Abstract:The traditional detection methods for the force of bridge stay cables have problems such as low efficiency, high risk and high cost. The existing non-contact measurement technologies are also often limited by equipment cost, field of view or environmental robustness. Aiming at this bottleneck, a rapid identification method for cable force based on unmanned aerial vehicle (UAV) platform and computer vision is proposed. In this approach, the high-definition videos of bridge cables are acquired via a UAV. The optical flow method is then applied to track the sub-pixel displacements of feature points, thereby extracting vibration signals. Subsequently, the natural frequencies are identified through signal processing and spectrum analysis to invert cable force based on vibration theory. After verification with a real bridge as an example, it is found that the recognition results are in good agreement with the results of the traditional detection report, indicating that this method is accurate and reliable in actual engineering, which can provide a new technical scheme for the rapid inspection and health status assessment of bridge cables.
