“The work of Marvi et al. demonstrates the strength of integrating biology, engineering, and physics, providing the finest example to date of the reciprocal use of animals and robots for mutual illumination. The drive to understand the mechanics of sidewinding has brought us one step closer to achieving lifelike locomotion in robots.” That was a commentary written by John Socha, Virginia Tech, in a study on making sidewinder snake robots for search and rescue operations.
For years scientists have always been baffled at the ability of sidewinder rattlesnakes, Crotalus cerastes, to move effortlessly across sandy surfaces like dunes, both flat and inclined. Most common in the sandy deserts of the Southern United States and northwestern Mexico, the sidewinder rattlesnake zigzags in an “s” shape movement as it slides or sidles across hot deserts – and it is the only snake that moves this way, or that can move across deep sand dunes in this way.
To this end, researchers at the Georgia Tech developed a sidewinder snake robot and tested its functions on challenging sandy slopes and in real hot desert situations. They wanted to understand what makes only sidewinder snakes move this way and be able to navigate sandy deserts, with a view to making sidewinder snake robots that could be used for search and rescue missions – to traverse rough terrains or enter damaged buildings in search of survivors.
Howie Choset, a roboticist at the Carnegie Mellon University had once built this kind of sidewinder snake robot, but the machine failed woefully – it tipped and pitched over when it slipped during tests at an ancient archaeological Egyptian cave. Choset after this effort teamed up with Daniel Goldman, a physicist at the Georgia Institute of Technology to perfect the movement of the sidewinder snake robot.
They had then gone to the Yuma Desert of Arizona to fetch sidewinder rattlesnakes which they brought back with some desert dunes to the back of the Zoo Atlanta for further study. According to Goldman, “the snakes were quite venomous, and we were not allowed to bring them to Georgia Tech,” but they had studied and found out that sidewinder snakes actually elongated the contact length of the “zig” segments of their bodies with the sand, and this allowed them to move in dunes without getting stuck at all.
The researchers finally added this factor into the sidewinder robot’s software and to their surprise, the snake robot moved effortlessly across sandy inclines without any wriggling efforts whatsoever. And again, John Socha stated that “this suggests that the evolution of sidewinding may have required a change in neuromotor control, shifting the timing of muscle activation to match the required template for sidewinding.”