Fart jokes aside, this three-legged silicone robot leaps nearly a yard into the air on an explosion of methane. It’s a project from the Whitesides Research Group at Harvard to make soft robots move faster. Research on flexible robots have produced machines that crawl, swim, morph and color.

The problem with traditional mechanisms for soft robots — air, for instance — is that they are pretty slow. It can take a whole second to fill up a body part and make it move. The tiny natural gas explosion happens in a fraction of that, said Robert Shepherd, a postdoctoral researcher at the Whitesides group and an assistant professor at Cornell University.

Here’s how it works: The three “legs” of the robot each contain a valve — a simple flap of silicone — and a small amount of a methane-oxygen gas mixture. When a spark hits the gas, it ignites and expands, forcing the valve shut. The leg then fills with gas and gets rigid. As the gas cools, the valve opens up letting the cool gas out. In the process, the leg contracts, making a kind of spasm and causing the robot to jump.

Ludovico Cademartiri, a professor of materials science and engineering at Iowa State, and a member of the team, also noted that methane was a natural choice of fuel, as it is well-understood, burns cleanly and packs in a lot of energy.

Shepherd plans to experiment with other kinds of movement, such as walking, but that will be complicated by the fact that the energy in the exploding gas is released so quickly.

The work appeared in the Feb. 6 issue of the journal Angewandte Chemie.

Credit: Harvard University / Whitesides Research Group