Robot Retrieval System
Millersville University
Contributors:
Frank Anamze
Ben Bowman
Brandon Dodson
Brad Lang
Jacquie Miley
Seth Powers
Ben Tarnowski
Matt Vazquez
Panama Beach City, Florida
November 6-9, 2002
Competition Rules/Objective
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Must be a tele-operated robot using no robotic kits,
only hobbyist level components are allowed.
The objective is to retrieve an unopened 12 oz. soda
can without creating damage to the can.
Must be able to travel in an unknown terrain obstacle
course while staying within the boundaries.
Manipulator may not be able to fly.
Multiple frequency channels are allowed but only one
operator.
Source: http://www.nait.org/divisions/roboticscontest.html
E-maxxbot
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Platform-Traxxas E-maxx:
Chose for sturdiness, high
clearance, and able to support a
heavy load.
Gripper:
Designed to surround the can
completely to ensure that it is
secure and free from any
damage.
Arm:
Designed to lift the can off the
ground to avoid the unknown
terrain in the obstacle course.
Platform-Traxxas E-maxx
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Purchased a hobbyist level
remote controlled racing
car that has the power to
withstand the weight of a
12 oz. soda can and the
rest of the mechanical
systems.
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Fabricated a light weight
aluminum frame for
mounting the arm and
gripper system.
Gripper System
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Fabricated a gripper that
mimicked the shape of a soda
can and completely
encompassed when closed.
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A shelf was mounted at the
bottom of the gripper to
restrict the can from falling
through when the arm was
lifted.
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To open and close the
gripper, a servo motor uses
rods to transfer circular
motion into linear motion.
Arm System
Overall IMA = Screw IMA * Lever IMA
Overall IMA = 4 * 1.57
Overall IMA = 6.28:1
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Used a first class lever system to gain a mechanical
advantage when lifting the soda can and gripper.
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A screw system is used to raise and lower the arm
assembly powered by a 14 volt DC motor.
Transmitters/Receivers
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Two transmitting signals are used:
27Mhz AM and 75Mhz FM.
27Mhz signal is used for driving,
steering (servo), and controlling the
gripper (servo) opened or closed.
75Mhz signal uses a servo motor to
mechanically switch back and forth
between the drive motors and the
screw system motor preventing both
motors from running simultaneously.
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This system activates relay coils between
the speed controller and the 14 VDC
motors to prevent high amperage flow
through the mechanical switch because
of the low amperage rating.
Troubleshooting
Problems
Solutions
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Interfering signals because of
metal frame.
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Replaced receiver unit with
different frequency.
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Shock absorbing springs were
too weak to support the full
load.
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Replaced with stiffer springs.
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Repositioned fulcrum to gain
mechanical advantage.
Replaced motor with a higher
power rating.
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Force needed to raise the
manipulator and load was too
great for motor being used.
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Acknowledgements
Special thanks to all who helped with their time and support.
Pit-Stop Hobbies
Dr. John R. Wright, Jr.
Dr. Haig M. Vahradian
Dr. John C. Hibberd
Dr. Kenneth P. Delucca
Mr. Mike Joy
Mr. Ken Stough
NAIT Millersville University Student Chapter