Robotics Reference
In-Depth Information
and Helen Greiner. In Europe Electrolux have also had a success in this
market, though a more modest one, with its Trilobite
TM
cleaner.
The intelligence displayed by these vacuum cleaners does not exactly
set the products at the high IQ level but is more a demonstration of
features based on common sense. One essential feature is that a cleaner
robot should be able to navigate around a room without bumping into
objects, a task easily accomplished in various ways, for example by using
ultrasonic signals—a kind of radar. While navigating a room a robot
cleaner can work its way along the walls in order to build up an internal
map of the outline of the room, and then, as it encounters part of an
object, it can note on its map exactly where that part of the object is
located. As the map of the room becomes more detailed, so the robot is
able to devise the most efficient route to clean it.
A sound recognition system is employed in some models to identify
areas on the floor that have a higher than usual concentration of dust,
which is detected by the different sounds that the cleaner hears as the
dust bounces off the machine's chassis.
12
When it finds an especially
dirty area of the floor, the cleaner focuses its efforts on that area until a
change in the sound reveals that the excessive dust has been removed.
One problem with some early models of cleaner robots was that they
would fall down flights of stairs simply because they did not know that
the stairs were there. This problem has been cured by the development
of a simple idea called a
virtual wall
—if the robot's infra-red detectors
finds a gap in a wall the robot assumes that danger lurks and inserts in its
map of the room a virtual wall that it knows to avoid in the future.
Robot Lawn Mowers
Mowing a lawn is similar to cleaning a carpet and so conceptually there
is very little difference between robot vacuum cleaners and lawn mowers,
the other early example of robots performing a household chore. Several
models of robot lawnmower have been launched, incorporating various
features to make them suitable for outdoor use. For example, some mod-
els have a rain sensor and know to take shelter when it is raining.
As with so many other areas of robotics, the fashion for competi-
tions to test the latest developments in the field has also been extended
to robot lawnmowers. The Satellite Division of the U.S. Institute of
12
This is a much simpler form of the technology employed for speech recognition (see the section
“Speech Recognition” in Chapter 4).
