Gear by Chris McDonald

The Treetech robotics team from Stephenville, Newfoundland, 
Canada went to the Canada First Robotics
games just a few months ago bringing home the Jim Floyd 
award for design excellence, the entrepreneurship award, 3rd in best
engineering panel presentation, and 2nd for Best dressed robot. 
This years sport was RoboHockey and we finished 7th over all out of
22 in the competion.

Our robot was controled by a standard R/C controler that was suplied by 
canada first along with a revicer and controler board.
Because of this the electronics side was pretty strait forward. Though 
we did have a few problems with the control board because of
bad instructions sent to us by canada first and a few faults in the 
design of the board. The robot was powered by two cord less
tools batteries.

The mechanics of this robot was where the challange was. We had to 
build and design a device that was contained inside of a
standard Rubermade garbage can 
as seen here on my head and shoot a street hockey puck 
around 20 feet. We also wanted to beable to shoot from either the 
left or the right of the robot so we decided that having a shaft 
that could shoot out from the center of the robot would do the 
job nicely. Then came the problem of how to store a large amount 
of energy and then relese it when we needed it. So we came up with 
a winding mechinism that pulled the shaft back storeing energy in 
the springs. Then when we are ready to shoot the puck we would 
release a cluch in the winding mech. that would let the cable free 
wheel letting the energy travel from the springs down the shaft, 
to the stick and then finaly into the puck.  Finaly turing the 
stick was done simply by bycicle cables attached to a pully on a 
motor on top of the robot and a pully on top of the stick.

The drive system was prety strait forward. We had two windsheild wiper 
motors(well thats what we think they are) that Canada first
sent us. We got sprokets from old 10 speed bikes to and had them 
modifled to fit on a 1/2 shaft and used chain's to connect the
motors to the drive shafts. We used a 1 to 3 gear ratio(I think) 
which gave us one of the fastest robots at the competition the
down side of this was that the robot was diffcult to control at
times.

Our design worked good during the compection execpt that they changed 
the rules during the competion allowing more contact bettween
the robots makeing it harder for us to line up a shot at the net. 
They also allowed robots inside the crease and there were often
robots blocking the net.

For more pictures see My home page
For more info and pictures see Treetech website
For more info on Canada first see Canada First's Website Email: garak@166warp76.newtel.com

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