This Gecko-Inspired Robot Tank Climbs Walls

Gravity is no obstacle for this climbing robot. It scales vertical walls?even those made of smooth materials like glass. Jeff Krahn, an engineer from Simon Fraser University in British Columbia, created this gecko-inspired tank of a robot, which he detailed in a paper in the journal Smart Materials and Structures this week.

Like a gecko, which can hang on to sheer glass with just one toe, the climbing bot uses what physicists call Van der Waals forces to stick to the wall. Its tanklike tracks are covered in a dry adhesive, a polymer resembling silicon that allows adhesion without chemicals or added energy. The molecules that make up this substance are temporary dipoles; they have a positively charged side and a negatively charged side. The charged sides of the molecules are attracted to their corresponding opposites on the wall the robot is climbing: negative to positive, positive to negative. Given enough surface area for these attractions to take place, Van der Waals forces can keep a pretty substantial weight stuck to a vertical wall. The climbing bot, for example, weighs in at half a pound.

To boost the climbing bot?s stickiness, Krahn needed to increase the surface area of its track, which allows more molecular interactions. So the tracks are covered with small bumps shaped like mushroom caps, each about the size of a human red blood cell. These bumps also allow the bot to cling to microscopic bumps and cracks in the surface of whatever it?s climbing. However, Krahn?s creation can?t scale a surface that?s too rough; the texture of concrete, for example, wouldn?t provide enough surface area for its tracks to get the proper grip, Krahn says.

Climbing up the walls is more than a neat trick. Krahn envisions more-advanced versions of this technology being used to replace humans in dangerous or difficult activities such as inspecting bridges, pipes, and nuclear plants, or even cleaning skyscraper windows. And since this robot leaves no trace of its path up the wall, it could be the perfect tool for sneaky surveillance. "These adhesives don?t leave residue, so once it?s taken off the wall, there?s no sign it was even there," Krahn says.

Other wall-climbing robots cling with claws, vacuum suction, or feet. Some of them even look like geckos. Krahn?s team went with a tank-style design instead, he says, because the tracks create simple, sustainable motion. A bot that climbs like a gecko, with feet, has to pull away each foot to move it higher and thereby climb. But the backward force of de-sticking a foot can cause enough vibration to knock the bot off the wall. Footed wall-climbers are also a bit harder to maneuver because each action must be controlled individually. The tank?s design makes it easier to direct and seems to affix the bot to the wall more successfully, Krahn says. "The one drawback with this design is that as the tank turns, the tracks have a tendency to come off its sides," he says. "We?re working on that."

The next step for Krahn and his team is to improve the sticking ability of the robot. They?re experimenting with coating materials for its tracks to determine which ones might allow the robot to scale something rough, like concrete. "We?d like to have a robot that can climb anything, basically," Krahn says.

Source: http://www.popularmechanics.com/technology/engineering/robots/this-gecko-inspired-robot-tank-climbs-walls-6537652?src=rss

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