Snails and slugs are so commonplace that we overlook the weirdness of how they move, gliding on a thin film across all sorts of terrain and obstacles. Popular imagination focuses on how slow this movement is, the snail defined by its pace, but it is at least as remarkable that the same mechanism lets a snail climb walls and move along ceilings. The movement is novel enough that there is now a snail-inspired robot, sliding across surfaces on an adhesive membrane, powered by a laser.
The snail robot, produced by a joint research team at the University of Warsaw Poland, together with colleagues from Xi'an Jiaotong-Liverpool University in Suzhou, China, created a centimeter-long robot powered by light. The research, published July in Macromolecular Rapid Communications, sheds new insight on how animals move in the wild, and on how small machines could be built to take advantage of that same motion.
Why might military planners or designers be interested in snail-like movement? The ability to scale surfaces and cling to them alone is worth study and possibly future adaptation. There’s also the simple efficiency of a creature that maneuvers on a single, durable foot.
“Gastropods’ adhesive locomotion has some unique properties: Using a thin layer of mucus, snails and slugs can navigate challenging environments, including glass, polytetraﬂuoroethylene (PTFE, Teﬂon), metal surfaces, sand, and (famously) razor blades, with only few super-hydrophobic coatings able to prevent them from crawling up a vertical surface,” write the authors. “The low complexity of a single continuous foot promises advantages in design and fabrication as well as resistance to adverse external conditions and wear, while constant contact with the surface provides a high margin of failure resistance (e.g., slip or detachment).”
Snails can literally move along the edge of the spear unscathed. Surely, there’s something in a robot that can do the same.
The small snail robot looks like nothing so much as a discarded stick of gum, and is much smaller. At just a centimeter in length, this is not a platform capable of demonstrating much more than movement. The machine is made of Liquid Crystalline Elastomers, which can change shape when scanned by light. Combined with an artificial mucus later formed of glycerin, the robot is able to move, climb over surfaces, and even up a vertical wall, on a glass ceiling, and over obstacles, while it is powered by a laser.
It does all of this at 1/50th the speed a snail would.
This leaves the implications of such technology in a more distant future. Imagine a sensor that could crawl into position on the side of a building, and then stay there as combat roars around it. Or perhaps the application is as a robot adhesive, crawling charges into place at the remote direction of imperceptible light. Directing a robot into an unexpected position, and having it stay there with adhesive, could be a useful tool for future operations, and one that would be built upon research like this.
The robot may be comically slow now. The pace of the technologies around it is not.