Robots making robots, with some help.

To remind themselves how much better their final products could be, robot designers need only look in the mirror. Yet the exquisite biological machines they'll see there emerge from a blind self-replication process, called evolution, and not from a deliberate design effort. In the latter, an engineer devises a robot for welding metal or baking cookies, for instance.

Betting what works for life may also work for artificial life, researchers in Massachusetts have demonstrated the first robotic system that designs and builds robotic offspring from scratch with minimal human intervention.

"The idea that a robotic system can make another robot is not self-reproduction, but it's a step along the way," says Jordan Pollack of Brandeis University in Waltham, Mass. He and Hod Lipson, also of Brandeis, describe their automated robot maker in the Aug. 31 NATURE.

Last year, Pollack and another colleague set a computer to designing simple structures by a hit-or-miss process that mimics evolution (SN: 9/4/99, p. 156). After many generations, the researchers used Lego blocks to build the computer's designs.

The new project goes a step farther. As before, a computer uses the evolutionary approach to invent moving robots whose ability to travel in a straight line determines their fitness to survive. Now, however, the computer's designs go directly into a fabrication machine that fleshes them out in plastic, leaving only a few accessory tasks to humans: plugging in motors and microchips.