V5 Drivetrain Having Troubles Turning

Recently, I’ve had issues with my drivetrain where my robot will slowly come to a halt when turning. We’ve tried swapping out the motors and changing the ports however that doesn’t seem to be doing anything. The programmers also claim that the code should be fine as well. Has anyone else had this issue and if so, how’d you solve this?

Can you show a picture of your drivetrain?

You need to be more specific. Post pictures of your drive train as well as your code. What you’re describing to me now seems like a friction issue and mass imbalance.

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image
This is a bit of an old photo but somewhat the same besides that the motors are now connected directly to the wheel

I know your coders say the code is fine, but I would advise having everyone look over the code. The omnis should turn, and I dont see any reason why you shouldnt be able to turn, unless the wheels are catching on something

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Try taking off the motors and seeing if the wheels turn freely; If they don’t or are hard to turn then you have too much friction. If you spin one by hand it should spin for a good number of seconds.

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Did it work before you went to a direct drive?

Your wheels look really close to that C-channel. Is there a spacer in between them? If the wheels are rubbing against the metal it will make them hard to turn. Same thing with the sprockets.

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Nah, the c channels aren’t touching the wheels and they can spin freely when not connected to the motor. A direct drive also didnt fix the problem either. We haven’t checked the code yet tho

If you have checked @PortalStorm4000 caution about wheels touching c-channel and inserted extra washers or spacers, then, please, check that your rollers on the omni wheels . If old goo accumulated they will not spin easy. Wash them in soapy water and then carefully dry.

Then, please, follow @Railgunawesome advice and check everything in your code. It may be that one of your motors is trying to drive in wrong direction when turning.

Edit:
One more thing I forgot to add: try to switch to the larger sprokets. 6T sprokets are not efficient for the drive. A lot of power loss.

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Alright, i’ll try checking my omni wheels as they are quite old. I’ve checked the code now and everything seems to be doing what it’s mean to be.

There might be a slight misunderstanding, my robot does turn, however will gradually start to slow down as you continue to turn and eventually come to a complete stop.

This may seem like it won’t matter with Omni wheel, but if the center distance between front and back wheels is greater than the center distance side to side, you are increasing the effort required to turn the robot.

Also, which gear cartridges are you using in the motors?

I don’t think this is the issue, because the omni wheels reduce turning scrub to almost 0, so there would be minimal resistance, although there might still be some

Edit: Don’t rule out this possibility yet, it could be a potential issue, its just that it seems unlikely

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I used to think that as well but did some testing awhile back and found that the current draw on the motors was greater if the drive was longer than it was wide.

My drive currently is 25 wide and 30 long. The front wheels are just behind the chassis and my back wheels stick out from the chassis. I’m also using 200rpm cartridges.

ok. u use 4 motor . i suggest u refer to VEXcode, motor groups and drivetrain example