by David Geer
Contact the author at geercom@alltel.net
Intellibot Robotics IV800 Vacuum
Makes Autonomous Clean Sweep
The Intellibot Robotics autonomously operating IV800 Vacuum was
designed to cut commercial floor care labor costs by up to 85 percent.
According to David Knuth,
director of engineering at
Intellibot Robotics, the IV800 is
an autonomous mobile floor vacuum
with an off-the-shelf, single board
computer running navigation software
and communications to several sensor
and control subsystems.
The sensor subsystems collect data
about the surrounding environment,
including the floor (or lack thereof,
such as stairs and stairwells). The
processor uses that data to make
decisions about how to move and
control the cleaning effectors, which
include the main broom, side broom,
and vacuum motors, according to
Knuth. The processor sends those
commands to the control subsystems.
The robot’s sensor subsystems
include an ultrasonic sonar array, an
angular rate sensor (also known as a
gyroscope), contact sensors, and
infrared distance sensors used to
detect the presence of the floor to
avoid a flight of stairs, for example.
The sonar arrays and angular sensor
provide data to the navigation engine
so it can calculate the robot’s path. The
sonars are also the primary sensors for
detecting and avoiding obstacles.
control for speed and direction to
each wheel. This allows the machine
to move forward, backward, and turn
or pivot in place simply by varying the
speed and direction of each wheel.
No More Slip
Sliding Away!
A Sense of Touch
If for some reason a sonar does
not get a reflection from an obstacle,
the contact sensors found in the
touch shield provide a backup sensor
to alert the robot to an object’s
presence. The robot needs a variety of
sensors and wide coverage pattern to
achieve total floor domination.
“Unlike most mobile
robots, our machine does not
simply move from point A to
point B, but must cover the
floor surface completely in a
given area. That’s what sets
our machine apart and that’s
where the challenges are,”
says Knuth.
The sensor technology
also includes positional
feedback from the drive
wheels that tells the machine
how much each wheel has
turned, as the robot uses a
differential drive. This type of
drive provides independent
Here is a close-up of a front sensor array from
one of the Intellibot Floor Care Robots. The
robots use arrays of sonar and infrared sensors
to map rooms and avoid objects and stairs.
One challenge for the industrial
vacuum robot’s maneuverability is
wheel slippage. “When the drive
wheels slip, they can report that the
robot has traveled a certain distance
when in reality it hasn’t traveled that
far,” explains Knuth. Using data from
the sensor subsystems can help the
robot to know whether it has traveled
the correct distance.
To determine its course of direction,
the robot uses an angular rate sensor
that tells it how fast it is rotating. The
robot uses this information when it is
purposely turning or pivoting to determine when the maneuver is complete.
“The software on the SBC makes
decisions about 20 times per second
about how the robot should respond
to the various sensor inputs. The
decision may be to continue on the
current course, stop because of an
obstacle, or turn to avoid something
that doesn’t move out of the path of
the machine,” says Knuth.
Homegrown Software
The robot’s software runs on a
10 SERVO 09.2008
