James McLurkin's Research Projects
Robotics — The Next Generation
Much of the current robotics research aims to create practical robots that
can function in today’s society. Through the advent of robots designed to
perform certain human tasks, robots can be deployed for difficult and
dangerous missions that may otherwise jeopardize human lives.
Swarm Reporting for Duty
To create robots that can explore caves, landmines or even Mars, the robots
must be plentiful and autonomous. The Swarm, a fleet of 100 robots, runs on
the Swarm Operating System (SwarmOS), which is based on distributed
algorithms that allow the input or commands to be divided among multiple
recipients. This software is also scalable, so that the number of robots in
the swarm can increase or decrease without affecting the work
accomplishments of the group. While a centralized system is easier to
program and control, it is not readily scalable and thus does not react well
if one member of the group fails to perform during the task. Distributed
algorithms also set the platform for local communications among the robots
so each can work independently toward achieving one common goal.
Mother Nature’s Secrets
As lead scientist at iRobot, McLurkin began the Swarm project in 1999 with
colleagues Jim Frankel and Jennifer Smith. The aptly named Swarm was
inspired by the biology of bees and ants, both swarm insects that are
reproductive labors and work autonomously but toward a common goal such as
collecting nectar. The Swarm was a progression of McLurkin’s robotic ants,
which he built as a freshman at MIT. Software research for the Swarm was
sponsored by the Defense Advanced Research Projects Association (DARPA) from
Off To Work They Go
The Swarm project is a hardware simulation, in which the software is written
and tested on a real swarm robot prototype. The five-cubic inch robots are
equipped with light sensors, drive motors, a bump skirt and more. In
deploying the Swarm, hands-free maintenance is crucial and implemented with
Robot Ecology™, a physical extra-structure composed of a beacon navigation,
camera, testing station, and chargers to enable the Swarm to work at its
optimal performance, sans direct human contact. The beacon navigation is a
long-range navigation center that acts like a compass to inform the swarm
where they are going — particularly used to direct the robots to the docking
stations to charge. The beacon is turned to guide the robots in the correct
path of the dock. The chargers along the docking station resemble the
robots, so that the Swarm will be attracted to them when they need to
refuel. It is critical that the chargers are hands-free, because it would be
an overwhelming task to charge 100+ robots by hand — impeding work by the
The Art of Communicating
LEDs, radio and audio serve as output to keep humans informed of what the
Swarm is doing while at work. Illustrating feedback through these methods
allows humans to watch the robots directly rather than study a computer
screen to observe their actions or see if anything has gone awry. Human
connection is made through the HIVE™ interface, a centralized system that
collects data, debugs, turns them on and off, and controls their functions.
During the tasks, certain robots can be designated as Swarm leaders to take
on a higher post and delegate specific orders among the fleet.
The Swarm robots communicate with each other via lateral inhibition (a
gradient communications system). Each robot has a unique serial number I.D.
When the robots are working in a small group, the robot with the lowest
number is usually appointed the leader and the other robots obey or
disregard its message based on their own I.D. being higher or lower with
respect to the number of the leader. The robots have a communications range
of approximately three feet. Hence, they use other robots as landmarks to
transmit information. The message will “hop” from the source to the targeted
receiver, using the shortest range possible. The message is disregarded by
the robots that pass the message along based on the number of each one’s
I.D. with respect to the source.
LEDs signify the behaviors of the robots. The tasks/commands can be
implemented as a primitive (single) being, duo or other numbers of groups.
The robots “clump” to form distinct groups to execute specified tasks. Some
examples of other typical commands are:Orient to robot
Follow the leader
Cluster (robots group into same spot)
In working with a fleet of robots, a multiple of navigational functions are
necessary, because generally all the robots would not be sent to the same
spot to do the same function. Instead different groups within the Swarm will
be assigned to specific tasks to get the job done.
Research on the Swarm is ongoing. Certain improvements that may be worked on
are increased accuracy with the commands and the ability of the robots to
travel in a straight line (when necessary). The Swarm represents the future
of robotics and will help humans to accomplish otherwise daunting tasks.
Click here for swarm videos.