Many-legged robots that take inspiration from centipedes have been shown to be capable of moving across uneven surfaces without any additional sensing or control technology.
Researchers at the Georgia Institute of Technology said their robots can move over complex, bumpy terrain and there is potential to use them for agriculture, space exploration, and even search and rescue.
“When you see a scurrying centipede, you’re basically seeing an animal that inhabits a world that is very different than our world of movement,” said researcher Daniel Goldman. “Our movement is largely dominated by inertia. If I swing my leg, I land on my foot and I move forward. But in the world of centipedes, if they stop wiggling their body parts and limbs, they basically stop moving instantly.”
Baxi Chong, a physics postdoctoral researcher, said: “We started this project to see what would happen if we had more legs on the robot: four, six, eight legs, and even 16 legs.”
The team developed a theory that adding leg pairs to the robot increases its ability to move robustly over challenging surfaces – a concept they call spatial redundancy.
This redundancy makes the robot’s legs successful on their own without the need for sensors to interpret the environment.
If one leg falters, the abundance of legs keeps it moving regardless. In effect, the robot becomes a reliable system to transport itself and even a load from A to B on difficult or “noisy” landscapes.
“With an advanced bipedal robot, many sensors are typically required to control it in real time,” Chong said. “But in applications such as search and rescue, exploring Mars, or even micro robots, there is a need to drive a robot with limited sensing.
“There are many reasons for such sensor-free initiative. The sensors can be expensive and fragile, or the environments can change so fast that it doesn’t allow enough sensor-controller response time.”
The researchers tested their design on artificial terrains designed to mimic an inconsistent natural environment. They increased the number of legs on the robot by two per test, starting with six and eventually expanding to 16.
As the leg count increased, the robot could more agilely move across the terrain, even without sensors, as the theory predicted. Eventually, they tested the robot outdoors on real terrain, where it was able to traverse in a variety of environments.
Phd student Juntao He said: “While bipedal and quadrupedal robots heavily rely on sensors to traverse complex terrain, our multi-legged robot utilises leg redundancy and can accomplish similar tasks with open-loop control.”
The researchers now want to refine the robot and determine the optimal number of legs to achieve motion without sensing in a way that is cost-effective yet still retains the benefits.
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