A better robot, brick by brick 

At Brandeis, Lego blocks put computer's designs to test 

By Lee Dye, 09/15/99 

Computer scientists at Brandeis University say they have taken a
significant step toward creating robots that will evolve into
ever more sophisticated machines, capable of repairing and
modifying their own hardware. 

What they have come up with isn't exactly the ''2001'' film
star, Hal, or even R2D2 of ''Star Wars.'' But they have produced
software that allows a computer to design structures, such as
bridges and cranes, without human intervention. 

''It's a kind of science fiction,'' conceded Jordan Pollack,
associate professor of computer science at the university's
Volen National Center for Complex Systems in Waltham. ''But it

They pulled off their achievement with the help of toys designed
for children, Lego blocks. The small plastic blocks,
manufactured by international toy giant Lego Group, can be
attached to each other in a variety of ways, making it possible
to build robotic prototypes in minutes and with minimal cost. 

Lego blocks were chosen because they lend themselves to modular
construction techniques, according to graduate researcher Pablo
Funes.''Legos are modular in the sense that they can be combined
in different positions,'' Funes said. ''Any brick can attach to
any other brick.'' 

The Brandeis scientists created algorithms, or computer
programs, that established the basic physics needed to build
strong structures. Then the computer was given a single Lego
brick, along with a goal, called a ''fitness function'' - in
this case to design a bridge two meters in length. 

That single brick ''mutated'' into other bricks, and the
computer tried many ways to assemble the bricks into a bridge.
Each step along the way, it compared the structure with the
physics model contained in the software. 

''That program basically calculates whether or not the structure
will collapse,'' Pollack said. 

A day and a half later, the computer produced a cantilevered
design for a bridge. The scientists then used Legos to build a
bridge like the computer had designed. 

It not only worked, Pollack said, but it was a good design. In
fact, it took humans centuries to develop similar structures
bridges that are based on counterbalances. 

The computer also designed a crane, based on an inverted
triangle, and a table. The computer came up with the designs
through a trial-and-error process, adding one Lego at a time and
checking against the physics model to see if that strengthened
or weakened the structure. 

The scientists say they gave the computer no commands other than
to start the task. However, did the computer succeed because
they told it too much about what it was supposed to do, or did
it succeed because it was able to ''think'' through the
challenge, aided by fundamental principles of physics? 

Pollack said he thinks the computer did its own work because
human values, such as symmetry, were left out of the equations.
''It doesn't know about the triangle, and it doesn't know about
the counterbalance any more than a bird knows about a wing,'' he
said. ''It's simply exploiting those structures because the
physics makes them better.'' 

The scientists see the experiment as a ''baby step'' on the road
to computer-driven machines, or robots, that evolve both
mechanically and ''intellectually'' as they work through
increasingly complex assignments. 

Still, the field of robotics is progressing at a very slow pace.
The Brandeis computer might be able to design a pretty good
bridge, but it can't pick up a single Lego brick. 

''These are designed for an 11-year-old's hand,'' Pollack said.
''No one has a clue how to build a robot with that kind of
manual dexterity.'' 

So the human body, as well as the mind, will remain in control
for a long time. But someday ... 

Distributed by The Los Angeles Times 

This story ran on page F4 of the Boston Globe on 09/15/99.