Yeti Roves the Ice Sheet
May 9, 2012
Dartmouth engineering Ph.D. candidate Rebecca Williams drove a farm tractor retrofitted to roll along the barren snowy landscape of a glacier in Greenland. Like soldiers scouring for landmines, Williams and a small team of mountaineers set out to find massive crevasses hidden by ice sheets that, if broken, could within seconds swallow them and others traveling regularly between Thule Air Base and the Greenland Environmental Observatory (GEOSummit). She recalls hours of boredom broken up by moments of terror.
"When the first sign of a crevasse appears on the radar screen, you have four-and-a-half seconds to respond to the signature and to hit a switch to stop the tractor before it drives over the crevasse. I was sitting in the hot seat with my hand hovering over a switch, knowing I had five people's lives in my hands," says Williams, who was monitoring the crevasse detector for just 12 hours. Actual operators sit in the loud tractor for months on end to ensure safety for vehicles transporting fuel and vital supplies between the two locations. It was clear this was a job better suited for a robot—one named Yeti built by a group of Dartmouth engineering students in 2006. This fall, the four-wheeled rover will augment the tractor to conduct ground penetrating radar (GPR) surveys of polar regions. Yeti will eliminate stress, fatigue, and risk of injury posed to individuals from cracks that can stretch 30 feet wide and hundreds of feet deep. This lightweight robot is also paving the way for resources, which are now limited, to support and mobilize scientific efforts in these extreme environments.
Working with advisors Professor Laura Ray and Adjunct Professor James Lever, a mechanical engineer at CRREL, Williams is writing intelligence software that Yeti will use to navigate crevassed regions of the ice sheet. Those machine-learning algorithms are already being tested to run in real time to classify incoming GPR data, allowing Yeti to detect crevasses on a pre-programmed route before returning with the findings.
"This past winter, Yeti was called in to survey the old South Pole station from the 1960s that is under 30 feet of snow. Now, Yeti is on its way to Greenland again to transport supplies to and from Thule Air Base in a money saving effort," says Ray, who with Lever first created Yeti's solar-powered cousin, Cool Robot. Originally designed to pull an instrument sled to take weather and atmosphere measurements, Cool Robot is now receiving hardware and software updates to resemble its battery-powered counterpart, Yeti. The two Dartmouth-made robots will eventually both be programmed to support collection of both GPR and atmospheric data.
"We're going to program Yeti to make him completely autonomous. He'll be his own survey team," says Williams. "He'll be able to further explore the extent, depth, and width of crevasses he discovers, improving detection and mapping, and taking the life-threatening uncertainty out of the situation."