Blade is the core working components of an aero-engine, and its blade tip clearance (BTC) exerts a direct influence on the efficiency and safety of the engine. Aiming to extract the BTC region from the echo signal, a novel microwave-based dynamic measurement system through nonlinear I/Q imbalance correction is proposed. Firstly, to achieve accurately correction of the sensor under non-linear amplitude attenuation, a new correction method is proposed to map the amplitude decay attenuation into the imbalance parameters distribution. Secondly, to effectively localize the extraction BTC region, the Amplitude-phase Half Wave Extraction (APH) is proposed, which utilizes squared I/Q amplitude information to determine the BTC position and extract clearance information. Finally, in comparison to existing methods, the proposed algorithm exhibits excellent performance in signal correction under non-linear amplitude attenuation and achieves high-accurate BTC extraction. Experimental studies show a mean absolute error below 2 μm and a repeatability mean error of 0.154 μm for a BTC variation of 0.17 mm.

中文翻译：

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一种基于微波的新型动态测量方法，通过非线性 I/Q 不平衡校正测量叶尖间隙


叶片是航空发动机的核心工作部件，其叶片尖端间隙 （BTC） 直接影响发动机的效率和安全性。为了从回波信号中提取 BTC 区域，提出了一种基于微波的新型非线性 I/Q 不平衡校正动态测量系统。首先，为了实现传感器在非线性振幅衰减下的精确校正，提出了一种新的校正方法，将振幅衰减衰减映射到不平衡参数分布中。其次，为了有效地定位提取 BTC 区域，提出了振幅相位半波提取 （APH），利用平方 I/Q 振幅信息来确定 BTC 位置并提取清除信息。最后，与现有方法相比，所提算法在非线性幅度衰减下的信号校正方面表现出优异的性能，实现了高精度的BTC提取。实验研究表明，对于 0.17 mm 的 BTC 变化，平均绝对误差低于 2 μm，重复性平均误差为 0.154 μm。