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A revolution in robotic
evolution
 A
computer-designed and automatically built "arrow" robot crawls
through the sand. Its symmetric shape arose after hundreds of
generations' worth of simulated
evolution.
In
what’s being hailed as a first step to bridge the gap between the
cyber-world and the real world, researchers programmed a computer to sift
through hundreds of generations’ worth of virtual progeny — then actually
construct the contraptions that proved best able to crawl. What’s more,
they’re offering a screensaver program that allows you to do it,
too.
THE EXPERIMENT
represents an advance in the field known as “artificial life” — the study
of whether machines, working with a minimal set of components, can figure
out how to build better and better machines.
“We have demonstrated for the first time a robotic bootstrap, where
automatically designed electromechanical systems have been manufactured
robotically,” Hod Lipson and Jordan Pollack of Brandeis University
reported.
As described in Thursday’s issue
of the journal Nature, Lipson and Pollack programmed a computer to put a
population of simple robots through an evolutionary process: The computer
tested each “generation” to see which primitive robots could crawl the
farthest, then made refinements in the design.
In the course of 300 to 600 generations, some of the robot species
went extinct, while others converged toward optimal (if sometimes weird)
designs. When the selection was winnowed down to a handful of the fittest
survivors, the computer carved them from a block of plastic, using a 3-D printer.
 The 3-D printer, also known as a plotter or
milling machine, could create the complete robot, joints and all, within
its 8-by-8-by-12-inch parameters. All the humans had to do was snap in the
motors and hook the robots up to their electronic “brain,” which evolved
along with the physical parts in the simulation.
Of course, humans set the rules of the game at every stage. “We
constrained the universe that can be simulated,” Pollack said.
Nevertheless, Pollack said his biggest surprise was
finding out that the contraptions actually worked. “By October, the first
robot was fabricated, and it worked right away,” he said.
“The other surprising thing was that the robots discovered
symmetry,” he said. There was no rule in the program that the robots had
to have the mirror-image look found in most living things, but the
simulation program discovered for itself that balanced designs tended to
crawl more efficiently.
 “The ‘breast stroke on the ground’ motion was
done without any human intervention at all,” Pollack said.
Pollack said another key point was that the robots’
hardware and artificial-neuron software evolved together: “What you have
in a real animal is a sequence of iterations where the body and the brain
have small changes that can’t survive without the other, and we’ve
captured that in a simulation.”
He said more
progress has been made since the submission of the research paper, which
describes the first six months of work on a five-year effort partially
supported by the Pentagon’s Defense Advanced Research Projects
Agency.
REAL ARTIFICIAL
LIFE
Even though it’s just the beginning, the work at Brandeis has gotten
glowing reviews. The experiment represented “a first step toward bridging
the gap between computer models and physical reality,” Rodney Brooks of
the Artificial Intelligence Lab at the Massachusetts Institute of
Technology wrote in a commentary also published by Nature. Most other
efforts in the field of artificial life have focused on computer
simulations rather than the evolution of real-life robots.
Even in the Brandeis experiment, there was no feedback
from the real world to the virtual evolutionary process. “At best, this
system is like a virus that uses other more complex machines (which in
this case are not life forms themselves) to carry out reproduction,”
Brooks said.
Pollack said closing the
feedback loop would be one of the natural next steps.
Self-replicating robots would be a
boon to the exploration and exploitation of extreme environments. As far
back as the 1960s, NASA investigated the possibility of seeding the moon
with a self-reproducing factory, Brooks noted, and similar schemes
involving robot factories have been proposed for Mars missions.
Another study in this week’s Nature looked at how
efficiently swarms of small mechanical “antbots” could locate simulated
food items and bring them back to a central nest.
“Groups of robots using ant-inspired algorithms of decentralized
control techniques foraged more efficiently and maintained higher levels
of group activity than single robots,” the University of Lausanne
researchers reported. “But the benefits of group living decreased in
larger groups, most probably because of interference during
foraging.”
The bottom line was that “group dynamics of swarms of robots may
follow rules similar to those governing social insects,” said the study’s
authors, Michael Krieger, Jean-Bernard Billeter and Laurent
Keller.
ROBOTS RUN AMOK?
All this may sound like the setting for a
science-fiction plot — the kind in which self-replicating robots
eventually run amok — and Lipson and Pollack are already working hard to
downplay those kinds of descriptions of their work.
“It’s not the dreaded ‘robots making themselves,’” he told
MSNBC.com.
At another point during the
interview, he said, “The robots that we’re building now are really like
bacteria. We’re trying to get to insects in a couple of years. It’s not
like a humanoid is going to walk out of our fabrication plant.”
The name of the simulation program itself —
Genetically Organized Lifelike Electro Mechanics, or GOLEM for short —
provides some perspective, Pollack said. In Jewish legends, a golem is an image or form that is given life through a
magical formula. In the legends, the creator usually loses control of the
creation.
"Golems are sort of a warning about
hubris, about taking God’s power into your own hands, and we pay a little
bit of attention to that,” Pollack said.
With that cautionary note, Lipson and Pollack are making a
screensaver version of the simulation program, dubbed Golem@Home,
available via their Web site. A standalone version of the simulator,
called
LiveTruss, is also available. Both programs simulate the evolution
of the kinds of robots involved in the Brandeis experiment, and the
screensaver has the added twist that robot prototypes can be traded back
and forth over the Internet.
To create a
Golem robot from the simulation, you’ll need access to a 3-D printer — and
don’t
expect a magical formula that works instantly. It took up to 22
hours for the computer to carve out the crawlers described in the Nature
paper
By Alan Boyle
MSNBC
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