FireBot: An Autonomous First Responder
Group Project
Project Mentor: Dr. Michael Schuller, TAMU
Fall 2015 - Spring 2016
Item 1a: A SolidWorks Render of the complete FireBot, with labels identifying the major components
Item 1b: Overall dimensions of the assembled system.
ALL DIMENSIONS IN MM.
This is our senior capstone project. The 'FireBot' was designed and analyzed over the course of two semesters with a team of 4 students. I was the team lead on this project.
Update: Our project cleared the first round for the 2016 'Musabaka' design competition organized by National Instruments!
Motivation
In 2012, a fire at a daycare center at the Villagio Mall in Qatar was responsible for the death of 13 children. The fire had sealed off the only entrance to the center and consequently, two firemen also lost their lives trying to save the children. This tragedy rocked the entire nation of Qatar. Investigations revealed that the root cause was an electric fire at an adjacent clothing store, which spread because the untrained staff at site did not attempt to contain the fire, even though dry powder cylinders were available nearby. By the time the firefighters arrived, it was too late.
It was evident that if the fire had been subdued in its initial stages using the extinguishing cylinders, this disaster could've been averted. Consequently, we wanted to design a solution that functioned as an autonomous first responder. Moreover, we also wanted it be able to provide visual information to a remote operator from inside the fire affected area - information that could be crucial for firefighters for identifying safe passages. From this need arose the FireBot.
The long term goal of this project is to have a FireBot stationed in each room or floor of a building, much like how fire extinguishing cylinders are mounted on walls in hallways.
Need Statement
"Provide a means to detect, navigate towards, and extinguish indoor ‘ABC’ fires using existing extinguishants, with basic autonomy, while providing visual feedback to a remote operator. The solution will be used as a first responder within a multi-story building, and it should be portable and operable by two firefighters. It should be built within the allocated budget and be manufacturable in Qatar by April 2016, using existing technology."
Subsystems
For the complete Preliminary Design Report (including the Function Structure, Performance Requirements, FMEA, assembly drawings etc.,) click on the PDF icon at the bottom of the page.
The major subsystems of the FireBot are elucidated below.
Motion
The key demand placed on this subsystem was that it had to be robust enough to maneuver at least one flight of stairs, apart from agile navigation around a flat terrain (as on a level floor). While there are many dynamically complex robots that can climb stairs, they are often too slow for use in the case of a fire. So instead, we opted to use continuous tracks ('Caterpillar Wheels') coupled with a Christie suspension (similar to the ones used in military tanks!)
Item 1c: Closeup of the Navigation system design.
ALL DIMENSIONS IN MM.
Extinguisher
Since dry powder cylinders are widely available and since most malls, offices and residential buildings have already acquired them, part of our need statement requires that the proposed solution be able to interface with existing cylinders. Consequently, we designed a bracket that can lock a commerically available extinguisher in place while allowing easy removal of the cylinder for replacement. To activate the release of the chemical, we are planning to use a 2" (5 cm) linear actuator that can exert 25 lbs. of thrust to squeeze the trigger. The hose of the cylinder will be guided by a nozzle mount, which will aim the dispersant at the target using servo motors.
Vision
Item 1d: The Extinguisher subsystem with bracket and linear actuator. ALL DIMENSIONS IN MM.
Smoke is the biggest deterrent for relaying visual information from inside a fire. Hence, we incorporated an IR camera along with a visible light camera to provide visual feedback to the remote operator. Both the cameras will be housed in a casing with a Quartz lens. Quartz was picked for its hight melting point, exccellent optical transmission properties and resistance to thermal shock. The mounts for the cameras will be linked to servo motors, adding horizontal and vertical degrees of freedom, thereby increasing the field of view.
Detection
This subsystem spans all detection mechanisms: detecting the presence and locating the fire, and detecting obstacles in the path for collision avoidance. Our system incorporates a wireless smoke detector for detecting the presence of a fire. For locating the fire, rather than using traditional IR sensors (which only have a range of about 1m), we are planning to perform image processing using the IR camera along with longer range (5m) UV sensors. Fun fact: These UV sensors are 'Solar Blind' so they won't be affected by the noisy UV radiation coming from the sun!
For collision detection, ultrasonic sensors will be placed around the perimeter of the FireBot.
The Microcontroller
This is the brain of the FireBot. Given that the microcontroller would have to handle over 8 motors, and 10 sensors, apart from transmitting live video feed from two cameras wirelessly, using the low-capacity Arduino platform was out of question. While there was a possibility of using multiple controller boards, the 'myRio' controller from National Instrumentsoffered a clean solution with its ample inputs, a powerful A9 dual-core processor and Wi-Fi capabilities. (Given that all our team members preferred LabVIEW over C++ was also a plus!)
Thermal Protection System
Fires get pretty hot (Duh!). In fact, the National Fire Protection Agency suggests that equipment such as thermal cameras used by firemen be able to resist an external temperature of 260°C (Source: NFPA 1801). So, in order to keep all the internal components functioning in such ab environment we decided to enclose the robot with a thermally protective material. After evaluating multiple alternatives, Stonewool, a material that is typically used for insulation in lofts. With a thermal conductivity of under 0.04 W/mK, we calcuated that we needed a mere 17mm thick layer of material to protect the robot. Moreover, Stonewool can withstand over 1000 °C, meeting the NFPA requirements.
Finally, we also incorporated two LiFePO batteries. The primary battery can hold 36Ah of charge, which is enough to power the robot at full speed for about 30 minutes. There is also an 18Ah secondary battery, as a backup.
For more details, feel free to check out our Conceptual Design presentation, which was delivered during the initial stages of the project, or the final, Detailed Design presentation and the Final Report, which includes everything from the Need statement, Function Structure and Performance Requirements to detailed subsystem descriptions, FMECA and assembly drawings. (PDF of the report, presentation and link to the Prezi are on the right)
Click the PDF icon below for the Design Report
Click the PDF icon below for the Final Presentation
Please do not plagiarize!
Oh, and a BIG SHOUTOUT AND THANKS to all my amazing team members!!!