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Unread 25-03-2009, 18:16
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221 Robotic Systems Engineer
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PID on a one directional Shooter

Just wondering if anyone has a good solution for pulling off some sort of PID on some shooter wheels that can only spin one direction. We're using encoder feedback to get the current speed of the shooter wheels and we have setpoints for how fast we want them to be spinning.

The issue is that the error is so far off that the shooter wheels spin up very fast and overshoot (even with an extremely low P and no I/D). We had to set the motor power so that if the PID sends a value less than 0, that it's set to 0. What we're experiencing is the motor power going between full on and full off.

Any ideas would be greatly appreciated. Thanks!
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Eric Barch
221 Robotic Systems
Controls Engineer
http://team221.com