Tiny robots climb walls carrying more than 100 times their weight

Mighty things come in small packages. The little robots in this video can haul things that weigh over 100 times more than themselves.

The super-strong bots – built by mechanical engineers at Stanford University in California – will be presented next month at the International Conference on Robotics and Automation in Seattle, Washington.

The secret is in the adhesives on the robots' feet. Their design is inspired by geckos, which have climbing skills that are legendary in the animal kingdom. The adhesives are covered in minute rubber spikes that grip firmly onto the wall as the robot climbs. When pressure is applied, the spikes bend, increasing their surface area and thus their stickiness. When the robot picks its foot back up, the spikes straighten out again and detach easily.

The bots also move in a style that is borrowed from biology. Like an inchworm, one pad scooches the robot forward while the other stays in place to support the heavy load. This helps the robot avoid falls from missing its step and park without using up precious power.

Heavy lifting

All this adds up to robots with serious power. For example, one 9-gram bot can hoist more than a kilogram as it climbs. In this video it's carrying StickyBot, the Stanford lab's first ever robot gecko, built in 2006.

Another tiny climbing bot weighs just 20 milligrams but can carry 500 milligrams, a load about the size of a small paper clip. Engineer Elliot Hawkes built the bot under a microscope, using tweezers to put the parts together.

The most impressive feat of strength comes from a ground bot nicknamed μTug. Although it weighs just 12 grams, it can drag a weight that's 2000 times heavier – "the same as you pulling around a blue whale", explains David Christensen – who is in the same lab.

In future, the team thinks that machines like these could be useful for hauling heavy things in factories or on construction sites. They could also be useful in emergencies: for example, one might carry a rope ladder up to a person trapped on a high floor in a burning building.

But for tasks like these, the engineers may have to start attaching their adhesives to robots that are even larger – and thus more powerful. "If you leave yourself a little more room, you can do some pretty amazing things," says Christensen.