AUTONOMOUS VISUAL ROVER

Sean DayDiante ReidLiem Huynh

Project Overview

To create a vehicle that autonomously follows a moving object

To design a low cost, mobile robot that can track objects based on image processing

Implement all of the parts using the Atmel microcontroller

Fire at target object when specified

Requirements

Autonomously track and follow a moving object using color detection

Operate on battery power and not other external source of power

Keep a minimum of 7 inches away from it target at all time.

Operate both indoor and outdoor Operate for more than one hour on a fully

charged battery. Have a dimension of no more than 14x7x7

inches

Optional Features

Autonomous weapons system Solar Power The AVR shall be able to

communicate and upload telemetry data to the user via Bluetooth

The AVR shall be able to map its surrounding and navigate to a designated target with GPS.

Top Level Diagram

CMUCam2+

Maxbotix LV-EZ2

IR Detector

Sensors

Manager

Guidance, Navigatio

n and Control

Actuators

Environment Images

UltrasonicSignals

Encoder Patterns

On-Off

Pulses

PWM

Centroid and Servo Location

Target Location

Target Range

ChassisVelocity

PWM

Software

Hardware

Environment

Target

Microcontroller - Arduino

ATMEGA328 USB Interface Cross-platform Easy to program Open source Well documented

Printed Circuit Board

PCB123 software

$100 student credit from sunstone

Prototyped on the Arduino board

2 layer design Using through

hole and surface mount techniques

CMUcam 2+ Vision Sensor

•Performs image processing duties for AVR

•Track user defined color blobs at up to 50 Frames Per Second (frame rate depends on resolution and window size settings)

•Track motion using frame differencing at 26 Frames Per Second

•Find the centroid of any tracking data

•Gather mean color and variance data

•Gather a 28 bin histogram of each color channel

•Process Horizontally Edge Filtered Images

Image Processing Requirements Color detection Motion detection Flexibility for programming Ability to distinguish between

specified color and other colors in environment

Work efficiently in well lit environment

Image Processing Techniques

Edge Detection Canny detection Edges are areas

where a jump in intensity from one pixel to the next occurs

Able to reduce the amount of data processed by filtering out useless information

Blob Detection

Middle Mass Determines if a group

of connecting pixels are related to each other by surroundings

Efficient in identifying separate objects in a scene

CMOS vs. CCD Sensor

CMOS CCD

Transistor based Flexible design Average picture

quality Low power

consumption Low Price

Analog device Rigid design Excellent picture

quality Power hungry Very Expensive

Choosing a Vision System

CMUcam1 CMUcam2 CMUcam3 AVRcam Logitech QuickCam Orbit AF Webcam

+ RoboRealm

CMUcam Comparison

Price Frame Rate Resolution RAM ROM SPEED

CMUcam1 $109.99 17 fps 80x143 136 bytes 2048 words 75 MHz

CMUcam2 $179.99 50 fps 176 x 255 263 bytes 4096 words 75 MHz

CMUcam3 $239.99 26 fps 352x288 64 KB 128 KB 60MHz

AVRcam $99.00 30 fps 88x144 700 bytes 512bytes 16MHZ

CMUcam2+ Software

Open Source Programmable

Hybrid Version of C Language

CMUcamGUI

Why CMUcam2+

Compact Size Frame Buffering Affordable price Flexible Multiple Servo

Control User Support

Power NeedsVolts milliamps

Ultrasonic Sensor

2.5-5 2

Motor 2.5-5 30-60

Steering Servo

3-6 5x1

CMU Camera

5-12 200mA

CMU servos

3-6 5x1

Voltage Regulation

All parts on AVR can run off of 5volts DC

 Stepping Down 7.4 volt battery

LM317 adjustable regulator

Ultrasonic Sensor Requirements Purpose is to keep AVR within 6

inches of target object Be able to fit on front bumper Will not loose the target object Low power consumption

Maxbotics Ultrasonic Sensor Maxbotics EZ1 Will easily fit on

bumper Only draws 2mA of

current Easy to interface

Interfacing the Sensor

Pulse Width Modulation 147 microseconds/inch

Analog Input (Vcc/512)/inch

Batteries

Chassis

RC car from ToysRus 4 wheels 2 front turning wheels 2 rear wheels for going back and

forward 2 DC motors Roomy

Servos

DC Motors RC Servos Stepper Motors

Sensors Manager

getRange() Returns range from Ultrasonic Sensor in

inches getVelocity()

Returns velocity from IR detector/reflector in inches/seconds

getCentroid() Returns centroid location of target in x

and y format

Sensors Manager

getPan() Returns location of panning servo

getTilt() Returns location of tilting servo

getTime() Returns microprocessor’s time

GNC

Determine velocity using the encoder wheel and IR detector/reflector

GNC Tracking the target’s centroid

1 44 88

GNC CMUcam to Body alignment Body Frame, CMUcam Frame

β

Servo Positions

128, 0°

210, 90°46, -90°

β Servo Pos

Offset

-90° 46 -44

0° 128 0

90° 210 44

Offset = 44 sin( β )

Centroid_B = Centroid_C + Offset

GNCInitialization

ForwardStraight

Locate Centroi

d

Forward Right

yes

no

Target’s range

<=5 inches?

Centroid > 54

Forward Left

Centroid < 34

else

Stop

Navigation Flowchart

GNCP (Range)

D (Velocity)

Plant++

--

Input Output

Error

Proportional-Derivative Controller

• Variable speed depends on range from target and how fast the AVR is moving

• P and D gains need to be tuned• All control process is done through software• Sum of error terms multiplied by the gains translate to voltage to drive the

actuators(Error*Range) + (Error*Velocity) = Voltage

Testing

DC Motor/ H-bridge test Range Finding Test CMUcam2+ Pan and Tilt Test

Testing

DC Motor/H-Bridge turning wheels test

IR Detector/Reflector test IR Detector/Reflector encoding wheel

test Chassis/Locomotion test with turning

wheels Locomotion test with IR

detector/reflector

Testing

Locomotion test with ultrasonic sensor stationary target

Locomotion test with ultrasonic sensor moving target

Locomotion test with CMUcam2++ with stationary target

Locomotion test with CMUcam2++ with moving target

Locomotion test with all sensors

BudgetPart

NumberPart Name Qty Cost Order Date Supplier Manufactur

erN/A Basic

Breadboard1 $11.95 6/30/09 SparkFun SparkFun

LV-EZ2 Ultrasonic Range Finder

Maxbotix LV-EZ2

1 $27.95 6/30/09 SparkFun Maxbotix

N/A Arduino Starter Kit

1 $49.95 6/30/09 SparkFun Arduino

LTE-302,LTR-301

Infrared Emitters

and Detectors

1 $1.95 6/30/09 SparkFun Lite-On Electronics

SN754410 H-Bridge 3 $12.00 7/21/09 Acroname Texas Instruments

R245-CMUCAM2+-

Plus

CMUcam2++

1 $169.00 7/21/09 Acroname Acroname

FT232R USB to Serial kit

1 $29.00 7/21/09 Acroname FTDI Chip

n/a Battery/charger

1 $55.45 8/28/09 Battery Junction

Tenergy

n/a RC servo 2 $25 9/3/09 Colonial Photo and

Hobby

n/a

Total Cost $383.25

Part Allocation

Testing

Design

Contruction

Total

0 10 20 30 40 50 60 70 80 90100

RemainingCompleted

Part allocation – 90% Testing – 10% Design – 95% Construction/Prototyping – 20% Total completed -50%

Progress