Aerial robotic platforms are an increasingly sought-after solution for a variety of sensing, monitoring, and transportation challenges. However, as invaluable as unmanned aerial vehicles (UAVs) have been for these applications, fixed-wing and multi-rotor systems each have individual limitations. Fixed-wing UAVs are generally capable of high-altitude surveillance and long flight times, while quad-rotors are most effective when used for their maneuverability and close-quarters surveying. This paper improves upon the prototypes discussed in [1] by creating a series of three next-generation prototypes to isolate the aspects of solar powered fixed-wing flight, quad-rotor flight, and transformation modes of the SUAV:Q platform. Improvements to the transformation mechanism, airframe design, variable pitch propulsion system, and custom-designed power electronics are presented along with validation of the designs through empirical testing.

Throughout the wide range of aerial robot related applications, selecting a particular airframe is often a trade-off. Fixed-wing small-scale unmanned aerial vehicles (UAVs) typically have difficulty surveying at low altitudes while quadrotor UAVs, having more maneuverability, suffer from limited flight time. Recent prior work [1] proposes a solar-powered small-scale aerial vehicle designed to transform between fixed-wing and quad-rotor configurations. Surplus energy collected and stored while in a fixed-wing configuration is utilized while in a quad-rotor configuration. This paper presents an improvement to the robot's design in [1] by pursuing a modular airframe, an optimization of the hybrid propulsion system, and solar power electronics. Two prototypes of the robot have been fabricated for independent testing of the airframe in fixed-wing and quad-rotor states. Validation of the solar power electronics and hybrid propulsion system designs were demonstrated through a combination of simulation and empirical data from prototype hardware.