Moniter Motor Speed

[markulrich]

My team is planning to create a shooter similar to this one (http://www.youtube.com/watch?v=ZIlRWFW9jsk&NR=1), with 1 CIM motor directly driving the bottom wheels. The goal is for the camera to detect distance from the trailer and then automatically set the motor speed.

Do you think we'll need to set motor rpm using a PID loop, or will just setting the PWM output be enough?

If you think we do need to monitor the speed, what sensor should we use? Geer-tooth counter? Encoder? Pots? How are they mounted? Do you know what part number will work with the WPI Libraries?

Thanks in advance!

[360skier]

I would recomend a PID loop if you want to be changing the motor's speed, although they do take time to tune. Most encoders should work with WPI providing you set them up right. However, if you are changing the speed you will also need to take into account the inertia of the wheels.