2 speed swerve prototype design, unfinished
 

https://www.youtube.com/watch?v=AO-n...ature=youtu.be

So this preseason we decided we would try our hand once again at attempting a swerve drive! We have twice previously done a swerve and both times had good success so we are stepping it up a notch!

What's better than a swerve you may ask? well a two speed swerve i say!

Going into it this pre season we quickly ran into some issues with initial designs in regards to the wiring, especially if we wanted two speeds! There did not seem to be any sufficient slip rings(price,size,etc...) and we wanted to avoid dealing with entanglement so the only option seemed to be to gear around it. Hence the design you see in the video was born.

It may seem like a lot of parts and weigh a ton, but all things considered it really doesn't appear to be that bad.

Thoughts, ideas?

Re: 2 speed swerve prototype design, unfinished
 

Looks interesting, for sure. I would want to take a closer look at the CAD, particularly the shifting mechanism, but this view is fine.

Good stuff:
The overall design is nice. Coaxial, that's a plus. Shifting is great. I really like what you're doign for turning the module, as it saves a ton of space. Efficiency with worm gears and mounting could be problematic, but that's just to me. The overall space usage of thise drive looks really good, as most of it hangs over the 2x1 or other elements of the chassis.

First off:
What size wheels are those? 6"? Anything more than 3" is overkill IMO unless the game demands it. Smaller wheels means smaller axles, lower gear ratios, and overall much less weight. If you flip your CIMs upside down, it will be much more workable with those size wheels.

What are you trying to solve with the shifting mechanism? The massive amounts of weight that cylinder and its mounting will add to your drivetrain is not worth the change from ball or dog shifting.

What is the total weight? #2 problem with swerves (behind complexity) IMO is weight and space, especially because you are only running 4 cims. Space looks good, but what is the overall weight of the drivetrain? Optimizing this would be great.

Also, plan for failure (in a manner of speaking). Will it be easy to swap out modules between matches? Especially with that shifter.

Re: 2 speed swerve prototype design, unfinished
 

the mounting for the steering isn't really a problem any which way just needs to be worked out. The worm is just one idea and a place holder, there are several options we can do for steering.

yes those are 6" wheels. the point was to start large and we can design down if need be but from previous years there may be a need for large wheels so good to have the option.

the goal of that shifter is just having a shifter at all. we can certainly use other systems but that's what just initially came to mind in regards to weighing a minimal amount and ease of construction.

the weight is unknown. our goal is to start off with the lightest materials available then upgrade parts as they fail. because yes weight always comes up as an issue.

aha oh yes failure... no matter how hard you try it's always just around the corner =p At least from this design everything is easily accessible and swappable. a screw or two(and maybe a retention clip) and absolutely any part on this should be able to be easily replaced.

Re: 2 speed swerve prototype design, unfinished
 

Sounds okay to me, except for the shifter. The reason I don't see it working out is because it will be unreliable and inefficient. The pneumatic cylinder approach won't work in your application because it will shove the gears into one another too close, causeing them to bind (especially once the teeth wear down), and this could potentially destroy your entire drivetrain. There is no easy way to shift gears penumatically unless you want to machin dog or ball shfiter shafts, or buy them.
Due to the height of your assembly, I would definitely flip the cims unpside down too, and shift on the coaxial shaft of the module. That will save a lot of weight and space. For shifting, just slap a 2-cim ballshifter on there or make a custom gearbox using ballshifter parts and then put the output of that to the coaxial shaft. This will lower your COG considerably and provide more reliable shifting, and it shouldn't be too difficult to machine. The base ballshifter only give a little bit of reduction, so teh final reduction can still be on the chain going to the wheel.

Re: 2 speed swerve prototype design, unfinished
 

"it will shove the gears into one another too close, causeing them to bind"

not in the video but there will be additional hard stops preventing just this. we certainly don't want all the force pushing the gears together leading to any kind of binding. the spacing can be made to be ideal relatively easily.

But yes we can fit a premade shifter assembly as well if this doesn't work out. The same approach goes for using smaller wheels. the flexibility with the chain allows us to compensate for several different variables. There is certainly a lot of flexibility here and we'll see where we end up but we'll start with something nearly identical to this then start changing stuff up.

Re: 2 speed swerve prototype design, unfinished
 

Here is an update video of initial test after assembly.

https://www.youtube.com/watch?v=VRcOsjI2gkE