Overcoming the Challenges of Using Unmanned Aircraft for Bridge Inspections

Abstract

Applications for small unmanned aerial vehicles have exploded over the past decade. Small size, maneuverability, low cost, and versatility enable utilization for applications not readily accessible by traditional manned aircraft, such as bridge inspections. However, the challenges associated with conducting inspections in a safe, cost efficient manner currently exceed the benefits of using an unmanned aircraft for inspection. The development of a multirotor-based inspection aircraft capable of maintaining flight for over eight hours is presented. Flight results from a bridge inspection conducted in collaboration with the Missouri Department of Transportation (MoDOT) and Shafer, Kline, & Warren (SKW) bridge inspection crews are also discussed. Feedback and recommendations for inspection platform improvement from MoDOT and SKW inspectors was collected. Inspectors and flight crew identified challenges with camera exposure, dual pilotinspector remote control, and aircraft stability. As a result, a new inspection platform was developed allowing for wireless dual remote control and manual control of camera exposure. Finally, and most importantly, a new metric for quantifying UAS handling and pilot workload in GPS denied environments is introduced through rigorous flight testing and the use of a modified Cooper-Harper rating scale. Inspection of the bridge substructure prevented GPS lock and increased pilot workload. To mimic the effects of flying around a bridge flight testing is conducted at the UMKC parking garage where GPS lock is denied. The aircraft and inspection solutions discussed herein have demonstrated success for acquiring meaningful inspection data while conducting safe flight operations.