Rockwell Collins has won a contract to show that it can use software algorithms to automatically stabilize an operational unmanned aircraft system (UAS) even after experiencing the sudden loss of 80% of its control surfaces on one side.

The demonstration scheduled by the first quarter of 2010 will complete a three-year series of flight tests funded by the Defense Advanced Research Projects Agency (DARPA), said David Vos, Rockwell's senior director of control technologies.

More importantly, Rockwell's damage tolerance system acquired when it purchased Athena Technologies last year is hoped to smooth the entry of UAS into commercial airspace in the future and perhaps improve safety margins for manned aircraft as well.

So far, the system has been tested on subscale F/A-18s normally operated by hobbyists. Previous tests have shown that the algorithms can recover control of the aircraft after losing up to 60% of a single wing.

The goal of the next round of tests is to show both the subscale F/A-18 and the undisclosed operational UAS can recover even after losing four-fifths of its wing and tail control surfaces, Vos said. The tests will also include a recovery attempt after an engine out scenario.

By demonstrating the technology on an operational UAS, the test could ease the damage tolerance control system's transition into a programme of record, Vos said.

Vos began developing the damage tolerance control surfaces as an aerodynamics student at the Massachusetts Institute of Technology. His early tests showed used a unicycle to mimic the control responses of the Northrop X-29 forward swept-wing aircraft.

That led to developing control laws that allows the autopilot to continually adapt and learn as the aircraft's flight conditions change dramatically, he said. The system can also re-plan the aircraft's flight plan in order to make an emergency landing at an alternate airport, if necessary, he added.

Source: Flight International