Taking its inspiration from the grasshopper, a tiny two-legged robot that stores elastic energy in springs has leaped 27 times its own height, smashing the record of 17 times set by a previous robot.

Its creators hope that swarms of such hopping robots could spread out to explore disaster areas, or even the surfaces of other planets.

The robot is only 5 centimetres tall, and weighs just 7 grams. A motor designed to power the vibration unit of a pager drives a system of gears that gradually wind two metal springs (see image, right).

When they are fully wound and then released, they straighten two metal legs that propel the robot upwards. The jumping robot was developed by researchers at the Swiss Federal Institute of Technology in Lausanne, Switzerland.

Hop on over

Hopping provides an effective way for tiny robots to get around on rough terrain, says Dario Floreano, who worked on the robot with colleague Mirko Kovac.

Just as for insects like crickets, or animals such as frogs, small robots whether legged or wheeled find even small obstacles insurmountable barriers. Hopping can be the only way to get over them.

The new robot's motor takes 3.5 seconds to fully recharge the springs, and its 10 mAh battery is enough to power 108 jumps.

Each of its legs has two segments that attach at an angle, making a knee-like bend in the legs. Adjusting the angle of the "knees" makes the robot hop either more vertically, or further forward.

The prototype doesn't have any way to direct itself, and as yet can't even land on its feet ready for the next hop. Floreano says they are working on a number of refinements.

Just add wings

First, they want to build a wire superstructure to make the robot automatically regain its feet when it lands and add wings to let it glide like a real grasshopper while airborne.

After that they hope to add solar panels, some simple sensors and a microprocessor. These would allow the robot to control its hopping and possibly communicate with other robots in the swarm, as well as recharge its battery.

Such robots might be simple, but they could also be cheap. A group could coordinate themselves to spread across an area to, for example, trace an environmental pollutant, Floreano says.

"They have done excellent work, making this very light robot that can cover very long distance," says Umberto Scarfogliero, at the Institute for Advanced Studies in Lucca, Italy. Scarfogliero and colleagues presented a similar jumping robot called Grillo last year at the IEEE robotics conference.

Floreano and Kovac's robot will be presented today at the IEEE International Conference on Robotics and Automation in Pasadena, California, US.

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