Giant leaf-tail gecko, Uroplatus fimbriatus, clinging to glass.
Image: Tim Vickers (public domain) [dinosaur-ise]
Geckos are amazing animals for so many reasons, but their ability to climb glass windows is especially amazing since their sticky toes are not at all moist, as one would expect. Instead, gecko toes are dry, their adhesive ability the result of van der Waals forces. These are very weak, attractive forces that occur between molecules. For this reason, the gecko's dry but sticky toe pads have long inspired scientists and engineers, especially mechanical engineers trying to design wall-climbing robots.
It looks like someone has finally succeeded. According to a hot-off-the-presses paper, a group of researchers from Simon Fraser University in British Columbia, Canada, have finally developed a robot – nowhere near as elegant in form as a gecko – that has the gecko's ability to scale smooth walls and shuffle across ceilings without crashing down onto anyone's head. They did this by simulating the gecko's dry but sticky toe pads from long-chain silicones known as polydimethylsiloxane (PDMS). This material had been specially manufactured to contain very small mushroom cap shapes.
Here's a video of this bio-inspired robot climbing walls:
This technology offers an alternative to the magnets, suction cups, spines and claws that have all been presented as possible wall- and ceiling-sticking mechanisms, but which all fail when it comes to climbing smooth surfaces such as glass or plastic. This development opens up all sorts of possible applications, ranging from robots that inspect pipes, buildings, aircraft and nuclear power plants to search and rescue operations.
Source:
J Krahn, Y Liu, A Sadeghi, & C Menon (2011). A tailless timing belt climbing platform utilizing dry adhesives with mushroom caps. Smart Materials and Structures, 20 (11) doi:10.1088/0964-1726/20/11/115021
Simon Fraser University is on facebook and can also be found on twitter @SFU
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