[Chris Hibner]

I'm going to disagree with PitBull a little bit...

I think the key to an easy-to-drive drivetrain is having the optimal lateral coefficient of friction (not the lowest). That is much easier said than done, but here is why I feel this way:

1) If you have too much lateral friction, your drivetrain will not turn well (or maybe not turn at all). This is obviously not desirable for many reasons that everyone knows, so I'm not going to explain further.


2) If you have too little lateral friction, the robot can become difficult to drive. Why? Inertia!

When your driver let's go of the stick, the robot will continue to turn. The amount of excess turn is inversely proporional to the amount of lateral friction you have. If you have too little friction, the robot becomes hard to control since the driver will let go of the stick where he/she want the robot to stop turning, and the robot will overshoot past the stopping point. This can be overcome with a lot of practice, but the whole point of this thread is to make a robot that doesn't require as much practice to drive.

Over the years, we have had robots that had very little lateral friction and I will definitely say that they were our most difficult robots to drive. Once we went to 4-wheel drive, the robots would stop turning the instant the driver let go of the stick - these robots were very easy to drive.

So, the moral of the story is: less friction is not always better. There is an optimal amount of friction - good luck achieving it.