[FTC]: LabView Encoder Problem

Other FIRST Tech Challenge
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Hi. We are having problems with our LabView autonomous programming, specifically with the encoders. As a trained chemistry teacher, I have little experience with programming, so I hope you can help us out. The problem we are having is that the robot will not move as we think we have it programmed to. For example, in the file titled Encoder1Test, we believe the robot should move forward a little, then turn, then move forward again. However, it actually will never get to the turn. It seems to be stuck on the first move forward and will not stop until it slams into the wall and we disable. While in Encoder2Test, the robot barely moves at all, even though the numbers for the encoders are much bigger. The programmer has changed numbers and everything we could think of; however, it has not worked. So, does anyone have ideas of what is wrong, and what to fix? Thank you for any help that you can provide. We appreciate it.

By the way, our robot is driven at the two back wheels. The encoders are attached to the motor with an 80 tooth gear which drives the wheels, which have a 40 tooth gear.

Encoder1Test.doc (103 KB)
Encoder2Test.doc (123 KB)


Encoder1Test.doc (103 KB)
Encoder2Test.doc (123 KB)

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I’m not too familiar with this year’s FTC LabVIEW, but what I’ve seen messes most programmers up with going a fixed distance is the encoder reading’s sign. Check to make sure that the encoders you’re using are going in a positive direction, not a negative one. If they’re going in a negative one, you’ll have just over 2,100,000,000 degrees to go before your robot stops.

If they’re going in a negative direction, flip the sign on your ‘distance’ parameter.

If this fails, then try the Constant Speed (move motors with PID Control) function, then wait X milliseconds, then stop the motors. I’ve found that this is more than accurate enough to base a solid autonomous around.

Good luck!

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