In our outdoor experiments, DyRET used a machine learning model, seeded with knowledge about the best leg configuration for a given combination of terrain hardness and roughness taken from the controlled tests. As the robot walks, it continuously predicts the best body shape for the terrain as it encounters it, while updating its model with measurements of how well it can walk. In our experiments, DyRET's predictions improve as it walks, allowing it to quickly generate efficient movements, even for terrain it hasn't seen before.

The four-legged robot Dyret can adjust the length of its legs to adapt the body to the surface. Along the way, it learns what works best. This way it is better equipped the next time it encounters an unknown environment. The name Dyret (Norwegian for "The Animal") is an acronym for Dynamic Robot for Embodied Testing. "We have shown the benefits of allowing a robot to continuously adapt its body shape. Our physical robot also proves that this can easily be done with today's technology," says senior lecturer Tønnes Nygaard at UiO's Department of Informatics.

Sure, evolution invented mammals that soar 200 feet through the air on giant flaps of skin and 3-foot-wide crabs that climb trees, but has it ever invented a four-legged animal with telescoping limbs? Meet the Dynamic Robot for Embodied Testing, aka DyRET, a machine that changes the length of its legs on the fly--not to creep out humans, but to help robots of all stripes not fall over so much. Writing today in the journal Nature Machine Intelligence, researchers in Norway and Australia describe how they got DyRET to learn how to lengthen or shorten its limbs to tackle different kinds of terrains. Then once they let the shape-shifting robot loose in the real world, it used that training to efficiently tread surfaces it had never seen before. "We can actually take the robot, bring it outside, and it will just start adapting," says computer scientist Tønnes Nygaard of the University of Oslo and the Norwegian Defence Research Establishment, the lead author on the paper.

The science fiction multiverse is well populated by all manner of robots. Pick your favorite: Dr. Who fans may favor K9, the Time Lord's mechanical mutt. Maybe the Transformers represent the coolest robots in the galaxy. The more literary-minded might prefer a character like R. Daneel Olivaw out of the Asimov universe. Those of us from a certain generation, however, will always have an affection for the Laurel and Hardy of robots--C-3PO and RD-D2.

Don't even worry about Dyret the robot. At first glance, the scrawny quadruped looks pathetic, as it struggles to walk without collapsing. But keep watching, and you'll see it start to improve--walking slowly, yet ever more proficiently. Dyret the robot is teaching itself to walk. Machines like Cassie the biped or SpotMini the robot dog are quickly mastering locomotion, thanks to line after line of meticulous code.