Geckos inspire wall-climbing robot at SFU
VANCOUVER — Researchers at Burnaby’s Simon Fraser University have created a tiny, tank-like robot that can scale walls using an adhesive that mimics the sticky toes of a gecko.
A clingy silicone compound formed into tiny bumps shaped like mushroom caps enables the 240-gram robot to climb such smooth surfaces as glass or whiteboards.
Jeff Krahn — lead author of the research published Tuesday in the British science journal Smart Materials and Structures — said the technology could one day help robots perform a wide range of dangerous tasks, such as cleaning nuclear power plants or doing search-and-rescue work in collapsed buildings.
“An obvious [application)] would be for cleaning glass on skyscrapers or inspecting bridges where it’s hard or dangerous for a person to get in there,” Krahn said. “The adhesives don’t leave any residue like a tape or a glue.”
Known as the tailless timing belt climbing platform (TBCP-11), the prototype can climb up and over corners onto walls at up to 3.4 centimetres a second.
Without using suction cups, claws, glue or other liquid bonds, the prototype sticks to surfaces using hundreds of minuscule silicone bumps that are just 0.017 millimetres wide and 0.01 mm high. By comparison, human hair is around 0.1 mm thick.
They stick to walls by relying on Van der Waals forces — the weak attractive force between molecules.
“The material itself is able to be attracted to the glass, but the shape enables a much larger area to be in contact because it can conform to the surface,” Krahn said. “While Van der Waals forces are considered to be relatively weak, the thin, flexible overhang provided by the mushroom cap ensures that the area of contact between the robot and the surface is maximized.”
“The adhesive pads on geckos follow this same principle by utilizing a large number of fibres, each with a very small tip. The more fibres a gecko has in contact, the greater attachment force it has on a surface.”
Sensors allow the robot to detect its surroundings, change direction, as well as reattach itself when losing its grip.
While the silicone adhesive is modelled after the gecko’s sticky toes, only its reptilian counterpart can climb rougher surfaces like concrete.
“It’s not quite as effective because it’s not able to work on the same range of materials as geckos,” Krahn said.
Now Krahn and other researchers will try to increase the strength of their adhesive compound and create a robot that can disconnect from its power source and rely on its own battery and computer brain, allowing it to move wirelessly and autonomously.