The flapping wings of the hovering robotic insects (known as ornithopters) are very thin, lightweight and yet strong. Traditionally, the manufacturing process for these wings is time-consuming and a case of trial and error. However, advances in rapid prototyping have greatly expanded the possibilities for wing design, allowing wing shapes to replicate those of real insects or virtually any other shape. Furthermore, this can be done in minutes.

Researchers have managed to create a ornithopter with 3-D-printed wings weighing just 3.89 grams that can hover untethered for 85 seconds.

In order to create the ornithopters, the Cornell roboticists used an Objet EDEN260V 3-D printer. The wings are made of a polythene film stretched over a carbon fiber frame. The “fuselage” of the robotic insect was designed to hold a small GM14 motor, crank and wing hinge. The wings are driven by a crankshaft that is connected to a gearbox. Having initially connected the ornithopter using a DC power source, they realized that the device could lift 1.5 grams of payload, which was roughly the mass of the batteries required for flight.

When they experimented with a free-flying ornithopter, they needed to introduce lightweight sails above and below the winged robot in order to maintain stability (see second part of the video above).

The work at Cornell is testing hypotheses of insect propulsion and control. Researchers will test how different wing angles affect flight. If successful, these principles could form the basis of hovering ornithopter control. In other words, we could be seeing some seriously cool navigable robot insects.

Engineers have only been able to replicate flapping wing flight in the last decade. Major challenges include the lack of any established body of theoretical and experimental work on the unsteady aerodynamics of flapping wing flight for the purpose of wing design (most aircraft are designed for smooth flight). Researchers also need a sophisticated solution to make sure the robot remains upright. And they must solve problems with the energy density of batteries.