I definitely
want a box of these for Christmas. And
once again we have a delightful solution suggested by theoretical
considerations now out in search of a problem beyond the obvious one of
providing wondrous Christmas presents.
It should be
possible to generate complex blocks in nXnXn matrices that disassemble into
complex configurations able to challenge puzzle players forever. Better yet make it color coded as well and we
will drive everyone crazy. Sudoku on
steroids.
Can you just see
a swarm of these charging a wall and swiftly building a step system to allow
most to pass over the wall?
Go for it. They are coming and by the by this likely
means real robots are now possible.
Surprisingly
Simple Scheme for Self-Assembling Robots
Oct. 4, 2013 — Small cubes with no exterior
moving parts can propel themselves forward, jump on top of each other, and snap
together to form arbitrary shapes.
In 2011, when an MIT senior named John Romanishin
proposed a new design for modular robots to his robotics professor, Daniela
Rus, she said, "That can't be done."
Two years later, Rus showed her colleague Hod
Lipson, a robotics researcher at Cornell University, a video of prototype
robots, based on Romanishin's design, in action. "That can't be
done," Lipson said.
In November, Romanishin -- now a research scientist
in MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL) --
Rus, and postdoc Kyle Gilpin will establish once and for all that it can be
done, when they present a paper describing their new robots at the IEEE/RSJ
International Conference on Intelligent Robots and Systems.
Known as M-Blocks, the robots are cubes with no
external moving parts. Nonetheless, they're able to climb over and around one
another, leap through the air, roll across the ground, and even move while
suspended upside down from metallic surfaces.
Inside each M-Block is a flywheel that can reach
speeds of 20,000 revolutions per minute; when the flywheel is braked, it
imparts its angular momentum to the cube. On each edge of an M-Block, and on
every face, are cleverly arranged permanent magnets that allow any two cubes to
attach to each other.
"It's one of these things that the
[modular-robotics] community has been trying to do for a long time," says
Rus, a professor of electrical engineering and computer science and director of
CSAIL. "We just needed a creative insight and somebody who was passionate
enough to keep coming at it -- despite being discouraged."
Embodied
abstraction
As Rus explains, researchers studying reconfigurable
robots have long used an abstraction called the sliding-cube model. In this model,
if two cubes are face to face, one of them can slide up the side of the other
and, without changing orientation, slide across its top.
The sliding-cube model simplifies the development of
self-assembly algorithms, but the robots that implement them tend to be much
more complex devices. Rus' group, for instance, previously developed a modular
robot called the Molecule, which consisted of two cubes connected by an angled
bar and had 18 separate motors. "We were quite proud of it at the
time," Rus says.
According to Gilpin, existing modular-robot systems
are also "statically stable," meaning that "you can pause the
motion at any point, and they'll stay where they are." What enabled the
MIT researchers to drastically simplify their robots' design was giving up on
the principle of static stability.
"There's a point in time when the cube is
essentially flying through the air," Gilpin says. "And you are
depending on the magnets to bring it into alignment when it lands. That's something that's totally unique to this
system."
That's also what made Rus skeptical about
Romanishin's initial proposal. "I asked him build a prototype," Rus
says. "Then I said, 'OK, maybe I was wrong.'"
Sticking the
landing
To compensate for its static instability, the
researchers' robot relies on some ingenious engineering. On each edge of a cube
are two cylindrical magnets, mounted like rolling pins. When two cubes approach
each other, the magnets naturally rotate, so that north poles align with south,
and vice versa. Any face of any cube can thus attach to any face of any other.
The cubes' edges are also beveled, so when two cubes
are face to face, there's a slight gap between their magnets. When one cube
begins to flip on top of another, the bevels, and thus the magnets, touch. The
connection between the cubes becomes much stronger, anchoring the pivot. On
each face of a cube are four more pairs of smaller magnets, arranged
symmetrically, which help snap a moving cube into place when it lands on top of
another.
As with any modular-robot system, the hope is that
the modules can be miniaturized: the ultimate aim of most such research is
hordes of swarming microbots that can self-assemble, like the "liquid
steel" androids in the movie "Terminator II." And the simplicity
of the cubes' design makes miniaturization promising.
But the researchers believe that a more refined
version of their system could prove useful even at something like its current
scale. Armies of mobile cubes could temporarily repair bridges or buildings
during emergencies, or raise and reconfigure scaffolding for building projects.
They could assemble into different types of furniture or heavy equipment as
needed. And they could swarm into environments hostile or inaccessible to
humans, diagnose problems, and reorganize themselves to provide solutions.
Strength in
diversity
The researchers also imagine that among the mobile
cubes could be special-purpose cubes, containing cameras, or lights, or battery
packs, or other equipment, which the mobile cubes could transport. "In the
vast majority of other modular systems, an individual module cannot move on its
own," Gilpin says. "If you drop one of these along the way, or
something goes wrong, it can rejoin the group, no problem."
"It's one of those things that you kick
yourself for not thinking of," Cornell's Lipson says. "It's a
low-tech solution to a problem that people have been trying to solve with
extraordinarily high-tech approaches."
"What they did that was very interesting is
they showed several modes of locomotion," Lipson adds. "Not just one
cube flipping around, but multiple cubes working together, multiple cubes
moving other cubes -- a lot of other modes of motion that really open the door
to many, many applications, much beyond what people usually consider when they
talk about self-assembly. They rarely think about parts dragging other parts --
this kind of cooperative group behavior."
In ongoing work, the MIT researchers are building an
army of 100 cubes, each of which can move in any direction, and designing
algorithms to guide them. "We want hundreds of cubes, scattered randomly
across the floor, to be able to identify each other, coalesce, and autonomously
transform into a chair, or a ladder, or a desk, on demand," Romanishin
says.
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