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Enabling In-Air Interactions for Aerial Vehicles
Aerial robots, specifically multirotors, combine two invaluable field robot skills: computational sensing, and spatial mobility. Unmanned aerial systems (UASs) have hence found rapid adoption into various domain sciences, as well as algorithmic and systems research. Today, they are computational organisms that can hover precisely as well as travel fast, and can transport sensors across volumes as well as avoid obstacles along the way. They remain, however, fairly limited in their ability to undertake physical and contact-based interactions in their environment. In this thesis, we propose mid-air tactile interactions between multiple UASs as the next step in the advancement of multirotor flight. Specifically, we develop novel methods that enable multirotors to dock with another moving system, and transfer payloads while remaining simultaneously airborne. These pose unconventional challenges in state estimation, control, and system development, especially when in close proximity to each other. We address these methodically through optimal algorithmic frameworks that anticipate these challenges and are robust even `in the field'. Towards this end, we develop FREYJA, a fully open-source optimal flight control stack that enables precise and accurate control over agile maneuvers. We then present novel algorithms and systems for a multirotor to recover free-drifting parachutes in the air, and then develop more deliberative means for an in-air transfer of payload between two multirotors. We also extend our aerial interactions to enable multirotors to dock with aircraft in forward flight, a novel contribution that dramatically expands the scope of their operations. The approaches developed in this thesis together form the first instances of multirotors exchanging payloads mid-air and docking while in motion. This work collectively enables multirotors to interact more closely with each other and their environment, and react gracefully to external tactile forces. Our concluding remarks expound the rich space of opportunities offered by interacting robots that coordinate to undertake contact-based missions. Doing this outdoors is crucial for the next generation of robotic systems that are practical as well as resourceful.
Robotics|Computer science|Artificial intelligence
Shankar, Ajay, "Enabling In-Air Interactions for Aerial Vehicles" (2021). ETD collection for University of Nebraska - Lincoln. AAI28712999.