Engineers from Stanford University have created miniature robots named "MicroTugs" capable of pulling and lifting objects more than 100 times their own weight. The strongest of the bots weighs just 12 grams but can pull objects 2,000 times heavier than itself, reports the New Scientist. This is the equivalent of a human dragging a blue whale, says David Christensen, an engineer from the lab that created the robots.

Another of the robots weighs just 9 grams but can climb up vertical walls carrying objects heavier than a kilogram — the equivalent of a human hoisting an elephant up the side of a building. Even the smallest of the bots — a miniature beast of burden that weighs 20 milligrams and was assembled under a microscope with a pair of tweezers — can pull objects 25 times its own weight.

borrowing secrets from the gecko and the inchworm

The secret to the bots' strength comes from techniques borrowed from the animal kingdom. Inspired by the gecko, the engineers covered the robots' feet with tiny rubber spikes that bend when pressure is applied. This increases their surface area and thus their stickiness. When the foot is lifted, the spikes straighten out, making them easy to detach from surfaces. And from the inchworm, the engineers borrowed the wall-climbing bot's method of locomotion: while one half of its body moves forward, the other stays locked in place. This allows the bot to climb walls without losing its grip.

A close-up of the tiny rubber spikes on the robots' feet. (BDML Stanford/Youtube)

The robots will be presented next month at the International Conference on Robotics and Automation, with the Stanford team hoping they could be set to various tasks in the future. Larger and more powerful versions could be used to move heavy loads around factories or building sites, while specialized models could be useful in emergencies — climbing buildings, for example, to deliver rope ladders to trapped people.

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