When geckos jump headfirst into vertical surfaces like tree trunks, they can cling to that surface instead of bouncing off and falling to the ground. Scientists have discovered what allows them to do so and replicate this ability in a small robot.
The new study was led by Professor Robert Full from the University of California-Berkeley, Dr Ardian Jusufi from Germany’s Max Planck School of Intelligent Systems Research, Dr Robert Siddall from the UK’s University of Surrey, and Dr Gregory Byrnes from the High School of Science. Siena College in New York.
During several field seasons in Singapore, Jusufi shot and analyzed many slow-motion videos of Asian flat-tailed geckos (Hemidactylus platyurus) jumping/gliding from one tree trunk to another. Although the animals try to avoid making those awkward first landings, when they do In the end, they are moving at about 6 meters (20 ft) per second.
While their heads, shoulders, and front legs bounce back off the tree, the lizards can grab the trunk with their powerful hind legs. This gives them leverage to press their long tail down into the tree, allowing the appendage to act as a brace to keep them from tipping backwards and falling to the forest floor.
That bracing mechanism was then recreated in a 3D printed soft-body robot designed by the scientists. The device has four Velcro-coated legs, a tail, and an internal motorized tendon that automatically activates to press the tail down whenever the front foot makes strong contact with the surface.
When that robot was launched onto a felt-covered wall, it was able to latch on without falling back 55% of the time. While that doesn’t sound great, its success rate dropped to just 15% when its tail was cut off. This is consistent with what’s been observed in wild geckos – tailed geckos have an 87% success rate, but wild individuals lose their tails to predators or in schools. Other risk cases are almost unsuccessful.
“With the robot, we can measure things that we can’t do with geckos in the field,” says Jusufi. “The wall response forces on impact during landing confirm that the tail is an essential part of facilitating landings during critical skids. Our soft lander not only helps create impact in another area, but could also help improve robot motion by dramatically increasing and simplifying control.”
An article on the research was recently published in the journal Communication Biology. The robot can be seen in action, in the following video.
Stabilized tail Gecko’s landing crashes Head into tree trunk
Source: University of California-Berkeley, Max Planck School for Intelligent Systems via EurekAlert