Swerve Chassis Question

This is our first year attempting to use a swerve drive system. We’ve got the pieces to make the chassis; however, we were wondering if you could do an open front chassis with swerve.
Obviously you would have to have a support in the middle of the frame with an open front but I wasn’t sure if this was even possible.

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As long as your modules are fixed and secured, and you don’t have any wiring in the way, nothing inherent to swerve drives should get in the way of that.

You could, in theory, have a big “X” with modules on each corner, and it should work as expected (I leave any assumptions of usefulness of this concept up to the reader).

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910 ran an open front swerve drive in 2019. Seems to have worked out for them.

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Yes you can. Just keep in mind that chassis stiffness and flatness are your friends with swerve. So you will want to ensure flex is kept to a minimum. This can be done through heavier guage materials, epoxy/rivets on gussets, welding as opposed to bolting, passing load through a super structure, and/or adding geometry to your bellypan (i.e. not a flat sheet)

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I was just about to post the same question as the OP here, but then I found this via search.

With so many teams doing swerve and with new motors that are likely to increase average robot speeds and thus the average severity of robot collisions, the topic of best practices when designing an open front chassis and the bumpers for such a chassis seems worth exploring further. I know our team’s open front chasses in the past have been… not awesome structurally. I’m concerned they would not hold together in 2024.

So how about it? What are best practices for a bulletproof open front swerve chassis that incorporates the corner COTS modules that have taken the world by storm? And bumpers (which can be trickier with open front)?

I know this has already been answered but we ran a gap in the frame with swerve this year. we had some difficulties making everything fit whiles still being strong but when we got it worked out it ended up working very well.

I think we have a new champion to the Necromancer thread.

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You can use swerve in many variations, it’s completely up to you (within the rules) I probably have the strangest swerve chassis :smiley:

Its certainly possible, we ran a gap this year too:

We even had to cut parts of the robots top plate off and it was still fine.

Thank you for using the search function. A lot of CD could learn from you.

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This was 3739’s swerve chassis this year, with a sizeable 13" wide x 14" deep gap in the front of our 24x24" frame.

It was a robust chassis that didn’t give us a single issue all season (no bending or twisting, no repairs ever needed).

The 2 biggest things contributing to the strength of this chassis (despite the fact it’s missing basically the entire “front”), is the 11ga steel belly pan tying all the various structural elements together, along with the use of WCP’s tube plugs (plugs on either end of the 1x1 tube in the middle, and plugs on either end of the 1x2 tubes on the sides of the cutout).

The combination of these 2 elements prevented the chassis from being split/twisted/bent, even when taking hard hits to primarily the front area (where one would expect this style of chassis to fail first).

Here’s a screenshot of our CAD with a better view of the bellypan:

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Indeed it is possible to make an open front chassis. This year we needed a long tunnel to transfer the game objects from back to the front of the robot. That is why we elevated the middle extrusion and achived a no/open front chassis.


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This is an excellent example of “be sure to think in 3 dimensions”

Remember, with a little bit of planning you can use some pretty light gauge material in some relatively large load areas, just by limiting the mechanical advantage exerted on components and keeping structure as 2-force members.

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This is almost exactly the same design we had last year. We took a couple of hard, oblique hits to the front sides of the frame, which bent them inwards quite significantly (almost 2" deflection). It did not seem to impact the driveability of the robot much. We unbent the tubes as best we could, then inserted .75" steel tubes inside the aluminum. Hit us as hard as you like, we ain’t bendin no mo!

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