ERI: Drones-Enabled Active Sensing System (DEASS) for Detection of Subsurface Defects in Civil Infrastructure through Synchronized Drone Swarming and Thermal Imaging

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).

This Engineering Research Initiation (ERI) project will explore an active thermal imaging system carried by a pair of drones, one (leader) for thermal imaging and the other (follower) for active heating (e.g., microwave), to enable subsurface defect detection in the next-generation inspection of civil infrastructure in a GPS-denied environment (e.g., underneath bridge decks). Due to its limited payload and battery time, a single drone cannot support additional payload and its associated accessories required for active sensing.

The concept of two leader-follower drones is thus introduced. This award supports fundamental research for the development of a drones-enabled active sensing system through synchronized drone swarming and thermal imaging. The new technique will transform the current passive surface deterioration inspection practice, which is subject to the change in sunlight conditions, into an active thermal imaging inspection for subsurface condition deterioration, such as delamination and horizontal cracks in reinforced concrete structures.

In addition to infrastructure inspection and maintenance, the new technique will impact multiple frontiers with cooperative robot swarming and active sensing, such as interactive manufacturing and healthcare, and academic communities in science and engineering. The technique and research results will be transferred into the hands of engineering professionals through a national workshop.

The drones-enabled active sensing system will be investigated via software/hardware-in-the-loop simulations and experimental tests. This research will overcome two technical challenges: (1) to synchronize drone swarming and thermal imaging in an energy-efficient strategy and (2) to enable new thermal imaging detectability with a heat source distributed on a leader-follower drone platform to stimulate the appearance of subsurface defects in active imaging.

It will lay a foundation on cooperative robot swarming and active sensing research in multiple frontiers. First, it will develop a new strategy of leader-follower formation for drone swarming with visual relative navigation and collision avoidance based on a three-dimensional stereo vision and potential field algorithm during cooperative active sensing and inspection of subsurface defects in a GPS-denied environment.

Second, it will establish optimal characteristics of active sensing of microwave heated concrete decks with optimized microwave excitations (energy source, frequency and duration) and sensing protocols (measurement sensitivity, frame rate and time window). Third, it will develop a method to evaluate and improve the performance of cooperative drone swarm formation and active thermal imaging of defects in a markup solid deck concrete bridge and a potential field infrastructure inspection.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.