Engineers
at NASA's Goddard Space Flight Center (Greenbelt,
MD) have successfully tested a shape-shifting
robotic pyramid. Robots of this type will eventually
be miniaturized and joined together to form "autonomous
nanotechnology swarms" (ANTS) that alter
their shape to flow over rocky terrain or to create
useful structures like communications antennae
and solar sails.
The robot is called "TETwalker" for
tetrahedral walker, because it resembles a tetrahedron
(a pyramid with three sides and a base). In the
prototype, electric motors are located at the
corners of the pyramid, which are called nodes.
The nodes are connected to struts, which form
the sides of the pyramid. The struts telescope
like the legs of a camera tripod, and the motors
in the nodes are used to expand or retract the
struts. This allows the pyramid to move: changing
the length of its sides alters the pyramid's center
of gravity, causing it to topple over. The nodes
also pivot, giving the robot great flexibility.
Engineers Ken Lee (right, foreground)
and Caner Copperrider work on the TETwalker prototype
at NASA's Goddard Space Flight Center. (NASA)
The team
anticipates TETwalkers can be made much smaller
by replacing their motors with micro- and nanoelectromechanical
systems. Replacement of the struts with metal
tape or carbon nanotubes will not only reduce
the size of the robots, it will also greatly increase
the number that can be packed into a rocket because
tape and nanotube struts are fully retractable,
allowing the pyramid to shrink to the point where
all its nodes touch.
These miniature TETwalkers, when joined together
in "swarms," will have great advantages
over current systems. The swarm has abundant flexibility
so it can change its shape to accomplish highly
diverse goals. For example, while traveling through
a planet's atmosphere, the swarm might flatten
itself to form an aerodynamic shield. Upon landing,
it can shift its shape to form a snake-like swarm
and slither away over difficult terrain. If it
finds something interesting, it can grow an antenna
and transmit data to Earth. Highly collapsible
material can also be strung between nodes for
temperature control or to create a deployable
solar sail.
