Knight Sweeper 4200 Group 9

Knight Sweeper 4200Group 9Phong Le (EE)Josh Haley (CPE)Brandon Reeves (EE)Jerard Jose (EE)

Sponsor: WCFMentor: Ryan Reis (Lockheed Martin)

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

Motivation

Use of IED has increased since the Vietnam War

Low Budget spending on platforms used for detecting IEDs

Technology improves but yet death by IED increases

More creative ways of utilizing IEDs

3Knight 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

4Specifications

ComponentParameterDesign SpecificationBatteryOperational time1 hoursIED DetectionRange3 centimetersWireless moduleMinimum range50 metersGPSAccuracy1 metersGPSUpdate time1 secondCompassAccuracyOne cardinal directionMotorsSpeed2 miles per hourObstacle AvoidanceMinimum distance 16 inchesHardware Block DiagramPowerData

Rover PlatformIdentify type, size, wheels and motors.

A New Design

Use an existing design

Rover PlatformCarry 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.

Rover Platform Comparison

Lynxmotion A4WD1

ChassisLength is 9.75Width is 8Height is 3.5Lexan Panels

WheelsDiameter is 4.75Width is 2.375Rubber TiresOutput Shaft is 6 mm

Additional levels can be added if necessary

Motors

Motor GHM-02Brushed DC Motor TypeAllows for Pulse Width Modulation ControlFits the A4WD1 chassis

Motor ControlIdentify how the vehicle will move.

Determine algorithm for obstacles.

Determine algorithm for detected IED.

Verify motor controller functionality.

Motor Controller

H-Bridge configurationForwardReverseBrakeClockwise RotationCounterclockwise RotationIC H-Bridge

L298N

InputsFunctionEnable = HC = H; D = LForwardC = L; D = HReverseC = DFast Motor StopEnable = LC = X; D = XFree Running Motor StopL = LowH = HighX = Dont CareL298N

L298N

IED DetectionBeat 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

TDA0161Metallic 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 4-35VIED Detection

IED Detection

Two external circuits to implement two TDA0161 ICs.

IED Detection

IED Detection

When the search coils detect metallic objects pin 6 outputs 1v

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

IED Detection

Old PCBs found in the lab will be used to simulate IEDs

Copper is easily picked up by the search coils

FREE

Obstacle Avoidance One Maxbotix LV-MaxSonar-EZ0 High Performance Module mounted on frontDetection Range 6-245 w/ 45 degree beam width

Maxbotix LV-MaxSonar-EZ0Use of three pinsGND (Ground)Vcc (+5 V)Analog Pin (Output)

Analog PinOutputs a voltage proportional to the distanceRange Formula : Vm/Vi=RiVm = Measured Voltage, Vi = Volts per inch (scaling factor of 9.76mV), Ri = Range.

Serial CameraOption NumberNameResolutionInterfaceCurrent Consu-mptionCostLink1LinkSprite JPEG Color Camera TTL Interface160x120TTL UART80-100mA$49.95http://www.sparkfun.com/products/100612CMOS Camera - 640x480640x480I2CNot Given$9.95http://www.sparkfun.com/products/866734D Systems microCAM Serial JPEG Camera Module - TTL80x60,160x120, 320x240,640x480TTL UART62mA$59.00http://www.robotshop.com/productinfo.aspx?pc=RB-Fds-15&lang=en-US4TTL Serial JPEG Camera with NTSC Video160x120, 320x240,640x480TTL UART75mA$42.00https://www.adafruit.com/products/397TTL Serial JPEG Camera w/ NTSC VideoExtrasManually Adjustable FocusAuto white balanceAuto brightnessAuto contrastMotion detectionMultiple Resolutions

GPS NavigationPro Gin SR-92Update time: 1 secondBaud rate 9600 bps3.3V Required40 mA continuous tracking mode5 Pin interfaceSend data over serial

CompassLSM303DLHSupply voltage of 2.5-3.3V16 bit data outSerial interface 3 magnetic field and 3 accelerometer channels Sleep-to-wake up modeCurrent consumption of (3uA-83mA)

Wireless Module XBee-PRORange of 300m indoorRange of 1500m outdoor

Microcontroller Stellaris M3 8962 Dev board.Stellaris offers high computational power at 62.5 MIPS.Offers 64K of RAMImportant for the A* algorithmInterrupt DrivenAbundance of code examples and libraries74HC4052 Analog MUX for UART multiplexing

Power SystemIntegrated Power Supply14.8 VDC DC motorsIED Detection 5 VDC Stellaris MicrocontrollerSerial CameraObstacle Avoidance 3.3 VDCGPS Navigation WirelessCompass

POWER MCUIED Detection GPSCompassSerial CameraDC MotorsObstacle Avoidance 5V Reg3.3VReg

Wireles14.8V14.8V5V3.3VLithium Polymer Battery Tenergy Lithium Polymer Battery 14.8V at 5500 mAh

Reasons for choosingHigh 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% efficientClean voltage

Switching Regulators Up to 88% efficientRequires more componentsReduction 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.

Switching Regulator Circuit

POWER MCUIED Detection GPSCompassSerial CameraDC MotorsObstacle Avoidance 5V Reg3.3VReg

Wireles14.8V14.8V5V3.3VSoftware Overview

PC SoftwareOperator InterfaceAllows for controlDisplay of robot statusWireless

Embedded SoftwareInitialize SystemsInterrupt Driven Obstacle and IED detectionAutonomous NavigationPC SoftwareWritten In javaDisplays current locationCommand Modes

Communication InterfaceLayered Approach via Xbee wireless

Application LayerUART LayerXbee WirelessApplication LayerUART LayerXbee WirelessPC SoftwareEmbedded SoftwareEmbedded SoftwareC++ via Code ComposerEach hardware system has a classUtilizes Stellaris Ware Libraries4 ModesStandbyAuton-omousManualError

Not Depicted:1Hz Telemetry MessageNo Valid PathAI 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 WikipediaSystem Classesvoid initchip()void PCSerialISR()void processRXmessage()Void send1HzTM()Void navigate()Void runNextMove()Int main()MainVoid initPCSerial()int sendMessage(char* buff, int num)Bool getMessage()PCserialvoid init()Int getStatus()returnLocation()GPSvoid init()void getPicture(unsigned char* returnPointer)SerialCameravoid init()Float getReading()void IEDISR()IEDDetectionvoid init()Float getReading()void ObstacleISR()ObstacleDetectionvoid initDisplay()void dispSplash()void clrScreen();Void printLn(char* string);OLEDvoid init()void getHeading()Compassbool validMessage()Bool setChecksum()Int getPayload(unsigned char* returnDatapointer)Bool setPayload(messageType, char* ipayload, int payloadLength)Int getLength()Int getRawMessageData()

MessagePacketPrototyping

CompletedMotor controllerPower RegulationWireless CommunicationManual ControlVoltage vs. Time

TESTING

Knight Sweeper test

Printed Circuit BoardsUsing Eagle 6.1.0

2 PCBs will be madePower Regulation and Motor ControlSensors, camera, GPS and wirelessPrinted Circuit BoardPower Regulation & Motor Control Top Layer Bottom Layer

Printed Circuit BoardSensors Top Layer Bottom Layer

55Printed Circuit BoardFabrication

56Printed Circuit BoardFinal Boards

Motor Control and PowerSensors57Distribution of Responsibilities Phong LeIED DetectionProject ManagementJosh HaleyGPSSerial CameraMain BoardLead Software EngineerBrandon ReevesObstacle AvoidancePower Systems LeadJerard JoseMotor control leadPlatform SelectionPCB Fabrication Lead

Budget

Project Schedule

Project Schedule

What Keeps Us Awake At Night

-GPS Accuracy

Camera

-IED Detection range

-Noise from Various Components

-Deviation between internal map and real world.

-INDUCTORS!!!!

QUESTIONS?

Knight Sweeper 4200