Anders Nelson (EE)
anelson7@iastate.edu
Kshira Nadarajan (CprE)
kshira90@iastate.edu
Mathew Wymore (CprE)
mlwymore@iastate.edu
Mazdee Masud (EE)
mmasud@iastate.edu
Client: Space Systems & Controls Laboratory (SSCL)
Advisor : Matthew Nelson
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
SSCL(Space Systems & Controls Lab)

Unmanned Aerial Vehicle

AUVSI Aerial Robotics Competition
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
Aim: To participate in the International Aerial
Robotics Competition(IARC)
 http://iarc.angel-strike.com/
 Overall Challenge: To penetrate a building,
navigate through the corridors and completing
tasks such as replacing a USB stick
▪ Our specific challenge: To build a platform capable of
flying autonomously, stabilizing and avoiding obstacles
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

1.5kg Maximum Total Platform Weight
Low Power
 Battery Powered
 Capable of >10 minutes of flight time (20+
minutes reached with 1278g weight)

Operational
 Capable of onboard stability control (Generation
of PWM signals from Pic )
 Wireless base station communication
▪ Wireless link capable of at least 42 meters
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
Expandable
 Potential for navigation in a GPS-denied
environment
▪ Obstacle Detection Module using Laser Range Finder
▪ Support for computer vision system
 Connectivity for manual remote kill switch
 Potential for remote autonomous commands
 Connectivity for wire-burn USB stick drop-off
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
Working with 2 other teams this semester
 Engr 467 – Platform Team worked with last
semester
 Engr 466 – Second Semester, Controls Team for
Project

Weekly team and large group meetings
 Team lead from Engr 467 leads group meeting
and combines agendas from each team

Working closely with Controls Team to set API
and sensors to their requirements
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

Quad-Copter
Sensors
 9 DoF IMU
 Laser Range Finder
 Camera Vision System

Control System
 Dedicated stability
controller

Remote Kill Switch and
Manual Control Ability
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

WiFi to base station for vision processing
Two separate control modules
 PIC dedicated to stability control
 Main controller for system control and
communication

Internal and External Sensors
 IMU - stability algorithms in PIC
 Altitude - detection through Sonar
 Laser Range Finder - collision avoidance and
navigation
 Cameras – finding room and USB as part of challenge
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
Hardware System
 Processing

Software System
 Software Architecture

Sensors System
 Internal and External

Power System
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
Laser Range Finder - >$2000
 Hokuyo URG-4LX - 240º
 Obstacle Detection

range : 2mm – 5m
Sonar – LV-Max Sonar-EZ 4
 Depth Sensing
 Obstacle Detection, Control System

IMU – Analog ADIS 16400
 9 Degrees of Freedom
 12bits Resolution: +/- 300˚/s, +/-18g, +/-2.5 gauss

Gumstix Overo Fire COM
 TI OMAP3 720 MHz w/ 256 MB RAM
 Angstrom embedded Linux kernel
 Integrated USB, WiFi

PIC32MX795F512L
 80MHz, 32-bit MCU
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
Larger number of teams
 Controls Team: Vision and Navigation




Improved budget
Re-evaluation of system design
Arrival of some parts
Communication Breakdown
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

Manually flyable platform
Table-top test system
 Hardware
 Software
 Sensors
 Power
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
Gumstix
 SPI
 Ad-hoc WiFi w/ DHCP
 Gcc

PIC
 Sonar
 PWM
 SPI

PICstix
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
Overall system level software

Obstacle Detection Module
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



int isLeftBlocked();
int isRightBlocked();
int isFrontBlocked();
int isBlocked(int index1, int index2);
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
Hokuyo URG-04LX Laser Range Finder
 Connection through software established
 Program developed for initializing and reading in data
▪ Sub function of forward and side obstacle detection

Sonar
 Connects via USART serial in
 Consistent altitude measurements into PIC32

IMU
 Was not acquired, deemed a low priority
▪ Gaui 330 by Controls team used to simplify controls
▪ IMU still needed, but flight capable through stability system on Gaui
 Were advised to concentrate on integration of other parts
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
Lipo Battery
 2 – 3cell pack combination will be used
 11.1V, 6400mah, 20 C
 320g

BEC voltage regulator
 11.1V (ESC’s, 4 motors)
 3.3V (PIC)
 5V (Laser, Gumstix, Camera, Sonar, IMU)
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Motor
Motor
Motor
Motor
ESC’s
Laser
11.1 V
Gumstix
Current Measure
11.1 V Lipo Battery
3-cell
Voltage Regulator
5V
Camera
Sonar
3.3 V
IMU
PIC
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
SPI
 Oscilloscope, register watch, Gumstix terminal

Sonar
 Oscilloscope, register watch
 Fixed position, yard stick, LEDs

Power
 Manual flight endurance test
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
SPI
 PIC and Gumstix run at different voltage

Sonar
 Sonar is accurate to 1 inch
 Ranges up to 44 inches

Power
 Flight time of almost 21 minutes
 With 1278g weight
21
15 trials in each test case
Side
True Positives
(%)
True
Negatives (%)
False
Positives(%)
False
Negatives(%)
Left
100
0
14.28
85.71
Right
100
0
35.71
64.28
Front
98.4
1.6
28.571
71.42
Average
99.46
0.5
26.19
73.81
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Implement IMU with format for use by Controls
team
 Set up cameras with frame grabber
 Order designed PCB

 Test all connections and functions


Conduct stability tests with all items on platform
Implement navigation algorithm
 Basic algorithm designed by Controls team

Test runs on complete platform
 Debug as needed
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
Importance of Communication
 Too many visions, too little time
 But I thought….

Full team from start
 Playing catch up
 Defining roles


Attention to detail
Biting off more than you can chew
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
First successful flight
 http://www.youtube.com/watch?v=SKbRr4Nj6V4

Demo of ESC shutoff at low voltage
 http://www.youtube.com/watch?v=Hx0s8WKSEH
8

Endurance Flight
 http://www.youtube.com/watch?v=jSsSbn8tQgk
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