Utility Fog: The Stuff that Dreams are Made Of
Source: Rutgers University Nanotechnology is based on the concept of tiny,
self-replicating robots. The Utility Fog is a very simple extension of
the idea: Suppose, instead of building the object you want atom by
atom, the tiny robots linked their arms together to form a solid mass
in the shape of the object you wanted? Then, when you got tired of
that avant-garde coffeetable, the robots could simply shift around a
little and you'd have an elegant Queen Anne piece instead.
The color and reflectivity of an object are results of
its properties as an antenna in the micron wavelength region. Each
robot could have an "antenna arm" that it could manipulate to vary
those properties, and thus the surface of a Utility Fog object could
look just about however you wanted it to. A "thin film" of robots
could act as a video screen, varying their optical properties in real
time.
Rather than paint the walls, coat them with Utility Fog
and they can be a different color every day, or act as a
floor-to-ceiling TV. Indeed, make the entire wall of the Fog and you
can change the floor plan of your house to suit the occasion. Make the
floor of it and never gets dirty, looks like hardwood but feels like
foam rubber, and extrudes furniture in any form you desire. Indeed,
your whole domestic environment can be constructed from Utility Fog;
it can form any object you want (except food) and whenever you don't
want an object any more, the robots that formed it spread out and form
part of the floor again.
You may as well make your car of Utility Fog, too; then
you can have a "new" one every day. But better than that, the
*interior* of the car is filled with robots as well as its shell.
You'll need to wear holographic "eyephones" to see, but the Fog will
hold them up in front of your eyes and they'll feel and look as if
they weren't there. Although heavier than air, the Fog is programmed
to simulate its physical properties, so you can't feel it: when you
move your arm, it flows out of the way. Except when there's a crash!
Then it forms an instant form-fitting "seatbelt" protecting every inch
of your body. You can take a 100-mph impact without messing your hair.
But you'll never have a 100-mph impact, or any other
kind. Remember that each of these robots contains a fair-sized
computer. They already have to be able to talk to each other and
coordinate actions in a quite sophisticated way (even the original
nano-assemblers have to, to build any macroscopic object). You can
simply cover the road with a thick layer of robots. Then your car
"calls ahead" and makes a reservation for every position in time and
space it will occupy during the trip.
As long as you're covering the roads with Fog you may as
well make it thick enough to hold the cars up so they can cross
intersections at different levels. But now your car is no longer a
specific set of robots, but a *pattern* in the road robots that moves
along like a wave, just as a picture of a car moves across the pixels
of a video screen. The appearance of the car at this point is
completely arbitrary, and could even be dispensed with--all the road
Fog is transparent, and you appear to fly along unsupported.
If you filled your house in with Fog this way, furniture
no longer need be extruded from the floor; it can appear instantly as
a pattern formed out of the "air" robots. Non-Fog objects can float
around at will the way you did in your "car". But what's more, your
surroundings can take on the appearance, and feel, of any other
environment they can communicate with. Say you want to visit a friend;
you both set your houses to an identical pattern. Then a Fog replica
of him appears in your house, and one of you appears in his. The "air"
fog around you can measure your actions so your simulacrum copies them
exactly.
The pattern you both set your houses to could be
anything, including a computer-generated illusion. In this way,
Utility Fog can act as a transparent interface between "cyberspace"
and physical reality.
Tech Specs
Active, polymorphic material ("Utility Fog") can be
designed as a conglomeration of 100-micron robotic cells ("foglets").
Such robots could be built withthe techniques of molecular
nanotechnology (see Drexler, "Nanosystems", Wiley, 1992). Using
designs from that source, controllers with processing capabilities of
1000 MIPS per cubic micron, and electric motors with power densities
of one milliwatt per cubic micron are assumed.
Each Foglet has twelve arms, arranged as the faces of a
dodecahedron. The central body of the foglet is roughly spherical, 10
microns in diameter. The arms are 5 microns in diameter and 50 microns
long. A convex hull of the foglet approximates a 100-micron sphere.
Each Foglet will weigh about 20 micrograms and contain about 5
quadrillion atoms. Its mechanical motions will have a precision of
about a micron.
The arms telescope rather than having joints. The arms
swivel on a universal joint at the base, and the gripper at the end
can rotate about the arm's axis. The gripper is a hexagonal structure
with three fingers, mounted on alternating faces of the hexagon. Two
Foglets "grasp hands" in an interleaved six-finger grip. Since the
fingers are designed to match the end of the other arm, this provides
a relatively rigid connection; forces are only transmitted axially
through the grip. When at rest, foglets form a lattice whose structure
is that of a face-centered cubic crystal (i.e. an octet truss).
For a mass of Utility Fog to flow from one shape to
another, or to exert dynamic forces (as in manipulating objects), a
laminar flow field for the deformation is calculated. The foglets in
each lamina remain attached to each other, but "walk" hand over hand
across the adjacent layers. Although each layer can only move at a
speed differential of 5 m/s with its neighbor, the cumulative shear
rate in a reasonable thickness of Fog is considerable, up to 500 m/s
per centimeter of thickness.
The atomically-precise crystals of the foglets'
structural members will have a tensile strength of at least 100,000
psi. As an open lattice, the foglets occupy only about 3% of the
volume they encompass. When locked in place, the Fog has a more or
less anisotropic tensile strength of 1000 psi. In motion, this is
reduced to about 500 if measured perpendicular to the shear plane. As
a bulk material it has a density of 0.2 g/cc.
Without altering the lattice connectivity, Fog can
contract by up to about 40% in any linear dimension, reducing its
overall volume by a factor of five. (This is done by retracting all
arms simultaneously.) Selective application of this technique allows
Fog to simulate shapes and flow fields to a precision considerably
greater than 100 microns.
An appropriate mass of Utility Fog can be programmed to
simulate most of the physical properties of any macroscopic object
(including air and water), to roughly the same precision those
properties are measured by human senses. The major exceptions are
taste, smell, and transparency. The latter an be overcome with
holographic "eyephones" if a person is to be completely embedded in
Fog.
Consider the application of Utility Fog to a task such
as telepresence. The worksite is enclosed in a cloud of Fog, which
simulates the hands of the operators to assemble the parts and
manipulate tools. The operator is likewise completely embedded in Fog.
Here, the Fog simulates the objects that are at the worksite, and
allows the operator to manipulate them.
The Fog can also support the operator in such a way as
to simulate weightlessness, if desired. Alternatively, the Fog at the
worksite could simulate the effect of gravity on the objects there (in
any desired direction).
http://nanotech.rutgers.edu/nanotech/Ufog.html