by David Geer
Contact the author at firstname.lastname@example.org
Kilobot Swarm Robots
A Swarm You Can Program, Power Up, and Charge Collectively
The idea behind swarms of robots is that they can accomplish more together
than they could individually. This only works if the number of robots that
can be programmed and managed in a swarm collectively (rather than
individually) scales up easily to hundreds and thousands of robots that can
accomplish massive tasks.
Until now, swarms have not been up to the task due to the cost of multiple
robots, assembly time, and the simple lack of a way to program them,
start them up, and recharge them as a group (rather than one by one).
Kilobots bring us a step closer with affordable robots ($14 each) that can
be assembled in five minutes each and which can scale up (for now) to a
collective of 25 robots working together.
The roboticists in the Computer Science Group at
Harvard University designed Kilobots so each could move in
an environment, run a “user defined” program,
communicate with neighboring Kilobots, measure the
distance to its neighbors, display something about its
internal state to assist with debugging, and allow for
scalable operations, according to the paper, “Kilobot: A Low
Cost Scalable Robot System for Collective Behaviors” by
Michael Rubenstein, Nicholas Hoff, and Radhika Nagpal.
Bottom of a Kilobot with three
legs and circuitry.
To enable these capabilities, the designers endowed the
robots with vibration motors, lithium-ion batteries, rigid
supporting legs, infrared transmitter/receivers, and three-color RGB LEDs. The robot test environment included 25
Kilobots, a laptop-based control station, an overhead
controller unit, and a charging station on a flat, smooth,
level reflective table.
The simple means of movement for these robots is not
wheeled motion — as popular as that design option may be
— because it was simply too expensive. Instead, the robots
each have two “sealed coin-shaped vibration motors.”
When one of these motors is activated,
the centripetal forces generated by the
vibrating motor are converted to a forward
force on the Kilobot located at the motor’s
mounting location. The vibration of one motor
[causes] a rotation of the Kilobot about its
vertical axis in one direction, while the other
motor rotates the robot in the other direction.
This is an application of differential drive
where the robot can move forward, and in
clockwise and counterclockwise rotations,
according to the Kilobot paper.
While this method provides no “odometry”
and no measure of distance over time can be
made for individual robots, the collective can
Standing view of a Kilobot.
10 SERVO 10.2011