A new tilt-arm transitioning unmanned aerial vehicle: Introduction and conceptual design

In this paper, a novel hybrid unmanned aerial vehicle (UAV) concept is developed. This UAV is capable of transitioning between VTOL, hover, and efficient (fixed-wing type) forward flight. The overall configuration comprises a blended-wing-body, with two rotor arms mounted at the two wing tips using span-wise shafts; the arms can rotate about the span-wise axis, and each contains two propellers at its two ends. A conceptual design automation framework is developed, comprising mass and balance analysis, aerodynamic analysis and optimization. Vortex Lattice Method (VLM) is used to perform the aerodynamic analysis. Furthermore, using wind distribution models, redundancy modeling, and probabilistic UAV airspeed constraints derived thereof, a robust design optimization formulation is presented to explore the mission envelop flexibility of this new hybrid UAV. Mixed-discrete Particle Swarm Optimization is used to identify optimum geometry and component choices. Multiple case studies are performed to separately maximize forward-flight range and hovering endurance, subject to various aerodynamic and geometric constraints. The range optimizations converge to distinct designs under calm, windy, and stormy scenarios while offering promising flight ranges going from 40 km to 150 km, and the hovering optimization outcomes provide a 25 min hovering endurance subject to a 40 km round-trip flight.