I’ve almost had enough of just arguing, debate, and throwing words back and forth at each other.
I want to challenge one very, very common claim about mecanum drives - the premise that mecanum drives are significantly more maneuverable than a six wheel skid, and in particular that mecanum drives can “run circles” around their six wheel skid defenders. I’ve personally never seen a mecanum behave that way.
So here’s your challenge. Find a video that demonstrates a mecanum drive doing just that - being defended actively by a skid steer drive and repeatedly scoring successfully by outmaneuvering the opponent.
Do not post anecdotes. Don’t post stories about how your team totally dominated Whatever Regional with your mecanum drive. I’m looking specifically for video - something that we can all objectively observe and critique.
If what I think is the case is true - nothing will be found.
If the opposite of what I think is true happens - we’ll have a pretty cool video to watch and use as a reference point when debating the merits and drawbacks of a drive system.
Look at 188 from last year, they had really good drivers that used mecanum to its fullest ability. It really is a trade off though, its nice that we all have such easy access to a simple omni-directional drive system thanks to AndyMark! Some times we look over how much easier AndyMark make it for us all. I remember the days talking thinking about either trying to build a complex Swerve Drive or underpowered pure omni drive and it was never worth it due to the manufacturing complexities. If driven right mecanum can be a better option then 6wd, all depends on your strategy and the game.
Not good enough. I know how a mecanum works and I’ve seen them drive on empty fields all day long. I want to specifically see this “feature” of the drive if it’s really as prominent as everyone says.
I like what you tried to do with this thread, except you decided to ask for video in the middle of an outage of The Blue Alliance. Containing your annoyance a day or so until the site was back up would be a little less one-sided.
Unfortunately all of our competition vids are on TBA which has been down for about 3 days now. If we end up assembleing out kop bot chassis, when we finish our competition chassis we could make a video seeing which one can out-maneuver the other.
Or no one can find the video he is asking for. I am personally of the opinion that no one will find a good video which consistantly shows a mec drive driving circles against a decent 6wd. They are, in my opinion, very overhyped. I have seen many many mec drives, most of them were opporated poorly (that is, like a skid-steer drive.) The few that I saw which were well driven performed pretty well, but their performance suffered under defense. (re: Elims).
It’s traction deficit outweights its sideways capabilities. You can argue about effieciency loss and manuverability all day long but at the end of the day I don’t want to use a drivetrain which can be pushed sideways with one hand, end of story.
Of course, others value sideways motion above traction, as a comunity we will never completely agree because, frankly, we want different things from our drivetrains.
Just remember, The best drivetrain is the one that gets you where you need to go when you need to be there. If it doesn’t do that then it has failed.
This isn’t 100% what you want, Chris, but I think it’s pretty close:
Watch 2337 and 2619 duke it out. 2337 had 8" mecanums and custom gear boxes. 2619 had 4 wheel tank drive with a wide bot. 2619 was the red alliance’s main scoring robot and 2337 shut them down until the end game.
You’ve got a good point… the FRC field is just too crowded for a mecanum to really open up and put its maneuverability to use repeatedly and consistantly. For years I’ve been hoping to see a larger field, but realize there are physical limits at the venues.
Ever since we built our mecanum, years ago, I’ve advocated that you don’t build an omni-drive because of competitive advantages, but because of aesthetic ones. A well-driven mecanum (or other omni) is a thing of beauty that will be a joy to drive long after the competition is over.
Mind you, taking our torquey, tractiony, 8wd from last year and burning doughnuts and pushing cartloads of people down the hallway with it is kind of fun, too… but even through it was probably the superior drive train for competitive mobility it wasn’t as magical as a mecanum.
Jason
"No fair. Using 1114 in ANY comparison is like arguing Mustangs vs Camaros and then posting a video of Bumble-Bee. "
Great analogy… even if they weren’t specifically referring to 1114!
The 4WD bot they’re defending is way too slow. Like 8 FPS max. If you can find a mechanum driving circles around a 16 FPS 6WD with competent drivers I’d be impressed.
The too slow robot that was top seed at Ann Arbor and a first round pick at MSC and the CMP? They were geared for torque and couldn’t take advantage. That said Chris spcifically asked for videos of mecanums against six wheels drives + and we didn’t even score until the endgame.
If you give us a couple of weeks we may be able to come up a video that either proves or disproves a Mecanum drive running circles around a 6 wheel drive.
