Tank Stearing - 4 wheel drive

[ngreen]

We are currently using a four wheel drive with four pneumatic rubber slicks. They get great traction. They are so good on carpet that the robot would jump. They had no problem on the ramp. To fix the jumping we added 2 casters on the back which are raised up and down with a pneumatic actuator. When we need turning on the carpet we push a button and they are down. They don't lift the back tire off the ground but push down enough to reduce the frictional force. Now it doesn't dance, unless we want it to, and we have more than enough traction for hardcore pushing. Yay!