Parafoil Control Using Payload Weight Shift

Autonomous guided airdrop systems based on steerable ram-air parafoils rely on differential deflection of the canopy trailing edge for lateral control with very limited longitudinal control. This work explores an alternative method that achieves both lateral and longitudinal control by shifting the center of gravity of the payload relative to the canopy rigging attachments. A multibody simulation model is required to capture the complex motion associated with the flexible nature of the parafoil, payload, and rigging system and simulate the effects of both longitudinal and lateral shifting of the center of gravity. Simulation results show that longitudinal weight shift can be an effective means of providing airspeed and glide slope control, and lateral weight shift can be an effective means of providing turn rate control. Results demonstrate that, for both lateral and longitudinal control, spreading the attachment points of the rigging to the payload will cause the aircraft to be more sensitive to shifts in the payload center of gravity. It was also found that, for both lateral and longitudinal control, decreasing the vertical distance from the rigging attachments to the center of gravity on the payload causes the aircraft to be more sensitive to shifts in the payload center of gravity. Finally, dynamic results demonstrate that the forces and moments required to induce a weight shift in the payload will often cause an initial response in the opposite direction of the final steady-state response.