pic: 6 Wheel Drivetrain

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This was just something I mocked up as a drivetrain base we could use for any contracts we receive by sponsorships. This one has the colors for the Tampa Bay Rays. Any changes that should be made? The large amount of 80/20 was to allow anything to be attached to it as a manipulator for whatever we would have to design

-Approx 30lbs
-6 wheel drive system
-AM Toughbox
-2 AM 8" Performance wheels
-4 AM 8" Omni Wheels
-36" 1/4" thick Aluminum side plates. 5"wide
-80/20 Reinforcement
-25 Chain
-Direct drive to the center wheels

Bryan Gallo

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Before anyone flips about the pocketing on this…

Note that this is for sponsored robots, not for competition use. IE: t shirt launchers

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Looks like fun.

Even with it not being a competition robot, I’d still be a little worried on the pocketing. Would having a little less of it be out of question?

-Nick

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Each frame will have its own paneling to cover everything up.

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The fact that it’s not for comp is even more reason not to pocket it.

Just leave the 1/4" plate solid, it’ll be stronger, prettier, and waaaaaaaaaaay quicker to manufacture. It will also make the base more stable for whatever it’s being used for.

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6 wheel drive and all that pocketing seems like a lot of work for a non-competition robot.

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I didn’t want to leave it solid. It will be covered by bumpers and the perimeter will be lined with .5" square tubing. The looks of it won’t matter, and in my opinion pockets make it look pretty neat. But that’s besides the point…

I do agree that the holes for the wheels need more beef. It is .5" width now, I should have put it as .75" width. The rest of it is identical to the plate we used for our 2009 bot. Its just a foot longer.

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Before anyone flips about the pocketing on this…

Can someone explain what “pocketing” is?

Thanks

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Pocketing is pretty much “how” much material you take out of a solid piece. Pretty much also the CNC cutouts of a piece.

Also on CAM programs, pocketing is an option for type of toolpath.

-RC

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Maybe higher ground clearance. If its noncompetition, I can see it going around sidewalks, pavements and grassy areas.

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You plan on using 25-series chain to drive the omnis…how will you tension the chains? Also make sure the alignment between each pair of sprockets is acurate.

With 8" wheels and a 5"-wide plate (assuming wheel centers are in the center of the plate–at least it looks that way) gives you a 1.5" ground clearance? Should be OK.

I have to agree with others that you need more meat on the side plates…1" on the webs at least, and big radii in the corners of the pockets. Always start with a strong base, even if it’s not for competition.

80/20 is good stuff, but you have to watch that the bolts holding the frame together don’t come loose–they always seem to eventually. If you’re not going to take it apart, you may want to consider Lok-tite (or tack welds).

All that said, it looks like a solid, simple design that should go together very quickly.

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I would be concerned with the front and rear driven omni-wheels. In our experience, having no side-force resistance to turning will lead to a robot that is very difficult to accelerate in a straight line.

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It appears as though you are using AM toughboxes, you might want to leave the cover over the gears to keep dirt and FOD out of the gears and grease.

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A piece of .030 to .062 polycarbonate will do the same thing for less weight. :wink:

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I’m still a little confused as to why this chassis is being built with weight in mind (other than to keep it liftable, roughly under 150ish pounds), but it looks simple and effective.

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We’ve used that drivetrain in 2007 and 2008. 2007 we used 4 banebot KOP gearboxes. 2008 we used an AM supershifter. Both years we had no problem with the robot driving straight. Even in autonomous with a little help from a gyro, we were able to drive straight.

I was considering adding those tensioners that Andymark sells for #35 but purchase them from McMaster for #25. But now I’m going to just cut slots into the plates and have an idler sprocket with a shoulder bolt. That’s always worked for us in the past. And lok-tite is a definate for everything we use

I agree with that. It’s not a lot of weight, and I’m going to put the aluminum one back on. Should look nice too. Thanks for the tip!

I’m assuming that there would be cheerleaders and people who cannot lift as much as we can. With safety in mind, I want to keep the actual weight of the robot between 120-150lbs. That includes bumpers around the perimeter, 2 batteries, and the rest of the robot. With this 30lb drivetrain, assuming bumpers are at a max of 18lbs like FIRST. There is approx 45-75lbs for electronics, and the manipulator.

Thank you for all for your input

Bryan Gallo

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I’d recommend ditching the wedgetop tead and omni wheels for normal solid rubber wheels like colsons.

They’re cheaper, and won’t need replacing/maintenance.

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Bryan,

Nice work. I am trying to get my class to evaluate different disigns with different materials. Could i get a copy of the CAD file? It would help with the analysis.

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There are some bots here:

http://team1323.com/cad/pages/teamhosting.html

If you would like to check these out, Bryan has 5 of his bots on there.

-RC

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Yeah! there are 5 up there. 2006-2009 are very durable tank drive drivetrain systems. They’ve been through pretty harsh competitions, and worse yet, off-season, and they’ve lasted through that. If you have any questions about any of those designs i’ll be more than happy to help. PM me or email me.

I’ll try to post more drivetrains on the team hosting website. I have a few on here, along with our T Shirt Shooting Robot the Screamin’ Eagle! I just need to finish up some work on it.