Drive Train Speed

[T^2]

Originally Posted by Ether

Those two statements contradict each other. Increased frictional losses will affect the final speed.

In addition, due to the pliability of the carpet and wheel tread, more weight will mean more loss to rolling resistance.

The friction and acceleration models taught in high school physics classes are usually not complete enough to be accurate in FRC. I recommend testing for the top speed of your robots, then weighing them down and testing again. I doubt you'll produce the same numbers.

[nuttle]

This is why I used the word directly -- I agree that weight makes a difference indirectly, and that this needs to be modeled if you want to really understand what is going on and design for optimal performance (which has to be defined in the context of the requirements). Losses through interaction with the carpet can be considered a form of friction, again with a dependency on weight...

I often write too much, but I guess I wrote too little before!

[T^2]

Originally Posted by nuttle

Losses through interaction with the carpet can be considered a form of friction, again with a dependency on weight...

Rolling resistance has nothing to do with friction unless the wheels are slipping, which they aren't if the drivetrain is moving in a straight line. Rather, the losses are the result of deformation within the contacting surfaces.

[AdamHeard]

Originally Posted by T^2

Rolling resistance has nothing to do with friction unless the wheels are slipping, which they aren't if the drivetrain is moving in a straight line. Rather, the losses are the result of deformation within the contacting surfaces.

I think the point he was making is that in terms of modeling a system and seeing it's speed, rolling resistance can be lumped in with friction. A single friction term that covers all sources of "friction".

It's a fair point, and simple models are commonly done that way.

You are correct that rolling resistance isn't friction, but it shows up in the same way.