Investigating Ballistic Launch Capability of a Coaxial-Rotor Micro Air Vehicle

Abstract:
This paper presents the development of a ballistically launchable, 360 g coaxial Micro Air Vehicle (MAV) utilizing a two-axis gimbal thrust-vectoring system for pitch and roll control. A combined experimental and analytical framework is employed to characterize aircraft performance across the full ballistic profile, from the initial projectile phase to the transition to hover. Wind tunnel experiments are first used to quantify passive stability during the projectile phase. Subsequently, a nonlinear six-degree-of-freedom (6-DOF) flight dynamics model is developed by synthesizing the mechanical and aerodynamic models of the individual aircraft subsystems. These subsystem aerodynamic models are obtained by combining experimental lookup tables with analytical models. The flight dynamics model is then leveraged to analyze the transition phase, characterize the effectiveness of the thrust-vectoring mechanism, and establish performance guarantees across the ballistic flight profile. A key finding of this work is that the effectiveness of the two-axis gimbal thrust-vectoring mechanism is fundamentally limited by the axial velocity experienced by the propellers at the point of transition. This operational limit is quantified for the coaxial MAV, and the vehicle's ability to successfully transition to hover during a ballistic launch is validated through a single-degree-of-freedom (1-DOF) experimental testing.

Did you attend Forum 82? Click the preview below to access the full paper.