Geckos living in nature are able to jump quite deftly from one vertical surface, from a tree trunk, for example, to another. In doing so, geckos use a sequence of rather peculiar movements that allow them to gain a foothold, stay on the surface and not fall off, falling down to the ground. And recently, a team of scientists from the University of California at Berkeley, the Max Planck Institute, Germany, and the University of Surrey, UK, found out what allows geckos to do such acrobatic tricks. Moreover, the scientists managed to copy it quite accurately and implement it in the form of a small robot design, made on a three-dimensional printer.
The research began with scientists filming the behavior of Asian flat-tailed geckos (Hemidactylus platyurus) with a high-speed camera for several seasons, focusing on their jumps from tree to tree, during which these small lizards moved at a speed of about 6 meters per second. Analysis of the filmed videos allowed the scientists to reconstruct the entire sequence of movements that allowed the gecko to gain a foothold on the surface.
It turned out that the gecko’s tail plays a major role in all this, oddly enough. When the gecko clings to the surface with its hind legs, it has time to press its tail against it, which gives it another fulcrum and a lever that allows it to extinguish the inertia of the movement.
Later, all the intricacies of the gecko’s jumping mechanism were embodied in the design of a robot with a soft body. The robot has four paws covered with ordinary Velcro, and a tail with a separate actuator that triggers and presses the tail to the surface when the front limbs of the robot come into contact with the surface.
When the robotic gecko made jumps on a vertical surface covered with felt, it was able to secure itself and not fall down 55 percent of the time, but when the researchers detached the robot’s tail, the percentage of successful jumps dropped to 15 percent. Live geckos show greater dexterity in jumping, with a success rate of 87 percent. However, once a live gecko loses its tail, for example in a fight with a predator, it completely loses its ability to jump from one vertical surface to another.
“Using our robot, we took a number of measurements that we could not do with live geckos in the wild,” the researchers write, “We determined that the tail and its movements are the main part that makes it easier to land in difficult conditions. And we believe that the principles we have developed can be used in other types and designs of robots, equipping them with the ability to maintain balance and stability in critical situations.”
