Video of Mecanum Drive Running Circles Around 6 Wheel Drives

[Kevin Sevcik]

Originally Posted by hipsterjr

@ Mr. Lim

No fair. Using 1114 in ANY comparison is like arguing Mustangs vs Camaros and then posting a video of Bumble-Bee.

*polite cough* I think he was pointing our the quick maneuvering of the blue robot with the mecanum wheels. Not 1114 with their 8-wheel drive.

[dtengineering]

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!

[Mr. Lim]

Originally Posted by Kevin Sevcik

*polite cough* I think he was pointing our the quick maneuvering of the blue robot with the mecanum wheels. Not 1114 with their 8-wheel drive.

Which is unfortunate, because I don't think people were actually paying attention.

http://www.youtube.com/watch?v=7mBxVPvyYwQ

There's the link again, and watch the one robot with mecanum wheels play to its strengths.

Does this one video mean mecanums are definitively better or worse? No, but this mecanum drivetrain did its job in this particular match.

Count the balls scored for the winning alliance - 3 in autonomous, and 3 in teleop. I would challenge a LOT of teams to hold an alliance of 1114 and 2056 to 3 balls scored in teleop, and the little blue mecanum bot was a big reason why that happend.

[GGCO]

Thank you Chris for this post!!! In theory Mecanum should be faster, but the complexity of control and their lack of precision makes them worse.

[Eugene Fang]

Hmmm. Not exactly what you wanted, but to show the other side, here's a video of an 8wd running circles around mecanum drive.

2010 SVR, 971 vs 675:
http://www.youtube.com/watch?v=0X27bojZ26k

[BoilerMentor]

I appreciate what you tried to do with this thread, but it doesn't look like any such video really exists.

I'll give you the reasoning that 1747 chose mecanum this year though.

1: Ability to strafe in front of the scoring grid.
2: help avoid defensive interaction.

Reason 2 was considered to be more secondary through the design process. The students also decided on a very aggressive ratio in the Tough Box Nanos that we are using (8.45:1) giving us a calculated maximum speed of nearly 14fps. Using a ratio like that completely prevents us from serving any kind of defensive role and means our drivers must use that speed to an advantage.

With the drive train (finalized) running on day number 9 of build season we were able to put it through its paces and even with as fast as it is, the robot has proven to be very easily controllable.

I guess the real relevance to this thread is that the issue I believe you to be addressing (Mecanum will lose out to a 6 wheel when you're considering defensive interactions) is absolutely the truth, but I don't believe it to be the reason teams used for choosing them.

Sorry if I missed your point.

[JamesCH95]

Originally Posted by Joe Ross

I think a 6 wheel drive train would have trouble doing this: http://www.youtube.com/watch?feature...shqAVY#t=72 s

I see no reason why a 4wd or 6wd with wheel in the same position couldn't do the same.

[Chris is me]

Originally Posted by BoilerMentor

I appreciate what you tried to do with this thread, but it doesn't look like any such video really exists.

I'll give you the reasoning that 1747 chose mecanum this year though.

1: Ability to strafe in front of the scoring grid.
2: help avoid defensive interaction.

I guess the real relevance to this thread is that the issue I believe you to be addressing (Mecanum will lose out to a 6 wheel when you're considering defensive interactions) is absolutely the truth, but I don't believe it to be the reason teams used for choosing them.

I'm really confused - it seems your team picked mecanum for the reason I am addressing, which you claim is (un)true.

More or less, I'm challenging the idea that mecanum drive's capabilities allow it to avoid defense.

[UltimatJose]

I really don't think that is true. Last year in Breakaway our team managed to keep the scores minimum against a robot with mecanum wheels eventhough we were using the wheels supplied in the kit

[Captaindan]

6wd is power and pretty good with turning mecanum can run away and turn like its goin outa style either way they make pretty good robots it all depends on the end effector that is what makes the robot a winner

[Grim Tuesday]

A good defensive robot (treads, 6WD, or 8WD) should be able to push around a mecanum robot no problem. Depending on how they are set up, they MAY be faster. However, with any tank drive robot, if you want to score (atleast in this years game), you have to come onto the pegs perfectly: If your off, you have to backup and try again.

There are cases where one is better than the other. I don't feel that Mecanum could perform well enough against a good defender to account for its pushibility. But thats just an opinion.

[gabrielau23]

Originally Posted by hipsterjr

@ Mr. Lim

No fair. Using 1114 in ANY comparison is like arguing Mustangs vs Camaros and then posting a video of Bumble-Bee.


Edit: Sorry, jumped the gun and forgot that 1114 was not mecanum drive. But the statement still stands.

LOL...unfortunately it is true

[gabrielau23]

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

[robowrestler]

At a recent meeting we had our robot from this years game with a 6 wheel drive and the mechanum bot out.The kids driving the mechanum couldnt get around the 6 wheel bot enough or by anymeans run circles around it. also if our six wheel cought the mechanum and started pushing it it was all over. so in the end mechanum is manuverable but its not great

[Andrew Schreiber]

Originally Posted by Aren_Hill

Let me quickly convince Truck Town to do a mecanum this year, and you'll get your footage in a few months

Convince?