Snakes have one of the most versatile locomotions on the planet, easily able to navigate any terrain, which is why so many engineers have tried to replicate their special movements in robots. The sidewinder snake is particularly fascinating to scientists and engineers because it has perhaps the fastest and most efficient natural motion, quickly moving through unforgiving sand, even at steep inclines.
So far, scientists had been unable to replicate that special movement in a robot, but researchers at Georgia Tech, Carnegie Mellon University, Oregon State University, and Zoo Atlanta have teamed together to study the movements of the desert snake and make a robot that can navigate difficult sandy slopes.
“Our initial idea was to use the robot as a physical model to learn what the snakes experienced,” said Daniel Goldman, an associate professor in Georgia Tech’s School of Physics. “By studying the animal and the physical model simultaneously, we learned important general principles that allowed us to not only understand the animal, but also to improve the robot.”
A robot previously developed by Carnegie Melon was used to test the movements they were discovering in the real snake. The snake robot was designed to pass horizontal and vertical waves through its body to move in three-dimensional spaces like real snakes do. The robot is 37 inches long, two inches in diameter and has 16 joints, each arranged perpendicular to the previous one. The modular joints allow it to be configured to take on several different movement patterns.
At first, the robot had one principle of sidewinding movement down, but failed to make it up a sandy slope in a real world test, but after observing the real snake climbing various sand-covered inclines, the researchers discovered that the snakes had a particularly wave like motion they used to create maximum body contact with the sand and allowed them to make it up inclines.
Once the robot was programmed with this special wave-like motion, it was able to climb hills.
“We realized that the sidewinder snakes use a template for climbing on sand, two orthogonal waves that they can control independently,” said Hamid Marvi, a postdoctoral fellow at Carnegie Mellon who conducted the experiments while he was a graduate student in the laboratory of David Hu, an associate professor in Georgia Tech’s School of Mechanical Engineering. “We used the snake robot to systematically study the failure modes in sidewinding. We learned there are three different failure regimes, which we can avoid by carefully adjusting the aspect ratio of the two waves, thus controlling the area of the body in contact with the sand.”
The sidewinding robot could be beneficial in search and rescue operations, archaeological studies, even exploration of other planets. The robot can also move through pipes, and is being tested to check its potential for inspecting nuclear power plants.
The Georgia Tech team working on the project has been studying animals that move on sand for quite some time now. They have also created the Flipperbot, a robotic sea turtle, that demonstrates how those animals use their flippers to move across sand.
You can watch a video about the sidewinder research project below.