So this is my first year in v5 along with my entire team and my second year of vex ever so I dont have alot of experience. We got a late start to the season were way behind and were stuck trying to figure out our drivetrain. We have had major friction issues and we dont really know how to fix it. We’ve learned alot of stuff and applied it and im pretty sure it should work way better than this. Everything besides the motor axles is a screw joint, there isnt any metal on metal, nothing is over tightened and nothing wiggles. Without motors it can spin for around 2-3 seconds with a medium push but as soon as we put motors on its clearly way worse than everyone else’s already finished drivetrain. Were using 36:60 gear ratio and green motors. Any ideas as to what might be going wrong?
Try testing your motors to make sure if they work properly? We had like 3 bust on us last year. Also, it might be that something’s going on when you’re screwing in the motor. It may be that you screwed in the motor a little off (using bearings on those screws or shoulder screws could help?) or you’re overtightening the motor. Also, keep in mind I’m like a second year in V5RC so maybe listen to someone more experienced. Pictures would help:)
You can try an insanity check first, sometimes it’s just some bad parts (particular motors) and/or dirty contact points (gears with dust tend to have more friction1). There is also the possibility of not enough power is getting to the motors, which you can swap out the brain, battery, and/or cables. Probably the stupidest way it is happening is faulty code, but I really doubt that. (Just in case you didn’t know, you can set the maximum torque of each motor with code)
My next idea would be that the axles are too tight. Last year my team has this issue and it was caused by collars on the axle contacting the bottom of the C-Channel and creating friction there. Collars on axles also create friction from just existing, so you can try to reduce the amount of collars you have and/or loosen them if you’re using the metal collars.
Your robot may be too heavy as well; since you are only on the drivetrain (I presume) then this probably isn’t it.
Lastly, you can try to overcome the friction with more torque, this can be done by switching to the red motors or using a lower gear ratio. You are using a 3:5 ratio, which means that for every 3 rotations of the input gear, the output gear rotates 5 times. To lower a gear ration make the input gear bigger and/or output gear smaller. A higher gear ratio has the output gear spin faster but with less torque, a lower gear ratio has the output gear spin slower but the with more torque
I hope this is of some help to you and your team : )
1 - This is just a quick explanation of why dirty surfaces have more friction (you don’t have to read this if you already know why)
Friction itself is caused by a bunch of tiny little bumps on surfaces; those imperfections catch the object that is sliding on, you can also think of it as a dirt road with lots of tiny little pebbles creating bumps as opposed to smoother asphalt roads. Dirty surfaces add to those bumps and would be like gravel road made entirely of pebbles as opposed to a dirt road with mostly packed dirt and a few pebbles