Has 6 wheeled designs surpased tank treads

[Warren Boudreau]

With the advent of pneumatic tires in the competition, wheeled robots are now competitive with treaded designs when it comes to traction. I say competitive, not superior. Some timing belt backings can deliver a coefficient of traction of 2.0. That means the pulling force is twice the weight of the robot. I know that this is true because we measured it many times with our highest traction robot, Fluffy. They are competitive because they are more simple to design and build.

As you may have noticed in the past years, those teams with pneumatic tires have a hard time (harder than properly designed treaded systems) turning. The 4-wheel drive systems bounce around like Mexican jumping beans. It is quite fun to watch.

The trick to making any high traction configuration turn is to have what we have termed a "boogie" wheel midway between the front and back rollers on the treaded system. This boogie wheel is a little bit lower than the front and rear rollers. What this does is roughly cut you turning moments in half since you are supporting the robot on the boogie wheel and either the front or rear roller. In a 6-wheel configuration, just lower your center wheel a little bit.

Therefore, I would say, no 6-wheeled designs have not surpassed tank treads in terms of traction. But they can give them a good run.