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THOUGHTFUL ROBOTS 87

of AI in the Stanford Artificial Intelligence Lab (SAIL). He also
joined in the innovative projects being conducted by researchers,
such as Hans Moravec, who were revamping the rolling robot called
the Stanford Cart and teaching it to navigate around obstacles.
In 1984, Brooks moved to the Massachusetts Institute of
Technology. Like Stanford, MIT was a burgeoning center of AI
research and robotics. There he would undertake more than two
decades of innovative research. Much of it would stem from a
decision to begin thinking about artificial intelligence in a dif-
ferent way.

The Challenge of Vision

For his Ph.D. research project, Brooks decided to tackle one of the
toughest challenges in AI: creating systems that can identify and
“understand” objects in a three-dimensional environment. First,
Brooks and his fellow graduate students needed a robot chassis on
which to mount the cameras and other gear. Fortunately, a high
school student named Grinnell More and two of his friends had
started building a simple steerable robot called VECTROBOT.
Brooks not only bought one of the machines but also enlisted Moore
as an informal research assistant.
They equipped the robot with a ring of sonars (adopted from a
camera rangefinder) plus two cameras. The cylindrical robot was
about the size of R2D2. Since this was still the 1980s, there were
no small computers powerful enough to run the AI software, so the
robot was connected by a cable to what was then a powerful mini-
computer.
One reason why computer vision is so difficult is because the
appearance of an object can change radically depending on the angle
from which it is being viewed. A human has no problem knowing,
for example, that an upright glass and a glass lying on its end is the
same object. Computers, however, have to use complex mathematics
to identify objects and their relative positions. These calculations
are so intensive that a robot such as Stanford’s Shakey, from the
1960s, had to “think” sometimes for hours before being able to
move around an obstacle in the room. It took that long to create or