We are using a 4 motor 1:1 torque drive not chained together. We are looking to speed up our base some but we burn out if we do highspeed motors of any sort, and external sprocket or gear ratios also tend to burn out for us when going over the bar; does anyone have any suggestions on how we could speed up our drive without burning out?
How heavy is your robot?
About 15-17lbs
That’s pretty heavy. However, it is not heavy enough for a High-Speed Direct Drive to be stalling. I would say check your friction and lower your weight a bit
Here’s a quick tip. Take off your motor so that the wheel is free spinning, then spin it. If it spins freely and takes quite a while to stop spinning you’re fine. If not, try to align the two bearings holding the wheel together so that the wheel spins for longer.
I would check for any unnecessary friction that may be in you base i.e. the bearings not being aligned as Entropy mentioned. Also, check if the shafts within the bearings can move with ease as some bearings are not perfectly drilled. Hope this helps.
Definitely make sure that there’s no additional friction and that the wheels aren’t caught on anything. That’s happened to me several times, but it’s a pretty easy fix.
Look at where your weight is most concentrated, if it is more to one side (front/back), then make a 2-motor direct drive to the wheels with the most weight on them, and then add a HS chain to the remaining wheels and put that on the direct drive axle.
By my calculations, 4 motor high speed on 4 inch wheels can carry about 18 pounds, so your bot is probably just a little bit too heavy or you have just a little bit too much friction, so metal washer it up (metal washers provide less friction than plastic, just because they’re smooth, and cut out some extra pieces off your robot.
I have been told it is not the case, can someone clarify this? I was told that metal on metal is bad, and to always use the teflon washers. But I may be wrong too, just wondering if this is an opinion because they “feel smooth”, or if the metal washers are proven better.
I always thought that too, until my friend Kyle told me about and I conducted a finger test and got the result the metal were actually better. You might want to conduct more extensive tests before you do anything to your bot, though, I could be wrong.
Teflon has just about the lowest coefficient of friction of any material you will run into in your normal life. I would question the conclusion about the metal washers, which have coefficients of friction (mild steel-to-mild steel or mild steel-to-aluminum) of 10-15 times that of Teflon-to-steel.
Ok, I will do some more research (search the forum), but if I can’t find anything, I may just create a new thread.
[Edit: answered by @Rick TYler ]
No common engineering materials have less friction than teflon.
Here are the coefficients of dynamic friction for each of the indicated materials running against dry steel or aluminum:
Dry steel: .70
Greasy steel: .23
Nylon: .10
PTFE: .05
in the list above, low values indicate lower friction. PTFE (teflon) is the best, but nylon is good as well.
Ok, my tests must have been wrong. Thanks for letting me know, that could have turned out badly.