Why are there no COTS differential swerves?

Looking at the three major COTS swerve modules (SDS MK4i, REV MAXSwerve, WCP SwerveX), every one of them has a drive motor and steering motor. Is there are a reason for this design being used over differential swerve?

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Holy ground clearance! …and I guess that’s why it’s less popular?

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with the power of falcons and neos, differential swerve is just too much software complexity with marginal performance benefits

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Well maybe the programmers deserve to suffer, but seriously I agree with this fully unless you have a highly experienced programming team differential swerve isn’t worth it.

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Has anyone run these?

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A few teams ran differential swerve, Team 2383 used it this year with a nice design, and its becoming more common in FTC nowadays in combination with omni wheels as a way to only use 4-6 motors for the drive instead of 8

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FTC ≠ FRC
Big difference in what makes sense between the programs.

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5687 uses a custom diffy swerve that we’ve been refining since 2020. I don’t think we would consider a COTS module.

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Oops, replied to wrong person.

I meant has anyone run the arrmabot module.

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True FRC should be far more competent, I’m aware an LQR controller isn’t exactly simple and building half a dozen PID controllers isn’t convenient, but it shouldn’t be discouraged to try, remember even regular swerve before common software support form WPIlib and third parties like YAGSL was horribly complicated or functioned inefficiently for most teams.

More people use it and more support would be available.

This is just a commercialization of one of the very “first” diff swerve designs.

Like it or not Revolution Swerve was about the only game in town COTS wise fow quite a while.

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It’s still 221, but wasn’t the WildSwerve on its own for the longest time before Revolution Pro 2? I’m only a 2016 rookie, so I’m not sure of anything pre 2015. Were there cots modules before Rev Pro 2? A Rev 1 maybe?

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@Joe_Johnson was any further progress made wrt your differential swerve modules? The new Phoneix Pro content should make this easier apparently.

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I would caution anyone looking to try differential swerve against the armabot modules. we tried them in the off-season between 2019 and 2020 and the plastic pulleys actually fused together. I don’t know whether we did something wrong or it’s a flaw with the modules but honestly differential swerve provides very little benefit and comes with a lot of downsides. It takes a lot of work to pull it off well.

For 99.9% of teams, I’m sure diffy swerve is not worthwhile. For the very top teams who are pushing the limits of max weight and super traction, is having two drive motors worth the mechanical and software complexity? Or will 2-drive-1-steer modules become more of a thing, perhaps something like @ClayTownR’s design?

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Orrrr 3 motor differential because it’s more fun and more ridiculous.

I think this probably answers your own question. Why would anyone sink the development and production costs on a product that maybe 0.1% of teams would be interested in? A product needs to be commercially viable, not just technically feasible, for someone to make it into a COTS product

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I’m assuming they’re referring to making your own rather differential swerve over a COTS one drive, one steer module. pre-COTS swerve wasn’t worth it for 99.9% of teams, but it now is. Good COTS modules and easy to use code would presumably make differential swerve worth it.

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