Tarzan the robot was actually inspired by a sloth | Science News for Students

Tarzan the robot was actually inspired by a sloth

This farm worker swings hand-over-hand to save energy — and avoid getting stuck in the mud
Aug 31, 2018 — 6:45 am EST
Tarzan the robot swinging over a field of crops

Tarzan, shown here, travels over crop fields with an energy-efficient swinging motion. One day, such robots might help with farm work.

Georgia Tech Research Institute

This is one in a series presenting news on technology and innovation, made possible with generous support from the Lemelson Foundation.

Working on a farm and tending crops can be hot, time consuming and difficult. Engineers have long wanted to build robots to lighten the load. But it has proven no easy task. Robots that walk or roll along the ground can trample delicate plants. And they can get bogged down when rain turns fields muddy. “Tarzan,” however, could overcome some of those challenges. Like its namesake, this new robot swings through the air.

Jonathan Rogers is a robotics expert at the Georgia Institute of Technology in Atlanta. When it comes to a farm environment, he realized, many robots would face a number of problems. “They tend to get tangled. They tend to get stuck,” he says. What’s more, he notes, “It’s very hard to leave them out for long periods without a human assisting them.”

That’s when inspiration hit him: What if the robot could move above the crops? After all, he realized, “Sloths move from tree branch to tree branch to avoid having to walk around the forest floor.”

Inspired, his team set out to design a robot that could swing hand-to-hand along wires suspended above a field. He named their invention Tarzan, after the jungle-swinging character of books and movie fame. Why not name it for a sloth? “There’s no famous sloths that I know of,” he says. (Apparently, Rogers never watched the 2016 Disney flick, Zootopia. If he had, he’d know about Flash, the “fastest working sloth in the DMV.”)

Drones, another type of robot, fly above the land. Yet these, too, have some disadvantages. A gust of wind can blow them off course, for instance. And if their propellers got too close, drones might damage plants. More importantly, drones have a short battery life. To tackle long tasks, farmers might have to recharge them every half hour or so.

Swinging, in contrast, is an energy-efficient motion. The reason: It makes use of gravity to power movement. This is similar to the way a child can pump her legs to get a playground swing to go higher and higher. With that efficiency, a robot like Tarzan can work out in a field for months at a time, without needing to be recharged, Rogers says.

What makes this swinger new

Tarzan is not the first swinging robot, notes Mark Spong. He’s a robotics researcher at the University of Texas at Dallas. Some teams have built robots that do gymnastics. Others imitate primates. He says one inventor even covered a swinging robot in fur to make it look like an orangutan. But what’s new, he says, is using swinging motion to save energy — and the idea of building a wire structure to move around above crops.

“When you’re out in the field and can’t plug into a wall socket, energy is really important,” he points out. “These [robots] can live out there and hang around and swing when they need to, maybe even recharge with solar cells.”

Rogers first envisioned that Tarzan could help farmers monitor crops with sensors and cameras. But future versions could do other work as well. They might deliver water to a particular thirsty plant or fertilize one that needs a nutritional boost. And adding a third “hand” could allow such an automaton to harvest fruits and vegetables.

Eventually the robot could move off the farm and into the city, Rogers says, doing jobs such as inspecting power lines or crawling around wires to move traffic sensors and security cameras from place to place.

While Tarzan has shown it has what it takes to swing around the lab, Rogers says the next step is to test the robot in the field. “We really want to get this robot crawling around networks of cables,” he says.

a photo of the farm robot
Ai-Ping Hu and Jonathan Rogers watch, in the lab, as their farm robot swings hand-over-hand along a wire.
Rob Felt/Georgia Institute of Technology

Power Words

(more about Power Words)

automaton     A mechanical machine or device that can function based on predetermined, computer-controlled behaviors. Some of these may resemble a person in shape, function or tasks. However, as a machine it would work in a mechanical way, often with no sign of emotion.

battery     A device that can convert chemical energy into electrical energy.

colleague     Someone who works with another; a co-worker or team member.

crop     (in agriculture) A type of plant grown intentionally grown and nurtured by farmers, such as corn, coffee or tomatoes. Or the term could apply to the part of the plant harvested and sold by farmers. 

drone     A remote-controlled, pilotless aircraft or missile.

engineer     A person who uses science to solve problems. As a verb, to engineer means to design a device, material or process that will solve some problem or unmet need.

environment     The sum of all of the things that exist around some organism or the process and the condition those things create. Environment may refer to the weather and ecosystem in which some animal lives, or, perhaps, the temperature and humidity (or even the placement of components in some electronics system or product).

fertilizer     Nitrogen, phosphorus and other plant nutrients added to soil, water or foliage to boost crop growth or to replenish nutrients that were lost earlier as they were used by plant roots or leaves.

forest     An area of land covered mostly with trees and other woody plants.

fruit     A seed-containing reproductive organ in a plant.

gravity     The force that attracts anything with mass, or bulk, toward any other thing with mass. The more mass that something has, the greater its gravity.

monitor     To test, sample or watch something, especially on a regular or ongoing basis.

network     A group of interconnected people or things. (v.) The act of connecting with other people who work in a given area or do similar thing (such as artists, business leaders or medical-support groups), often by going to gatherings where such people would be expected, and then chatting them up. (n. networking)

orangutan     One of the great apes (which also include gorillas, chimpanzees and bonobos), this red-haired tree dweller shares 97 percent of its genes in common with humans. They can live for 60 years, with adults weighing 48 to 130 kilograms (105 to 286 pounds) depending on gender, age and health, with males being bigger. They have opposable thumbs (as humans do) and also opposable big toes, which aids in their gripping.

primate     The order of mammals that includes humans, apes, monkeys and related animals (such as tarsiers, the Daubentonia and other lemurs).

robot     A machine that can sense its environment, process information and respond with specific actions. Some robots can act without any human input, while others are guided by a human.

sensor     A device that picks up information on physical or chemical conditions — such as temperature, barometric pressure, salinity, humidity, pH, light intensity or radiation — and stores or broadcasts that information. Scientists and engineers often rely on sensors to inform them of conditions that may change over time or that exist far from where a researcher can measure them directly.

sloth     A slow moving, plant-eating mammal that lives in tropical rainforests in the Western Hemisphere. Most of these tree dwellers sleep all but four to nine hours a day.

solar cell     A device that converts solar energy to electricity.

technology     The application of scientific knowledge for practical purposes, especially in industry — or the devices, processes and systems that result from those efforts.

tedious     (n. tedium) An adjective for something that is disturbingly slow, boring, monotonous and/or repetitive.


Meeting: S. Farzan et al. “Modeling and Control of Brachiating Robots Traversing Flexible Cables,” IEEE International Conference on Robotics and Automation (ICRA), Brisbane, Australia, May 21-25, 2018.