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Phong Le (EE) Josh Haley (CPE) Brandon Reeves (EE) Jerard Jose (EE) Sponsor : WCF Mentor: Ryan Reis (Lockheed Martin). Knight Sweeper 4200 Group 9. Goals and Objectives. Scan terrain based on s tart to end autonomous route Detection of IED Notify and pinpoint location of detection
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Phong Le (EE) Josh Haley (CPE) Brandon Reeves (EE) Jerard Jose (EE) Sponsor: WCF Mentor: Ryan Reis (Lockheed Martin) Knight Sweeper 4200Group 9
Goals and Objectives • Scan terrain based on start to end autonomous route • Detection of IED • Notify and pinpoint location of detection • Avoid any obstacles encountered on route • Navigate on desert like terrain
Motivation • Use of IED has increased since the Vietnam War • Technology improves but yet death by IED increases • More creative ways of utilizing IED’s • Low Budget spending on platforms used for detecting IED’s
Knight Sweeper • Knight Sweeper will be able to operate in autonomous and manual mode. • During autonomous mode Knight Sweeper will be able to navigate itself from a start to end point • During the autonomous operation Knight Sweeper will be able to avoid any IED or obstacle within its path
Hardware Block Diagram Power Data
Rover Platform • Identify type, size, wheels and motors. • A New Design • Use an existing design
Rover Platform • Carry maximum payload of 5 lbs. • Able to place sensors forward facing and down. • Capability to traverse different terrain types, i.e. dirt, grass, sand etc.
Lynxmotion A4WD1 • Chassis • Length is 9.75” • Width is 8” • Height is 3.5” • Lexan Panels • Wheels • Diameter is 4.75” • Width is 2.375” • Rubber Tires • Output Shaft is 6 mm • Additional levels can be added if necessary
Motor GHM-02 • Brushed DC Motor Type • Allows for Pulse Width Modulation Control • Fits the A4WD1 chassis
Motor Control • Identify how the vehicle will move. • Determine algorithm for obstacles. • Determine algorithm for detected IED. • Verify motor controller functionality.
Motor Controller • H-Bridge configuration • Forward • Reverse • Brake • Clockwise Rotation • Counterclockwise Rotation
L298N L = Low H = High X = Don’t Care
IED Detection • Beat Frequency Oscillation • Two separate coils oscillator and a search coil • Oscillator creates a constant signal at a set frequency • Detection of metal by search coil creates a magnetic field • Magnetic field interferes with radio frequency, offset in frequency then creates an audible beat
TDA0161 • Metallic detection done by detecting variation in high frequencies • Output signal determined by supply current changes • Current is high or low depending on the presence of a close metallic object • Output Current 10mA • Oscillator Frequency 10MHZ • Supply Voltage 4-35V
Obstacle Avoidance • Two Maxbotix LV-MaxSonar-EZ0 High Performance Module mounted on front • Detection Range 6”-245” w/ 45 degree beam width • Combined beam with of approximately 90 degrees
Maxbotix LV-MaxSonar-EZ0 • Use of three pins • GND (Ground) • Vcc (+5 V) • Analog Pin (Output) • Analog Pin • Outputs a voltage proportional to the distance • Range Formula : Vm/Vi=Ri • Vm = Measured Voltage, Vi = Volts per inch (scaling factor of 9.76mV), Ri = Range.
TTL Serial JPEG Camera w/ NTSC Video • Extras • Manually Adjustable Focus • Auto white balance • Auto brightness • Auto contrast • Motion detection • Multiple Resolutions
GPS Navigation • Pro Gin SR-92 • Update time: 1 second • Baud rate 9600 bps • 3.3V Required • 40 mA continuous tracking mode • 5 Pin interface • Send data over serial
Compass • LSM303DLH • Supply voltage of 2.5-3.3V • 16 bit data out • Serial interface • 3 magnetic field and 3 accelerometer channels • Sleep-to-wake up mode • Current consumption of (3uA-83mA)
Wireless Module • XBee-PRO • Range of 30m indoor • Range of 100m outdoor
Microcontroller • Stellaris M3 8962 Dev board. • Stellaris offers high computational power at 62.5 MIPS. • Offers 64K of RAM • Important for the A* algorithm • Interrupt Driven • Abundance of code examples and libraries • 74HC4052 Analog MUX for UART multiplexing
Power System • Integrated Power Supply • 14.8 VDC • DC motors • IED Detection • 5 VDC • Stellaris Microcontroller • Serial Camera • Obstacle Avoidance • 3.3 VDC • GPS Navigation • Wireless • Compass
POWER 14.8V 5V 3.3V DC Motors IED Detection 5V Reg MCU Obstacle Avoidance 14.8V Wireles GPS Compass Serial Camera 3.3V Reg
Lithium Polymer Battery • Tenergy Lithium Polymer Battery • 14.8V at 5500 mAh • Reasons for choosing • High energy density (Wh/kg) • High energy/dollar (Wh/$) • High charge efficiency (80-90%) • Low self-discharge
Linear vs. Switching Regulators • Linear Regulators • Easy to implement • Heat sink usually required • ~50% efficient • Clean voltage • Switching Regulators • Up to 88% efficient • Requires more components • Reduction in size of Heat sink needed • Sawtooth ripple voltage at the switching frequency
Switching Regulators • Texas Instruments TL2575 Family (3.3V ,5V, 12V, and adjustable. • Up To 88% Efficient (about 1V goes to heat) • Apply a small LC filter to reduce output ripple by a factor of 10.
POWER 14.8V 5V 3.3V DC Motors IED Detection 5V Reg MCU Obstacle Avoidance 14.8V Wireles GPS Compass Serial Camera 3.3V Reg
Software Overview • PC Software • Operator Interface • Allows for control • Display of robot status • Embedded Software • Initialize Systems • Interrupt Driven Obstacle and IED detection • Autonomous Navigation Wireless
PC Software • Written In java • Displays current location • Command Modes
Communication Interface • Layered Approach via Xbee wireless Embedded Software PC Software Application Layer Application Layer UART Layer UART Layer Xbee Wireless Xbee Wireless
Embedded Software • C++ via Code Composer • Each hardware system has a class • Utilizes Stellaris Ware Libraries • 4 Modes Standby Auton-omous Manual Error
Not Depicted: • 1Hz Telemetry Message • Sending photo’s of IEDs
AI Navigation • Problem: Quickest Way from A to B avoiding all known obstacles and suspected IEDs • Use the A* algorithm to find the shortest path • Upon IED/Obstacle detection, remove location from the search path and run A* again!
AI Navigation Example Creative Commons License 3.0 from Wikipedia
System Classes ObstacleDetection IEDDetection SerialCamera GPS MessagePacket PCserial Main OLED Compass boolvalidMessage() BoolsetChecksum() IntgetPayload(unsigned char* returnDatapointer) BoolsetPayload(messageType, char* ipayload, intpayloadLength) IntgetLength() IntgetRawMessageData() void initchip() void PCSerialISR() void processRXmessage() Void send1HzTM() Void navigate() Void runNextMove() Intmain() void initDisplay() void dispSplash() void clrScreen(); Void printLn(char* string); void init() void getPicture(unsigned char* returnPointer) Void initPCSerial() intsendMessage(char* buff, intnum) BoolgetMessage() void init() Float getReading() void ObstacleISR() voidinit() void getHeading() voidinit() IntgetStatus() returnLocation() void init() Float getReading() void IEDISR()
Prototyping • Completed • Motor controller • Power Regulation • Wireless Communication • Manual Control
TESTING • Wireless • Motor Controller Test