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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