Modsnake represents a new development in the design of robotic snakes, with a locomotion system based on a highly-successful trait of a familiar desert reptile.

Sidewinder snakes are able to slither up sandy slopes with little effort, a talent which served as inspiration for investigators looking to design a better robot.

Carnegie Mellon researchers developed a new robotic snake capable of mimicking the motions of sidewinders, in order to cross terrains that could pose a challenge to other devices. Investigators from the Georgia Institute of Technology, Oregon State University, and Zoo Atlanta also participated in development of the new robot snake.

The Modsnake was originally designed with a gait loosely based on the movement of snakes, but part of its body would press into the sand in order to push the mechanical animal up a slope. Snakes do not behave in that manner. Instead, sidewinders keep most of their body on the ground, sending waves down its belly, while moving just the parts held in the air.

"Think of the motion as an elliptical cylinder enveloped by a revolving tread, similar to that of a tank. The snake lifts some body segments while others remain on the ground," Howie Choset, robotics professor at Carnegie Mellon University said.

The earlier design of Modsnake traveled effectively on level ground, but could not climb sandy slopes. Sidewinding behavior seems counter-intuitive, as snakes turn 90 degrees to the slope, before moving up a sandy slope. But, the motion is efficient while bringing slithering reptiles up a hill.

"Our initial idea was to use the robot as a physical model to learn what the snakes experienced. 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,"  Daniel Goldman, from Georgia Tech's School of Physics, said.

Snakes at Zoo Atlanta were monitored as they scurried up slopes of various grades. Researchers discovered that sidewinders kept a greater portion of their bodies in contact with the sand on steep slopes than on gentler grades.

Snake robots are highly-flexible, making it possible for the devices to access locations that may not be accessible to other automated machinery.

"Moreover, these highly articulated devices can coordinate their internal degrees of freedom to perform a variety of locomotion capabilities that go beyond the capabilities of conventional wheeled and the recently developed legged robots. The true power of these devices is that they are versatile, achieving behaviors not limited to crawling, climbing, and swimming," Carnegie Mellon University researchers reported on the their Web site.

The Modsnake is now able to easily climb sandy slopes with grades as 20 degrees - roughly the same capability as biological sidewinders.

Development of the Modsnake was detailed in the journal Science.