变形机翼薄膜蒙皮形状监测光纤传感方法研究

Optical fiber shape sensing of polyimide skin for flexible morphing wing

为解决变体飞行器变形机翼薄膜蒙皮形状实时监测问题,研究光纤传感及重建方法。采用实验方法标定光纤光栅传感器,得到聚酰亚胺薄膜蒙皮变形光纤传感校正曲线,实现光纤光栅传感器中心波长漂移量与薄膜蒙皮变形曲率参数的准确转换;实验测得不同翼型下光纤传感器反射谱特征及其随翼型变化规律,利用光纤光栅中心波长漂移量和线性插值算法计算得出不同翼型下聚酰亚胺薄膜蒙皮型面曲率数据,结合插值曲线拟合算法,重建出薄膜蒙皮三维形状;采用数字摄影测量系统进行对比实验,验证了光纤传感重建蒙皮形状参数的正确性。研究结果表明,聚酰亚胺薄膜蒙皮型面曲率的光纤传感与摄影测量误差小于5%,光纤传感方法可以实现变形机翼薄膜蒙皮三维形状传感与重建,在变体飞行器柔性蒙皮实时传感监测方面具有应用前景。

In order to real-time monitor the shape of the thin film of the deformation wing,fiber sensing and reconstruction are studied.The experimental method is used to calibrate the fiber Bragg grating（ FBG） sensor and obtain the calibration curve of the polyimide film.Accurate conversion of the Bragg wavelength shift（ BWS） of sensors and the deformation curvature parameters of thin film is achieved.The characteristics of the reflectance spectra of sensors in different airfoil profile and the changes of the airfoil profile are obtained. The bending curvatures of the polyimide thin film skin at different airfoil profiles are calculated using the measured BWS values of the FBG sensors and the linear interpolation algorithm. The 3D shapes of the polyimide skin at different airfoil profiles are reconstructed based on the measured bending curvatures and the interpolation and curve fitting functions. The 3D precise visual measurements are conducted using a digital photogrammetry system,and then the correctness of the shape reconstruction results is verified. The results prove that the maximum error between the 3D visual and FBG measurements is less than 5%,the FBG sensing method is effective for the shape sensing of polyimide skin for flexible morphing wing.