[Jon Stratis]

For what it's worth, back in college, I took an Autonomous Robotics class - essentially, we played with MIT's HandyBoard and a bunch of Lego's all semester, with a game/competition at the end of the semester. I ended up designing a caster wheel (out of the provided Lego's) to use on the robot (2 drive wheels in front, 1 centered caster wheel in back) The biggest problem we had with the wheel, before we got it designed right, was it pulling apart or pulling out of the joint where it attached to the robot - there was simply too much force on it when the wheel was trying to turn (and we designed for 90% of the weight to be over the drive wheels)!

Now, given the situation, the caster wheel provided us with a great advantage - Unlike all the other robots (which had 4 traditional drive wheels - no one tried doing a 6-wheel drop center... hadn't even heard of it at that point), ours didn't have to overcome scrub on the wheels when it was turning, and we could turn around the center point between our drive wheels. This simplified other aspects of the design, as the robot could rapidly spin in place to identify the polarized guide lights, while other teams had rotating sensors and then had to line the robot up with the sensor.

Based on that experience, I say casters do have their purpose... but it's going to be a very rare game/robot design where it provides a benefit to a FIRST robot, given all the other options we have (dop center, omnis, etc).