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 Technology School of Electrical and Computer Engineering April 28, 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 $1,600

Automated Football Launcher Components Two Logitech Webcam Pro 9000’s Phidgets Motor Control Board Two 12V DC Motors Pan/Tilting Platform Phidgets Relay Board Compressed Air Launcher

Final Design

18.5 in

Final Design

Logitech Webcam Pro 9000 Utilized dual Logitech Webcams to implement stereovision Both webcams used blob-detection algorithms to locate a color in a frame The object’s location in each webcam’s frame was passed along to the main program

Webcam Tracking Algorithm

Data interaction A TCP Server/Client protocol was used in order for the webcams to communicate with the motor control program Each webcam detection program ran concurrently as two separate TCP clients and connected to the main program (server) Each webcam detection program outputs an X coordinate Multiple threads were used in order to obtain concurrency Motor & Relay Control (Server) Left Webcam (Client 1) Right Webcam (Client 2)

Angle Calculation Use proportions to calculate angle from plane perpendicular to webcam lens Webcam viewing angle: 75° Resolution: 640x480 pixels Half screen: 320 pixels Formula: (320- xPos)/640 * 75° ƟƟ - + Webcam Lens

Distance Triangulation Use two webcams with a known distance apart Use Law of Sines to calculate object distance with the two calculated angles from each webcam d Ɵ ƟƟƟ

Final Position Calculation Calculate theta and distance at two points at time t apart from each other Calculate change in Z velocity and theta velocity: Δ Ɵ = (Ɵ 2 - Ɵ 1 )/t Δ Z = (Z 2 - Z 1 )/t Predict Y and theta at future time t f Ɵ f = Ɵ 2 + (Δ Ɵ * t f ) Z f = Z 2 + (Δ Z * t f )

Phidgets Motor Control The angle and distance calculations are sent to the motor control board Set tilt and rotate motor velocity to 80% of their maximum value Hold rotational velocity constant for 200ms per 10 ° of Ɵ f Hold tilting velocity constant for 2000 ms per 30 feet of depth

Phidgets Relay and I/O Board The Relay board is connected to a digital output on the I/O board This allows the relay to be turned on on-demand from the main program The relay opens a sprinkler valve after the route is completed by a receiver

Orbit 1” Sprinkler Valve The sprinkler valve routes pressurized air from the fill tank to the barrel This is accomplished by sending the integrated solenoid a 24V AC signal Valve transfers air from the fill tank for a duration of 300 ms

Operation Algorithm Start tracking receiver Find theta and Z for position 1 Hold algorithm for 2 seconds Find theta and Z for position 2 Calculate future position of receiver Timely rotate and tilt launcher to desired trajectory Launch ball after specified time

Marketing Estimated System cost – Two Logitech Webcam Pro 9000’s: $200 – DC Motors and control board: $200 – Moderately powered computer: $500 – Air compressor launching system/platform: $700 Total: approximately $1600

Design Objectives Continuously track a moving object using webcams 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

Goals Create reliable Motion tracking Use optical tracking with webcam Improved algorithm with bounding box Distance calculations are within ±15% Trajectory algorithm is 80% reliable Complete passes up to 50 yards accurately Completes stationary and slow routes Can launch ball up to 85 yards

Future Work Consider more complicated tracking methods such as RF frequency modulation for better performance in all conditions Integrate with the Jugs Football Thrower Create a hopper system to automatically feed and reload multiple footballs Improve visual packaging

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