Page 113 - Modern Robotics Building Versatile Macines

THOUGHTFUL ROBOTS 93

that read the sensor signals sent a signal to the “prowl” program if a
target was detected. The sensor program also sent data to a program
that would continuously correct the robot’s path, steering toward the
target.
Brooks refers to robots like Genghis as being situated and embod-
ied. A situated robot responds directly to sensory input. Its behavior
is shaped by response and interaction, not some abstract model of
the world. An embodied robot is just that—in a body that in some
sense experiences the world.
As Brooks and his crew began to build more robots that “embod-
ied” these concepts, he had a conversation in 1992 with Apollo
15 commander David Scott that inspired Brooks to begin explor-
ing ideas for roving robots for planetary exploration. Following
the “glory days” of Project Apollo and such probes as Viking and
Galileo, putting mobile robots onto the surface of Mars or other
planets seemed to offer an exciting (and perhaps affordable) way to
take space exploration to a new level.
Brooks’s new layered architecture for embodied robots offered
new possibilities for autonomous robot explorers. Brooks’s 1989
paper, “Fast, Cheap, and Out of Control: A Robot Invasion of
the Solar System,” envisaged flocks of tiny robot rovers spreading
across the Martian surface, exploring areas too risky to venture into
with only one or two very expensive robots. Colin Angle soon built
Tooth, a 1.1-pound (0.5-kg) microrover. Although the Jet Propulsion
Laboratory did not use Brooks’s rovers, the Sojourner rover that
explored Mars in 1997 used wheels similar to those in Tooth and
had autonomous functions at least partly inspired by Brooks’s lay-
ered behavior architecture.

Humanoid Robots

In 1992, about 25 years after the movie 2001: A Space Odyssey
was released, Brooks was thinking about HAL 9000, the humanlike
intelligent computer featured in the story. According to the movie,
HAL was “born” in a laboratory sometime in the 1990s. In the real
1990s, though, computers and robots still seemed to be decades
away from HAL-like behavior.