Salamander Robot Precisely Mimics Motion - Walks, Crawls, Swims Underwater

EPFL scientists have invented a new robot that mimics the gait of a salamander and features 3D-printed bones, motorized joints, and electronic circuitry as its 'nervous system.' Inspired by the salamander species Pleurodeles waltl, 'Pleurobot' can walk, crawl, and swim underwater. The scientists used x-ray videos of a salamander from the top and the side, tracking up to 64 points along its skeleton while it performed different types of motion in water and on the ground. The robot features only 27 motors and 11 segments along its spine, while the amphibian has 40 vertebrae and multiple joints, some of which can even rotate freely and move side-to-side or up and down. The researchers believe that understanding the fundamentals of the interplay between the spinal cord and the body's locomotion will help with the development of future therapies and neuroprosthetic devices for paraplegic patients and amputees.

Transcript

00:00:07 We are interested in animal locomotion and would like to make robots to study animal locomotion. Because animal locomotion is a very interesting interplay between the body, the spinal cord and the environment. But to understand this interaction, we really need a body and that's where the robot is a key tool. So we designed a salamander robot that very closely mimics the real motion of the real salamander, and it can both walk and swim exactly like the real salamander. It's a very old animal, it's an amphibian and it's almost a living fossil of the first terrestrial vertebrates, so the ancestor of vertebrates like us, mammals. So by studying the salamander we can study this key moment in evolution, the switch from swimming to walking,

00:00:44 and especially how the spinal cord has reorganized itself to allow a new mode of locomotion. So the novelty of this work is really the approach we took two to try to be as close as possible to the real physics of the body. The species is called Pleurodeles. We looked at detailed x-ray recordings from the animals so we could track the bones in 3d space and that enabled us to create a very detailed model of the movements of the bones of the animal. Neurobiologists have shown that if you electrically stimulate the spinal cord, at low level of stimulation, it will induce a walking like gait. If you stimulate a bit

00:01:19 more, this gate accelerates, and at some point there's a threshold and it switches to swimming so just changing the global drive that the brain sends to the spinal cord makes a complete switch between different modes of the locomotion. So understanding this is very important, for instance, for neuroprosthetics. Being able to re-stimulate those circuits in humans in the long term is something very important and for that you need to understand how the spinal cord works.