Our team has some 2X2 1/4” thick aluminum square stock lying around and we were wondering if this could be possibly used for our second swerve base. would like to hear the communities pros and cons. Some pros I thought up were a lower COG and a more rigid body so the frame resists bending. Some cons being manufacturing. I don’t know the specific type of aluminum unfortunately. Would love to hear some opinions
What Swerve Modules are you using? Depending on the modules it may not be possible without modification. (e.g. with mk4is the motors are in the way)
Its not ideal but assuming you have the ability to machine and its a 2nd drive base I don’t see why not
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7461 ran mk4is with 2x2 in the offseason, but I think there was a bit of modification from stock set up
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That would make a bomb proof frame! It would shrink your wheelbase a bit unless you are willing to do some milling to install your swerve modules.
2x2 1/4" would certainly be a super strong frame that would resist bending!
One downside of using it with most COTS swerve modules is those are designed assuming the frame is 2x1". The extra width of inch in your frame rails will mean that your bumpers will be pushed outward relative to the size of your wheelbase. If building a tall/extending/tippy robot this could make it more likely to tip, although I think the 1/4" wall tubing in the frame will add a lot of weight down low and you’d probably be fine?
I think especially if your plan is to make a “defense bot” or just a swerve chassis for driver practice, this sounds like a totally fine reuse of existing materials.
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I think 4414 did this in '22. They notched their 2x2 so that it was 2x1 at the ends where their MK4is had to fit into the frame. Not sure how helpful this is though or what advantages they got from doing this considering the notches might mess with the structural integrity a little bit.
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I would personally just use 2"x1" and add a 1" x 1/4" (or thicker) strip of steel around the bottom.
2"x2" is going to make a fabulously strong frame though. May provide some cool opportunities for interesting robot architecture as well, depending on fabrication capabilities.
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I don’t think structural integrity will be much of an issue with 2x2 1/4" wall. That’s basically 3 1/4" plates supporting the corner.
That’s fair, I meant more like the fact that you’re notching out the corners might take away from some of the benefits that using 2x2 1/4" would provide. Not sure though, I don’t have any evidence to back up my claim, just a thought.
Is there any smart person that would like to point out the added moment of inertia in a such setup?
The robot may act more stabilized on head to head collisions with the added weight on outer edges. I just can’t guess its significance.
Okay so hear me out. It is expensive, difficult to machine, but the CoG will be the frame.
2x2 Steel
Wild Stang did something similar
2x1 Steel
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Without doing any calculations, my concern would that the swerve modules might become the weak point in the frame and get damaged if they are your only corner structure and you get in some bad collisions. Some good internal structure would mitigate that and make the toughest frame I’ve ever seen.
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Nah, just mill it out of one solid block of 7075 aluminum. It’ll be fine.
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nah its gotta be 7071, you need that 1%
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How about if I weld a few of these together?
I know that it was a bit of track but, using 2x2x1/4 is perfectly reasonable for a swerve.
You have it available, it’s smart to use that rather than buying something else.
With that said, 4414 in 2022 did it, and this thread has some gems regarding their build.
They did have to support the external portion of the 2x2 after the cutaway, I would do it similarly if you have access those parts. @khillans
May as well take it to the extreme
In that same thread there was talk about tungsten sheets as belly pan add-ons.
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You are correct, there are definitely cases where the distributed mass from the COG (moment of inertia) will have an effect.
Rotational (heading,) changes will require more energy. Perhaps a consideration with swerve and spin to win. This may impact how one plays defense or absorbs defense. Will also impact things like balancing slightly.
As far as tipping goes, this probably won’t have much of an impact in the real world, a simple model would be a lever and the mechanical advantage should be close to linear. This is a simplification and there may be a bit more going on with the dynamics.
As far as most teams are concerned, the takeaway should be just “get weight down low”
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