Flights of Fancy

A robotic helicopter that does amazing aerial maneuvers has captured the attention of the military and the movie industry alike.

By Megan Vandre

April 2003

A one-and-a-half-meter-long helicopter sits on a table in the basement of Building 33. Instead of a sleek fiberglass shell, its body is a roughly soldered metal framework with the "finish" of an Erector set. It is utilitarian, not ornamental, but what it lacks in style, it makes up for in substance. This minicopter can do things larger helicopters can't. And even more important, it can do them on autopilot. It is essentially a flying robot. Apart from takeoff and landing, all its movements are controlled by mathematical equations.

Last fall the machine, dubbed Mr. Chopper, broke new ground when it became the first helicopter to perform a split-S maneuver-a half roll followed by a half loop-without human intervention. The maneuver capped a host of accomplishments by a research team from the Departments of Aeronautics and Astronautics and Electrical Engineering and Computer Science. Led by aeronautics and astronautics associate professor Eric Feron, the team is focused on enhancing aircraft agility so that flying machines can do loops and turns in tight spaces. Members say that in the next 10 years, nimble, unmanned vehicles like Mr. Chopper could be used for military reconnaissance and filming movies.

"I think it's probably the craziest flying project throughout the country in the university environment," says Feron, who began working with minicopters in 1998 after watching the pilot of a remote-control helicopter direct a chopper through several stunts. Previously, Feron had studied automatic control systems, and the idea of automating helicopter flight intrigued him. He enlisted two graduate students, Alex Shterenberg, MNG '00, and aeronautics and astronautics PhD candidate Vlad Gavrilets, SM '98, to build the avionics box that now directs Mr. Chopper's movements.

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The four-and-a-half-kilogram avionics box acts as the controller's eyes in the sky by continuously measuring and transmitting flight data to the ground. Attached below the helicopter's three-kilogram body, the box contains three sensors, a Global Positioning System receiver, an altimeter, and a flight control computer. It communicates via Ethernet with a ground computer, which the graduate students also built.

"What Vlad and his coworkers have done is literally build an entire computer system, sitting underneath the helicopter, from basic components," Feron says. "It has to work in an environment that shakes a lot and not only computes things, but also sends orders to physical devices."