微波叶尖间隙传感器信号校准研究

Study on the signal calibration of microwave blade tip clearance sensor

利用微波雷达传感器测量叶尖间隙时,传感器存在信号泄露、背景回波叠加、电路元器件不平衡以及空间滤波效应等问题,根据这些问题的来源及影响机理,提出了一种具有环境适应性的传感器误差模型,通过将模型从空间域变换到频率域并优化误差提取算法,建立了一套提高传感器线性度、减小测距误差的校准方法。同时,选用小型24 GHz雷达传感器构建了模拟叶尖位移测量平台,使用该校准方法后,传感器线性度由±13.79%提高到±1.57%。拟合标准距离与测量值后,量程内最大测距误差下降到0.021 3 mm,最大标准差下降到0.019 7 mm。该方法有利于提高微波叶尖间隙测量精度。

When using microwave radar sensor to measure the blade tip clearance, there are some problems, such as signal leakage, background echo superposition, unbalance of circuit components, spatial filtering effect and etc. According to the source and effect mechanism of these problems, a sensor error model with environmental adaptability is proposed in this paper. Through transforming the model from spatial domain to frequency domain and optimizing the error extraction algorithm, a calibration method for improving the sensor linearity and reducing distance measurement error is established. A miniaturized 24 GHz radar sensor was used to construct the experiment platform for simulating the blade tip displacement measurement. Using this calibration method, the linearity error of the sensor is decreased from ±13.79% to ±1.57%. After fitting the standard distance and measurement value, the maximum measurement error within the range is decreased to 0.021 3 mm, the maximum standard deviation is decreased to 0.019 7 mm. This method is benefit of improving the accuracy of microwave blade tip clearance measurement.