Biplane-Quadrotor Tail-Sitter UAV: Flight Dynamics and Control

This paper presents the development of 6-degrees-of-freedom (6-DOF) flight dynamics model and nonlinear control design for a novel hybrid biplane-quadrotor unmanned aerial vehicle capable of efficient operation in both vertical takeoff and landing (VTOL) mode and forward flight mode. The development of vehicle dynamics model considers a complete description of flight dynamics, wing aerodynamics, and prop wash modeling. Rotor and wing aerodynamics during hover, transition, and forward flight are the key components of the vehicle dynamics equations and are systematically validated with experimental data available in the literature. The rotor aerodynamic loads calculated using blade element theory and uniform inflow–based model is found to offer adequate fidelity during both axial and edgewise flights of the rotor. The rigid body rotation of 90° about pitch axis during transition from hover to forward flight and back necessitates the use of quaternions for representation of the attitude of the vehicle to avo...