A novel videogrammetry-based full-field dynamic deformation monitoring method for variable-sweep wings

The measurement of wing dynamic deformation in morphing aircraft is crucial for achieving closed-loop control and evaluating structural safety. For variable-sweep wings with active large deformation, this paper proposes a novel videogrammetric method for full-field dynamic deformation measurement. A stereo matching method based on epipolar geometry constraint and topological constraint is presented to find the corresponding targets between stereo images. In addition, a new method based on affine transformation combined with adjacent closest point matching is developed, aiming to achieve fast and automatic tracking of targets in time-series images with large deformation. A calculation model for dynamic deformation parameters is established to obtain the displacement, sweep variable angle, and span variation. To verify the proposed method, a dynamic deformation measurement experiment is conducted on a variable-sweep wing model. The results indicate that the actual accuracy of the proposed method is approximately 0.02% of the measured area (e.g., 0.32 mm in a 1.6 m scale). During one morphing course, the sweep variable angle, the span variation and the displacement increase gradually, and then decrease. The maximum sweep variable angle is 36.6°, and the span variation is up to 101.13 mm. The overall configuration of the wing surface is effectively reconstructed under different morphing states.