When it comes to mastering flight for small craft, humans could stand to learn much from the insect world. Insects have iterated small-scale flight for generations upon generations, stretching back literal millions of years, which means there exists an entire biomechanical library of potential answers to problems facing drones that researchers can tap into.
Drawing inspiration from insects, a team of researchers at Purdue University’s School of Engineering Technology showed that flexible arms for quadcopters are more efficient, and the energy saved enables quadcopters to carry larger payloads.
“Our drone design was inspired by the wings and flight patterns of insects,” said paper co-author Xiumin Diao, an assistant professor in Purdue’s School of Engineering Technology. “We created a drone design with automatic folding arms that can make in-flight adjustments.”
The net effect of those in-flight adjustments on modeling yielded a savings of 13 percent energy with the rotatable arms. In winds, adjusting the angle and position of rotors provided greater stability by maintaining the center of gravity while hovering, the robot actively adjusting to its environment rather than staying rigidly fixed and buffeted about by wind.
Any improvement in quadcopter efficiency could ripple through the entire drone world, as quadcopters provide in many cases the cheapest, simplest entry point for hobbyists and government or military users alike. Cheap hobbyist quadcopters provide low-cost scouting and surveillance, a capacity that could be improved with longer flight times thanks to the greater energy efficiency of flexible arms. While camera payloads are typically small and light, cheap quadcopters have been outfitted with heavier explosive payloads to deadly effect by nonstate actors, and if commercial drones incorporate these findings in new designs, then they could likely carry bigger payloads.
The fully study, “Optimize Energy Efficiency of Quadrotors Via Arm Rotation,” is published in the ASME Journal of Dynamic Systems, Measurement and Control. While quadcopters and bio-inspired design are not exactly new, there are depths to both that have yet to be fully explored, and there is much room for iterating upon existing forms to create more efficient and versatile designs. This is true regardless of what market the design is ultimately aimed at, and given the dual use nature of drone technology, improvements in the commercial world can carry with them implications for military customers.
While insects evolved an ability to fly efficiently through wind over millions of years, drone designers are starting to catch up, over a time frame orders of magnitude shorter.