Thread: Measuring RPM
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Unread 17-01-2016, 18:06
nighterfighter nighterfighter is offline
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Re: Measuring RPM

Quote:
Originally Posted by dradel View Post
We are using a wheeled shooter this year, and I am thinking to have a repeatable shot the wheels need to spin at same rate every time so was thinking using the versa planetary encoder to read and set rpm on the wheels
Yes, you do need a feedback mechanism to control the speed of the shooter wheel. Just always setting the motor value to ".75" or what have you, won't work, as the actual speed will fluctuate.

To control the RPM, you can use a variety of methods. One method is Bang-Bang (what we used in 2012) and a whitepaper can be found here.

Another option is to create a PID loop that runs on the roboRIO.

Another option, at least in years past, was to feed the encoder values directly to a Jaguar, and the Jaguar would run the PID loop for you after you give it a set point. I am not sure what the equivalent motor controller of today is that can do that, however.
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