But are they the droids you're looking for?

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From: Strata Rose Chalup (strata@virtual.net)
Date: Wed May 10 2000 - 14:02:24 PDT

[Xposted to fork & tbtf-irr]


     A droid that can change shape

     UK CONTACT - Claire Bowles, New Scientist Press Office, London

     US CONTACT - New Scientist Washington office

     New Scientist

     Imagine an automaton that can design itself, assemble itself and
even kill itself. No, it's not the liquid metal robot from
     Terminator 2 -- but this droid can certainly build itself to
perform a particular task, melt itself down and recycle itself,
     say researchers in Massachusetts.

     The scientists have developed what they call a polymorphic robot --
a machine that can change its shape to suit the
     job in hand. Shape-shifting robots could be used as planetary
explorers, or for search-and-rescue missions, changing
     their shape to meet each new challenge and adapting to strange and
unpredictable environments.

     The researchers have produced a simple thermoplastic-framed robot,
says Hod Lipson, who developed it with
     Jordan Pollack at Brandeis University, near Boston. "All the robot
has to do is find a way to move," he says. The
     prototype is very basic and has no sensors, so it is unaware of the
world, though sensors could be added at a later
     design stage.

     The idea is that a task will be set for the robot, such as: "Figure
out how to move using only one leg and one motor."
     A computer will then attempt to design a body that will help it to
meet this challenge most efficiently. At present, the
     robot's body is built using the "rapid prototyping" technology
common in the car industry, which can produce
     complex three-dimensional structures very quickly. A device called
a 3D printer uses a nozzle to build up progressive
     layers of thermoplastic, slowly creating the required structure
(see Diagram).

     Although 3D printers are large and cumbersome, says Lipson, much
smaller ones could one day be built into a robot,
     allowing it to change parts of its body, for example, to reshape an
arm to produce a new tool for a novel situation.
     Mark Yim of the Xerox Palo Alto Research Center (PARC) in
California says this is one area in which polymorphic
     robots could be most useful. There's no point in taking an entire
toolkit into space, he says, when you don't know
     which tools you'll need: a single robot arm can be shaped to do the
job of all of them.

     It is also conceivable, says Lipson, that the 3D printing
technology will allow several materials to be printed, including
     conductive, nonconductive and even semiconductive materials.
"Wires, motors and logic circuits, as well as structure,
     could be printed in one pass without the need for assembly," Lipson

     With each new task, the look of a polymorphic robot is impossible
to predict, because each design is "evolved" using
     a genetic algorithm. The physical structure, and the neural network
that will be the brains of the proposed robot, are
     treated like genetic information that can be combined and mutated
in simulation to produce entirely new designs. The
     "fitness" of these offspring is then evaluated and the best are
"bred" to produce more offspring. This process is
     repeated many times until the design has evolved to do the best

     To keep things simple, Lipson allowed the algorithm only basic
components with which to design the prototype
     robot: straight plastic bars of varying lengths and electric motors
that can extend or shrink the length of a bar. Joints
     are all ball-and-socket designs, as these are easily created by a
3D printer. From these basic parameters a host of
     complex -- sometimes lifelike -- structures have been evolved.

     Some versions push themselves along on one leg, while others
produce a hinge-like motion and crawl about like a
     fish out of water. Yet another moves sideways like a crab. "The
robot is ready to move when it comes out of the
     printer," says Lipson. Its motor, however, must be inserted by a
person. But the aim is to make the robots totally
     independent, much like the vengeful shape-shifter in Terminator 2.

     When the robot has performed its task, it offers itself up to be
melted down, so its thermoplastic components can be
     recycled into another useful droid by the 3D printer.

     The idea of building and melting down robots is novel, says Yim,
who makes modular robots that reshape
     themselves by fitting smaller robots together. "I've never seen
anything like it." But he warns that to make truly useful
     robots, stronger plastics and more materials are needed.


     Author: Duncan Graham-Rowe

     See video footage of a shape-shifter walking at

     Please mention New Scientist as the source of this story and, if
publishing online, please carry a hyperlink to:

     Back to EurekAlert!

Strata Rose Chalup [schalup@netscape.com]   |        strata@virtual.net
Project Manager                             |     VirtualNet Consulting
iPlanet/Netscape Professional Services      |    http://www.virtual.net/

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