Mecanum or 6WD

[EagleEngineer]

To get across the field.

[Dr Theta]

I really think whatever drive you choose is less important than it being designed properly, the people programming it, and the person driving it. Our team will be using mecanum again this year, not because it is inherently superior to all other drive platforms, but because we have experience with it, it works well with our strategy, we know how to program it for our purposes, and we have a driver who is crazy good with it. It isn't so much about the drivetrain, but how you use it.

[2bkrul]

6WD but have 2WD and 4W Floaters...either with Omni's or the Lunacy wheels

[davidthefat]

Now my team captain said we are doing the 6 wheel drive with the middle wheel slightly lowered. We are extremely tight on budget this year, so any other would be asking for too much (except for 4 wheel drive)

[davidcone315]

Originally Posted by Stephen of REX

Depends how much you drop by. If you drop the center wheel by 1/8 of an inch (which I believe is enough to get the desired effect) then rocking should be minimal, especially if you have distributed your weight to prevent rocking while hanging.

The rocking is the reason why we want to use a mecanum drive

[Charmander]

Mecanum isn't going to help much if you can't get to the scoring area. If a team on the other alliance plays defense, mecanum loses its value since it can't push

[Chris is me]

Originally Posted by davidcone315

The rocking is the reason why we want to use a mecanum drive

Rocking has at most maybe 1/2" effect on an extended manipulator. If you need that much precision to score, you won't be scoring frequently.

[BrendanB]

Originally Posted by Chris is me

Rocking has at most maybe 1/2" effect on an extended manipulator. If you need that much precision to score, you won't be scoring frequently.

Agreed! Last year was the year that rock was bad when dealing with ball manipulators and lifting off the ground or losing your ball. That is what made 8wd so popular. We almost went with 8wd to eliminate rock, but choose 6wd since it was faster to make, cheaper, easier, and the rock wasn't going to affect our design.

[IndySam]

Originally Posted by Charmander

Mecanum isn't going to help much if you can't get to the scoring area. If a team on the other alliance plays defense, mecanum loses its value since it can't push

may not be as able to push as well but if it dances around the defense it doesn't need too.

[davidthefat]

Originally Posted by IndySam

may not be as able to push as well but if it dances around the defense it doesn't need too.

Then I can argue that the defense is doing its job; the more time you take away from the enemy, the less they score. That is an argument why my team should go defensive this year, but everyone wants to be quarterback and score.

[rutzman]

Originally Posted by Charmander

Mecanum isn't going to help much if you can't get to the scoring area. If a team on the other alliance plays defense, mecanum loses its value since it can't push

Mecanums strafing ability allows for added maneuverability.
6WD allows for more traction.
Neither is inherently better than the other in a 1v1 match up.
The aspect that pushes that match up towards one side is going to be the amount of practice the drivers get with their robots, and robots with similar drive bases. If a defensive bot has experienced drivers that have had a couple years and a practice bot, and the mecanum offensive drivers have never touched a holonomic drive in their lives, the mecanum drive will be completely dominated. However, if the mecanum drivers have spent a hundred or more hours with the 3-axis joystick in their hands and the 6WD drivers are taking their first turn behind the drivers' station, a juke and a spin is all it will take to get into the scoring zone.

[Chris is me]

Originally Posted by IndySam

may not be as able to push as well but if it dances around the defense it doesn't need too.

Can you point to a video of a mecanum drive that's ever done that?

[goffchris]

We are going to test both. We have a team working on each type. We have found our past mecanum systems to be plenty fast. I also think that they are advantageous this year with the narrow feeder chute. It might be easier to make lateral corrections to our position with the crabbing ability. Rather than having to back up and turn, we can make small moves sideways if our tubes are a bit off.

As for dealing with defenders, our drivers have been able to use crabbing to outmaneuver less agile robots. We are sometimes a bit slower in a straightaway than 6 wheeled robots, but haven't been significantly disadvantaged by that.

We are interested in whether the rocking motion of the CA drive will make use vulnerable to tipping when extended. Jury is still out, of course.

[Jeffy]

Originally Posted by rutzman

a juke and a spin is all it will take to get into the scoring zone.

I sure hope to see a spin move this year. Very cool.

[Andrew Schreiber]

Originally Posted by Chris is me

Can you point to a video of a mecanum drive that's ever done that?

Not exactly, I do have a couple of pictures of 2337's mecanum drive shoving HOT up the bump though.

The key to either system is having a skilled driver who communicates effectively with the coach and his other driver. There are benefits and drawbacks to everything and we must be able to effectively figure out which downsides we can live with and which we can't.

I personally am doing either 6wd or 8wd this year, we talked about mecanums (3450/314) but we are building multiple bots and doing that makes cost highly prohibitive. (4 gearboxes + 4 mecanum wheels for each bot) I am also an alumni from the Martian "defense" era. The best defense is having more traction than your opponent. For the record we also considered doing a swerve drive but buying 3 Revolution modules or 3 WildSwerve modules was out of the question price wise.