SUMMARY

With the advent of steerable, ram air parafoil canopies, aerial payload delivery has become a viable alternative for situations involving remote or undeveloped areas, hostile environments, or otherwise inaccessible locations. Autonomously guided systems utilizing such steerable, ram air canopies are typically controlled by symmetric and asymmetric deflection of the canopy trailing edge left and right brakes providing an effective means for lateral-directional control. Although these systems have demonstrated substantial improvement in landing accuracy over similarly sized unguided systems, their low number of available control channels and limited ability to alter vehicle glide slope makes them highly susceptible to atmospheric gusts and other unknown surface conditions near the target area often leading to large errors in landing position. The proposed research aims to improve landing accuracy in such adverse conditions by replacing the standard trailing edge deflection control mechanism in favor of upper surface canopy spoilers. Upper surface canopy spoilers operate by opening and closing several span-wise slits in the upper surface of the parafoil canopy thus forming a virtual spoiler from the stream of expelled pressurized air. Similar to conventional aircraft spoilers, opening of these span-wise slits creates a disturbance in both lateral and longitudinal vehicle dynamics. Using a six degree of freedom (6-DOF) rigid body parafoil and payload system dynamic model combined with experimental flight testing, a novel guidance and control strategy will be developed specifically designed to leverage the added control authority of the upper surface canopy spoiler mechanism. Additionally, turning performance using upper surface canopy spoilers for two identically sized canopies comprised of differing material stiffness is also investigated as well as detailed canopy actuator design and practical issues related to upper surface canopy spoiler implementation.