http://www.sciencentral.com/articles/view.php3?type=article&article_id=218392587

Reproducing Robots

It's an ability usually attributed to the birds and the bees â?" but
now mechanical engineers at Cornell University have created the first robot
capable of reproducing itself. This ScienCentral News video has more.

Building the Next Generation

Robots are standard fare in the realms of movies and science fiction,
offering an unshakable uneasiness that they could one day become so
high-tech they would replicate themselves and take over the world. But,
in practice, self-reproduction in the mechanical world is extraordinarily
difficult to achieve, both in the challenges of technology and
software.

Even Star Wars' CP30, a truly futuristic, walking, talking robot born
of Hollywood imaginations, needs a fix-me-up from his friend Chewbacca
when he gets into trouble and loses an arm or a leg.

In the biological world self-repair and self-reproduction are
prerequisites for sustainability. "Self-reproduction is something thatâ?¦ is
prevalent in biology but hasn't been explored as an engineering principle," explains
Cornell University mechanical engineer Hod Lipson. "What we want to
have are robots that can take care of themselves and can repair and fix others."

Lipson and his colleague Viktor Zykov created simple machines that act
as "autonomous modular robots" capable of reproducing themselves using
building blocks provided to them. These robots could one day work in
environments that are too hazardous or inhospitable for people.

But Lipson says there's nothing to worry about these machines taking
over the world. "Really there's nothing to worry about," he says. "There are
other forms of artificial self-reproduction â?" such as computer
viruses, genetically modified crops â?" these are self-reproducing systems that
are much more difficult to control because they're less dependent on
mechanical supply. Here, our robot depends very much on the supply of power, on
the supply of material and the supply of a very specific environment in
which they can reproduce â?" so they're much easier to control."

Reproducing Nature

Taking ideas inspired by biology, Lipson and his colleagues worked to
see how those ideas could change the way they did engineering. "And in the
same way taking ideas from engineering and seeing if they can give us new
insight into biology," Lipson says.

As robots go Lipson's doesn't exactly look high-tech. It's made up of
several 10-centimeter (four-inch) cubes linked together, with each unit
having the same microprocessor and instructions for picking up new
units. "A robot made out of repeated unitsâ?¦ able to pick up modules supplied to
it and assemble them into the form of a new robot which is identical to
the original," says Lipson. A four-module robot is able to construct a
replica in two and a half minutes. Because the replica is as large as the
original, the replica reconfigures itself to assist in its own construction.

The cubes have electromagnets on their faces that allow them to
selectively attach to and detach from one another. Each cube is also divided in
half along a diagonal, which allows a robot composed of many cubes to bend,
reconfigure and manipulate other cubes â?" bending from a tower into a
right angle or a square.

Although these machines can't walk, can't talk and don't have any
function beyond replicating themselves, Lipson says the point was to demonstrate
that mechanical self-reproduction is possible and not unique to biology.
"This was a demonstration of principle," he says. "We're looking at different
ways to expand this ability, to adapt the morphology or the shape of
machines."
Lipson says in the future the modules could be made to have unique
tools that perform certain functions (a camera, a drill, etc.) and believes
that ones day, the robots could be sent to work in hostile environments such
as nuclear reactors or war zones, or on missions deep into space. If they
got damaged or broke down they could repair themselves or simply create
their own replacements.

Beyond Reproduction

Self-repair and reproduction are certainly central to long-term
survival, but as with biological systems, sustainability also requires the
ability to adapt and evolve to a changing environment. With animals and plants,
genetics â?" as well as the environment â?" enable them to evolve
through generations. Lipson and his research team have also been working on the
evolutionary side of robotics. With their "Golem Project" a computer
program builds virtual robots for a specific task and then pits them against
each other (again, virtually). Whichever robots perform the task the best
survive while others are eliminated. This survival of the fittest process
continues for a specified period of time until the most highly evolved robot
emerges.

"What's very interesting about this is the kind of solutions that you
get are different than what we human designers often think about," says
Lipson.

"It might solve the problem in a slightly different way than what we
expect. It kind of explores outside the box." And because this evolution
happens virtually, it takes only a few days rather than over many thousands of
years.

But even if such extraordinary advances are enough to spark all kinds
of Hollywood-scale scenarios, Lipson's self-reproducing robots are still
well anchored in the lab, and he feels those story lines will remain in the
realm of science fiction.

Lipson's work was published in the May 12, 2005 issue of Nature, and
was funded by NASA's Intelligent Systems Program.