Numerical Investigation of the Flight Dynamics of a Robotic Boomerang

Flight dynamics of a remotely piloted powered boomerang having VTOL and continuous flight capabilities is studied in this paper. The powered boomerang is controlled using a motor-propeller combination, which is used to control the spin rate of the boomerang, and by varying the blade pitch angle of individual blades. A flight dynamic simulation is developed to solve the equation of motion for the proposed vehicle and predict the trajectory and flight behavior based on the geometric and input parameters. The simulated trajectory is qualitatively verified through flight tests of prototype models. Mainly four kinds of trajectories have been observed in open loop simulations - hovering, spiral, helical and level circular flight. The altitude and vertical translational velocity of the vehicle can be controlled by varying the spin velocity by regulating the motor RPM and the radius of the flight is controlled by symmetrically changing the blade pitch angle on both the blades. Thereby, the flight control of the robotic boomerang can be achieved. Unlike other rotary wing vehicles, the attitude of the robotic boomerang is observed to be inherently stable in both simulation as well as flight test resulting in open loop test flights.