Unmanned Systems Technology 028 | ecoSUB Robotics AUVs I ECUs focus I Space vehicles insight I AMZ Driverless gotthard I InterDrone 2019 report I ATI WAM 167-BB I Video systems focus I Aerdron HL4 Herculift

A team of engineers at NASA and the Massachusetts Institute of Technology have developed a deformable wing that can be passively configured for different modes of flight (writes Nick Flaherty). The wing is made from hundreds of tiny identical pieces of polymer that are bolted together to form an open, lightweight lattice framework and then covered with a thin layer of the same polymer. Instead of needing separate moveable surfaces such as ailerons to control a plane’s roll and pitch, the new assembly system makes it possible to deform all or part of the wing by incorporating stiff as well as flexible components in its structure. The resulting wing is much lighter and therefore more energy- efficient than metal or composite designs. The lattice has a density of only 5.6 kg/m 3 , compared with rubber for example, which has a density of about 1500 kg/m 3 . Each phase of a flight has its own set of optimal wing parameters, so a deformable wing could provide a much better approximation of the best configuration for each stage. Instead of using motors and cables to produce the forces needed to deform the wings, the team designed a system that automatically responds to changes in its aerodynamic loading conditions by shifting its shape in a self-adjusting, passive wing- reconfiguration process. “We’re able to gain efficiency by matching the shape to the loads at different angles of attack,” said Nicholas Cramer, a research engineer at NASA’s Ames Research Center. “We’re able to produce exactly the same behaviour as you would have actively, but we’ve done it passively.” This is achieved by careful design of the relative positions of struts with different amounts of flexibility or stiffness so that the wing, or sections of it, bend in specific ways in response to particular kinds of stresses. This follows on from a prototype wing about 1 m long for a typical remote-controlled model aircraft. This new version measure 5 m, a limit set only by the size of NASA’s high-speed wind tunnel at its Langley Research Centre. The elements are built using injection moulding with polyethylene resin in a 3D mould. Each part is produced in just 17 s, bringing it much closer to scalable production levels. Structures could be easily constructed using a swarm of small, simple autonomous assembly robots. The design and testing of the robotic assembly system is the subject of an upcoming paper. Wing bends to the mode Aerial vehicles