Powered by small explosions, the robot can jump 20 times its height and carry 22 times its weight. Its makers say these robots can be cheaply produced in bulk and are ideal for search and rescue missions or even for exploring other planets.

Most robots are powered by electric motors and batteries, which are reliable and proven technologies but cannot be scaled down beyond a certain point. Robert Shepherd of Cornell University in New York and his colleagues instead used methane, a chemical fuel that can store energy at a much higher density than lithium-ion batteries and can be scaled down into tiny insect-sized devices.

The team created a 3D-printed combustion chamber actuator that weighs just 325 milligrams. A pair of electrodes creates a spark and ignites a mixture of methane and oxygen, and the resulting explosion pushes against the flexible membrane with a force of 9.5 newtons.

The membrane rapidly expands outwards during each explosion, but safely contains gases that are then expelled when contracted. The actuator can produce up to 100 such explosions per second, and at lower frequencies, one of the actuators survived an 8.5-hour endurance test, withstanding 750,000 successful firings.

Next, the team created a prototype four-legged robot equipped with two such combustion chambers, each connected to an expanding diaphragm attached to one leg. The fuel was delivered remotely through thin pipes. During the tests, it was found that the robot was able to move 22 times its own weight.

Source: New Scientist