Update: We added a short video from the MIT team showing the glider landing on a wire in super slow motion after the jump.

Researchers at the Massachusetts Institute of Technology have developed an autonomous glider that can land on a wire like a bird. The tiny glider could lead the way to highly maneuverable UAVs that could emulate many bird-like flight maneuvers, including landing on a wire to recharge, or navigating complex and cluttered airspace.

When pilots talk about flying like a bird, they’re usually referring to the simple things a bird can do. Even the most difficult maneuvers in an airplane are mundane for many birds. The secret to our avian role models’ abilities is their complete control in the near-stall and post-stall flight regime.

Rick Cory, a post-doctoral researcher at MIT, and his Ph.D. advisor Russ Tedrake took on the unusual project as a means of pushing the limits of robotic controls. The goal was to find a complex maneuver in nature and develop a mathematical model that would allow them to build robotic controls to emulate it.

The result of their effort is a breakthrough in aircraft control that could lead to an entirely new way of thinking about controllable flight for airplanes.

The project started in 2005. Tedrake, an associate professor in the Computer Science and Artificial Intelligence Lab at MIT, said the first step was figuring out the complex aerodynamics that occur when a bird approaches a perch and transitions from normal, forward flight to a pinpoint landing in a relatively short distance.

“One of the things that birds do very well is they interact very well with complicated fluids and they handle post-stall flight conditions,” Tedrake told us from England, where he and Cory are attending the Farnborough International Air Show. Cory was awarded Boeing’s 2010 Engineering Student of the Year award at the airshow.

An aircraft, or bird, experiences a stall when the air flowing over a wing no longer smoothly follows the shape of the wing. When the airflow separates from the wing, lift is decreased dramatically, drag is increased, and the aircraft or bird will stop flying and start descending or falling.

Experiencing stalls in an airplane are a normal part of a pilot’s training but generally avoided during flight. The exception for some airplanes is during the final moments before landing, when an airplane — like a bird — approaches the stall and then as the lift disappears, it touches down on the runway.

Unlike a bird, however, an airplane usually needs a lot of room to land because the control in the near-stall and post-stall is limited for most airplanes. Some experienced bush pilots manage to land in very short distances, but even then they require more room than the average bird, and cannot land on a point (unless aided by the wind).

Cory and Tedrake noticed that when a bird makes an approach to land, its entire body and wings are tilted back at a much steeper angle than an airplane making a landing. Those steep angles create very turbulent airflow that is difficult to model.

Once the MIT researchers were able to model the airflow and the path needed to land on a wire, they set about using the data to control their tiny glider. Built with simple foam and off-the-shelf equipment, the glider weighs just 90 grams (a bit more than 3 ounces) — roughly what a blue jay weighs.

The control system allows the glider to follow a path through space that will allow it to make the perched landing. If the glider deviates from the path, nearby cameras notice the deviation and corrections are made. Based on the deviation, the glider continuously checks its position, and inputs are sent to the control surfaces that allow the glider to adapt the approach until the touchdown is made on the wire.

Cory says this kind of control ability could eventually lead to a wide range of applications, particularly for unmanned aerial vehicles. Today most UAVs are limited by the same limited control as piloted aircraft. Using these new types of controls could aid search-and-rescue crews by providing a viewpoint that could fly through a dense forest.

“A search and rescue aerial vehicle would be able to land on a branch of a tree and search for victims,” Cory said as just one example.

In the experiments, the glider is launched 12 feet away from the wire at various speeds between 13 mph and 19 mph. It is slowed down using only the drag created by the approach-to-stall maneuvers developed by Cory and Tedrake.

The researchers say they are continuing the research and will next be moving outside into real-world conditions. They also plan to explore the use of flapping-wing vehicles as well as more typical propeller-driven aircraft.

Images/Video: MIT