Complete Dynamic Modelling of a VTOL QuadPlane UAV

Unmanned aerial vehicles (UAVs) have two predominant configurations: fixed-wing, efficient in cruise flight and with long endurance, but dependent on runways or large areas for operation; and multirotor, capable of vertical take-offs and landings and precise maneuvers, although limited by their shorter range and efficiency. Hybrid VTOL UAVs, and especially QuadPlane UAVs, offer an intermediate solution, combining the aerodynamic efficiency of the fixed-wing UAV with the maneuverability of the multirotor through simple and versatile architecture. This work develops a complete and unified dynamic model of the Skywalker VTOL UAV, derived from the Skywalker X8 with the addition of four vertical rotors. The resulting dynamic model is formulated using a system of nonlinear ODEs, which realistically and comprehensively describe the vehicle behaviour, considering that the inputs from the airplane and quadcopter sections can act simultaneously, thus improving its efficiency. Implementation in MATLAB-Simulink and validation through simulations under equilibrium conditions and with varying inputs confirm the expected behaviour of a QuadPlane. This model provides a strong foundation for developing advanced multivariable control, guidance, and navigation strategies for next-generation hybrid UAVs.