Page 23 - Hacking Roomba

4 Part I — Interfacing

Originally released as just Roomba in 2002, the Roomba design and functionality have evolved
over the years. Currently there are five varieties of Roomba available with names like Roomba
Discovery and Roomba Red. According to iRobot, with over 2 million units sold, not only is
Roomba one of the most successful domestic robots to date, it is also one of the very few robots
to have sold over a million units. This accomplishment is the result of a long evolutionary
process of robotics design at the iRobot Corporation.

iRobot Corporation

The creators of Roomba have been making robots for over 15 years. iRobot was founded by
Rodney Brooks, Colin Angle, and Helen Greiner. These three MIT alumni have been instru-
mental in guiding robotics research for many years, not only through their research but also
through the practical application of their ideas through iRobot.

Subsumption Architecture
Rodney Brooks coined the term subsumption architecture in 1986 in his classic paper “Elephants
Don’t Play Chess.” This paper began a shift in artificial intelligence research. At the time it was
believed that to create a thinking machine, one needed to start with a symbolic representation
of its world from some set of base principles. (For example, a robot butler having a built-in map
of a house would be a kind of basic symbol.) This top-down view of cognition is opposite to
how nature works: When we enter a new house, we must explore and build up our own unique
perception of how to get from place to place. Brooks codified a bottom-up, behavior-based
approach to robotics.

In subsumption architecture, increasingly complex behaviors arise from the combination of
simple behaviors. The most basic simple behaviors are on the level of reflexes: “avoid an object,”
“go toward food if hungry,” and “move randomly.” A slightly less simple behavior that sits on
top of the simplest may be “go across the room.” The more complex behaviors subsume the less
complex ones to accomplish their goal.

Genghis and PackBot
In 1990 while at MIT, Rodney Brooks and iRobot created the Genghis Robot, an insect-like
robot with six legs and compound eyes. It was a research platform that bucked the trend in
artificial intelligence at the time by using Brook’s subsumption architecture. Genghis was
designed from an evolutionary perspective instead of the normal high-level cognition perspec-
tive of traditional AI. It looked and acted like an insect. This behavior-based robotics architec-
ture would inform the design of all future iRobot robots.
From Genghis, iRobot developed a few other research robots but quickly moved into devel-
oping robots for real-world use. iRobot has had great success with their PackBot, a series of
ruggedized telepresence (able to withstand harsh outdoor environments and remotely con-
trolled) and autonomous robots for the military and law enforcement. Instead of sending sol-
diers or a SWAT team into a dangerous area, the PackBot can be pulled from a backpack and
thrown into the area. With its onboard video and audio sensors, the area can be inspected
without risking a life. The PackBot can withstand 400+ gs of force. This makes it much