Ali Alkuwari Patrick Swann Jad Farah Marcus Schaffer Korhan Demirkaya

Long Quy Denden Tekeste Ngoc Mai Steven Weaver

Project Description

• Design and Build an Autonomous Robot

• Robot must successfully navigate around a predetermined course

• Robot must pass through selected beacons

Project Requirements

• Detect beacons within 15 - 25 feet

• Fits within a 16”x16”x16” cube

• Has a clearly labeled emergency stop switch

Yertle’s Journey

Flow Chart

HOW WAS THIS ACHIEVED Navigation

◦ Beagleboard

◦ AVR microcontroller

◦ Ultrasonic Sensors

◦ Flex Sensors

◦ Compass

◦ GPS

Locomotion◦ AVR microcontroller

◦ H-Bridge

◦ Wheel Encoders

◦ Power Supply

NAVIGATION

Block Diagram: Navigation

Path Finding

• Graph of course

• Destination Points are put into the code. • 14 x = [125, 256, 294, 85, 85, 80, 75, 75, 60, 60, 16, 16, 8, 8, 48,

48, 10, 10, 44, 10, 33]• 15 y = [170, 170, 66, 66, 55, 50, 50, 42, 42, 10, 10, 87, 87, 120,

127, 135, 135, 140, 150, 152, 167]

• Dead Reckoning and Compass to calculate current position• 20 delta_x = math.sin(compass) * feet traveled from last waypoint• 23 delta_y = math.cos(compass) * feet traveled from last

waypoint

• Compass direction computed:• 9 distance = calcDistance(pt1, pt2)• 11 diff = pt2[1] - pt1[1]]• 16 return math.asin(diff/distance)

Path Finding

Object Avoidance

Robot instructed to go to point A to B Calculate trajectory from interpreted data from sensors

Rotate robot to avoid collisions. Calculate new path

Robot avoids collision with new path recognition

Actual Device EZ1 Flex Sensors

LOCOMOTION

Block Diagram: Locomotion

BEAGLE BOARDOMAP 3530

H-Bridge

Motor LEFT

Motor RIGHT

2 PW

M /

4 Di

rect

ion

Wheel Encoder RIGHT

Wheel Encoder

LEFT

1 Di

gita

l

2 2

AVR ATmega 328 Serial(USB)

Motor Control : H-Bridge

• Motor direction

• Speed by PWM

Motor Control : Wheel Encoders

• Keeps track of speed/ displacement

• Resolution

1kHz–slowest speed≈ 0.8 feet/second

3kHz–fastest speed≈ 2.5 feet/second

Motor Control : Software

•Issue : DC Motor Performance

• Solution: PID Control

Change Voitage accordingly for each motor in every 30 ms

Motor LEFT

Motor RIGHT

Actual ticks in 30 ms

Actual ticks in 30 ms

Send the actual distance traveled to NAVIGATION

Get the desired direction/distance/speed from NAVIGATIONDesired ticks for each motor in every 30 ms (Speed) /

Direction / Displacement

HOW IT ALL COMES TOGETHER

Overall System: Block Diagram

• HBridge + Voltage Regulator

• Wheel Encoder

• Sensors: Beacon, Ultrasonic, & Flex

PCB Design

Daughter Board

Final Robot

Budget

Beagle Board $150

Batteries $115

AVRs $105

Sensors $78

GPS $50

Milestones• Turtle’s Body 4/5

• AVR Code Complete 4/10

• Beagleboard & AVR communicate together 4/12

• PCB complete 4/28

• Parts Mounted 4/30

• Robot assembled 5/2

Website

http://turtle.sdsu.edu