Dynamics of a UAV With Parafoil Under Powered Flight

*This paper presents a derivation of the dynamics of a small propeller driven fixed wing unmanned air vehicle with a parafoil deployed. The parafoil and aircraft are both modeled using six degree of freedom representations, and are then coupled using constraints that produce an eight degree of freedom system. Accurate modeling of the apparent mass effects of the parafoil make the modeling, simulation, and control design a challenge. Flight tests were used to measure key aerodynamic coefficients for the models, and was used to validate responses. The simulation was then used to develop an automatic landing control system. Accurate steering and landing of such a system is possible in low wind scenarios, and was successfully demonstrated in flight.