Even in the realm of robotics, slow and steady wins the race.
That at least seems to be the case for SlothBot, a new solar-powered robot designed to monitor long-term changes in the environment, such as the weather, by lingering in forest canopies for months at a time. The job it’s built for is one that requires a lot of waiting around—but luckily, SlothBot lopes along at the pace of… well, a sloth, and moves only when absolutely necessary, a strategy that’s great for conserving energy.
The brainchild of a team of engineers led by Magnus Egerstedt at Georgia Tech, SlothBot was announced in a paper published in April in the journal IEEE Robotics and Automation Letters, before making an on-screen debut at the International Conference on Robots and Automation in Montreal on May 21. It works by wheeling itself along a series of cables, and can even switch from one wire to another—a skill the researchers hope will eventually translate to the trees. Though the robot has yet to be put to work in the forests it’s intended for, the researchers already have plans to test it in the Atlanta Botanical Garden in the near future.
“In robotics, it seems we are always pushing for faster, more agile and more extreme robots," Egerstedt said in a statement. "But there are many applications where there is no need to be fast. You just have to be out there persistently over long periods of time, observing what's going on.”
To be clear, the current SlothBot, which consists of two motorized, wheel-based components connected by a hinge, bears only a passing resemblance to the actual sloth—a drowsy, tree-dwelling mammal that spends its days lounging in the jungle canopies of South and Central America.
But what machine and animal have in common is arguably the hallmark of the sloth’s existence: extraordinary energy efficiency. Subsisting mostly on leaves and twigs, a wild sloth spends up to 20 hours a day slumbering, and may expend as few as 100 or so calories in any given day—about the equivalent of four large carrots. SlothBot is powered by sunlight instead of roughage, but its wheels give it an energetic advantage: Unlike drones, which use up a lot of fuel hovering and zipping from landing site to landing site, SlothBot can dangle from a tree or wire when it’s not working, and simply amble into a sunny spot when it needs to recharge.
That’s a huge plus when it comes to collecting environmental data, which often spans observation periods of months or more. Drones deployed for that amount of time don’t come cheap.
“The thing that costs energy more than anything else is movement," Egerstedt said in the statement. "Moving is much more expensive than sensing or thinking. For environmental robots, you should only move when you absolutely have to.”
Eventually, the researchers hope to put SlothBot to work in the field in a cacao plantation in Costa Rica—where it could eventually come face to face with an actual sloth. On these farms, wild sloths have made something of a playground out of the cables workers install to shuttle cacao crop. The wiry network could also provide the perfect platform for SlothBot to explore its surroundings, and potentially even gather data on the sloths themselves.