A modeling and calibrating method of FBG sensors for wing deformation displacement measurement

The airborne distributed Position and Orientation System (POS) is a key piece of equipment for providing high-precision motion parameters for aerial remote sensing systems. However, wing deformation degrades the performance of distributed POS, thus, it is urgent to obtain high-precision deformation information to assist distributed POS. In this study, a modeling and calibrating method of fiber Bragg grating (FBG) sensors for wing deformation displacement measurement is proposed. First, based on the cantilever beam theory and piecewise superposition, a modeling and calibrating method for wing deformation displacement measurement is established. The wing is then placed under different deformation conditions, and the changes in the wing deformation displacement and corresponding wavelength variations of the pasted FBG sensors are obtained using theodolite coordinate measurement system and FBG demodulator, respectively. Subsequently, linear least square fitting is deployed to develop the relationship model between the wavelength variations of the FBG sensors and wing deformation displacement. Finally, the wing deformation displacement at the measuring point in the temporal and spatial dimensions is obtained by fitting and interpolation. An experiment is conducted, and the results show that the accuracy of the proposed method can reach 0.721 mm with a wing length of 3 m, which can be used in the motion compensation of an airborne distributed POS.