- By Joab Jackson -
When most people think of robots, they envision walking, talking mechanical
humanoids along the lines of The Jetsons' domestic Rosey the Robot,
Futurama's grouchy Bender, or Lost in Space's B-9, frantically
waving its mechanical arms at impending danger.
But to judge by robot pioneer Rodney
Allen Brooks' new book "Flesh
and Machines," as well as several recently published robot-building
how-tos that follow in the path Brooks blazed, robot science is scooting
off in a less anthropomorphic direction. Rather than general-purpose sentient
machines walking about, offering advice, cracking wise, and helping with
the chores, robots have mutated into specialized creatures, dumb machines
that undertake complex, useful tasks such as cutting lawns, crushing fellow
bots for our entertainment, and serving as mechanical pets. And like most
people who hire domestic help, their owners don't care how smart they are.
Brooks runs the artificial-intelligence laboratory at the Massachusetts
Institute of Technology. "Flesh and Machines" is a fascinating account
of how he got involved in the field and where he thinks it will head. Brooks'
speculations have the weight of years of garage-shop-level practical
behind them. He and his lab have built a number of robots, including the
wheeled prototypes for NASA's
Sojourner vehicle, which tooled around Mars.
"Flesh and Machines" revolves around an epiphany that Brooks had early
in his career. When he first got involved academically in the robotics
field, the prevailing wisdom was that a well-designed robot required some
sort of brain, a central processor to regulate the mechanical tasks it
would undertake, and that this brain would need to build and hold an internal
map of everything it could sense about its surroundings. The problem was
that rendering a computerized representation of every obstacle in a robot's
path, and then executing the orders to the limbs to avoid those obstacles,
takes an immense amount of computational power.
Brooks takes delight in describing a slow-moving robot that he helped
develop while a research assistant at Stanford University in the late '70s.
Tethered to a mainframe computer by a large cord as it tried to make its
way around the lab,"the Cart made its forward lurches about once every
15 minutes," he writes. "Once every 15 minutes if [the device's] main computer
wasn't busy running jobs for other people."
This struck Brooks as absurd. Why, he asked himself, could insects with
roughly the same amount of computational power (in the form of slower
interconnected neurons) move about the world at speedy predator-avoiding clips? The conclusion he reached is that insects don't employ an internal representation of the
world. The world itself is their model; the bugs just bounce off of it
using simple reflexes. And so, instead of designing robots with bulky
command-and-control noggins, in the mid-'80s Brooks began building creatures with numerous simple control systems.
When enough of these simple, largely independent circuits were overlaid,
the sum total of their combined actions produced remarkably sentient-like
effects. One of Brooks' robots was designed to walk visitors about the
lab, giving them a guided tour of the facilities. Another, named Kismet,
was a disembodied metal skeletal face with two eyes and ears that mimicked
the physical cues of a person participating in a conversation, down to
the raising of the eyebrows at the appropriate times. With 15 independent
computers controlling Kismet's reactions, people would find themselves
unwittingly chatting with this thing, even though it was only babbling
well-timed nonsense syllables.
Although this decentralized approach may seem obvious now, at the time
the academic community greeted Brooks' ideas with shock. "Without quite
being explicit," he writes, "I was saying that all previous work in artificial
intelligence was misguided."
Brooks' ideas have taken hold. The growing presence of simple novelty
robots since the mid-'90s -- Sony's mechanical pet Aibo,
the fighting robots of TV's BattleBots
and Robot Wars -- are his legacy,
in that they rely more on crafty mechanical engineering than raw computational
power to do what they do.
Brooks' simplified approach serves as the basis for a number of recently
released guides on how to build robots. In fact, David
Building for Beginners" could be subtitled, "Robot Building for Liberal
Arts Majors Who Flunked Shop Class in High School." It really does assume
its readers have no mechanical or electrical experience.
Wisely, Cook devotes the entire 568-page volume to building one robot,
a simple four-wheeled device with a small plastic food container for a
body that can follow light and dark colored lines. For intelligence, the
only microchip Cook's robot uses is a simple preprogrammed "comparitor"
that can be purchased at Radio Shack. The chip operates by comparing the
voltage of two inputs and sending signals to fire up the wheel motors on
either side of the bot based on what it gets from those inputs.
In other words, Cook's robot is a mental ninny, one evolutionary step
up from a radio-controlled toy car only by the virtue that it doesn't take
orders from a remote unit.
Cook doesn't get into more complex robot technologies. Once you start
thinking in a robot-building way, he calculates, you can design more complex
stuff pretty easily. Besides, he offers examples of other quasi-useful
bots that can be built from similar simple designs, such as a slug squisher,
a window washer, a houseplant-watering robot, and so on.
Pete Miles and Tom Carroll's "Build
Your Own Combat Robot" doesn't dwell too much with internal logic either.
This book was written for those interested in participating in those
gladiatorial robot-war tournaments on TV. Unsurprisingly, combat bots don't require
much higher-level thinking to find opponents and pulverize them with their
kill-claws and whatnot. "Of course, if you're building a BattleBots-style
[radio control] machine," the authors note, "you probably won't need any
software, and the 'sensors' are your own eyes as you guide it across the
floor of the battle arena."
Combat robots, however, are not simple creatures. In fact, "Combat Robot"
presents designs for mechanical marvels that blow away anything in Cook's
"Robot Building." Unlike Cook's book, however, "Combat" assumes you already
possess considerable mechanical skills and are only seeking wisdom on how
to harden your bot against thrashings.
The debt of these how-tos to Brooks' ideas is clear. At one point the
authors of "Combat Robot" even discuss swivel-mounted wheels, referencing
the success of early Sojourner prototypes that Brooks' lab worked on. Both
books harp on the theme that Brooks devised -- off-load as much intelligence
as possible in favor of clever mechanical design.
Naturally, neither of these how-tos has any advice regarding the
construction of something resembling consciousness -- the trick the original AI researchers were after with their brainy bots. Nor do they even venture the idea that
it can be done, given enough circuits. Brooks admits near the end of his
book that his ideas of decentralization probably won't engender artificial
intelligence, arguing that the secret ingredient to producing consciousness
is something scientists just haven't discovered yet.
But maybe this is as it should be, given people's attitudes toward bots.
The late Douglas Adams understood the inherent tension in what is desired
from robots -- namely to be smart enough to do their owners' bidding, yet
not smart enough to think on their own. One of the mechanical characters
Hitchhiker's Guide to the Galaxy" was Marvin, a robot that, because
it was programmed with human-like traits, was relentlessly depressed by
the futility of its own existence. "Here I am, brain the size of a planet
and they ask me to take you down to the bridge. Call that 'job satisfaction'?
'Cos I don't,'" Marvin would kvetch. It's as if Adams was warning against
making robots too smart.