基于加权最小二乘法的光纤光栅应变传感器参数敏感性自动优化算法

Automatic optimization algorithm for parameter sensitivity of fiber bragg grating strain sensors based on weighted least squares method

常规光纤光栅应变传感器参数优化方法主要依托于麻雀搜索算法,但此方法忽略了应变传递的影响,导致传感器灵敏度较低,无法保证测量精度。为此,提出基于加权最小二乘法的光纤光栅应变传感器参数敏感性自动优化算法。依据光纤光栅应变传感器的组成结构与工作原理,充分考虑应变传递系数的变化规律,计算应变传递损耗,并采用光传输矩阵计算光纤中心波长的电场振幅,由此得到传感器敏感场分布,结合模式耦合理论,以敏感场分布均匀性和最大电容与最小电容比值最小为目标函数建立参数优化模型,并采用加权最小二乘法对采样点加权获取优化响应值,进而得到传感器最优结构参数。对比实验结果表明,利用所提方法对光纤光栅应变传感器参数进行优化后,传感器的灵敏度较高,保证了传感器的测量精度。

The conventional parameter optimization method for fiber Bragg grating strain sensors mainly relies on the sparrow search algorithm,but this method ignores the influence of strain transfer,resulting in low sensor sensitivity and inability to ensure measurement accuracy.Therefore,an automatic optimization algorithm for parameter sensitivity of fiber Bragg grating strain sensors based on weighted least squares method is proposed.Based on the basic structure of the sensor,combined with the direction of strain transfer and engineering,considering the regular changes in strain coefficient,and the strain transfer loss is calculated.Calculate the amplitude of wavelength change using the coefficient of change model.From this,the sensitive field distribution of the sensor is obtained.Combined with the mode coupling theory,a parameter optimization model is established with the objective function of uniformity of the sensitive field distribution and minimizing the ratio of maximum capacitance to minimum capacitance,and the weighted least squares method is used to weight the sampling points to obtain the optimal response values,thereby obtaining the optimal structural parameters of the sensor.Taking a certain fiber optic sensor as the experimental object,the structural parameters were optimized using the design method.The results showed that the sensitivity of the sensor was guaranteed and the measurement accuracy was improved.