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Unread 01-03-2012, 23:01
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Alpha Beta Alpha Beta is offline
Strategy, Scouting, and LabVIEW
AKA: Mr. Aaron Bailey
FRC #1986 (Team Titanium)
Team Role: Coach
 
Join Date: Mar 2008
Rookie Year: 2007
Location: Lee's Summit, Missouri
Posts: 763
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Re: Team Titanium 1986 Reveal

From what I can tell from today's practice matches everything is working within tolerable perameters. So in an effort to help others be competative we will share our stupidly simple method of controlling the shooter wheel speed without using an encoder or PID. Feel free to let us know if it is helpful to anyone.

Motor Output to Jags on shooting wheel was set to [(Constant x Shot Distance)/(Battery Voltage)].

In this manner as the battery voltage drops during the match (or fluctuates with other robot demands on power) we still end up putting the same voltage (if available) to the shooting wheel motors and achieve a predictable speed. If the desired voltage is not available an indicator light alerts the co-pilot.

The constant was determined by graphing the value needed to make shots at various distances and using the equation for the best fit line. In this manner the constant became a function of distance as well.

We are prepared to implement an encoder with PID, but this method is working really well. They great thing is almost any team who is struggling with shot consistancy over the course of a match can add this idea into their code without having to add any hardware.
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Last edited by Alpha Beta : 02-03-2012 at 01:12.