pic: Practice Mecanum Chassis

[Madison]

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[Billfred]

Whoa, nice work.

Are y'all planning on using a belt drive for the wheels, or is that just a placeholder?

[Madison]

Originally Posted by Billfred

Whoa, nice work.

Are y'all planning on using a belt drive for the wheels, or is that just a placeholder?

It just means that I'm too lazy to model roller chain.

[Billfred]

Originally Posted by M. Krass

It just means that I'm too lazy to model roller chain.

I guessed so (the would-be pulleys didn't look like pulleys).

Can you post a close-up of the transmission? Unless I'm a victim of forced perspective, it looks like a right compact number.

[=Martin=Taylor=]

What is the purpose of that third sprocket? Sensor perhaps?


Why exactly are you using an AM mecanum anyways? Didn't you make some really neat mecanums earlier this year?

[SamC]

What program is that modeled in?

[Madison]

Originally Posted by Billfred

I guessed so (the would-be pulleys didn't look like pulleys).

Can you post a close-up of the transmission? Unless I'm a victim of forced perspective, it looks like a right compact number.

Yes, as soon as I finish modeling the rest of their parts. They're missing a bearing, a bushing and encoders. There's not much to look at, really. It's a two-stage reduction based on some of the parts provided in the kit transmissions.

What is the purpose of that third sprocket? Sensor perhaps?


Why exactly are you using an AM mecanum anyways? Didn't you make some really neat mecanums earlier this year?

The idler will drive encoders for position sensing. They also increase chain wrap.

I'm using AM's wheels because the wheels I developed do not belong to me. They were also far more expensive to manufacture.

What program is that modeled in?

Solidworks 2005

[Jeff 801]

what motors are you going to use?

[Bill_Hancoc]

Wow that is some amazing modeling...what was that done with....looks very cool and promising

[Joe_Widen]

Almost looks real. Great CAD. Good luck with your mecanums.

[DB_UPS]

wow ... thats really good!!

[edit]
Are they the AndyMark Mecanum wheels?
[/edit]

[Greg Needel]

Originally Posted by DB_UPS

wow ... thats really good!!

[edit]
Are they the AndyMark Mecanum wheels?
[/edit]

From picture description: "This is a look at what FRC488 is planning to prototype this Fall thanks to AndyMark's new mecanum wheels."

[Lil' Lavery]

What's the purpose of the large plates on either side of the wheel? Why not a much smaller system to mount the wheels and/or bearings?

[Madison]

Originally Posted by Jeff 888

what motors are you going to use?

Each of the four wheels will be driven by its own, small Chiaphua motor. I'm presuming the kit will remain unchanged in that respect next season.

What's the purpose of the large plates on either side of the wheel? Why not a much smaller system to mount the wheels and/or bearings?

They're so large so as to protect the wheels from impact some. Last season, our omniwheels were unprotected and took a few good hits from robots with higher chassis rails, causing them to bend. We were always able to bend them back, but they were also a lot cheaper and easier to reproduce so we had plenty of spares. They also look pretty cool.

Wow, great work. Thats an impressive model. I have one question though, do you plan on putting a suspension on you chassis? I can tell you from our experience with mecanum that constant contact is important. Our team, 40, used rubber bumpers on our wheel pods to keep contact. Also at nationals we saw another team (I'm terrible at remembering team numbers) who used small pnumatic pistons for a suspension.

Thanks. Do you have any photos of the arrangement you used? I've currently arranged for the large wheel guards that hold the axles to use vertical slots so that we can adjust their position relative to the frame. This would allow us to raise or lower the wheels individually to ensure contact in case the frame warps or bends, but it wouldn't do this dynamically during a match. How important do you think it is that the wheels sit on an active suspension?

The design I've made previous to this included a more substantial, pivoted subchassis for the two rear wheels that would dynamically stabilize things, but it seemed a bit like overkill. That's shown below:

It's an older model, so there're no chains on this one. They didn't disappear or anything.

[Andrew Blair]

Perhaps an active suspension can be implemented without too much redesign.



When totally locked down with the spacers you've designed in, I believe that this could be strong enough to give you what you want. It appears you're using 1/8" or 3/16" stock- maybe an upgrade to 1/4" would give you all the strength you need there. I would think that if you got hit really hard, the ability of the mecanums to slide would keep you from bending the modules. The chain would still be an issue though perhaps.