A strange machine with 20 legs could change the way scientists think about the ideal robot form.
For decades, roboticists have been inspired by nature and built machines that look alike people, dogs, insects And even horses. But new research suggests that the most useful robot body may look less like a human and more like a sea urchin.
The robot has no front or back. The 20 telescopic legs, which cost $300 each, radiate from a central body, with a depth camera at each leg tip, leading the researchers to name it Argus, after the all-seeing monster from Greek mythology. This design results in a machine that can move in any direction, stabilize itself after being pushed, cross rough terrain, carry a load of 10 pounds, and even climb walls.
The Duke University scientists who created the robot published their findings May 27 in the journal Science Robotics.
“Watching Argus move is different than watching any other robot we’ve worked with,” Jiaxun Liua doctoral candidate in Duke’s General Robotics Lab and co-author of the study, said in a statement. “The first time we saw it navigate trees and rough terrain, even in heavy impacts [when someone pushed it]We knew this was something different.”
Simulate symmetry
The team arrived at the design of Argus after running more than 1,500 simulations of different robot shapes. Instead of asking what animal the robot should resemble, the researchers focused on how symmetrical a machine could be in all directions – a mathematical concept called dynamic isotropy.
The dynamic isotropy score ranges from 0 to 1 and measures how smoothly a robot can accelerate its body, or center of mass, in any direction. A score of 1 means that a robot can react or move almost identically in all directions.
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‘If a robot can accelerate equally well in any direction, it no longer has to face the world in a certain way’ Boyuan Chendirector of Duke’s General Robotics Lab and co-author of the study, said in the statement. “Forward and backward become the same. Left and right become the same. The whole problem of robot control changes in character.”
According to the researchers, most robots today are also advanced four-legged robots, humanoids and conventional drones score lower than 0.6, meaning they can move or react in certain directions better than others. With his 20 legs, Argus scored a 0.91, close to the theoretical maximum.
To achieve this high score, the team arranged Argus’ body around a shape called a regular dodecahedron, a three-dimensional shape with twelve pentagonal faces. The setup gives the robot a nearly uniform field of view and allows it to move without having to orient itself as a conventional robot would.
Chen said that based on these findings, robots do not need to imitate humans or dogs to increase their agility, but are instead designed based on deeper mathematical principles.
Releasing the robot
To test whether Argus’ design was truly optimal, the team took the robot to the Duke campus, where it rolled over concrete, grass, dense foliage, soft sand, wet surfaces and bark. It could tackle obstacles up to 12.7 centimeters high, kept moving even after three of its legs were broken, and pushed a 1 meter long cube while rolling.
Argus, the twenty-legged robot, rolls along a sandy beach.
(Image credit: Duke University)
Argus is a proof of concept and not the final answer to optimal robot design, the researchers wrote in the study. Its broader importance may lie in how it is designed rather than where and how it can be used in real-world scenarios. It could be a mathematical way to compare different robot bodies and design new form factors from scratch.
“It shows that designing for dynamic symmetry is not just a theoretical curiosity,” Boxi Xiaa postdoctoral researcher at Duke’s General Robotics Lab and co-author of the study, said in the statement. “It provides a robot that you can use in the wild, on uneven terrain and in cluttered environments, even in low gravity. It changes what is possible.”
