Quote:
Originally Posted by ablatner
Shifters are great, but I'd have to recommend against Mecanum wheels for the usual reasons. You can find many threads on the subject. Many of the top teams use 6 or 8 performance wheels. I know 254 almost always uses the same drive train with eight 4" wheels (this year maybe six because of reduced size). Many other teams have the same setup too, unless they have a good swerve drive like 1717 last year.
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254 almost always uses 6wd, not 8wd because you have a lot less parts to make. They also usually vary their wheel size based on the game, but usually stay very small. If I remember correctly in the past few years they've been using wheels that range from 3.5" - 4.5" in diameter.
The kitbot on steroids is a very good drivetrain. It's very easy to make and will give you a drive that is better than 90% of teams. Having a reliable, easy to make drivetrain will give you more time to build a reliable manipulator, tune your programming, and get drive practice.
I find that omnidirectional movement is usually overrated. Mecanum and holonomic drives tend to have a lot of problems, especially when you want to try to get around or play defense. Swerve drives take up a lot of resources. First of all, they are complex, hard to design right, and take a lot of time to machine. Also, code is very complex, and if you don't do your code right you will be a sitting duck.
One of my favorite examples of the complexities of doing swerve right is 973's 2012 robot, Encore. 973, being a powerhouse and the 2011 World Champions, they had the resources to build a very good independent swerve drive. However this took up a lot of their resources, and ended up detracting from the other parts of the robot. This year, 973 decided to revert back to a west coast drive. In my opinion, this decision benefitted them tremendously. With more time and resources to divert to their manipulator, 973 was able to spend more time tuning and practicing with their robot. I feel 973 had by far the best robot at the LA regional, leading them to their 2nd regional win.
That said, I think you should work with building the kitbot on steroids during the offseason. With so many good new products from many new vendors, you may eventually want to spend time improving the kitbot on steroids(i.e. add shifters) and even creating your own custom drive. However the kitbot on steroids will put you on the right path.