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Unread 22-01-2014, 14:35
aldaeron aldaeron is offline
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AKA: -matto-
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Re: Driving Straight Error

Quote:
In the videos, we commented out the gyro code, but the gyro was still attached. Would that affect the driving?
There is no significant reason to electrically unhook it if you are sure all of the code is commented out. I have found that I thought all code related to a sensor was removed and there was some hidden code 3 levels deep. Unplugging the sensor makes sure the cRio is not using the sensor (and helps find hidden code relating to said sensor)

Quote:
Unfortunately, we didn't document when we got the motors, so I'm not sure if they are the same vintage. However, the labels on the CIMs are different. There's a picture of it attached.
We typically write the year of purchase on the rear of the CIM case in sharpie. We have seen that after a full season some motors don't have the same power response to a given voltage as brand new motors.

Did you try swapping out PWM ports?

Did you read the drive voltages put out by the Talons?

Did you try driving with just 2 motors at a time (I realize this is time consuming to swap them in and out)?

Another (crazy) thought

Is your left-right weight distribution equal? Are your wheels making equal contact with the carpet? Are the wheels of approximately the same Coefficient of Friction (i.e. same material, same wear)? What I am getting at here is that for an identical power transmitted from each gearbox to the left and right side wheels - is there something causing a different force to be applied at the left and right sides? From the video this does not appear to be the case.

I am not surprised that a tuned (or almost tuned) PID fixes the problem. The PID will drive the error to 0 if tuned correctly by correcting the PWM signals. However, I don't think you want to be at the competition and have your driver press forward on the controller and get a non-forward motion.

-matto-