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Suspended beneath a thick canopy of trees, the sloth inches along with slow strides . Painfully slow. Intentionally slow. Crawling high up among the branches, traipsing along a 100-foot steel cable, the little creature is like a lethargic acrobat. But its goal is not to delight or to put on a show; in fact, just the opposite. This sloth is all about stealth, observation, and collecting as much sunlight as possible. After all, this is a solar-powered robot.
At the Atlanta Botanical Garden, SlothBot is under direct supervision from the researchers who built it. If you stroll along the garden’s raised Canopy Walk, you can catch a glimpse of the robot’s googly eyes and 3D-printed shell. It might not seem like it, but the sloth is hard at work collecting vital environmental data, such as temperature and carbon dioxide levels.
SlothBot serves as a private investigator of sorts. Its leisurely, languid locomotion helps the robot avoid suspicion—and it’ll need that inconspicuous appearance if it hopes to achieve its mission.
A FLOWERING MYSTERY
Deep in the Ecuadorian rainforest, a mystery is blooming. Ecologists at the Siempre Verde research center, an 825-acre Andean nature preserve, are puzzling over a genus of rare orchids.
“We know where the orchids are, but we don’t know what is pollinating them,” says Emily Coffey, vice president for conservation and research at the Atlanta Botanical Garden.
Currently the botanical garden holds specimens from about 90 percent of the world’s Stanhopea orchids. Understanding their relationship with pollinators could be the key to preserving these flowering plants. Stanhopea orchids, also called euglossine-pollinated orchids, are mostly found at low elevations, living in harmony with their namesake pollinators, euglossine bees.
These bees are “the most gorgeous bees you’ll ever see in your life,” Coffey says. She has studied these flying insects for years, so she’s intimately aware of their vivid, metallic-looking heads, thoraxes, and abdomens. She’s not exaggerating: the U.S. Forest Service even calls them “living jewels.”
But euglossine bees are not known to live up high in the Andes, where scientists have also spotted these orchids. “Are bees going up rivers to get oils, and coming back down to live?” Coffey wonders. “Or is there another insect that has a relationship with these orchids?”
That’s where SlothBot comes in.
Examining rainforest wildlife is not easy. Researchers must install massive nets between trees to help them gain access to certain species, but these nets are expensive, hard to deploy, and they interfere with the surrounding natural habitat. Humans are also big, loud, clumsy, disruptive. Meanwhile, a small robot could hang out undetected for long stretches of time, collecting data that scientists might otherwise miss.
“It’s a detective story,” says Magnus Egerstedt, the creator of SlothBot. Egerstedt is the chair of Georgia Tech’s School of Electrical and Computer Engineering, where he works on robots that use complex motion. “We don’t know a whole lot about what goes on beneath the tree canopy in the rainforest.”
Egerstedt built SlothBot to help ecologists like Coffey study endangered plant and animal species, beginning with the euglossine-pollinated orchids.
The robot will use an array of sensors to collect environmental data. That could help ecologists cross-reference that information with what they already know about high-altitude insects, or provide new clues as to which tiny flyers are pollinating the flowers high up in the mountains. And there’s the hope that SlothBot’s onboard camera will capture those insects in the act.
LIFE IN THE SLOW LANE
Were it not for a family vacation to Costa Rica, SlothBot would not exist.
On this particular trip, Egerstedt became “mildly obsessed” with the two-toed sloths that he noticed scavenging for food in the canopy overhead. The sloths’ very existence stumped him: How could nature even support such a large body with such a small diet? The sloth’s metabolism is its silver bullet—and Egerstedt wanted to build a machine that could mimic this energy efficiency.
m a shameless borrower from biology,” Egerstedt says, laughing. “Because slowness was strategically advantageous to these animals…let’s turn that around and embrace slowness as a design paradigm.”
There’s an entire design ethos centered on this approach: biomimicry. The idea is to borrow ideas from living things that have flourished for millions of years, honed to perfection by the steady hand of evolution.
Altogether, SlothBot weighs between 15 and 20 pounds, with most of that bulk coming from its heavy 3D-printed shell, which protects the electronics and creates the machine’s slothlike appearance. That shell includes a special coating to ensure it does not negatively react to long-term exposure to the sun.
“It looks kind of cute and cuddly,” Egerstedt says, “but the insides are oversized Lego pieces with articulated joints and a solar panel.”
In remote locales, like the Ecuadorian rainforest where Egerstedt’s team will eventually deploy SlothBot, there are no power outlets, no utilities, no 24-hour teams available to regularly swap out batteries. A conservation robot like SlothBot needs to be self-sufficient, so Georgia Tech researchers outfitted the robot with solar panels on its belly.
A steady diet of solar energy is central to SlothBot’s success because it powers all of the robot’s key hardware: a camera, plus a slew of sensors to collect such basic ecological data as climate, temperature, barometric pressure, luminosity, and carbon dioxide levels.
Over time, SlothBot can adapt to its environment, learning when and where it should sunbathe along its steel cable to capture the most light. This time-varying solar map is a software feature that keeps the robot from running out of juice and getting stranded in shadow.
“You only move when you have to,” Egerstedt explains, just like a living sloth. “It’s really this idea of survivability of the robot, so that it only moves to recharge and sunbathe when it needs to.”
SlothBot’s solar panels have a few potential weaknesses. In the botanical garden, researchers can pull down SlothBot and clear its solar panels of debris. In Ecuador that’s not an option. Egerstedt compares this to the dilemma of Martian dust storms covering the sensors on NASA’s Perseverance rover, and he hopes to find a solution once SlothBot starts testing in the real world.
THE ART OF BLENDING IN
Hopefully, SlothBot’s impersonation skills will minimize suspicion on the part of other wildlife in the rainforest. It probably doesn’t matter if the robot looks like a sloth or an armadillo, Egerstedt speculates, but it’s important to implement any approach you can to minimize “messing with the ecosystem.”
“Ecology is finicky,” Egerstedt says. “By measuring the ecosystem, you don’t want to change it.”
Squirrels are already hanging out on the SlothBot, which makes Egerstedt “very happy.” But those promising interactions could hint at something darker when SlothBot leaves the botanical garden: a full revolt against the robot. In an ecosystem fit with extreme animals, like the spider monkey, what could happen if SlothBot doesn’t blend in?
“Who knows if they’ll go to town and try to tear it down,” Egerstedt says. “Part of me wants it to happen. It would be freakin’ awesome to see.”
“ECOLOGY IS FINICKY…BY MEASURING THE ECOSYSTEM, YOU DON’T WANT TO CHANGE IT.”
History offers some clues to SlothBot’s future success, as biomimicry has become the go-to design choice for robots in ecology. SoFi, a soft robotic fish created at the Massachusetts Institute of Technology, combs the oceans in search of rare marine creatures, like the ancient Greenland shark, who’d be too spooked by submarines or ocean divers.
“There’s been a lot of technological progress in the world of nature filmmaking, but it can still be very hard to document sea animals up close without disturbing them,” says Robert Katzschmann, an assistant professor of robotics at ETH Zürich, who worked on the SoFi project as a doctoral student at MIT.
Before the scientists took SoFi to Fiji’s Rainbow Reef to study the local fish, they put the robot through tests of varying scale. They came to two main conclusions: Several rounds of real-world testing are paramount, and conservation robots should have a high level of autonomy.
“Making the robot more autonomous can reduce its disruption of the wildlife, since people will need to supervise it less, but it can be very challenging to build and program robots that operate autonomously in unstructured environments,” explains Joseph DelPreto, a Ph.D. student at MIT’s Distributed Robotics Lab, who worked on SoFi.
The SlothBot team is already making those considerations. During testing in Chattahoochee National Forest and at another 170-acre site in Gainesville, Georgia, the scientists will closely monitor how SlothBot’s solar panels and sensors stand up to storm conditions. They’ll also evaluate the robot’s ability to remotely gather data with its sensors and transmit that back to the lab.
If all goes according to plan, SlothBot will finally make a home in Ecuador sometime in 2022, says Coffey. At the moment, she and Egerstedt are working on a grant proposal to support the trip.
In Ecuador, SlothBot will rely on its sensor suite and camera to solve the mystery of which insects are pollinating the Stanhopea orchids. That precious data will have to sit with the robot in the wild for a short period of time. SlothBot will transmit the information, using a local network, to an electronic device on the ground called a data logger, Egerstedt explains. Later, scientists can return to harvest that data.
If SlothBot can pull off its mission, stalking out these elusive pollinators while remaining incognito, ecological conservation could begin to experience a robotic revolution—one slow step at a time.
“It can be a beautiful melding of two fields,” Coffey says. “There’s no reason that robotics can’t inform conservation and that conservation can’t be strengthened by all the technologies that are out there.”
Excerpted from https://www.popularmechanics.com/technology/robots/a36356683/slothbot-conservation-robotics/