Precision Fully-Actuated UAV for Visual and Physical Inspection of Structures for Nuclear Decommissioning and Search and Rescue

The Dexterous Hexrotor is a fully-actuated multi-rotor UAV developed for precision operations close to and in contact with physical structures. The fully-actuated nature of this type of UAV allows it to exert forces instantaneously in any direction in R
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. This, in turn, provides higher closed-loop control bandwidth for better disturbance rejection in free space and high performance impact and force control in contact with the environment. This paper presents a numeric estimation for a new term in aerodynamic performance of the Dexterous Hexrotor as well as an optimization approach to configure the nonparallel thrusters with respect to operating parameters of the drone including the desired force signature of interaction with the environment. A previously-developed fully-actuated Dexterous Hexrotor UAV is used as an example to introduce the nonparallel actuation related benefits, including mobility measure, dihedral effect and efficiency. Then we implement the numeric estimation and optimization method to the Dexterous Hexrotor UAV prototype to setup the rotor configuration. Experiments were performed to validate the optimized result with a contact based force control test and sample tests of the device in a mock nuclear decommissioning task at the DOE Gaseous Diffusion Plant in Portsmouth, Ohio, USA and at a mock-up of the exhaust shaft of the Waste Isolation Pilot Plant.