UAV payload with collision mitigation for contact inspection

This document presents a payload designed to perform semi-autonomous collision-mitigation inspection tasks on UAVs. This system features no external aid positioning the UAV such as the motion capture systems or the Global Navigation Satellite System (GNSS), which makes these inspections possible in the GNSS-denied areas. The payload is composed of two distance measuring units that calculate the range and angle between the UAV and the structure. The payload controller uses this information to calculate the pitch and yaw signal to control approach and contact. A hybrid automaton has been implemented, which represents the corresponding UAV states during the approach and the contact with different control strategies for each one. For this study, an ultrasonic contact sensor was used as an inspection sensor, but the system can work with any other contact sensor. This sensor measures the thickness of the metal sheets when is in contact with it. Various tests have been performed on the system with accurate results, demonstrating that the system can maintain stable contact with a vertical structure.