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Unread 16-01-2007, 21:10
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Alan Anderson Alan Anderson is offline
Software Architect
FRC #0045 (TechnoKats)
Team Role: Mentor
 
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Re: quadrature

Quote:
Originally Posted by Andrew Schuetze View Post
...one is often powering the motor from which sensor data is being generated. Meaning you already know its rotation and just need rotational speed for closed-loop feedback.
It took us a few tries last year to find and correct a small problem with this idea. When turning a small amount, the output from the direction PID can sometimes be too small to get out of the Victor deadband on one side of the 'bot but still drive the other side. What happens is that the entire robot moves forward, while the feedback routine is assuming it's turning in place. We had to ensure that we always applied a high enough control value to the Victors to actually make the motors move in the desired direction.