Until now you can have big elaborate robots or very small microbots
but it is very difficult to have both. A blog
post from New Scientist (where this video is from) points out the
research on microbots, very small machines that will move, navigate and
perform simple tasks. The ability to remotely power a microbot, thus
eliminating the need for onboard battery or fuel, is already proven and
one of the methods is the application of an AC field to a liquid where
the robot is located. This microbot is essentially a diode, a one-way
electric conductor. The different electric charges at its ends force the
neighboring ions to move thus creating a small thrust that propels the
bot. The team of Rachita Sharma
and Orlin Velev from
North Carolina State University developed a method where a controlled
application of an additional DC field changes the ion distribution around
the microbot and this time the ion field creates a torque that rotates
the microbot. The DC field is applied until the completion of a
180-degree turn. Then the microbot moves again, now in the opposite
direction.
It is only 1.3mm long and as claimed by other scientists like
Vesselin Paunov
from the University of
Hull, UK this arrangement can be further scaled down where it can be
useful for diagnostic and localized drug supply applications.