Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 

Or turn?

(sorry this is not on the topic of the thread)

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 

Actually I should apologize, since my post inst really on topic. But to answer your question, many lift based scoring mechanisms need to be straight on, onto the tower, so you would have to back up and go for another pass.

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 

does this suffice as a J-Turn?
midway through video (were using.. you guessed it, tank drive w/6wheel drive)

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 

In our experience, not at all. There's no reason an arm bot has to be perfectly straight to score.

I'd post some video, but I kind of want to save it...

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 

I know, old thread, but does anything in this video qualify? It's 2052's mecanum showcase video. http://www.youtube.com/watch?v=Ogy65hEPIXk

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 

I'm really curious on what gear ratio they were using. It looks moderately quick, and it was able to push around other robots pretty easily.

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 

Those are side steps and jukes sprinkled with some spins that simply do what a 6WD could do in the same situations. While I do agree it's better than average Mecanum driving, I don't know that I'd call it 'running circles' around 6WD.

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 

I don't think the point of the thread was to find a video of mecanums literally driving circles around a 6wd. I think the point was to have video evidence that mecanums can be comparable/and maybe even better in some ways to 6wd, which I think the video did show.

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 

What I don't get is why you'd ever want to run circles around anyone. One circle sure, but multiple? Sort of kidding, but not really. What is it that we're actually looking to show?

They're not untouchable for sure, but they are maneuverable. Are they, as the OP asked, "significantly more maneuverable than a six wheel skid"? It depends on the six wheel skid. This guy's obviously a good driver, possibly with some unique control scheme. It's clear they've illustrated that mecanum can hold its own.

Have they illustrated that mecanum is comparable to 6wd in general, possibly better in some ways (in terms of specific performance)? Up for debate. I suspect what this is is an example of mecanum being driven as well some of the better 6wds...so now the playing field is more level. Until they're pitted head to head with one of them, it's hard to tell. (Of course, they've probably done this, if someone wants to check match video.)


The short course for those looking to decide, all else equal? The one you drive strategically better.

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 

This showcases 2 of about 5 robots I know of that I though Mecanums were used really really well.

The 573 robot that year was really clever and its "kicker" was more like a paddle wheel that cleared zones very well. The Mecanums were frequently used to dig into corners well. 2337 robot that year was a great re-director and hanger. It would also play some amazingly good defense for a mec.

I would actually say 2337 in 2008 and 2011 also used mecs fairly well. but I think you could find videos of those robots being defended or boxed out just as often as you would find amazing offense.

126 had a pretty good run with them this year. They were really good in Archimedes beating 868 (wiht a lot of help) in 1 match. This video is likely the closest to "driving circles aroudn teh defender":
http://www.thebluealliance.com/match/2013arc_qm51
126 is the little blue bumper bot, and a tall black red bot (I think 846?) repeatedly tries to defend with very little success. They have at least 4 altercations that match with the Defense slowing them down just a tiny bit. I don't know that "I" would credit mecs to this maneuverability, but I am pretty sure 126 would give them some credit. The mecs also seem to be good for lining up to the tower and to the feeder station.

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 

Having competed against 126 in Boston, they were one of the quickest robots this year. They did not use the mecanum strafing capabilities too often but their driver had the ability to use it when necessary. I would not give the mecs 100% of the credit for this maneuverability but I would at least give them some.

Irrelevant, but the tall defender was 701, 846 was the short yellow bot on that alliance.

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 

KnightKrawler used 2 AndyMark Nano Tube 20's with hex shafts in the stock 12.75:1 ratio. One CIM per wheel and each wheel driven directly from the gearbox. Since we need a drive motor per wheel, we used this as an opportunity to leave out chain. The wheels are AndyMark 8" HD mecanums that come with side rollers which we do think help to smooth out the movement of the robot as it transitions between mecanum rollers.

Nate
2052 KnightKrawler Mentor

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 

I made the thread specifically looking for videos demonstrating that mecanum's additional mobility and agility make the drive more adept at handling defense than a 6WD. This was a common claim on CD when I made the thread.

I've gotta go now, I'll post my thoughts on a few good mecanum bots I've seen when I get back. Just wanted to clarify the intent of the thread.

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 

LOL...unfortunately it is true

Re: Video of Mecanum Drive Running Circles Around 6 Wheel Drives
 

Our team has used 6 wheel drivetrain for the past 3 years and has been extremely happy with the results. Last year we pretty much perfected it for our purposes. This year the drivetrain all came together and I think we're going to be using it for the forseeable future. Our driver was EXCELLENT, so we had very few problems lining up to take shots, and we usually were able to hit 3 cycles on a bad match. Something I can tell you right now is that I really didn't see any mecanums utilize their maneuverability well enough to offset the disadvantages of us being able to
a. Either push right through them
or
b. Hit them on our way back and forth from the stations and screw up their shot occasionally.
Another robot for reference is 79, team KRUSH at the DC regional. They simply owned defenses trying to stop them, and they used a 6 wheel drivetrain. They juked, they used spin moves, they were able to outmaneuver pretty much every form of defense that was tried to be played on them.

Even last year there were problems. If you were balancing with another robot that had mecanums, you always had to push them up. And if you went too far towards the mecanum's side, the probability of a balance just went down since there was no way the mecanums were going to be able to push a 120+lb. 'bot up the bridge.

I think that it all comes down to practice. If the team using mecanums has little to no practice, the team is usually very ineffective since they can't utilize the crab function correctly. On the other hand, a team that has had significant practice with mecanums should be able to match up well against a 6 wheel drivetrain. I think that it is, more or less, like this.

Well-practiced Mecanum <= Well-practiced 6 Wheel Drivetrain
Well-practiced Mecanum >= Good 6 Wheel Drivetrain
Little-practiced Mecanum < Good 6 Wheel Drivetrain