mecanum vs. omni

[JesseK]

Originally Posted by Lil' Lavery

For any new system, particularly in a component of the robot as crucial as the drive-train, I would suggest doing some form of prototyping before the build season starts if possible. The added experience, ability to work out kinks, and test out your code are invaluable. Additionally, its a great way for drivers to practice on the new system before it is finished, and after it is shipped.

I agree to an extent. If you prototype something on limited resources and then realise after the game is announced that your prototype concept has little chance of success in the game, then you have 2 choices: 1. Come up with a creative way to implement your prototype or 2. (more common) Adapt your prototype so that it fits into the current strategy, therefore introducing (sometimes) very complex integration issues or unforseen behaviors --

e.g. Adapting mecanum to play pure defense will really put some wear on the treads of the wheels -- enough wear to be of concern if you attend 2+ competitions with success.

Ok, so this argument probably holds little weight in the case of mecanums, as it's more likely you can adapt your strategy to use mecanums with some sucess every year. However, if you're like most teams, you'd rather adapt your robot to your chosen strategy and not vice versa. This is also good engineering practice, whereas adapting your strategy to your robot is something that's good practice for learning how to find & fight problems (namely integration problems) after the fact.

Being a strategist and an engineer at heart, I personally choose the former. In the meantime, the "prototypes" I'm doing on mecanums extend into the VEX realm, by trying to make a 100% legal mecanum VEX wheel for $20 or less per wheel (very very tough to do atm unless they make the white nylon spacers come in the VEX kit -- easy to do with those). Another thing you can do, is take a look at the white papers, do that math, and create a VEX omni-wheel drive. The hardest part about holonomic drive is the physics, vectors, and programming, so getting started with developing an algorithm in programming or creating a full VEX omni-drive will get you headed in the right direction.

Save the purchase of the wheels for the big robot for after the game announcement so you know that you're getting your money's worth.