Blade tip timing (BTT) technology is the most effective means for real-time monitoring of blade vibration. Accurately extracting the time of blade tip reaching the sensors is the key to ensure the accuracy of the BTT system. The tip clearance changes due to various complex forces during high-speed rotation. The traditional BTT signal extraction method does not consider the influence of tip clearance change on timing accuracy and introduces large timing errors. To solve this problem, a quadratic curve fitting timing method was proposed. In addition, based on the measurement principle of the eddy current sensors, the relationship among the output voltage of the eddy current sensor, tip clearance, and the blade cutting magnetic line angle was calibrated. A multisensor vibration parameter identification algorithm based on arbitrary angular distribution was introduced. Finally, the experiments were conducted to prove the effectiveness of the proposed method. The results show that in the range of 0.4 to 1.05 mm tip clearance change, the maximum absolute error of the timing values calculated by the proposed method is 26.0359 us, which is much lower than the calculated error of 203.7459 us when using the traditional timing method. When the tip clearance changed, the constant speed synchronous vibration parameters of No. 0 blade were identified. The average value of the vibration amplitude is 1.0881 mm. Compared with the identification results without changing tip clearance, the average value error of the vibration amplitude is 0.0017 mm. It is proved that within the blade tip clearance variation of 0.4 to 0.9 mm, the timing values obtained by the proposed timing method can accurately identify the vibration parameters of the blade.

中文翻译：

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一种考虑叶尖间隙变化的改进叶片振动参数识别方法

叶尖定时（BTT）技术是实时监测叶片振动的最有效手段。准确提取叶尖到达传感器的时间是保证BTT系统精度的关键。在高速旋转过程中，由于各种复杂的力，叶尖间隙会发生变化。传统的BTT信号提取方法没有考虑叶尖间隙变化对授时精度的影响，引入了较大的授时误差。为了解决这个问题，提出了二次曲线拟合时序方法。此外，基于涡流传感器的测量原理，标定了涡流传感器输出电压、叶尖间隙与刀片切割磁力线角之间的关系。介绍了一种基于任意角分布的多传感器振动参数识别算法。最后，通过实验证明了所提出方法的有效性。结果表明，在0.4~1.05 mm叶尖间隙变化范围内，所提方法计算出的计时值的最大绝对误差为26.0359 us，远低于传统计时法计算出的203.7459 us的误差. 当叶尖间隙发生变化时，确定了0号叶片的恒速同步振动参数。振幅平均值为1.0881mm。与不改变叶尖间隙的识别结果相比，振动幅值的平均值误差为0.0017 mm。证明在叶尖间隙变化为 0.