Modeling and Evaluation of a Spherical VTOL Aerial Vehicle with Ground Mobility
Weng Kheong Loh, Jamey Jacob · 52nd Aerospace Sciences Meeting · 2014
A framework for the design, modeling and control of a spherical shaped aerial vehicle designed for both flight and ground operations, called the Unmanned Flying and Rolling Orb (UFRO), is introduced. Equations of motion derived from aerodynamic forces are employed to provide precise estimation in modeling and the resulting coupled model of longitudinal and lateral dynamical equations are abstracted from a physical airframe and used to simulate flight for tuning of the flight controller. A COTS PID controller is used to perform autonomous attitude-stabilized flight, and flight results are presented. Ground mobility is possible using short duration propulsion operation while on the ground to generate an airstream to allow the vehicle to perform a self-uprighting maneuver and then return to flight. One of the unique features of this vehicle are the movable vanes positioned radially around and close to the propeller tip, not typically seen in open rotor or ducted fan platforms. The deflection angle of the vanes are affected by the propeller inflow and generate lift for increased lifting capability and to provide passive stability control. Experiments are conducted to examine the flow and lift generated by the vanes and preliminary tests estimate a nearly 10% lift/vehicle weight ratio generated by these vanes when the propeller is operating under vertical take off or hovering flight conditions.