Turning with 4WD / Pneumatic Tires / Wide Config

Originally Posted by Nemo

Our team is running a wide configuration 4WD with 8" AndyMark pneumatic wheels. Its wheel base is 32" wide and 15" long. It is geared for about 5 and 12 ft/s. Tires are fully inflated.

It skips and jumps when it turns. We can still get around just fine, and maybe we will smooth out the turning one way or another. But my main question is should we have seen this coming? I had assumed that it would turn well with a wheel base that was twice as wide as it is long.

It depends. How far apart are your wheels? Our wheelbase on our wide robot this year is longer than the one for our long robot last year (we used 8" wheels then, and 4" wheels now). To answer your question: You couldn't have seen it coming, although with some thinking you maybe could have. Pneumatic tires are proven to have a higher coefficient of friction against the carpet than the traction wheels do, so they will be harder to turn. I can't say for sure, but maybe letting a bit of air out of the tires will help a bit. If anything, it will make it easier to go over the bump, which I assume you're doing, since the deflation will create its own shock absorb system for the robot.