TINY tetrahedrons could one day help humans colonise other worlds, scout out suitable landing spots, build communication masts and erect solar shelters.
A team of NASA scientists has begun manufacturing the first tetrahedral robots, which crawl across the laboratory floor by shape-shifting. These simple structures promise to be able to deal with uneven and unpredictable terrain more easily than wheeled or legged robots, because they can morph to get past obstacles.
The robot, dubbed a TET Walker, has a tetrahedral framework of six struts that can be independently retracted or expanded telescopically, like the legs of a camera tripod, by motors at each corner. It manoeuvres itself by either shrinking or extending its edges to shift its centre of gravity beyond its base, so that it falls over. By repeating the trick, the robot can steadily zigzag forwards (see Diagram).
Advertisement
The next prototype will be more complex, with eight additional joints connected inside the tetrahedron. Computer simulations show that such a structure could perform more gymnastic feats, such as clinging to the side of a crevasse. 鈥淚t could effectively climb up a chimney,鈥� says Steven Curtis, head of the project at NASA鈥檚 Goddard Space Flight Center in Greenbelt, Maryland. 鈥淚t lets you 鈥榝low鈥� over the terrain.鈥�
鈥淭he next prototype, with eight additional joints, could effectively climb up a chimney鈥�
In January the TET Walker was shipped to Antarctica for testing under extreme environmental conditions. The team hopes NASA will select the prototype for further field testing in Iceland. There, a sensor installed in the centre of the structure would be used to detect microbes, mimicking an expedition to find alien life on another planet.
The prototypes developed by Curtis and his team are still relatively cumbersome, with extendable sides that can stretch from 1 metre to 2 metres. The researchers eventually hope to miniaturise the design, so that swarms of microscopic TET Walkers will be able to explore an alien landscape together. These miniature robots could even latch onto each other to construct complex structures for human colonists, Curtis says.
鈥淭he lander could also be an antenna, and it could ingest samples by opening and closing compartments,鈥� Curtis says. The idea might seem ambitious, but he is confident that nanotechnology will advance sufficiently over the next 20 years to make it feasible.
Sethu Vijayakumar, a robotics researcher at the University of Edinburgh, UK, says modular robotics is a major area of interest. But he says that the main challenge is enabling each component to cooperate effectively. 鈥淭he key issue is the bottleneck between communications and the capacity of individual units,鈥� he says.
You can see computer simulations showing TET Walkers in action at
