Mecanum Drive Train

[Charmander]

Hello!
For all the teams deciding to go Mecanum, how do you plan on overcoming the bumps without damaging the wheels too badly. Also, do you think the wheels will have issues with going over the bridge. (the bridge has a plastic coating on top)

[tetravaal]

We are using 6in mech's and we DONT plan on going over the bump.. Are you sure about the info on the ramps? My guys who went to the kickoff swore they were coated with carpet like the field.

[EricLeifermann]

Originally Posted by tetravaal

We are using 6in mech's and we DONT plan on going over the bump.. Are you sure about the info on the ramps? My guys who went to the kickoff swore they were coated with carpet like the field.

the bridges are HDPE. Read the arena rules and watch the videos on FIRST's you tube channel

[Ninja_Bait]

Originally Posted by EricLeifermann

the bridges are HDPE

But their top surface is polycarbonate.

[EricLeifermann]

Originally Posted by Ninja_Bait

But their top surface is polycarbonate.

polycarb or HDPE doesn't really matter its going to be hard for mecanums to get a grip on them to climb onto them...

[Duke461]

We have done Mecanum/Meccanum/Mechanum/Whatever (someone who knows please do tell) for the past two years, and we are not doing it this year. Ignoring speed and being defended reasons, there are year specific reasons for not choosing it.

• Teams that try to cross the ridge unaided with only mecanums will fail miserably and probably damage the rollers or wheels
• The meccanums will not drive nicely on the slick material/polycarbonate of the bridge and the key.

For these reason among other prevolent ones, I urge all teams not to use Mecanum, unless you have a very specific design to overcome these obstacles (e.g. jumpdrive)
Hope this helps,
-Duke

[Ninja_Bait]

Originally Posted by Duke461

Mecanum/Meccanum/Mechanum/Whatever (someone who knows please do tell)

Mecanum.

[Charmander]

We plan on using Mecanum wheels and we plan on going over the bump. The question is, what should we use to prevent direct impact to the wheels. Right now, we are thinking of a plow or a a raised dummy wheel to take the initial impact of the bump and raise the bot up a bit before the Mecanum wheels hit the bump.

[Duke461]

Originally Posted by Charmander

We plan on using Mecanum wheels and we plan on going over the bump. The question is, what should we use to prevent direct impact to the wheels. Right now, we are thinking of a plow or a a raised dummy wheel to take the initial impact of the bump and raise the bot up a bit before the Mecanum wheels hit the bump.

More info here and here
Waittt a second. You already posted this thread. Please do not double up. The forums are bogged down enough already. Normally I'd be a lot more upset, but I'm in a good mood right now.

[Charmander]

Originally Posted by Duke461

More info here and here
Waittt a second. You already posted this thread. Please do not double up. The forums are bogged down enough already. Normally I'd be a lot more upset, but I'm in a good mood right now.

The other thread was oriented more toward the question of IF mecanum wheels could handle it. This one is oriented toward the question of HOW (design ideas) mecanum wheels could handle it. But there are similarities. I'm glad you're in a good mood however!

[mjgard]

We tested our mecanum bot from last year on a simulated ramp using whiteboards as the surface and managed to climb onto the ramp without a problem. The whiteboards should simulate the ramp surface for our purpose I feel.

[ThirteenOfTwo]

We tested last year's bot (mecanum wheels) on our prototype ramp after covering the ramp in regolith. It climbed up fairly easily and was able to balance within ten seconds. We're going to try to buy a sufficiently sized sheet of polycarbonate soon for testing purposes, but I feel pretty good about the chances of mecanum being able to do this.

[IndySam]

I really don't understand why everyone says mecanum wheel won't get a grip on the ramp. Mecanum wheels have no more problems with grip than any other rubber wheel on polycarb.

On the other hand, hitting the ramp crooked can cause difficulty because of the disruption of the vectors when one wheel hits the ramp causing other wheels to loose contact with the ground. This can be a big problem especially for chassis without much flex.

I think mechanum wheels will have less trouble with the bump than the ramp because of the natural tendency of the flat bump to actually straightening out the robot when hit.