Not only do cockroaches give many people the creeps, but often when you step on one of the critters, it just keeps on scurrying. Such resilience would be a good feature for mini-robots designed to scout disaster sites – among other applications – which is why scientists have created just such a device.

Approximately "the size of a large postage stamp," the robot was designed by a team at the University of California, Berkeley. It consists mainly of a thin rectangular sheet of a material known as polyvinylidene fluoride (PVDF), which is coated with an elastic polymer.

PVDF is piezoelectric, meaning that when an electrical current is applied to it, it expands or contracts. When two hard-wired electrodes are used to apply an alternating current to the elastic-coated robot, the resulting expansion and contraction is converted into a rapid series of bending and straightening motions. An angled "leg" on the front underside of the device in turn converts those motions into forward movement.

This arrangement allows it to scuttle along at an impressive 20 body lengths per second – reportedly the fastest pace of any insect-scale robot. It can also climb slopes, carry small payloads (such as a peanut), and even though it weighs less than a tenth of a gram itself, it can withstand a crushing weight of about 60 kg (132 lb).

The scientists are now looking into replacing the thin electrical wires with an onboard battery, plus they plan on equipping the robot with a gas sensor (for use at disaster sites), and making it remotely steerable.

"Most of the robots at this particular small scale are very fragile. If you step on them, you pretty much destroy the robot," says Prof. Liwei Lin, senior author of a paper on the research. "We found that if we put weight on our robot, it still more or less functions."

The paper was recently published in the journal Science Robotics. You can see the robot in action, in the video below.

And as an interesting side note, UC Berkeley scientists previously created another cockroach-inspired robot (that moves in a different fashion), called VelociRoACH.