Pneumatics or Mecanum

[CalTran]

Originally Posted by cpapplefamily

I'm a new mentor this year. The team always wanted mecanum and this past preseason I helped them successfully get them working with 8" wheels. We are designing for mecanum with an option to abort to 6" drop center 6 wheel drive. We are hoping for lowbar, agility shooting, helping open doors, defence. The traction up the ramps worries me.

Which ramps in particular? Things like the Cheval and Ramparts, the ramps that lead up to the Defenses in general, or the ramp that is the Batter (the front of the tower)? I suggest building whichever one you have fear about, "splurging" on a bit of correct material to cover them with, and get testing ASAP.

[alicen]

Originally Posted by Canon reeves

It depends on your strategy, but:
Mecanum:
-Likely not enough traction to go up the ramps, and definitely not over the defenses like the moat and bumpy road.

I just wanted to say that unless you've tested this, it's all just hypothetical.
In 2010, my team used mecanums, and that ramp was a much greater angle than those seen on this year's field. We did not have any issues going up and over.

Don't entirely rely on other people's opinions, make your own judgements based on your experience and testing!

(I will forever have a love for mecanum, but I might be biased since my coffee table is mecanum drive )

[cglrcng]

Partial Quote:...."(I will forever have a love for mecanum, but I might be biased since my coffee table is mecanum drive)"

______________________

Lol...Now I know exactly what "Special Personal Project" I am going to order that wonderful tank chain tread for now! I'm going to turn my living room coffee table into a Stronghold Defense crossing capable coffee table. It may be too heavy for our robot, but it surely isn't for my future coffee table bot.

Our living room is small (the house overall is large though), and we have a matching very comfortable loveseat and large couch and a chair that are all seating position reclining, so everyone is always moving the coffee table a couple inches at a time, all about the center of the room (just a little bit, but I'm always straightening it up later-"anal type A" that I am), as feet get very close to it when reclining.

They will be able to move it about using a tethered controller and their smart devices, laptops, or ipads.

Thank's for that idea. (I would have never thought of doing that....ever!)

Just wait until my glass & tile squares topped wooden coffee table is going over and through all the team edition of the defenses with the practice bot before season end (besides the Low Bar of course), that the students have been putting together all week. (It certainly won't be FRC Legal, as it will certainly violate the 120" perimeter frame rule (I think I will just mount a nicely stained marching dark cherry wooden electronics shelf about a foot below the glass top), and I'm not putting the bumpers on it, or it certainly won't fit our living room space again. (Though I admit that it would look really cool w/ legal 8" each direction reversible Blue/Red bumpers perfectly in the bumper zone on each corner & our Team 60 numbers, so maybe I will notch the wooden legs so they can be added or removed on a whim).

[cglrcng]

Originally Posted by alicen

I just wanted to say that unless you've tested this, it's all just hypothetical.
In 2010, my team used mecanums, and that ramp was a much greater angle than those seen on this year's field. We did not have any issues going up and over.

Don't entirely rely on other people's opinions, make your own judgements based on your experience and testing!

(I will forever have a love for mecanum, but I might be biased since my coffee table is mecanum drive )

_______________________
There were a lot of mecanum's in Rebound Rumble and those ramps were a wicked angle, plenty of mecanum's last year in Recycle Rush (is the angle of the ramps really any different this year?) Low Bar, Sally Port, Drawbridge, and Portcullis are all ramped but flat going through Defenses. (If one could push down & climb the Rebound Rumble ramps, one should certainly be able to push down & climb the Cheval de frieze too I'd certainly think). Moat isn't that tough, Rock Wall ehhhhh - I don't know about that 1, or the Ramparts without some killer type suspension added. I wouldn't even attempt to tackle the Rough Terrain without same killer suspension added....Like Monster truck suspension added.

Put Mecanum's in an "X" pattern to shoot though and it does not push around as easy as many think (especially if backed by rail and wall right in front of the opposition alliances RH Drivers Station.

I'm willing to bet we see at least 1 Supershooter this year that figures out how to sit in the Spybot only position and shoots into top goal only (or maybe even top & bottom), using the curveball effect, and has not much of a drivetrain at all (just enough to crawl over to and climb on the Batter to Surround & or Scale and can collect from 2 sides so robot defense against it is a bit lessened.

We will probably see at least 1 Spybot Supershooter without any drivetrain at all...But, that bot will not make it out of the qualifying matches due to not being able to surround/scale the tower...And it will skew the RP results highly at that specific event! (I certainly could be wrong about not making it out of Q matches if it finishes a low team count event top 8 and ends up an alliance captain due to shooting very well and so many others helping them w/ Defense RP's and scoring high by making all shots high and accurate leading to high scoring auto & tele, while others fail to surround/scale against them).

Said bot will never move anywhere once placed in that Courtyard corner except during the last 30 or so seconds of a match. Count on it happening.

** Setting that X pattern once surrounding on the batter. Certainly No Rolling Off.

[cglrcng]

Originally Posted by Kevin Leonard

For this game? I have no idea why you would even consider mecanum wheels unless the only defense you intend to be able to cross is the low bar.

Mecanum wheels are generally poor for traversing field obstacles, and the ability to strafe doesn't help you whatsoever in this game.

Pneumatic wheels are a great choice, but not the only choice for this game. Think about your team's priorities when making this decision.

______________________

I disagree highly...The ability to strafe for a fast Courtyard Supershooter being fed boulders at a fast clip by a Low Bar Specialist and a Killer fast Defenses Specialist at the same time, who can avoid a single defender pusher bot that cannot strafe, can and will work wonders in this game. I'd bet big money on it.

Give me that same fast Low Bar bot you just described as a partner please...I will open Sally Port, Drawbridge, & Portcullis for them and we will also kill them off by going bumper-to-bumper right through together w/ a boulder each on each trip and damage each Defense really fast....especially if they can strafe as it will make it easier and quicker during the "here, hold this door for me while I cross & boulder load up, then join you in a second" phase.

Personally The Heavy super low CG Chain Driven Tank Treads- 2 sprockets high out, 2 low in and a slightly dropped center low idler so it looked like a tank (Driven just like a tank also w/ 2 joysticks and shifting, boulder collector(s) rear and front as supershooter feeders/low goal delivery), are my favorite though, but my 2 favorite partners would certainly be a FAST STRAFING Mecanum Driven Courtyard Only Supershooter & a FAST STRAFING Mecanum or high grip Low Bar Specialist.

Together we'd Rule the KINGDOM (I'll take care of all those other nasty Defenses with a smooth fast moving super tank, and I'll open more doors for you than you can possibly imagine w/ my Killer Tank! It won't matter what they throw in front of us, we'll together have them all covered). You Low Bar, will strafe that Neutral Zone snatching boulders away like magic. Now just figure out how to get all that into a simple short 14" high, and at least ramp climbing (clearing), package. That is the tough part! And Supershooter plants all our ammunition high and accurate. And runs circles around that defender.

I'd go 1 step further (use your 15" and put a drop down loop on the front of Low Bar & I'll put a drop down pin on the rear of my tank in that same space-Pin goes in the loop we are towing in low gear), and I'll carefully & slowly pull you over whatever obstacle you wish to help Damage that they threw in front of us...But, please, please, please Low Bar Specialist Damage that Low Bar strategically, because I certainly cannot. Not that I absolutely need to either. Lol.

Why are people insisting you play this game all by yourselves....Didn't they learn anything from 2012, 2013, 2014, & 2015? It is all those games combined! It takes TEAMWORK...Teamwork will win and Damage Defenses and Capture the Tower in STRONGHOLD. (The single boulder per robot/per carry or defend in courtyard, makes it a required teamwork strategy to win game).

[Kevin Leonard]

Originally Posted by cpapplefamily

I'm a new mentor this year. The team always wanted mecanum and this past preseason I helped them successfully get them working with 8" wheels. We are designing for mecanum with an option to abort to 6" drop center 6 wheel drive. We are hoping for lowbar, agility shooting, helping open doors, defence. The traction up the ramps worries me.

See I'd be comfortable with your team running mecanum, at least more comfortable than the average team. You a) successfully prototyped it in the off-season, b) you understand the drive's limitations and advantages, and c) you picked a strategy that works to the strengths of the drivetrain.

With 8" mecanum wheels you should have no problem going under the low bar and over some of the obstacles. I'm not positive you'll be able to get over, for example, the rock wall, but I also haven't tested it to see.

Now when you do build the robot, make sure your drivers have a lot of time to practice using the robot. I've seen countless robots that have mecanum never really use it, they drive as if they have a traction drivetrain and fail because of it.

Good luck!

[TheJoe]

Originally Posted by cglrcng

There were a lot of mecanum's in Rebound Rumble and those ramps were a wicked angle, plenty of mecanum's last year in Recycle Rush (is the angle of the ramps really any different this year?) Low Bar, Sally Port, Drawbridge, and Portcullis are all ramped but flat going through Defenses. (If one could push down & climb the Rebound Rumble ramps, one should certainly be able to push down & climb the Cheval de frieze too I'd certainly think)

So much this. We had 8" mecanums in 2012 and were very, very fast with lowering and balancing on the bridge.

I also love mecanum wheels, but for our team this is just not the year to bring them out. Larger pneumatic tires or tank treads will be a lot better for our game strategy.

Originally Posted by cglrcng

I'm willing to bet we see at least 1 Supershooter this year that figures out how to sit in the Spybot only position and shoots into top goal only (or maybe even top & bottom), using the curveball effect

Teams might be capable, sure, but the game rules don't allow it.

[efoote868]

Originally Posted by Kevin Leonard

For this game? I have no idea why you would even consider mecanum wheels unless the only defense you intend to be able to cross is the low bar.

Mecanum wheels are generally poor for traversing field obstacles,

In 2006, the Mecanum wheels my team fabricated could easily climb the diamond plate ramp (the wheels weren't available as COTS yet).

In 2010 AM Mecanum wheels could easily traverse the bumps.
In 2012 AM Mecanum wheels could easily climb on the bridge.

Both of which were game elements that caused many teams to automatically rule Mecanum wheels out, prior to testing.

[alicen]

Originally Posted by cglrcng

Our living room is small (the house overall is large though), and we have a matching very comfortable loveseat and large couch and a chair that are all seating position reclining, so everyone is always moving the coffee table a couple inches at a time, all about the center of the room (just a little bit, but I'm always straightening it up later-"anal type A" that I am), as feet get very close to it when reclining.

Might I suggest mecanums for this since it is moving in *all* directions,even just a little bit? Seems to solve the issue of lining up your table much more precisely!

Also, I've attached a picture of my coffee table
sorry for cruddy image quality!

[EricH]

Originally Posted by CalTran

10:50PM, 1/14/16: I predict that hot dog wheels will grace Einstein before Mecanum wheels will. You heard it here first.

Wanna bet?



Before you answer, I should warn you that I only take bets I'm reasonably sure I can win. In this case, I'm better than reasonably sure, because hot dog wheels have yet to grace Einstein, while at least one set of mecanums has WON Einstein: the set on the bottom of 1671's robot last year!

[evanperryg]

Originally Posted by EricH

...because hot dog wheels have yet to grace Einstein...

Just wait till you see our drivetrain...

[Dominick Ferone]

Everyone has made valid points for both arguments, I can say I watched teams use mecanum in 2012. They get no traction on the bridge, and with that being said, trying to breach the tower would be alot of work. It would be possible since there is a little lip that might catch the wheel and stop you from falling off.

The argument that mecanum isn't good defensively is only partly true. It does have an advantage when playing defense. The object of defense isn't always to win a pushing match. If you are trying to just get in peoples way or slow them down, mecanum helps.

We had mecanum in 2014 and we mostly stuck to defense as we had multiple unforeseen problems, with little time to repair. We would get pushed around a bit, but it also meant that teams were targeting us instead of the ball. Plus with mecanums maneuverability you could easily strafe away from defends, or strafe into shots to block them.

That being said the only defenses mecanum could pass is the Portcullis, the low bar,possibly the ramparts if hit with enough speed, and the C defenses.

But theres also the option of other wheels:
Pnuematic
Plaction
Hi Grip
The Gray ones (Slick?)
Colson
Banebot
Tank Treads

There might be some I am missing, and i didn't count omni because they have less traction then mecanum.

[Dominick Ferone]

Originally Posted by alicen

Might I suggest mecanums for this since it is moving in *all* directions,even just a little bit? Seems to solve the issue of lining up your table much more precisely!

Also, I've attached a picture of my coffee table
sorry for cruddy image quality!

Do you sometimes get bored and drive your coffee table around the house?