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Bomb-Sniffing Robot Final Report May 3, 2011. Lahar Gupta Hieu Nguyen Kirtan Patel John Walthour. Overview. Design Problem Design Implementation Testing and Evaluation Time Constraints Cost Constraints Safety Features Ethical Concerns Recommendations. Scope and Purpose. - PowerPoint PPT Presentation
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Bomb-Sniffing RobotFinal Report
May 3, 2011Lahar GuptaHieu NguyenKirtan PatelJohn Walthour
Overview
Design Problem Design Implementation Testing and Evaluation Time Constraints Cost Constraints Safety Features Ethical Concerns Recommendations
Scope and Purpose
Present details design and evaluation of the Bomb-Sniffing Robot prototype
This presentation covers the period from January 18, 2011 through May 3, 2011
Design Problem
To save men and women from dying preventable deaths in combat.
Each year hundreds of men and women die in combat due to un-detected bombs and chemical exposure.
http://news.bbc.co.uk/2/shared/spl/hi/in_depth/baghdad_navigator/
Design Solution
Proof-of-concept prototype called the Bomb-Sniffing Robot Designed for military personnel and civilian bomb squads to
allow the remote detection of hazardous conditions and substances
Unmanned vehicle controlled wirelessly from a laptop with a gamepad
Sensors on the robot send information about hazardous chemicals to the operator
Specifications
Specification Range
Response Time < 500 Milliseconds
Wireless Range > 100 Meters
Battery Life > 1 Hour
Weight < 48 Lbs.
Budget $1,500
Hardware
Remote controlled robot Chemical Sensors GPS Tracking Video Camera
Laptop with Graphical User Interface (GUI)
USB gamepad controller
Laptop Interface
National Instruments LabVIEW GUI Gather control information from gamepad Process sensor signals Display video feed Display GPS location information Battery and connection status Configuration menu Technical support information
Microcontroller Software
PIC32 programmed in C with Microchip MPLAB IDE
Drivers required for design solution: UART SPI ADC PWM
Custom TCP server to communicate with LabVIEW Leverage Microchip TCP/IP
Application Library
Implementation
Data flow diagrams Software design
Microcontroller LabVIEW
Hardware components
Operational Block Diagram
Video Feed
GPS
Gas Sensors
Motor Control
Wi-Fi
LabVIEW GUI
ControllerUsers
Laptop Robot
LabVIEW Block Diagram
LabVIEWGUI
Sensor Graphs
Video screen
Google Location Map
Robot Path Map
USB Gamepad
TCP Receive
Gas Sensor
GPS
Video Camera
TCP Transmit
Controller Data
Input Output
Graphical User Interface
Multiple tabs to separate main display from auxiliary data Main Display
Video Sensor Data Battery Life Connection Status Location Tracking
Configuration Video Settings Network Settings
Tech Support FAQ Manual
Gamepad Controller
Simple and intuitive control Gamepad has two joysticks
Camera pan and tilt control Vehicle motion
Started with Joystick Input Device Control LabVIEW module Modified the module for use with Logitech USB Gamepad Read data from the gamepad controller
Embedded Software
Interrupt Driven Input/Output SPI interface for Ethernet
controller UART serial interface for GPS ADC sampling Output Compare and Timer
interrupts for PWM outputs Cooperative Multitasking
Loop Debugged and tested to verify
that all functions have no critical sections
Microcontroller SoftwareBlock Diagram
Custom TCP
Server (TCP/IP Library)
FIFO Queue
Ethernet (SPI)
Motor Control Values
PWM Driver
ADC Samples
ADC Driver
GPS Location
Data
UART Driver
Foreground
Interrupts
Storage
Network ProtocolNetwork Protocol
TCP used for reliable data transfer TCP messages are strings with values separated by commas Packet Types
Control DataCameraX,CameraY,MotorDirection,MotorVelocity<CR>ex. “3650,3725,2278,4502<CR>”
Sensor DataHeader,Methane,LPG,CO,Battery<CR>ex. “SD,13,0,508,1011<CR>”
GPS Data Format defined by NEMAHeader,NMEA Message<CR>
ex. “GD,$GPRMC,053740.000,A,2503.6319...<CR>” Keep-Alive
ex. “KA<CR>”
Robot HardwarePart ModelMicrocontroller Digilent Cerebot 32MX4
Wireless Router Linksys WRT54GS
Video Camera Asante Voyager I
Camera Pan and Tilt Lynxmotion BPT-KT
GPS Unit Locosys LS20031
Methane Sensor Hanwei MQ-4
Carbon Monoxide Sensor Hanwei MQ-7
Ethernet Controller Microchip ENC28J60
Motor Controller Dimension Sabertooth 2x25
Motors Hennkwell PD51M
Batteries Turnigy T5000.3S.25
Custom PCB Advanced Circuits
Microcontroller
Digilent Cerebot 32MX4 Based on Microchip PIC32MX460F512L 80 MHz 512K Flash 32K RAM
Compatible with Microchip’s TCP/IP application library 16 channel 10-bit ADC for sensor sampling
1 million samples per second 5 Pulse Width Modulation outputs 2 SPI Interfaces 2 UART Interfaces
Wireless Network Linksys WRT54GS provides wireless link between
laptop and robot Installed DD-WRT open source firmware > 100 Meter range 54 Mbps 802.11B/G
Microchip ENC28J60 connects the microcontroller to the router 10Base-T SPI Interface Compatible with Microchip’s TCP/IP application
library
Motor Controller and Motors
Dimension Engineering Sabertooth 2X25 Dual channel motor controller 25A continuous current per channel 50A burst current Thermal protection Overcurrent protection Lithium battery under-voltage cutoff
Direction and velocity selected with PWM Signal inputs VOH = 5V, so 3.3V output of
PIC converted using 7407 IC Controls two PD27M DC motors
12V, 5A (35A Stall) 300 RPM 694 oz-in torque (4.9Nm)
Robot Sensors
Hanwei MQ-4 Methane Gas Sensor Detects 200 – 10000 ppm 150mA
Hanwei MQ-7 Carbon Monoxide Gas Sensor Detects 20 – 2000 ppm 150mA
Locosys LS20031 GPS Unit 66 channel 10 Hz update rate Battery backup LVTTL UART interface
Video Camera
Asante Voyager I IP Camera 640x480 Resolution @ 30 Frames Per Second Wireless or Ethernet connectivity Infrared night-vision Audio recording ActiveX control for interfacing to LabVIEW
Lynxmotion BPT-KT Pan and Tilt Includes two Hitec HS-422 servo motors Provides 180º by 110º camera movement
Power System
12V Switching Regulator 2.5A maximum current Supplies power to camera and wireless router Over-current and over-voltage protection Based on the National Semiconductor LM3488
5V Switching Regulator 2A maximum current Supplies power to the microcontroller, servos, and sensors Over-current and over-voltage protection Based on the National Semiconductor LM22676
10 Ah of battery power Provided by two 3-cell Lithium-Polymer packs One battery supplies the voltage regulators The other battery powers the DC motors
Custom PCB Created with Advanced Circuits PCB Artist Combines several systems onto single PCB
12V Switching Regulator 5V Switching Regulator Two Gas Sensors and Filtering Battery Monitor GPS Interfacing Ethernet Controller 3.3V to 5V Level Shifter for Motor Controller
Chassis Made from acrylic plastic and aluminum 2 polyurethane treads from Lynxmotion 3 platforms to hold components Weighs 12 lbs. with components 14”L x 12”W x 10”H
Testing and Evaluation
Test Performed ResultWireless Range Passed
Robot Weight Passed
Battery Life PassedGas Detection Passed
Vehicle Mobility Testing Passed
Interface Ease and Usability Passed
Wireless Range Testing
Specification: Wireless range greater than 100 meters
Test Results Lost video feed at 168 meters The response time became
greater than 500ms at 182 meters
All response times less than 100ms within 100 meters
Robot Weight Testing
Specification: Weighs less than 48 lbs.
Test Results Robot weighs 12 lbs. Laptop weighs 6.4 lbs. Total weight of 18.4 lbs.
Battery Life Testing
Specification: Battery life greater than one hour
Test Results Starting voltage of 12.55V During the open house, continuous
motion for three hours Ending voltage
Battery 1 = 11.38V Battery 2 = 11.30V
Estimated total run-time of six hours
Gas Detection Testing
Specification: Detect unknown quantities of methane and carbon monoxide
Natural gas from a stove used to test the methane sensor
Smoke from a burning piece of paper used to test the carbon monoxide sensor
The test was repeated five times for each sensor and the results were all similar to the graphs shown
Vehicle Mobility Testing
Specification: The robot should be able to climb a 30º incline
Test Result: The robot can climb a 35º incline The center of gravity, not torque, is
the limiting factor
Interface Testing
Specification: Likert survey results of agree or higher. 1 = Strongly Disagree 2 = Disagree 3 = Neutral 4 = Agree 5 = Strongly Agree
Test Result: An averagescore of 4.2 was given
Change resulting from survey Location tracking enlarged Time zone taken into account
Cost Constraints
Total budget of $1500 Budget did not allow the purchase of actual bomb-
detecting sensors Removed radiation detector due to cost Built chassis from scratch to save money
Causes the frame to shake, which lowers the video feed quality
Current Project Cost = $1,263.66
Safety Features
Protection Mechanisms Zener diodes to avoid over-voltage and fuses to avoid over-
current Guards to protect the user Microcontroller monitors the battery level to perform an auto
shutdown before the batteries become depleted Hazards
Remove the batteries before recharging
Ethical Concerns
Recyclable plastics and metals for the chassis Restriction of Hazardous Substances (RoHS) certified lead-
free components for the electronics Lithium Ion batteries are the most hazardous components of
the robot Production model should offer an end-of-life recycling
program at no charge Invasion of privacy concerns
Recommendations
Proposed Changes Get access to new nano-technology research currently increasing
the sensitivity of bomb detection Construct the chassis from aluminum to increase strength and
durability Increase the ground clearance of the robot. Currently, on rough
terrain, the robot can become stuck on rocks or fallen branches.
Successes Digilent Cerebot 32MX4
TCP/IP Library from Microchip Wireless router to establish communication link between the robot
and laptop National Instruments’ LabVIEW for data processing and user
interfacing
Ver 2.0
Wrap up and Q&A
Topics Discussed:
• Design Problem• Design Implementation• Testing and Evaluation• Time Constraints• Cost Constraints• Safety Features• Ethical Concerns• Recommendations