We recently finished our new drivetrain and we noticed that it slightly drifts to the right. Before you ask, yes, we have used the search bar to see past topics, but none of the solutions worked for us. Here are pictures:
If anyone has recommendations or ideas on what is going wrong or how to fix it, I would love to hear. Thank you.
Maybe you could try using a four motor drive instead mainly just for torque. I don’t personally know if it would work fully but i would say its good to try. Another thing is maybe you could not use only omni wheels and instead have other traction based wheels (6 wheel drive) thats what my team is doing and it works well.
The drive might pull to one side either cause of uneven weight distribution or cause of increased friction on one side that cause that side to spin slower and then it turns to that side.
I don’t know what you have already tried, so I’ll offer my standard ideas, recognizing you may have already tried them…
Are you certain the floor/field is level?
Does it do this on other fields or other parts of this field?
Is the robot square & level?
It’s hard to tell, are there washers between the gears and the inside beams?
Are the wheels rubbing the outside beam on the right side?
The axels I can see appear to be metal. Are they all metal? Are any bent?
Does it continue if you swap or replace the motors?
Does it roll smoothly without the motors? Does everything turn smoothly by hand without the motors?
Does it do this at every speed?
Try testing the drivetrain at slightly lower rpm’s. One of your motors may be a bit slower or weaker than the other.
Just checking because I can’t see, you use thin spacers everywhere on the end of your axles right? Because if not that could 100% be your source of friction and therefore drift.
This might not be the problem, but check to make sure that the axles are straight, so if they’re in the 8th hole on one side, they are in the 8th hole in the other. That solved it when I experienced the same problem. If that does not work, try replacing the motor on the side that the robot is drifting towards.
I’ve noticed that the motors don’t always spin at the same speed/torque. I would test all of your motors and pair up similarly-scoring ones onto the drivetrain. (this only works if the rate if drift is linear. I can’t tell if you are stopping hte robot before it hits the beam)
We will test this and will see the outcome. Thank you!
When we can, we will test this and will give feedback. Thank you!
Yes, we did use washers between the gears and beams.
I believe the axles are straight, but I will check. Thank you!
We will try this and see the outcome, thank you! 
The shafts are all metal, there are washers between the gear and beam, and the wheels are not hitting against the outside beam. I will try your recommendations later and will give feedback. Thank you!
We would like to use a 2 motor drive cuz we are going to build a revolver once we finish the drivetrain.
Ahem, lemme silence this debate once and for all.
Hear me out; Stick Drift??
Nope.
We calibrated the controller before testing it again…
Shoot! I tried to be the hero to “Save the topic ;)”
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Obviously I failed
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Oh! I thought you were using a program and that the controller was not even in the situation. I’d recommend first then writjng a short program to drive forward say 36" and first make sure it isn’t the controller
My team had this problem last year, we never really sorted it out…
One thing we tried was changing one wheel on each side to be a non-omni wheel, maybe that would work for you?
Well I would still recommend to do a four motor drive, I believe you could do it (if you run out of motors you could use a Pto).
Have you tested this out? I often have this problem when my little kids build their first drivetrains because we have some bad motors. I also want to check if your field is level (It looks like it’s level in the video, but you never know). We also often have problems with faulty wires and controllers (regardless of drift calibration), causing some issues and needing to switch them out. The last thing I would suggest is to clean off your gears, axles, and wheels. Let me know how it goes, hoping for the best!
Thank you. It is definitely possible that the field is not level, since it is in our old garage (the drivetrain drift has become a problem in past seasons) so we will try it in another room or place tomorrow afternoon.
Yeah, that’s probably the issue. An unlevel field will make programing auto skills a nightmare.
