Swerve Drive Concept
 

Here is a swerve drive concept that I've been working on. Any suggestions/feedback is welcome. Not shown is a steering encoder and a schedule 80 PVC pipe that goes around the swerve module. The module has a disc connected to the side plates that has a delrin ring to provide another bearing for the module's rotation.

Re: Swerve Drive Concept
 

Question: Is this meant to also be the power unit for the entire drive? Or is one of those motors a Mini-CIM? (Or, is this for a 3-wheeled swerve?)

Re: Swerve Drive Concept
 

It can be a three wheel swerve, or it can be a four wheel swerve with a minicim.

Re: Swerve Drive Concept
 

8 motor drive, I love it.

What is the steering motor?

Re: Swerve Drive Concept
 

Design looks pretty good. I dig the 8 motor design.

The top orange plate on the module seems overly complicated, from a machining standpoint.

Instead of having those little flanges hanging down, why not just bolt downwards through the orange plate into the two side plates?

What are you using to rotate the module?

And how are you tensioning the chain? It's hard to see what's going on back there.

I sort of consider 1640 to be the gold standard of swerve (Well, tied with 1717 maybe :D), and they've really taken the time to iterate, improve their design, and cut out unnecessary things. They also released everything you could want to know online. I'm not saying ditch your design and go with theirs, but they've already solved a lot of the problems for you, so you can learn from their mistakes so to speak ;)

Re: Swerve Drive Concept
 

If you look at the first photo, you can see a second chain run going up to a motor hidden behind the top plate and the two CIMs. From the little I can see, I'd hazard a guess that it's a 550 with a BaneBots planetary.

Re: Swerve Drive Concept
 

You're right, to make the orange plate would waste a lot of material, so I think the little tabs could be replaced with a steel bracket, and then I could put a could more bolts straight down through the orange plate and into the blue side plate, like you described.

To keep the chains tight, we plan on putting spacers underneath one side of the lower gearbox plate until the chain is tight. We've done this in the past, and we only had to adjust the shims twice during the season to keep up with the stretching chain. The chain for the swerve module has a calculated center to center distance, and its small enough that it doesn't need tensioning.

Re: Swerve Drive Concept
 

You could use this type of joint.

Re: Swerve Drive Concept
 

I could, but then I would have to move the side plates in a little bit, or make the tabs thinner than the side plates. Also, I don't really know how those right angles could be machined easily.

Re: Swerve Drive Concept
 

You won't be able to machine the female slots the way they are in the picture (at least not with conventional subtractive manufacturing). What you could do though is do a pair of slots oriented orthogonal to each other (one provides constraint in the Z axis, the other provides constraint in the Y axis, and the screw/surface provide constraint in the X axis). As for the male bosses, you'd clamp the piece in the vice so that the bosses would be sticking straight up, and mill across the top. Not very nice if you've got a long piece (or you'll want to use a horizontal mill). That tab design is generally reserved for plastics cut on a laser cutter.

Re: Swerve Drive Concept
 

I assume you're replying to this post:

You're right, those sorts of joins are generally used in laser cut parts. However it can be done with normal machining, the design just needs to be modified a little. Your cutter will leave a radius in the corners of the female slots, so just add a matching radius to each corner of the male boss.

As long as there are still flats on each side of the boss and hole, there won't be a change in effectiveness. In fact, having the radii in the corners will increase the strength of both parts. (Sharp corners provide a convenient fracture point for the material)

Re: Swerve Drive Concept
 

Do you plan on making or buying the bevel gears? They would probably wind up being one of the most machining intensive pieces in this design.

Re: Swerve Drive Concept
 

The miter gears are from http://www.grainger.com/Grainger/wwg/search.shtml?searchQuery=l110y&op=search&Ntt=l110y &N=0&GlobalSearch=true&sst=subset

Re: Swerve Drive Concept
 

I don't think I've ever seen anybody make bevel gears besides gear manufacturers ;)

The process of cutting good gears is not a simple one, and it requires some pretty specific equipment, very few professional machine shops even have that kind of stuff.

Re: Swerve Drive Concept
 

Well then, check my video out :) :

Bevel Gear Tube Drive

I was asked to cut these high quality bevel gears, for the exact purpose to show that with today's machining capabilities, you don't have to be a gear manufacturer to produce high quality bevel gears.

Several of these displays are travelling to Trade-shows and Expos, to highlight the capabilities of the OMAX Waterjet's:

"A-Jet"
A-Jet Demonstration Video


I <3 my job :D

Re: Swerve Drive Concept
 

This is unbelievably cool. I assume you cut the bevel gears on a multi-axis head waterjet?

Re: Swerve Drive Concept
 

Wow. That is quite awesome

What would it take to get access to one of these fine machines ;)

Re: Swerve Drive Concept
 

Cool stuff!

Though I'd classify a five-axis waterjet as "specialized equipment", that most shops don't have. You could do a similar cut with a four-axis mill and some fancy cutters too, but a lot of shops don't have those either.

Re: Swerve Drive Concept
 

Thanks, as noted above, it was cut using the OMAX "A-Jet", which is a multi-axis head capable of cutting at angles up to 60 degrees relative to the material surface.

Thanks! I'm glad you asked, OMAX offers discounts for FIRST teams! If you are serious about getting a machine and would like a quote on a machine that would meet your needs, I could send your info. to the appropriate sales rep. Just PM me :)

Thanks. You are right, this capability is generally not wide-spread. The interesting thing is that a basic water-jet is pretty common, and it doesn't cost too much more to add on the A-Jet or retrofit one on an old machine.*


*Not sure of exact $