US Army Drones Can Change Shape In-Flight
Army Drones: Imagine drones changing shape in-flight!
According to new research presented at the AIAA Aviation Forum and Exposition’s virtual event on June 16th, it was announced that, before long, the U.S. Army will be able to deploy autonomous air drones that can actually change shape during mid-flight.
Researchers with the U.S. Army’s Combat Capabilities Development Command’s, which is the Army Research Laboratory and Texas A&M University, “published findings of a two-year study in fluid-structure interaction. Their research led to a tool, which will be able to rapidly optimize the structural configuration for Future Vertical Lift vehicles while properly accounting for the interaction between air and the structure.”*
It is estimated that, within the next year, this tool will be used to develop, and rapidly optimize, Future Vertical Lift vehicles capable of changing shape during flight, which will optimize the performance of the UAV through different phases of flight.
Dr. Francis Phillips, an aerospace engineer at the laboratory, explained:
“Consider an [Intelligence, Surveillance and Reconnaissance] mission where the vehicle needs to get quickly to station, or dash, and then attempt to stay on station for as long as possible, or loiter . . . During dash segments, short wings are desirable in order to go fast and be more maneuverable, but for loiter segments, long wings are desirable in order to enable low power, high endurance flight.”*
In other words, “The best of both worlds!”
This tool will enable the structural optimization of a vehicle capable of such morphing while accounting for the deformation of the wings due to the fluid-structure interaction, he stated the following:
One concern with morphing vehicles, is striking a balance between sufficient bending stiffness and softness to enable morphing,” Phillips said. “If the wing bends too much, then the theoretical benefits of the morphing could be negated and also could lead to control issues and instabilities.”*
Fluid-structure interaction analyses typically require “coupling between a fluid and a structural solver”* using software.
This research is very intensive in terms of computational hours, “. . . in the range of about 10,000s core hours – for a single fluid and structural configuration,”* according to researchers.
However, researchers have developed a process that decouples the fluid and structural solvers, which can reduce the cost for a single run by as much as 80%, according to Phillips.
While there have been advances in research in morphing aerial vehicles, for the past 20 years, by designing a vehicle first, and then seeing what the fluid-structure interaction behavior will be, what makes the Army’s studies different now, is the fluid-structure interaction during vehicle design and structural optimization.
Phillips explains this new fluid-structure interaction will be applied for future projects:
“This research will have a direct impact on the ability to generate vehicles for the future warfighter. By reducing the computational cost for fluid-structure interaction analysis, structural optimization of future vertical lift vehicles can be accomplished in a much shorter time-frame.”*
Phillips points out that the future warfighter will be able to use this tool to manufacture optimized custom UAVs for specific missions.
This new development in drone technology by the Army is incredible news. The ability to optimize the performance of UAVs through different phases of flight, opens up tremendous possibilities for the application of such a technological breakthrough.