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Top Half of a Robot Giraffe

The power and flexibility of giraffe necks have inspired a new robot in Japan

3 min read
On left a giraffe from the neck up browsing on a tree, on right a skinless robotic giraffe neck with a giraffe skull on top

This article is part of our exclusive IEEE Journal Watch series in partnership with IEEE Xplore.

When we think about flexibility in bioinspired robots, the best examples can usually be found in soft robots that mimic octopus arms or elephant trunks, which have some unique capabilities. But most animals are soft and flexible to some extent, just typically coupled with a rigid interior structure. It’s a complex arrangement, albeit one with some significant advantages in power and control.

Researchers at the Tokyo Institute of Technology have been experimenting with mimicking what is arguably one of the most impressive combinations of flexibility and power in the animal kingdom: the neck of the giraffe. Giraffe necks can weigh up to 150 kilograms and be 2 meters long, but they’ve evolved to be bendy and strong, not just to get those tasty high-growing leaves but also because male giraffes battle each other with their necks, occasionally to the death. What better inspiration for designing large robots, right?


As a first step toward realizing a powerful and flexible robot, we built a half-scale musculoskeletal robot, mimicking the structure and mechanism of the giraffe neck based on anatomical knowledge, and reproduced part of its characteristics.
The mechanism consists of a skeletal mechanism fabricated using a 3D printer, a gravity-compensation mechanism mimicking nuchal ligament using rubber material and tensioners, a redundant muscle driving system using thin artificial muscles, and a particular joint using rubber disks and mimicking ligaments.

The robotic giraffe neck does its best to mimic the structure of an actual giraffe neck (the paper includes a photo of the partially dissected neck of a real giraffe), with vertebrae and tendons arranged similarly—and thin McKibben pneumatic artificial muscles providing contracting forces the same way real muscles do. It’s complicated, but it enables a significant amount of flexibility:

Photo collage showing the different parts of the robotic giraffe neck along with photos showing the neck flexing partway around a cylinderTokyo Institute of Technology

The authors of the paper helpfully point out that giraffes are able to leverage the power and flexibility of their necks in contact with each other nondestructively, which is not something conventional mechanical systems can do:

Thus far, researchers have not developed machines or robots having similar powerfulness and flexibility characteristics on par with the giraffe’s neck. For example, if two actual industrial cranes fight, it would be easy to imagine that the damage would be catastrophic, resulting in two broken cranes.

I am now trying to imagine two actual industrial cranes fighting, which would almost certainly look nothing like this:

Compare this to real giraffes necking, which is both less destructive and doesn’t do weird things to a classic comic:

National Geographic

Anyway, the researchers suggest that developing a robotic system with a practical combination of power, flexibility, and control might be more straightforward to do with a giraffe neck model than an elephant trunk model. You’d sacrifice some softness and flexibility, but you might be able to actually make it work in a way that could execute the amount of force required to be useful in industrial applications.

The name of this robot is Giraffe Neck Robot #1, which, while not the most creative, does suggest that other robots will follow. From the sound of things, the next step will be cranking up the power by several orders of magnitude (!) by using hydraulic rather than pneumatic actuators.

Giraffe Neck Robot: First Step Toward a Powerful and Flexible Robot Prototyping Based on Giraffe Anatomy, by Atsuhiko Niikura, Hiroyuki Nabae, Gen Endo, Megu Gunji, Kent Mori, Ryuma Niiyama, and Koichi Suzumori from Tokyo Institute of Technology is published in IEEE Robotics and Automation Letters.

The Conversation (0)

How the U.S. Army Is Turning Robots Into Team Players

Engineers battle the limits of deep learning for battlefield bots

11 min read
Robot with threads near a fallen branch

RoMan, the Army Research Laboratory's robotic manipulator, considers the best way to grasp and move a tree branch at the Adelphi Laboratory Center, in Maryland.

Evan Ackerman
LightGreen

“I should probably not be standing this close," I think to myself, as the robot slowly approaches a large tree branch on the floor in front of me. It's not the size of the branch that makes me nervous—it's that the robot is operating autonomously, and that while I know what it's supposed to do, I'm not entirely sure what it will do. If everything works the way the roboticists at the U.S. Army Research Laboratory (ARL) in Adelphi, Md., expect, the robot will identify the branch, grasp it, and drag it out of the way. These folks know what they're doing, but I've spent enough time around robots that I take a small step backwards anyway.

This article is part of our special report on AI, “The Great AI Reckoning.”

The robot, named RoMan, for Robotic Manipulator, is about the size of a large lawn mower, with a tracked base that helps it handle most kinds of terrain. At the front, it has a squat torso equipped with cameras and depth sensors, as well as a pair of arms that were harvested from a prototype disaster-response robot originally developed at NASA's Jet Propulsion Laboratory for a DARPA robotics competition. RoMan's job today is roadway clearing, a multistep task that ARL wants the robot to complete as autonomously as possible. Instead of instructing the robot to grasp specific objects in specific ways and move them to specific places, the operators tell RoMan to "go clear a path." It's then up to the robot to make all the decisions necessary to achieve that objective.

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