Engineers in the US have created a machine out of intelligent cubes that can make copies of itself.
They say it is a small step towards developing robots that can repair and replicate themselves in space or hazardous environments where it is difficult for humans to venture.
Assistant Professor Hod Lipson of Cornell University led a team that reports the research in today’s issue of the journal Nature.
“Self-reproduction is central to biological life for long-term sustainability and evolutionary adaptation,” say the researchers.
“Although these traits would also be desirable in many engineered systems, the principles of self-reproduction have not been exploited in machine design.”
The machine Lipson’s team developed is made up of a set of modular cubes, called molecubes, which each contain the machinery and a computer program necessary for self-replication.
The 10-centimetre cubes use electromagnets on their faces to selectively connect and disconnect from each other and they draw power through contacts on the surface of the table they sit on.
Each cube is divided in half along its diagonal and this enables a robot made of a number of the cubes to bend and move its own, and other, cubes around.
The researchers have shown how a robot made of a stack of cubes can replicate itself.
camera For a video of the replication process, click here (requires Windows Media Player).
“A three-module robot is able to self-reproduce in just over 1 minute,” say the researchers.
The robot bends around, moving its own cubes and new cubes ‘fed’ to it by the researchers. Because it is not possible for the original robot to reach across another robot of the same height, the new robot must assist in completing its own construction.
“Although the machines we have created are still simple compared with biological systems, they demonstrate that mechanical self-reproduction is possible and not unique to biology,” the researchers say.
“The design concept could be useful for long-term, self-sustaining robotic systems in emerging areas such as space exploration and operation in hazardous environments, where conventional approaches to maintenance are impractical.”
Australian robotics expert, Associate Professor Richard Willgoss of the University of New South Wales, says mechanical replication provides building blocks towards doing a lot of other things that biological systems do, albeit at a much larger scale.
“If biology does it so well, why can’t we do it too.”
Willgoss, who is working on a modular robotic arm, says intelligent modules can communicate with each other, as cells in the immune system do.
He says such developments could lead to robotic systems that provide “tool kits” capable of, for example, making a vehicle one day and a bridge the next.
The idea is that if a module breaks down the robot can repair it, or perhaps a whole entire new robot can be built.
“If we can make robots that have distributed intelligence, we can perhaps give them a global request and they’ll do the rest for us. It’s very fanciful but you have to start somewhere,” says Willgoss.
Grey goo from nano-robots
While these self-replicating robots are 10 centimetres across, some scientists have discussed the idea of self-replicating robots the size of molecules.
This has led to the nightmare scenario of self-replicating nano-robots, or nanobots, reducing the Earth to a mass of seething “grey goo”.
So do the new developments make this more likely?
“The intelligence behind making that assembly could easily be taken down to the nano scale but the practicality of making the unit is a different matter,” he says.
“We’ve gone to the micro scale where we’re making tiny little cogs in wheels on a substrate with integrated circuits but nanotech involves the atomic scale and that requires very specialised equipment to do that.”