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Knight Sweeper 4200 Group 9

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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Knight Sweeper 4200 Group 9

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  1. Phong Le (EE) Josh Haley (CPE) Brandon Reeves (EE) Jerard Jose (EE) Sponsor: WCF Mentor: Ryan Reis (Lockheed Martin) Knight Sweeper 4200Group 9

  2. 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

  3. Motivation • Use of IED has increased since the Vietnam War • Low Budget spending on platforms used for detecting IED’s • Technology improves but yet death by IED increases • More creative ways of utilizing IED’s

  4. 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

  5. Specifications

  6. Hardware Block Diagram Power Data

  7. Rover Platform • Identify type, size, wheels and motors. • A New Design • Use an existing design

  8. 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.

  9. Rover Platform Comparison

  10. 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

  11. Motors

  12. Motor GHM-02 • Brushed DC Motor Type • Allows for Pulse Width Modulation Control • Fits the A4WD1 chassis

  13. Motor Control • Identify how the vehicle will move. • Determine algorithm for obstacles. • Determine algorithm for detected IED. • Verify motor controller functionality.

  14. Motor Controller • H-Bridge configuration • Forward • Reverse • Brake • Clockwise Rotation • Counterclockwise Rotation

  15. IC H-Bridge

  16. L298N L = Low H = High X = Don’t Care

  17. L298N

  18. L298N

  19. 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

  20. 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

  21. IED Detection

  22. IED Detection • Two external circuits to implement two TDA0161 IC’s.

  23. IED Detection

  24. IED Detection • When the search coils detect metallic objects pin 6 outputs 1v

  25. IED Detection • Two search coils needed to cover the width of the vehicle • Each coil made with magnet wire • Both coils set at about 155 uH • Fixture to extend the coils in front of the actual vehicle

  26. IED Detection • Old PCB’s found in the lab will be used to simulate IED’s • Copper is easily picked up by the search coils • FREE

  27. Obstacle Avoidance • One Maxbotix LV-MaxSonar-EZ0 High Performance Module mounted on front • Detection Range 6”-245” w/ 45 degree beam width

  28. 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.

  29. Serial Camera

  30. TTL Serial JPEG Camera w/ NTSC Video • Extras • Manually Adjustable Focus • Auto white balance • Auto brightness • Auto contrast • Motion detection • Multiple Resolutions

  31. 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

  32. 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)

  33. Wireless Module • XBee-PRO • Range of 300m indoor • Range of 1500m outdoor

  34. 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

  35. 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

  36. 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

  37. 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

  38. 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

  39. 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.

  40. Switching Regulator Circuit

  41. 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

  42. 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

  43. PC Software • Written In java • Displays current location • Command Modes

  44. Communication Interface • Layered Approach via Xbee wireless Embedded Software PC Software Application Layer Application Layer UART Layer UART Layer Xbee Wireless Xbee Wireless

  45. Embedded Software • C++ via Code Composer • Each hardware system has a class • Utilizes Stellaris Ware Libraries • 4 Modes Standby Auton-omous Manual Error

  46. Not Depicted: • 1Hz Telemetry Message • No Valid Path

  47. 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!

  48. AI Navigation Example Creative Commons License 3.0 from Wikipedia

  49. 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()

  50. Prototyping • Completed • Motor controller • Power Regulation • Wireless Communication • Manual Control

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