An Autonomous Firefighting Robot

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Abstract
Firefighting is an important but
dangerous occupation. A firefighter must be
able to get to a fire quickly and safely
extinguish the fire, preventing further
damage and reduce fatalities. Technology
has finally bridged the gap between
firefighting and machines allowing for a
more efficient and effective method of
firefighting. Robots designed to find a fire,
before it rages out of control, could one day
work with firefighters greatly reducing the
risk of injury to victims. The IEEE
SOUTHEASTCON 2003 Hardware
Competition tests the minds of college
students all over the nation with the
challenge of extinguishing a fire located in a
simulated house autonomously.



Introduction
The firefighting robot is designed to search
for a fire in a small floor plan of a house,
extinguish the fire (by placing a cup over the
LEDs), and then return to the front of the
house. This mission is divided into smaller
tasks, and each task is implemented in the
most efficient manner. The navigation of
the robot throughout the house is achieved
by data provided by a line tracker and
ultrasound transducers. The target
acquisition is achieved by data provided by
a camera. The deployment of the
extinguishing device is implemented with a
custom arm controlled by servos. Along
with these crucial tasks were other design
constraints, such as the size, speed, and
supply of power. Each defining
characteristic of the robot is described in
more detail in this document.

2. Software Design
The software for the robot was coded in C,
because of compiler availability, our
familiarity with the language, as well as the
greater control of the system offered as
compared to other higher languages. While
our Microcontroller supports assembly, it
was avoided because it’s a difficult to
maintain, and varies greatly from processor
to processor. C allowed us to easily break
apart the components of software design so
that different members of the team could
code the system. The software design had
four major components, including
interfacing its peripherals, control of its
motors and servos, navigation, and target
acquisition.


Target Acquisition
The CMUcam is used for video processing.
The CMUcam provides a way to recognize
if the candle is in the robot’s field of view,
and the position of the candle relative to the
robot. On entering a room, the camera is
used to detect the presence of a candle,
based on whether or not an object in view
meets the color criteria. The robot makes
one rotation in search of the candle. If the
robot detects the candle, robot proceeds to
track the candle until it is at the correct
distance. Otherwise, the robot exits the
room and continues with the navigation
routine.


Arm Design
A HiTec HS-55 MicroLite servo was used
as our elevation servo. The function of this
servo is to extend and retract our arm. This
servo not only had to be strong enough to
withstand the extra weight that is added by
torque, but the addition of the extinguishing
agent (the cup). We also needed this servo to
be compact and lightweight. Two HS-50
HiTec Feather servos were also used. These
provide half the torque of the HS-55 servos,
however we did not need a great deal torque
since the lower extremity of the arm
wouldn’t be stressed as much.