Project report on the development of a robot that autonomously picks up a blue/red ball. All photos and videos are copyrighted by Jeanna Nikolov-Ramirez and/or Konstantin Leidermann.

1. CogRobot
the
Team CogRobot:
Filip Birčanin,
Konstantin Leidermann,
Jeanna Nikolov-Ramirez,
Lennart Paar
29. 6. 2015, University Vienna
Lenni
Intro2Science

2. OUTLINE
• The Plan
• The Architecture
• The Process
• Hardware
• Technical Specifications
• Image Capture
• Code
• PID Controller
• Trials and Debugging
• Lessons Learned
2

3. THE PLAN
• Build a robot that detects and
item in a room and picks it up
• Detecting an item
• Discriminating task (blue or red)
• Exploration (Random walk)
• Navigation
• Lifting up device
(embodied, maybe even just a
paper device on a physical level)

4. THE ARCHITECTURE
NXT Brick GoPro
Laptop
Nxt-python[1]
Gopro-
Python[2]
Get sensor/motor
data (Bluetooth)
Send Motor Commands
(Bluetooth)
Get video feed
(http, wireless)
Integrate and
calculate motor

5. MARR’S LEVELS

6. THE PROCESS
• Camera Integration
• Algorithm for Object Detection
• Random Walk and Navigation
• Find out wheel speeds according to
approaching of the goal
• Feedback Control
(power values for different motors)
• Mechanical Lifting up Mechanism

7. BEGINNINGS
Requirements:
• Camera should be centered in
front of the wheels
• Ball lifting mechanism purely
mechanical
• Ball should disappear behind
camera
PEAS description
• P:
Successfully picking up a ball
• E:
deterministic, partially
observable, size not fixed, one
or two red/blue objects
• A:
Wheels, Grabber
• S:
Camera, (Bumpers?)

8. MEETINGS
5 Meetings

9. HARDWARE

10. SOFTWARE SPECIFICATIONS
• Mac OS 10.8
• Python 2.7
• OpenCV
• Mindstorms NXT

11. IMAGE CAPTURE

12. CODE

13. CONNECT

14. PID CONTROLLER
A PID Controller is a common technique used to control a wide
variety of machinery including vehicles, robots and even rockets.

15. CONTROL ALGORITHM

16. TRIALS & DEBUGGING

17. SH&%#*^#%T HAPPENS

18. LENNI LIKES BLUE

19. 19
LESSONS LEARNED
• Building robots is fun.
• It’s way more difficult than expected.
• Installing the framework is more complicated than
running it. These tasks are insanely platform
dependent!
• It needs a lot of installing of libraries and packages to
actually be able to start the work.
• Difficulty testing with 1 brick and 4 people.
• NXT doesn’t like Yosemite.
• Red fingernails are the same to a robot as a red ball.
Everything yellowish seems to be red, too.
• Each task needs a motor.
• Weight and volume matter big time in objects.
• Pairing with Bluetooth sucks.
• Batteries run out quickly.
• If it isn’t tested, it doesn’t work.
• Lots of trial and error.
http://tts.imtranslator.net/WW49

20. 20
THANK YOU!
Questions?