[joshyboy9987]

You mentioned keeping your distance accurate when the wheel is slipping. To do this, I'd use an accelerometer, and with some calculations, you can figure out what speed the robot should be at with a given voltage. Then if the robot is going slower than it should be, the wheels are slipping... I don't know how accurate this would be, but I know the kit accelerometers give you milliG's.. They do have to mounted just right though.