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-   -   Mecanum vs. Tank Drive? (http://www.chiefdelphi.com/forums/showthread.php?t=153445)

niklas674 11-01-2017 12:00

Re: Mecanum vs. Tank Drive?
 
Tank.

Lord Basket 11-01-2017 12:08

Re: Mecanum vs. Tank Drive?
 
Quote:

Originally Posted by Taylor (Post 1629226)
However, I have noticed that the people who proclaim they'd never ally with a mecanum robot, aren't usually in a picking position.

While that may be the case sometimes, look at what members of consistently great teams are posting in this thread. Members of Citrus Circuits, Techfire and Robovikes literally posted one-word answers that just say "tank" and a member of the Cheesy Poofs posted "Just say no to mecanum drive." A member of TORC posted a more detailed response, but the conclusion was the same. Those teams are some of the best in the world and are in a picking position every year. While they haven't explicitly said they'd never pick a mecanum robot, they don't seem to think too highly of mecanums, to say the least.

Koko Ed 11-01-2017 12:15

Re: Mecanum vs. Tank Drive?
 
Mecanums are effective if there's no defense present. There will be lots of defense this year and it will be brutal. Especially since there are no safe zones when you are looking to score gears.
Go with tank drive.

Ben Martin 11-01-2017 12:21

Re: Mecanum vs. Tank Drive?
 
Quote:

Originally Posted by Lord Basket (Post 1629264)
While they haven't explicitly said they'd never pick a mecanum robot, they don't seem to think too highly of mecanums, to say the least.

Only in contact games is it a factor. Mecanums make you both easier to defend against and a worse defender.

scaryone 11-01-2017 12:23

Re: Mecanum vs. Tank Drive?
 
Respectfully speaking, mecanums get a bad rap. While it does have a slight disadvantage in a pushing contest, in my opinion, it is way overstated on CD. Weight distribution is important but not mission critical. Hard programming? How is it harder? Practice is critical, but isn't it for every team/drivetrain? Humbly speaking, the students have 2 Blue Banners using mecanums. Not sure what we'll do this year but mecanums are in the running.

Tom Bottiglieri 11-01-2017 12:32

Re: Mecanum vs. Tank Drive?
 
Quote:

Originally Posted by Lord Basket (Post 1629264)
While they haven't explicitly said they'd never pick a mecanum robot, they don't seem to think too highly of mecanums, to say the least.

We don't have a rule against picking mecanums, but usually we ding them a bunch due to being susceptible to defense and not being able to play effective defense. I think we've picked maybe one or two mecanum bots since I joined in 2010.

I think this year's game may require defense. So I'd steer clear (get it?) of mecanum.

Michael Corsetto 11-01-2017 12:36

Re: Mecanum vs. Tank Drive?
 
Quote:

Originally Posted by Lord Basket (Post 1629264)
While that may be the case sometimes, look at what members of consistently great teams are posting in this thread. Members of Citrus Circuits, Techfire and Robovikes literally posted one-word answers that just say "tank" and a member of the Cheesy Poofs posted "Just say no to mecanum drive." A member of TORC posted a more detailed response, but the conclusion was the same. Those teams are some of the best in the world and are in a picking position every year. While they haven't explicitly said they'd never pick a mecanum robot, they don't seem to think too highly of mecanums, to say the least.

+1 to this. We do a first pass filter on our second pick list based upon drivetrain style. If it's not tank style, we often drop the team from our list right there.

Quote:

Originally Posted by Taylor (Post 1629226)
I will also say there is a stigma with mecanums, with questionable merit, and some teams say they would not pick a mecanum robot to ally with in eliminations. However, I have noticed that the people who proclaim they'd never ally with a mecanum robot, aren't usually in a picking position.

My experience has been the opposite, but YMMV. I know to us, and a few other teams usually in picking position, mecanum is almost always an instant "do not pick".

There's lots of jokes/meme's around mecanum, because for contact games, it's just not what teams in picking positions want out of a second pick, so those mecanum robots get instantly dropped from pick lists. Carefully consider if this is a risk your team is willing to take.

-Mike

"Friends don't let friends build mecanum"

BotDesigner 11-01-2017 12:36

Re: Mecanum vs. Tank Drive?
 
Quote:

Originally Posted by Tom Bottiglieri (Post 1629297)
We don't have a rule against picking mecanums, but usually we ding them a bunch due to being susceptible to defense and not being able to play effective defense. I think we've picked maybe one or two mecanum bots since I joined in 2010.

I think this year's game may require defense. So I'd steer clear (get it?) of mecanum.

Silly question, were those two mecanum bots picked in 2015? :]

MrForbes 11-01-2017 12:47

Re: Mecanum vs. Tank Drive?
 
Quote:

Originally Posted by euhlmann (Post 1629218)
Tank
Cons: go up to feeder station. You're not aligned. Drive back and turn. Go up again. Still not aligned. Drive back and turn again...

Or....build your collecting mechanism so it does not require precise alignment...and practice driving...

IronicDeadBird 11-01-2017 12:57

Re: Mecanum vs. Tank Drive?
 
The biggest thing that kills me about Mecanum is when I am at a competition and I see a Mecanum robot being driven around like a tank. Unless your design, driver, and auto really utilizes strafing then you should not be using mecanum at all. Look at your strategy and ask yourself "do we need mecanum or will drive practice also get us where we need to be"

Rosiebotboss 11-01-2017 12:57

Re: Mecanum vs. Tank Drive?
 
Interesting thread.

Mecanums get a bad rap. With a skilled driver a mecanum drive train can be very effective, ease of alignment to the high shot and placement of a gear negates the use of a turret for a quick "lock on" of the high boiler and a passive gear holding system can be used for the "lift."

As far as defense, I look at it this way, a running back on a football team charges the defensive line, usually made up of bigger, stronger guys. He'll hit the line, bounce off, rotate out and start upfield again, being more agile sometimes is better than stronger. As far as playing defense, All you have to do is hit the opponent on a corner of the frame to knock the robot out of their 'spot' of slow them down and prevent them from completing all their cycles. It's not always about brute force.

eedoga 11-01-2017 13:02

Re: Mecanum vs. Tank Drive?
 
I suppose I have a few questions...

If teams are in a position to pick and simply refuse to select an alliance partner that uses Mecanum simply because they use Mecanum then isn't that a problem? I would hope that teams are utilizing scouting and performance in order to determine alliance partners...though that may not be the case.

One thing that we might consider is, if a team on the opposing alliance is tied up defending however successfully against one alliance partner, then that is one less team member on the opposing alliance that is off scoring points...

Finally I think it comes down to strategy. Saying that mecanum means that a team will be easy to defend against isn't exactly accurate. A mecanum drive robot can work to avoid conflicts instead of engaging in them.

I hope I haven't tipped my hat too much...Oh...and best of luck to all.

Edoga

Michael Corsetto 11-01-2017 13:45

Re: Mecanum vs. Tank Drive?
 
Quote:

Originally Posted by eedoga (Post 1629317)
If teams are in a position to pick and simply refuse to select an alliance partner that uses Mecanum simply because they use Mecanum then isn't that a problem? I would hope that teams are utilizing scouting and performance in order to determine alliance partners...though that may not be the case.

I suppose that method is only a "problem" if it doesn't produce the intended results (win the event).

-Mike

RoboChair 11-01-2017 14:02

Re: Mecanum vs. Tank Drive?
 
Quote:

Originally Posted by MrForbes (Post 1629308)
Or....build your collecting mechanism so it does not require precise alignment...and practice driving...

+9001 This, Very this. Make the task of driving your robot such that the driver needs little aim.

niklas674 11-01-2017 14:09

Re: Mecanum vs. Tank Drive?
 
While our best year involved us using a mecanum drive (mistake), we practically never used it in matches, the positioning was close enough that we didn't have to make large changes. Bottom line is that with plenty of drivers practice, you won't need to be able to strafe because your drivers will get to the exact spot almost every time.


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