A New Drivetrain

[BJC]

So I've been working on a unique drivetrain over the summer. It's extremely functional, probably too much so, as it can act as a 8 wheel tank drive, a 4 wheel mecanum drive, and can bottom out so as to not be moved anywhere. Unfortunatly, its as of now way too heavy, but I'm sure the smart people of chief delphi can figure it out. Almost everything I've done on it is in the below folders.

p.s. Because I don't have the computing power to run Inventor or any like programs I used paint so all the blueprints are 2d. Then again, I couldn't make it too easy on you guys.

[JamesCH95]

Two things:

Do you have a weight estimate?

The third gear in the gearbox design will prevent the Mechanum wheels from functioning properly, unless it is removed for Mechanum mode (too complex?)

Otherwise it seems like a very versatile platform, good stuff.

[BJC]

Originally Posted by JamesCH95

Two things:

Do you have a weight estimate?

The third gear in the gearbox design will prevent the Mechanum wheels from functioning properly, unless it is removed for Mechanum mode (too complex?)

Otherwise it seems like a very versatile platform, good stuff.

Let me see, the chassis design #2 was about 16 lbs, on the heavery side. However, the pods weight an estimated 40 lbs total with everything on them and no lightening holes, way too much. Add battery and air compressor, and your sitting on something around 70 lbs, very heavy.

As to the #3 and #4 gearbox my teamate just whipped those up to better clarify what it could look like. The middle gear would still rotate around one of the other two despite not being it not being pictured. And It would require only one small pneumatic cylender to move it back and fourth 1/4 of an inch.

Other things you might find interesting. the mec wheels (entire pods actully) will be on a three degree angle when in mecanum mode, and rotating them about 31-33 degrees gets the pod cleanly above the plane of the frame so as to bottom out. Just fyi

[JamesCH95]

I would not worry about coupling each sides' CIMs together for tank mode, it would save you a pound or two right there

While the chassis design is heavy, it hasn't been lightened yet like you said. You were planning on making it from folded sheet metal? What lead you to that decision?

[JesseK]

Quietly someone somewhere is screaming "NOOOOOOOOOOOO" as the next potential iteration of Nonadrive has now been leaked

In all seriousness, from what I can piece together this seems somewhat practical. I'm having difficulty piecing it all together, thus perhaps I can offer a holistic analysis. I would look at the weight and manufacturing issues from a tradeoff perspective:

• Is the extra 20-25lbs of drive train worth the extra mobility / immobility for the game? This isn't a straightforward question every year.
• Is the extra manufacturing needed for this concept much more involved than manufacturing of other drive trains that have similar mobility?
• What concepts of this idea could be appiled to other drive trains to enhance their designs?
• What aspects of the complex manufacturing can be re-engineered to produce other modified COTS products (e.g. de-coupling 2 CIMs within a toughbox)
• I'm sure there are many more...

[Chris is me]

Looks interesting. I have trouble visualizing this kind of thing with just line sketches in Paint, but I like the idea and I'll look into it some more when I'm not on a tiny netbook If you make some pretty CAD of any parts, I'd love to see it.

[BJC]

Originally Posted by JamesCH95

I would not worry about coupling each sides' CIMs together for tank mode, it would save you a pound or two right there

While the chassis design is heavy, it hasn't been lightened yet like you said. You were planning on making it from folded sheet metal? What lead you to that decision?

The CIM coupling probably would end up going. To clarify the frame is made of 1" aluminum bar. and the pods are sheetmetal. So the pods are the only thing that can be lightened by holes without sacrificing strength.

Concerning the pods sheetmetal design: the fundamental and key design tradeoff with the pod is between making the traction and mec wheels in the pods as far apart as possible (so as to decrease the amount the pods need to turn to get to the mec mode) and leaving room in the for other stuff between the pods. Because sheetmetal is so thin, it allowed me get support on both sides of the wheels in the pod while still keeping the wheels as close to the outside as possible.

[JamesCH95]

Sounds like good reasoning to me.

You might want to consider a single beam for each pod with a wheel cantilevered off of each side on a dead axle. Possibly with the dead-axle welded in place. Some 1" square steel tube or 1.5" square aluminum tube might do the job. Just a thought...

[BJC]

This may help you get the picture. These two pics are from a 50% scale model made out of yes, legos. They should help you get the idea if the paint docs are giving you trouble.

[,4lex S.]

I like it, good thinking. As soon as I saw nonadrive, I expected the Mechanum pod idea to come up with a bunch of teams. Next season should be interesting . The dead stop is also a useful feature, but usually only in certain games.

As for CAD you can run... If you haven't heard of sketchup, it is an okay stop gap when you can't get decent CAD to work on your computer.

[BJC]

Originally Posted by ,4lex S.

As for CAD you can run... If you haven't heard of sketchup, it is an okay stop gap when you can't get decent CAD to work on your computer.

Thanks, thats a really useful tool. I'd never heard of it before. I'm sure I'll be using it alot in the future.

[BJC]

Using Sketchup I was finally able to finish what I started.

and yes, there's no chains, gearboxes, and you get circles instead of wheels but those would taken way way longer to make from scratch then I wanted to devote to finishing this. Overall though, pretty good for a first try I think (at both designing a chassis and sketchup).

Comments and opinions are welcome.