Researchers have developed lightweight robots that use strong and "smart" adhesive surfaces to pull up to 1,800 times their own weight.

Researchers from Stanford University looked at van der Waals force, the same force used by ants to pull heavy loads and geckos to climb on vertical glass walls, to develop "MicroTugs" robots.

The tiny robots use a special directional adhesive to pull 1,800 times their own weight. The robot's design incorporates a strong adhesive deposited onto a series of 100-micrometre flexible wedges made of silicone rubber, Gizmag reported.

Under normal conditions, only the very tips of the wedges make contact with the surface underneath, meaning that the robot is essentially free to move without resistance. But the micro robots are also able to push the wedges down, which makes them stick firmly to the ground when needed.

The robots can simply alternate between freely moving forward and pulling on a heavy weight while sticking firmly to the ground, using actuators that continuously and quickly switch between the two states. The result is a 12 g robot able to tow weights up to 21 kg, or 1,800 times its body weight.

The Stanford researchers have used the same principles to build several variations of their micro robots using different materials.