Self-assembling robots could one day replicate objects

Researchers in the US are developing tiny robots that can assemble themselves into products and then disassemble when no longer needed.

These magnetic cubes, described as ‘smart pebbles’ or ‘smart sand’, could one day replicate an object by surrounding it, determining its shape and then joining together to form a copy or larger version of the object.

The roboticists from the Massachusetts Institute of Technology (MIT), who have developed 10mm³ versions of the smart pebbles, have written a paper describing algorithms that would allow the cubes to talk to each other and work out how to arrange themselves.

The researchers, whose paper will appear at the IEEE International Conference on Robotics and Automation in May, foresee a time when you could place an object in a box of even smaller smart sand and shortly after pull out a replica model.

Kyle Gilpin, a research student from MIT’s Distributed Robotics Laboratory (DRL) who co-authored the paper, said: ‘Say the tire rod in your car has sheared. You could duct-tape it back together, put it into your system and get a new one.’

The cubes contain basic microprocessors and have unusual magnets on four of their sides that allow them to join together, break apart and communicate with one another using electrical pulses.

The biggest challenge, according to co-author Prof Daniela Rus, is developing algorithms that run on the very limited computational resources of the smart pebbles, which contain 32 kilobytes of program code and two kilobytes of working memory.

If every grain could simply store a digital map of the object to be assembled, ‘then I can come up with an algorithm in a very easy way’, she said.

Rus added: ‘But we would like to solve the problem without that requirement, because that requirement is simply unrealistic when you’re talking about modules at this scale.’

Robert Wood, an associate professor of electrical engineering at Harvard University, said that creating much smaller versions of the cubes was not an insurmountable obstacle, although it would take a lot of engineering.

‘They have the ability to latch onto their neighbours; they have the ability to talk to their neighbours; they have the ability to do some computation. Those are all things that are certainly feasible to think about doing in smaller packages.’