Unmanned aircraft search and rescue victory for US engineering students
They found “Outback Joe” in five minutes – but the engineering that went into the victory was no fluke.
On paper, it sounded like the most anticlimactic victory ever: The University of North Dakota team which took first place in an unmanned aircraft search and rescue competition in the Australian Outback found the target in one pass within about five minutes of taking off.
And the team competed against one other team.
"The actual mission was like 10 percent of the work?" team member Wyatt Shallbetter asked his teammates.
One!" said David Dvorak, a grad student.
It helps to know that Outback Rescue 2010, set near the town of Kingaroy in late September, started out with 42 interested teams from 11 countries.
Thirty were cut because they failed to meet stringent safety regulations designed to keep the unmanned aircraft from intruding in airspace used by manned aircraft, according to grad student Adam Gabbert. Another five dropped out because they were uncertain their expensive aircraft would survive intact. Two couldn't get their aircraft airborne.
And of the remaining five, two passed the flight tests and actually went to search for "Outback Joe," a dummy simulating a traveller lost in the wilderness.
In last year's competition, three teams competed, Dvorak said, and all three crashed.
So, the real competition wasn't the search after all, but the engineering of an unmanned aircraft system. This is why the UND team is made up of seniors and grad students in the mechanical and electrical engineering departments under the direction of Professor William Semke, a mechanical engineer, and the late Professor Richard Schultz, an electrical engineer who died shortly after hearing news of the team's victory.
Here's what went into UND's BTE Super Hauler, a 50-pound remote-control aircraft with a 12-foot wingspan: a video camera mounted on a gimbal, a GPS receiver, a radio to transmit the moving pictures and the coordinates, a system to drop a bottle of water near Outback Joe, an autopilot and a fail-safe system.
For the teams, the bulk of the competition was a systems integration exercise and, because of Murphy's Law (whatever can go wrong, will go wrong), the debugging that follows.
"You see all the systems failing around you and you ask, 'What about our system?'" Shallbetter said of what it felt like to be in the Outback competition.
The UND team faced two major bugs, one of which could have grounded or destroyed the aircraft, depending on when it happened, and one that cost the team $35,000 in prize money.
The No. 1 worry was the fail-safe because it had the power to destroy the aircraft.
"Figuring out how to make that system work was a multi-month endeavor," said Gabbert.
"The plane can only fail once," Shallbetter added, dryly.
All unmanned aircraft in the competition have autopilot systems that allow controllers to, essentially, point and click on a computer where they want their aircraft to go instead of fiddling with hand-held remote controls. The failsafe makes sure the autopilot is working. If it doesn't detect a signal from the autopilot, it manipulates the aircraft into a dive that it will never recover from.
Like the US Federal Aviation Administration, Australia's Civil Aviation Safety Authority, or CASA, is worried about the reliability of unmanned aircraft, and that they won't be able to detect and avoid collision with manned aircraft. They also worry controllers would lose contact. When the rogue aircraft runs out of fuel, it'll fall out of the sky and, at 100-plus mph, could do some real damage.
"CASA uses this event to see how they can integrate unmanned aircraft into their airspace," Gabbert said.
One day, just after the completion of a successful first flight, the autopilot went dead.
One for Schultz
The team spent the entire night trying to debug the autopilot, and, having tried everything, uninstalled and reinstalled the software. It worked. They shouted with joy. Then it didn't work. They moaned. Then it worked. Then it didn't work.
"It was like an emotional roller coaster," senior Jesse Sorum said.
Eventually, they made the reinstall work, but the team said it still doesn't know exactly how.
Contributing to their emotions was knowledge that Schultz was in Grand Forks, waiting to hear from them. A beloved professor who had advised the team since it was founded, he battled cancer for two years and had neared the end stage.
Shallbetter said the team knew it had to fix the aircraft because it didn't want to let Schultz down. "Without Dr. Schultz, this wouldn't have been possible; not even close." "He was very proud of his students," Semke said. Two days after the team's victory, he said, Schultz passed away.
The UND team had planned to use two search patterns to fly over the eight-square-mile area where Outback Joe was hidden.
One was what they called the Hail Mary, which is pretty much what it sounds like, a straight line down the middle of half the search area and then a straight line up the other half.
The other was the lawnmower pattern, a methodical back-and-forth track.
As luck, and skill, would have it, with just one leg of the Hail Mary, the team found the dummy not far from his pickup. It was only 5 minutes, 25 seconds after takeoff. The team had honed its spotting skills over some ten flights over the summer at the National Guard's Camp Grafton near Devils Lake, North Dakota, once finding the target within four minutes.
The next step to winning the $50,000 first prize was to drop a water bottle within 100m of Outback Joe.
For that, the team had devised a computer program that uses wind speed, aircraft velocity, even the drag coefficient of the bottle, to decide when to release, according to grad student Keith Straug. In practice, they dropped a bottle within 11 feet of the target from 1,000 feet up.
In the competition, Murphy's Law had something to say about that.
According to Gabbert, the drop mechanism didn't work in synch. When armed, it released the bottle immediately, instead of simply preparing for the drop The bottle ended up 551m away from Outback Joe, too far to win the full prize, but enough for a $15,000 consolation award.
"That's the thing," Gabbert said. "We worked all summer. It worked every time, but not that time.”