Team 1617: Autonomous Firefighting Robot Contest Katherine Drogalis, Electrical Engineering Zachariah Sutton, Electrical Engineering Chutian Zhang, Engineering Physics Advisor: Professor John Ayers

Overview Project Overview & Contest Background Mechanical Design & Layout Sensors & Routing Microcontroller Flame Extinguishing Power Supply Budget

Design a Fully Autonomous Robot to Find & Extinguish a Flame Trinity International Robot Contest (April 1-3, 2016) User initiated, autonomous start & navigation Search for and extinguish burning candle Design can be extended to real life situations

Trinity International Robot Contest 8x8’ plywood maze Arbitrary start position Competing in 2 of 3 levels Timed trials Unique robot 31x31x27 cm robot Level 1 ArenaLevel 2 Arena

Test Arena

Round Polycarbonate Body No rigid corners to bump walls Electrical insulating property Strong; Will not crack when cut Threaded rod for support Levels: Top to Bottom o Start button; LED; mic; kill-power plug; handle o Flame detection sensors; extinguisher o Microcontroller; laser scanner o Driving motors; control circuit; batteries

Two Motors Independently Driving Two Wheels Can turn different angles simultaneously Take commands from microcontroller Option 1: Stepper Motors o Position controlled: constant input voltage drives motor to specific position o Draws current to maintain position - waste of battery power Option 2: Servomotors o Similar to Stepper o Consumes power as rotates to position then rests - better, wastes less power! o Angle of rotation is limited to 180 o (or so) back and forth o Complicated setup with PWM tuning

Best Option: DC Motor w/ Encoder Velocity controlled: constant input voltage drives motor to specific velocity Can control position by applying velocity commands over a certain time o Pulse-Width Modulation signal FAST rpm 12V - perfect for battery operation Count wheel rotations with encoders 64 counts per rotor revolution (6400 counts per wheel revolution)

Need to Sense: Walls/Obstacles & Flame Range sensing options ○ Ultrasonic: cheap, easy to use, low interference, low resolution ○ Infrared: cheap, range limited, interference prone, low resolution ○ Laser: expensive, long range, low/no interference, processing required, high res Flame sensing options ○ Look for presence of both light and heat ○ Light: photoresistors/photodiodes, subject to external interference ○ Heat: IR non-contact sensing, must work at range of ~1 m

Choice: 360 o Laser Scanner by RoboPeak Scanner vs. Stationary ○ Stationary: cheaper, would need to be mounted on scanning platform ○ Scanner: set sample rate, configurable scan speed, built-in angular encoder Measurements in body reference frame polar coordinates (heading = 0º) ○ “r” coordinate useful in finding wall discontinuities ○ Need to convert to cartesian for SLAM 2000 samples per second ○ Vary scan speed to control angular distance between samples ○ Get ~1 sample per degree with 5.5 Hz scan rate

Video of Laser Range Sensor Video of Laser Range Sensor

Experimental Data

Flame Sensor RoBoard RM-G212 16X4 Thermal Array Sensor o produce a map of heat values o able to pick up the difference 1.5m away o low power consumption o 16 x 4 = 64 pixels o FOV: 60º horizontal, 16.4º vertical o 0.02 Degree Celsius uncertainty Can find center of candle at close range Have a particular pixel act as target location May be unecessary to add light sensing

Experimental Setup

Experimental Flame Sensor Heat Map Heat measurements at distance of 1.5 m Heat measurements at distance of 0.2 m

Candle in total field of view Experimental Flame Sensor Heat Map

Routing/Navigation SLAM (Simultaneous Localization and Mapping) Find current location in a map of landmarks ○ Use laser to pick out corners and terminal points in walls ○ Predict next position from current position and a given control command ○ Compare prediction with sensor result after command is executed ○ Correct based on previous reliability of sensor measurements and predictions Adaptive

Routing/Navigation

Microcontroller Arduino Mega 2560 o 256 kB of Flash Memory o 8 kB of SRAM o 4 kB of EEPROM o 7 to 12 Volts o Highly versatile o Many available open source libraries o Programmable in C++ Raspberry Pi (possible addition) o Helps the speed of processing o All real-time calculations with scanner data must be accomplished within 500 us o Will add if unable to make Arduino code this efficient

Flame Extinguishing Realistic: Compressed gas (CO 2 ) o Best option for large-scale fire - bonus points! o Cartridge at the back of the robot o Extended nozzle at the front aligned with the sensors o Pointed directed at the candle flame Unrealistic: Fan o Will make a large-scale fire worse! o Controlled by Arduino o Fallback option

Power Supply and Other Requirements Rechargeable DC batteries o Two sets - use one while charging other - save time! o 4 separate cells - option to pull power from individual cells o Max 14.8 V o 5500 mAh o grams Other requirements o Start button: green background o LEDs: white background o Microphone: blue background o Kill-power plug: yellow background o Handle

Budget

Questions?