Experts from the Army’s Research Laboratory presented their work on a new tool to develop the small shape-shifting drones at the American Institute of Aeronautics and Astronautics Aviation Forum and Exposition virtual event on June 16.
Army researchers and Texas A&M University published the 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,” explained the Army Research Laboratory, in a statement.
Within the next year, the tool will be used to develop drones that change shape during flight, according to the Army.
"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," said Dr. Francis Phillips, an aerospace engineer at the Army Research Laboratory, in the statement. "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."
Researchers, however, have to strike a careful balance between sufficient bending stiffness and softness that enables the vehicle to “morph” into a different shape.
“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,” said Phillips.
Fluid-structure interaction is a complex process that requires analysis of coupling between a fluid and a “structural solver” using software. However, this research is very intensive in terms of computational hours. “The computational cost for these analyses can be very high – in the range of about 10,000s core hours – for a single fluid and structural configuration,” researchers explained in the statement.
To streamline this process researchers devised a process that decouples the fluid and the structural solvers. Phillips said that this can reduce the “computational cost” by as much as 80 percent.
Using this approach, additional analysis can also be performed without reanalyzing the fluid, which can generate more computational cost savings, according to Army researchers. This means that the Army could design new vehicles much more quickly than current techniques, according to Phillips.
Army researchers regularly partner with U.S. universities to drive innovation. In 2018, for example, robotics experts developed software to ensure that if military robots fall, they will be able to get themselves up again.
Experts at the Army Research Laboratory and the Johns Hopkins University Applied Physics Laboratory built software to work out whether any given robot could get itself “back on its feet” after being overturned.
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