Salamander robot walks and swims with hi-tech vertebrae

Since scientists are making so many bio-inspired robots these days, why not add a salamander to the mix. Researchers from Ecole Polytechnique Fédérale de Lausanne have developed a new kind of robot that mimics the movements of a salamander.

The robot is comprised of 3D-printed bones, motorized joints and its “nervous system” is made of electronic circuitry. The team based their model —Pleurobot— on the salamander species Pleurodeles waltl, which can walk, crawl, and even swim underwater.

Salamander-inspired robot. (Image via EPFL)
Salamander-inspired robot. (Image via EPFL)

While the team, led by Auke Ijspeert have built salamander robots before, this is the first time that they have built a robot that is accurately based on the 3D motion of the animal’s skeleton. To achieve this, the scientists used x-ray videos of a salamander from the top and the side, and tracked up to 64 points along its skeleton while it carried out different types of motion in water and on the ground.

“What is new is really our approach to building Pleurobot,” said Ijspeert. “It involves striking a balance between designing a simplified bone structure and replicating the salamander’s gait in three dimensions.”

The researchers designed Pleurobot with fewer bones and joints than the real-life version. For example, the robot contains only 27 motors and 11 segments along its spine, while the amphibian has 40 vertebrae and multiple joints, some  can even rotate freely and move side-to-side or up and down.

The researchers figured out the minimum number of motorized segments they could get away with, as well as the optimal placement along the robot’s body. As a result, it could replicate many of the salamander’s types of movement.

“Animal locomotion is an inherently complex process,” said Kostas Karakasilliotis who designed the first versions of the Pleurobot. “Modern tools like cineradiography, 3D printing, and fast computing help us draw closer and closer to understanding and replicating it.”

According to Ijspeert, mimicking the salamander’s movement provides insight into how the spinal cord works and how it interacts with the body. A robot that so closely mimics the properties of the salamander body can serve as a useful scientific tool to investigate interactions.

Neurobiologists have demonstrated that electrical stimulation of the spinal cord is what determines whether the salamander walks, crawls or swims. At the lowest level of stimulation, the salamander walks, but with higher stimulation, its pace increases, and beyond some threshold the salamander begins to swim. Pleurobot is programmed to mimic all of these functions.

Ijspeert feels that a better understanding of the interactions between the spinal cord and the body’s movements can help develop therapies and neuroprosthetic devices for paraplegic patients and amputees, as well as lead to the creation of more bio-inspired robots that will further science fields.

Comments are closed, but trackbacks and pingbacks are open.