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Unread 15-04-2012, 18:10
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AKA: John Gillespie
FRC #1153 (Roborebels)
Team Role: Mechanical
 
Join Date: Sep 2011
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Re: paper: Shooter Wheel Speed Control

Quote:
Originally Posted by billbo911 View Post
Without actually tessting, I think one key to making this work well is a large enough moment of inertia. Actual testing should reveal what "enough" is.
During the season we used PID (with a feed-forward and other modifications) to control our shooter, giving us our speed to +/- 20 RPM (out of around 4000 max). Yesterday I tried to implement the "bang-bang" controller in order to compare it to our PID loop. It seems our shooter does not have sufficient inertia to maintain a stable speed, as it oscillates uncontrollably.

The wheel we are using is a 4 inch diameter by 4 inch width wheel, made out of the hub of a plaction wheel and 4 inch diameter PVC pipe, so it should have significantly less inertia than the 6 or 8 inch wheels that many teams are using.
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