Use of Variable Incidence Angle for Glide Slope Control of Autonomous Parafoils

Strictly speaking, most autonomous parafoil and payload systems possess only lateral control, achieved by right and left parafoil brake deflection. An innovative technique to achieve direct longitudinal control through incidence angle changes is reported. Addition of this extra control channel requires simple rigging changes and an additional servoactuator. The ability of incidence angle to alter the glide slope of a parafoil and payload aircraft is demonstrated through a flight-test program with a microparafoil system. Results from the flight-test program are synthesized and integrated into a six degree-of-freedom simulation. The simulation model is subsequently used to assess the utility of glide slope control to improve autonomous flight control system performance. Through Monte Carlo simulation, impact point statistics with and without glide slope control indicate that dramatic improvements in impact point statistics are possible using direct glide slope control.