2106-06-27: Autonomy Incubator Sees Successful GLARF Flights

John Cooper with the GLARF in the Ai flight range.

Harnessed to a specially-installed rope tether, missing its nose cone, and swaddled in electrical tape repairs, the GLARF is one of the Autonomy Incubator's (Ai) more unconventional research vehicles. Don't be fooled by appearances though— this little model plane has a big job to do.

"GLARF" is an acronym for "GL-10 Almost Ready To Fly," because it's a small-scale research model of the real thing. For the uninitiated, the GL-10 (short for Greased Lightning 10— it's NASA; we love acronyms) is the hybrid-engine tiltwing aircraft NASA Langley has been developing as a UAV for the past couple of years. Basically, the wings look the way they do because they articulate, combining VTOL (Vertical Take-Off and Landing) with forward flight by transitioning horizontally once GL-10 in the air. Although the GL-10 project has its own team focused on Dynamics and Controls, the Ai has served a cooperative role in its development. For some time now, we've been hosting the GLARF.

The GLARF waits for take-off while John and his crew get ready for flight.

The Ai's crack team of GLARF wranglers includes PI Paul Rothhaar, co-I John Cooper, NIFS intern Andrew Patterson from University of Illinois Urbana-Champagne (UIUC), and high school intern Nick Selig. Their goal, John explains, is to develop autonomous capabilities for the GL-10. 

"The GLARF is an avionics test bed for the GL-10," he said. "What we want to do, eventually, is fly the GL-10 autonomously."

John pilots the GLARF from behind the net and a shatterproof glass barrier.

Andrew remains a vigilant safety pilot.

John's research with the GLARF focuses on control algorithms. I didn't know what that meant either, so I did some research (read: asked the engineers to "explain it to me like I'm five") and here's what I learned: controls for autonomous vehicles have an inner loop and an outer loop. The inner loop takes care of the mechanics of flight—stabilization, thrust, that sort of stuff—and the outer loop tells the vehicle what to do, much like a remote human pilot. John is working on making it smart enough to fly by itself - without a remote pilot. The algorithms developed by the Ai team will sit on top of both control loops, bringing sensing, perception, and decision-making into the mix - an outer outer control loop, if you will.

The GLARF, mid-flight.

Understandably, testing autonomous control algorithms on a vehicle this big, indoors, can get unwieldy, but that's why John has high school intern Nick Selig belaying it on a tether during flight. 

"The tether is there in case it fails; we can catch it," John said.

Nick tightens the slack as the GLARF gains altitude.

Stay tuned to the Ai blog for more updates on the GLARF! Now that John and his team have it off the ground and running smoothly, there's going to be a lot to keep up with.