Tank vs. Mecanum

Hi everyone, we are in the yearly debate over what drive train type is best for this years game. We are currently between West Coast Tank because of its better strength and less weight, as well as not having to put a gearbox on each wheel, and Mecanum for its better agility and efficiency for putting power cubes on the scale/ switch. Have any teams decided yet or does anybody have any idea of what is best?

Tank. The plates are large targets and hard to miss. Not worth the tradeoff of being able to be shoved across the field with mecs

its almost never worth that tradeoff

I would have to agree

Our team hasn’t made any final decisions on which type to use. But we have had it mentioned, and it seems a good amount of the team thinks that the mecanum wheels make it easy for a bot to be pushed around, and defending or even standing your ground is going to be much more difficult.

Are you expecting defence to play a large role in this game or do you think that minor interactions with the other alliance will be enough to warrant not using mecanum?

This year we choose to stick with tank because of the following reasons.

Tank
Pro:
Traction
Defense
Stability
Easier Programming
Con:
Agility
Maneuverability

Mecanum
Pro:
Agility
Maneuverability
Con:
Stability
Drift
Less Practice for Drive
Need 4 gearboxes
Hard learning curve

In the end we thought that the cons outweighed the pros for mecanum and stuck with tank.

Do you want to be on teams pick lists? If so, use tank. It seems harsh but it is what it is.

I think its not worth the time to develop a new kind of drive for your team, assuming you have never done it, when the pros you gain don’t really outweigh the cons.

Build a simple tank, be done with it, move on to your manipulators and such, and practice practice practice.

This is a terrible answer.

There are plenty of drive trains out there. Choose what you think is best for your team.

If your team can drive circles around everyone else I can guarantee you will be on a pick list regardless.

To be fair, mecanum does NOT require much more development anymore. WPIlib has a built in class meaning programming is dirt simple. You can use any gearbox, and the AM13U3 (stock drive chassis) has mounting points for their Touchbox Micros meaning it’s very easy to mount 6" mecanums on. I agree that the pros don’t outweigh the cons, especially in this game, but at this point in the COTSification of the FRC market, mecanum is just as easy as a WCD (if not easier for some teams).

Argue all you want, but this is a reality. Hate to break it to you.

No it’s not. Mecanum robots received a penalty equivalent to roughly 1.5-2 gears per match on 2791’s picklist. Many alliance captains perceive it as a major liability, and teams need to be realistic about this in their design considerations.

You can achieve 90% of the effectiveness and 10% of the helplessness of mecanum with a well-practiced, well-built tank drive.

This year is far different than steamworks.

The null zones and placement of the field objets really limit defense this year, imo playing robot to robot defense in PowerUp only hurts your alliance. You are we better off trying to unbalance the opponents switch than playing contact defense

I’m a little confused by this mindset. If you were in a position to pick 1986, would you turn them down just because they used a mecanum drive? If they picked you (assuming you’re a top 8 seed) would you turn down their offer?

Hate to be “that guy”, but 1986 is an extremely effective robotics program whether they use mecanum or not. It is a case by case thing but a typical mecanum drive is usually not built anywhere near the quality of 1986 last year and not used in an effective manner. Just because you can use mecanum does not mean you should.

Do whatever your team can build the fastest and most effectively and your drivers have the most familiarity with. Don’t build either of them if your team has minimal experience with it and your drivers have minimal practice with it.

Unless you are one of the top 5ish teams at an event, you probably aren’t good enough to be defended consistently, so the potential defense-related aspects of either drive aren’t super important in my opinion. If you are planning to be a defensive robot you need to decide what type of defense is best first and then decide your optimal drive based on that. Driver practice is multiple times more important of a factor for playing effective defense than your drive system.

Do be aware that certain teams may not pick you because of your mecanum drive. I personally think that is largely unjustified but it is just a fact of the reality we live in.

If mecanum allows you to be literally world-class at part of the game, dominate the rankings at every event, and then be nearly unstoppable in playoffs, I’m all for it.

Otherwise, bear in mind that a mecanum drivebase will hurt how a robot is perceived by many alliance captains, especially in a game like Power Up or Steamworks where defense is going good to be dirty.

In case people aren’t getting the picture, for 95% of teams this means using the kit bot in some configuration. Figure out if you want it wide or long, build your kit chassis, and start driving.

What coast drive also is more resource intensive than a mecanum drivetrain, with the vex clamping gearboxes the machining time is pretty minimal.

Thoughts on a 2 speed wcd?