Automated Football Launcher: Methods for Completing Autonomous Football

Passes using Motion Tracking

Carmine Milone, Joe Milone, Alex Heydari, George Yue, and Joe Fyneface

Georgia Institute of TechnologySchool of Electrical and Computer Engineering

March 17, 2010

Project Overview• Continuously track a moving object using web-

cams to deliver a football accurately• Apply technology for football teams in order

to reduce work load for trainers • Estimated development costs at $80,000;

initial cost of a prototype system will be approximately $1,500

Automated Football Launcher Components

Design Objectives• Continuously track a moving object using web-

cams in real-time • Analyze the path of the object to determine

the launching angle and direction• Utilize a motor control algorithm to attain a

specified trajectory • Launch a football triggered by a relay board

Summarized Design Flow chart

Current Status • Web-cam tracking program completed• Motor control and relay board code written

and tested• Compressed air launcher and platform are

under construction

Logitech Orbit Web-cam• Resolution: up to 1600 by 1200 pixels– Currently using 640x480 resolution for better

performance• Color depth: 24-bit true color• Frame rate: 30 FPS– 15 to 20 FPS when detection algorithm is running

• Interface: USB 2.0

Phidgets HC Motor Control Board• Controls up to two DC motors• Updates data 50 times/second• Can provide up to 18A • Utilizes USB connection

Motor Specifications• Type: DC Gear motor • Voltage: 12V• Current: 14A-19A– Currently programmed to utilize 7A

• Controlled using Phidgets HC Motor control board

Pan/Tilting Platform

Phidgets Relay and I/O Board• Relay board:– 2 relays for switching AC/DC– Up to 240VAC at 10A – Up to 100VDC at 5A– Will open/close air valve

• I/O board– 8 analog inputs– 8 digital inputs / outputs

Compressed Air Launcher• 6 in. diameter PVC pipe– Can be interchanged with a 3 in. diameter PVC

pipe• 135 psi• 3 gallon air tank• Controlled with Sprinkler valve

Technical Approach• Calculate the offset between the center of

the web-cam's frame and the object’s position• Translate the offset into a motor control

launch angle and direction• Predict the object’s final position and launch

the football timely to the specified location

Web-cam Tracking Algorithm

Tracking using Blob Detection • Web-cam searches for a specific color• Code written in C# using .NET framework• Utilizes DirectShow library • Accesses pixel data directly from memory

Web-cam Tracking Demo

http://www.youtube.com/watch?v=162fvelALGU

Motor Control

• Coded in C#• Tracking determines degrees of rotation/tilt• Use small movements as a unit of translation• Keep velocity constant

Trajectory Algorithm

• Use kinematics to determine angles of the platform

θ

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Alternatives• Linx RF modules were developed and tested for tracking

– RSSI / Triangulation tracking methods were designed

• Did not work as intended due to destructive interference• Lower frequency RF modules are being considered

Challenges / Problems• Building the compressed air launcher and platform• Implement a web-cam algorithm to detect objects over 30

yards away from the launcher– Lighting constraints

• Lack of commercial football launcher• Develop RF modules for tracking

Marketing • Estimated System cost

– Logitech Web-cam: $100 – DC Motors and control board: $200– Moderately powered computer: $500– Air compressor launching system/platform: $700

Total: approximately $1500

Schedule• 03/29/2010: Finish building platform• 04/07/2010: Complete compressed air

launcher• 04/16/2010: Integrate all components• 04/30/2010: Complete system testing• 05/06/2010: Final Demonstration

Future Work• Consider more complicated tracking methods

such as RF frequency modulation• Integrate with the Jugs Football Thrower• Create a hopper system to automatically feed

and reload multiple footballs

Project Summary• Two candidate methods to track an object

have been compared and evaluated• Optical tracking has shown promising results

while RF needs more development• Optical tracking performs reasonably well if

the object is within 30 yards

Any questions, suggestions, or comments?