# Tri Motor Diffy Swerve

This might be fun project. What are you trying to solve with this tri motor diffy swerve? what are your spec expectation?

We can’t even buy Falcons right now and you are proposing insanity!! Preposterous!

I love it.

please don’t refer me to neos…sparks are a nightmare

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I dunno, seems reasonable to me

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Oh I’m well aware of the tuning challenges and I felt like taking on something new after building H-Drive systems from the ground up and trying coaxial swerve simulations with basic physics, I’ve already got an entire tool suite for tuning just for it, playing with current limits, spike limits, and voltage limits using the low level interfaces on the falcons should make it doable just a bit difficult. I’m really only concerned about how mechanically out of hand it could get to fit everything together, and I feel a little bad for all the batteries.

Trying to solve nothing much beyond pushing swerve drive a little bit further High Tide did show that using 3 motor swerve with 2 driving in a coaxial system is advantageous Upgrade Swerve MK4i Increase acceleration and speed w 2X drive motors - Technical - Chief Delphi and if you already have 3 motors why not make them differential it should give a minor performance improvement, assuming friction is enough for the extra force not to be wasted, not to mention it will better distribute the heat over the motors as they will not need to output full power in most cases helping alleviate strain especially in back to back matches or the practice field, & finally it just seems like a challenge to push the current systems to the physical limit.

Have you done any preliminary work to see if that assumption is valid? If it is not this entire thing is worth no more effort than a thought experiment.

(Hint: it probably isn’t)

What if we built a swerve drive robot but every module is its own tank
drive robot

EDIT: wait that might actually work with treads. The math for each
module is the conversion of differential drive to differential swerve.

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While that sounds insane I’ve been looking at belt driven swerve modules which can rotate down to become tiny tank drives.

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I think the issue with tread swerve is that treads don’t rotate well [citation needed]

I could definitely see it being an issue which is part of the reason for making this post, if I can’t have one insane drive then I want another.

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4 motor differential swerve–for the teams that can make their own brushless motors

I mean I can make one, just uh I do not believe that’s legal with FIRST same with custom motor controllers, it would also definitely perform worse then what’s available on the market*

CoussensSwerve 2024 gonna be four motor differential swerve. He’s just throwing us off his trail.

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Why stop there?

20 motor swerve - 4 falcon drive and 1 falcon steer on 4 modules.

40 motor swerve - 8 bag drive and 2 bag steer on 4 modules.

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I uh don’t think there is enough power ports sadly meaning no “legal” way to do this maybe bribe the robot inspector

https://firstfrc.blob.core.windows.net/frc2023/Manual/HTML/2023FRCGameManual.htm#R504

40 bag motors is legal

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At what points do we see aero upgrades on robots I think its somewhere around 16 motor swerve

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For starters, the fact that a Champs-winning team did something doesn’t mean that it has some magical properties that will automatically make your robot better: while I didn’t really follow their season at all, I can tell you that the more important thing is that they had the skills to do it right, and, more importantly, the skills to build a more competitive robot in other aspects as well.

The other thing that you’re missing here is is that a 2-motor differential swerve already has more-or-less the same advantage as a 3-motor coaxial swerve: 2 motors providing drive power. With a 3-motor coaxial setup, you have two motors driving the wheel, and then one motor to pivot the wheel. With 2-motor differential swerve, both motors drive the wheel, and then some of the power goes to pivoting when necessary (which doesn’t take a whole lot of power).

Then, there’s also a mechanical issue with 3-motor differential swerve, and that’s the fact that it makes the module “asymmetrical”. 2-motor diffy swerve relies heavily on the idea that both gear rings are getting the same amount of power. If one of the rings has an extra motor driving it, then the robot will drive differently under different pushing loads. While this could maybe be worked out with additional programming, that’s a lot of extra work to “upgrade” a system that’s already only a fraction of a motor (at worst) behind a 3-motor coaxial swerve with one less full motor.

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The second of the two linkages above would do the trick, too.