UAS Sensor Deployment and Retrieval to the Underside of Structures

Unmanned Aircraft Systems (UAS, commonly known as aerial drones) are widely used for remote inspection and evaluation in Structural Health Monitoring (SHM) applications. While in most cases the drone is only equipped with a camera and collects images and videos, there is a high interest for structural evaluation that goes beyond visual inspection and provides information on the internal structure. For the latter, specialized sensors need to be used which in many cases need to be attached to the structure. This work presents a low-cost autonomous UAS for attaching and retrieving sensor packages to the underside of structures for SHM applications. Such a system can be used for nondestructive evaluation of structures by deploying sensors like accelerometers on bridges or tunnels. The proposed system is experimentally evaluated and is shown to be capable of the task utilizing only onboard systems and an artificial landmark with an operator to change between deployment and retrieval missions.