Silicon Sidekicks
Silicon Sidekicks
Exploring our solar system will require a new breed
of intelligent robots.
Listen to this story
via streaming
audio, a downloadable
file, or get
help.
Sept.
13, 2002: Â Yelling "Fetch, Rover!" the man
tosses a frisbee far across the yard. His dog just stands there
and does nothing.
Oh yeah, he thinks, I forgot. "Rover! Turn
clockwise until you face north-by-northwest, move forward ten-point-five
meters and stop, lower your head fourteen centimeters, then close
your mouth on the frisbee," he instructs. "After that
... return!"
The dog bounds across the yard, only to return with nothing in his mouth. The frisbee had been 2 cm farther forward than the man said--but the dog couldn't make that small adjustment on its own. So the man gives his long-winded instructions again, substituting "ten-point-five-two" this time.
Right: Rover plays fetch with a frisbee. Image credit
and copyright: Lawrence Manning.
Playing fetch this way is no fun at all.
|
The Sojourner rover that explored Mars' surface in 1997 operated much like our clueless canine. Teams of scientists here on Earth had to feed Sojourner precise, step-by-step instructions for each task it performed. If the rover hit a snag, it would just stop and wait. The scientists then had to tell it exactly how to overcome the problem. It took days just to get simple tasks done.
Sojourner was nevertheless successful thanks to the ingenuity and patience of its controllers. Yet much more was possible. If we're serious about exploring the solar system, say mission planners, we must build smarter and more capable robots.
Common Sense Robots
"During the next decade," says NASA Ames roboticist
Liam Pedersen, "there's not likely to be a human presence
much beyond Earth orbit. So if we wish to explore places like
Mars, we'll have to send robots. No robots, no exploration. Period."
"Transmitting
detailed instructions to essentially dumb robots is grossly inefficient
and expensive--especially when there's lots to do," he adds.
For example: Robots scouting Mars, perhaps in advance of human
explorers, will reconnoiter vast areas. They'll sample hundreds
of rocks, drill holes in search of frozen water, and take thousands
of pictures. "If each of these operations takes several
days and a standing army of mission controllers ... well, you
can see how the cost increases."
Above: In 1997, the Sojourner rover "sniffs" a Martian rock named Yogi. [more]
The first humans on Mars will be just as busy as the scouts that precede them. Astronauts will have to set up the first base camp on an alien world and learn to survive in a place that makes Antarctica seem mild. And while they're at it, they'll collect thousands of measurements for scientists back on Earth.
"An astronaut's time will be more precious than edible gold," says Pedersen."They're going to need smart robot helpers."
How smart? The kind of intelligence that we usually take for granted in animals would do fine, says Pedersen. Animals effortlessly distinguish the objects in their environment based on the input of their senses. They can recognize threats, and they intuitively understand how objects move and behave. They can identify goals--like a little scurrying morsel of food--and then plan and perform all the actions needed to get it. And they know their own limitations of energy, strength, temperature, and endurance, and they're careful not to exceed these.
Getting a robot to do all this is not easy.
Above: An artist's concept of human and robot explorers
working together on Mars. Credit: John
Frassanito & Associates.
Pedersen says, "try teaching this simple lesson to a robot:
'You can't turn a glass of water upside-down because the water
will fall out.' To us, that's extremely obvious. It's common
sense. But if you want a machine to understand that, you've got
to spell it out in painful detail."
The computer brains of conventional robots operate in basically
the same way as home computers do: They execute a fixed program
of "if-then" logic and computations. The speed and
precision of this approach makes computers extremely good at
narrow, specialized tasks. But it also makes them inflexible.
Confront a conventional robot with a situation outside the scope
of its programming, and it's clueless about how to respond.
The adaptability and novel problem-solving ability of humans
(and many animals) has proven very hard to reproduce.
Learning from experience
Nevertheless, a patchwork of approaches to more-flexible computing
has emerged. Among these are technologies like probability theory,
evolutionary computing, natural language recognition and neural
networks. Each provides a way to add learning or flexibility
to a robot.
For example, scientists at Carnegie Mellon University taught
a robot to steer a car autonomously for 98% of a drive across
the U.S.--a project cleverly called "No Hands Across America."
They first trained the robot by letting it ride along and watch
as a human drove the car. The robot learned to associate certain
visual inputs with the correct steering responses.
The
"brain" of this robot was a computer simulation of
a neural network, which mimics in a rudimentary way the architecture
of animal brains. Input signals are processed by webs of "nodes"
(neurons) and "links" (axons). Neural networks learn
from experience and can associate general inputs with specific
outputs: four legs + a bark (the inputs) = a dog (the output),
for instance.
Right: a simple example of a neural network. Input signals enter from the left, pass through the two processing layers, then emerge on the right as output signals. This architecture can perform surprisingly sophisticated logic, especially when feedback loops are added. [more]
Pedersen cautions that the inner workings of organic brains are too poorly understood to mimic precisely. "While neural networks are in some ways similar to organic brains," he says, "they remain vastly less complex or capable."
Probability theory, especially Bayesian statistics, provides
another path to machine learning, says Pedersen. It allows computers
to operate not only in terms of black and white--true or false--but
also in shades of gray. Machines that "think" using
such statistical models learn well from new and unexpected experiences.
("This is where I would consider the excitement to be in
robotics," notes Pedersen. "Watch out for an explosion
in robot capabilities.") 
Yet another possibility is evolutionary
computing, in which computers "evolve" their own software.
"Mutants" of an original program are tried, and those
that produce better results are preserved. Their code is then
mixed and mutated again--like sexual reproduction--to produce
the next "generation," and so on for hundreds or thousands
of generations. This software "evolution" can produce
very effective problem-solving programs that are too complex
for the scientists themselves to understand.
Above: The human brain--we all have one, yet its inner workings are mysterious. Learning more about organic brains might help researchers program smarter robots. Image credit: Grey's Anatomy.
These and other novel approaches to computing form the foundation
for smarter, more autonomous robots. Scientists draw from this
toolbox to build into robots those abilities that we take so
much for granted in ourselves:Â understanding the meaning
of spoken language, figuring out all the little actions needed
to complete a task, navigating across terrain and avoiding dangers--the
nitty-gritty of autonomous exploration.
In search of R2-D2
Progress is indeed being made. One prototype robot called Hyperion
has shown the ability to autonomously traverse the terrain of
the Canadian Arctic. Developed by researchers at Carnegie Mellon's
Robotics Institute, this robot carefully navigates to avoid being
caught in shadows, so that its solar panels are always receiving
sunlight. And it's smart enough to know when it's lost or in
trouble.
Another experimental
robot, called the Extra-Vehicular Activity Robotic Assistant
(ERA), is a true astronaut partner--roving on wheels side-by-side
with a space-suited human. Scientists at the Johnson Space Center
are using it to test advanced technologies like natural-language
interaction and recognition of astronauts' gestures. Much of
what they learn will help design similar assistants, not only
for planetary surfaces, but also for Earth orbit and deep space.
Right: NASA's Extra-Vehicular Robotic Assistant alongside a space-suited astronaut. The pair are true partners in exploration. [more]
Notes Pedersen: "Here at Ames we're working on a rover
called K9 that will be able to do many things on its own. It
can look at rocks, make measurements, and decide what's 'interesting.'
K9 is a technology testbed for the 2003 Mars Exploration Rovers
and for the 2009 Mars Science Laboratory (a.k.a. the Mars Smart
Lander and Mobile Laboratory).
Other experimental robots are pioneering a different frontier:
life onboard a spaceship. The Personal Satellite Assistant (PSA),
for example, is a small floating sphere that can propel itself
using fans through a spaceship's corridors. Created by Yuri Gawdiak
and colleagues at NASA Ames, the PSA looks remarkably like Luke
Skywalker's robotic light-saber sparring partner from Stars
Wars. That's no coincidence, says Gawdiak, who dreamed up
the PSA after watching the movie.
The PSA will be able to do many things: talk to astronauts who want information from the ship's main computer; monitor the air (like a canary in a coal mine) for concentrations of potentially harmful gases, e.g., too much CO2; or simply venture into situations that might be too dangerous or uncertain for their human crewmates. Such high-tech helpers would be welcomed on the International Space Station.
Below: (left) An artists' concept of Robonaut working outside a spaceship. (center) Yuri Gawdiak of NASA Ames and his Personal Satellite Assistant. (right) The smart rover K9 during field tests at NASA Ames.
Other robots are best-suited for duty outside the spaceship.
Robonaut, for example, is under development at the Johnson Space
Center. It has the basic shape of a human--or rather a half-human.
Its body stops at the waist. Its arms and hands are designed
to be very dexterous, and its head contains video cameras. Astronauts,
safely inside their ship, could perform routine maintenance or
important repairs to the outside of the ship using Robonaut as
a remote-controlled proxy.
If robots are going to live onboard spaceships, notes Pedersen,
then the spaceships must be designed with robots in mind. "The
need for this kind of system-level design--designing the robot
and the spaceship to each suit the other--is often overlooked
by non-experts," he says. The ship must have facilities
for recharging and storing the robot, and the robot must be able
to access the ship's computers and handle any necessary equipment.
The International Space Station and its robotic arm, Canadarm2, are an example of a well-integrated system. The arm crawls on the outside of the station--flipping end over end like an inchworm from one specially-placed handhold to the next. A custom-made trolley can quickly transport the arm from place to place when speed is of the essence.
Canadarm2
is impressive, but like Sojourner on Mars it is neither smart
nor autonomous. The arm moves only when commanded by a human.
Right: Working together. Astronaut Jerry Ross floats above Earth, attached to one end of Canadarm2. [more]
The main reason for the gap in "smarts" between
the robots in scientists' laboratories (like K9) and those that
have flown in space is a lack of proven reliability. Pedersen
explains: "The problem is that these advanced technologies
do not have any flight history. Will they work under the demanding
conditions of spaceflight? Mission managers are rightly conservative;
they prefer to stick with well-proven solutions."
With time and field testing, though, the best among these technologies
will prove their mettle--or rather, their silicon. Good thing,
too, because future astronauts are going to want their silicon
sidekicks.
Robot links: Hyperion (Carnegie Mellon Robotics Institute); K9 (NASA Ames); Extra-Vehicular Robotic Assistant (NASA JSC); Personal Satellite Assistant (NASA Ames); Canadarm2 (Canadian Space Agency); Robonaut (NASA JSC)
Brainy 'Bots --Science@NASA article: NASA's own "Bionic Woman" is applying artificial intelligence to teach robots how to behave a little more like human explorers.
Building a "Droid" for the ISS --Science@NASA article: Inspired by science fiction classics, NASA scientists are building a talking, thinking and flying robot to help astronauts with their chores in space.
Learn more about Evolutionary Computation and Neural Networks from the Pacific Northwest National Laboratory.
Mars Rovers -- (JPL) amazing rovers--past, present and future. See also Advanced Rover Conceptsfrom JPL's Artificial Intelligence Group
Artificial Intelligence -- a subject guide from the Goddard Library
Join our growing list of subscribers - sign up for our express news deliveryand you will receive a mail message every time we post a new story!!!
Headlines