4 vs 6 wheels

[Chris is me]

Originally Posted by rytcd

are there any real advantages to having an extra 2 wheels? pros and cons? we dont see much of a difference in descriptions of their performances. (we are a rookie team)

All of this assumes a long robot. A wide robot can get away with 4wd high traction wheels with the ability to turn without having to use omni wheels.

Normal Year: Four wheel drive robots with high traction wheels on all four spots have massive problems turning correctly. Adding a 5th and 6th wheel in the center helps with this a little bit. On top of that, "dropping" the center wheels 1/8" so that at any one time, only four wheels are touching the ground will make turning even easier, since the robot's wheel base will be wider than it is long. This allows robots to turn easily while still maintaining a 100% high traction drive for pushing and dealing with defense, while a four wheel drive would need some lower traction or omni wheels, which makes them vulnerable to defense on one side of their drivetrain.

This year: The debate over four versus more than four wheels is more complex. As the Kitbot is built now, a four wheel drive with big wheels is more able to deal with the bump than a 6+ wheel drive, since half of the robot "falls down" before the other half when 6+ wheel systems have all of the robot "faling down" at once. Barring an unconventional design, you've reached a design tradeoff. If you can't make a cool suspension or something, do you want better, more safe bump climbing ability at the expense of half of your drive having less traction? Or do you want a full, high traction drive that has to deal with more forces when it comes to bump traversing?

This is pushing all active suspensions, etc. aside. This particular tradeoff is one that bothered me for the first whole week of build season, and I hope the decisions made were the best.