Deflection Angle Measurement of Flight Control Surfaces Based on RGB-D Images

Accurate deflection angle measurement of flight control surfaces is essential for verifying system responsiveness during flight control system testing (FCST). Traditional manual methods lack precision and efficiency, while non-contact techniques often require calibration, increasing resource consumption. Additionally, many vision-based approaches depend on prior geometric knowledge of flight surfaces. To overcome these limitations, we propose a calibration-free RGB-D method that combines RGB-based target recognition with depth-derived geometric point cloud data. The proposed method transforms angle variation into angular differences between Principal Component Analysis (PCA) axes coordinate systems of point clouds while enhancing accuracy through convexity-aware smoothing. Experimental validation conducted on an aircraft wing test platform demonstrates the high measurement accuracy achieved by this approach, with most angular measurement of the experiment error below 0.25 \(^{\circ }\) which satisfy the industrial demand in FCST.