensity from offline data, the filtered data verify the smoothness of the process, and the significant level is as low as 0. 001. Comparedwith the commonly used sliding window filtering method, the smoothness and stability of the new method are significantly improved, themeasurement standard deviation is 30% of the original method, the linearity can reach 6. 7×10-5, and the response time is as low as10%. The experimental data of four samples verify the feasibility and effectiveness of the proposed method.