Researchers at Harvard University in Cambridge, Massachusetts, have developed a three-legged silicon robot that uses chemical reactions to help it leap up to 30 times its own height. Combustion is typically used in hard systems like internal combustion engines where the heat generated by the chemical reaction can be withstood, but this latest demo proves that the material can withstand high working temperatures as well.

Rapid actuation of a soft robot (composed of silicone elastomers) was achieved using high-temperature chemical reactions. (c) Nature

Rapid actuation of a soft robot (composed of silicone elastomers) was achieved using high-temperature chemical reactions. (c) Nature

The key to the robots leaping ability lies in a smart soft valve, positioned at the end of a channel present in each of the three legs. This smart valve allows just the right mix of oxygen and methane to mix – one part methane to two parts oxygen. Then, the same computer that regulates how much gas is let in the channels  controls a high-voltage cable connected to electrodes in each leg. When it deems fit, the electrodes spark which causes the gas mixture to react in combustion, forming CO2 and water, while also releasing a lot of energy.

This energy kick is what allows the silicon robot to hop up to 30 times its own height, but this would have never been possible without destroying the robot were it not, yet again, for the tiny valve.  It closes in response to high pressure, thus making the pressure even higher, and then it opens after the explosion to let the exhaust gases out.


Up until now a similar effect was replicated using compressed air only, as it was thought that the high heat associated with combustion would simply fry it. The Sand Flea, another leaping robot we reported earlier on, uses compressed air to fling itself pass obstacles as high as 10 meters high. Using a smart valve system and a cleverly balanced chemical reaction, the researchers proved that combustion can be made in other soft system as well.

As for some genuine applications for this silicon leaping robot, the researchers envision their device could be used for search-and-rescue operations, leaping and cartwheeling its way over any obstacles that might block its path.

The robot was documented in a paper published in the journal Nature.

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