Shelled Unmanned Aerial System for Bridge Structural Health Monitoring

Bridge inspections are critical for maintaining structural integrity and must be inspected on a regular basis to ensure their dependability. Aerial vehicles provide a safer, costefficient, and time-saving method for inspection. However, UAVS (Unmanned Aerial Vehicles) are limited from flying near the bridge structure due to their exposed propellers. Using shelled UAVs addressed the collision problem while giving a good visual condition and increasing motion effectiveness.In this study, a shelled UAV system that structural inspectors can use to perform a close visual inspection of the bridge was developed. The newly developed shelled UAV features a passive rotating shell with a two-axis gimbal. This shelled UAV is waterproof, modular, capable of water takeoff and landing, and integrated with a crack detection system. A functional shelled UAV was fabricated, and test flights were successfully conducted.The results of the computational simulations and actual flight tests showed that the shelled UAV is overall safe and effective in terms of its strength-to-weight consideration, drag force, and stability performance. Moreover, crack detection systems and software applications were developed. A curated dataset was also produced for the purpose of training the crack detection system. The U-Net architecture was used as the segmentation model trained on the dataset. The trained model was effective and could predict and segment cracks in the gathered dataset images. The functionality of the Data Acquisition App, Damage Detection App, and Inspection Details App was tested and verified.