pic: 6 Wheel Drivetrain

[gallo26]

loading photo ...

[Akash Rastogi]

Before anyone flips about the pocketing on this...

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

[Nick Lawrence]

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

[gallo26]

Originally Posted by Nick Lawrence

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?

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

[AdamHeard]

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.

[gallo26]

Originally Posted by AdamHeard

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.

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.

[gburlison]

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

[rsisk]

Before anyone flips about the pocketing on this...

Can someone explain what "pocketing" is?

Thanks

[R.C.]

Originally Posted by rsisk

Can someone explain what "pocketing" is?

Thanks

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

[James Tonthat]

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

[M. Mellott]

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.

[Tom Line]

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.

[Jeff 801]

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.

[artdutra04]

Originally Posted by Jeff 801

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.

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

[gallo26]

Originally Posted by Tom Line

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.

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.

Originally Posted by M. Mellott

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.

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

Originally Posted by Jeff 801

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.

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!

Originally Posted by Chris is me

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.

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