Examples of wide-based robots using traction and omni wheels

I need to prove to my mentor that 1 set of omni wheels and 1 set of traction wheels will make really good turning for our wide-based robot. Does anyone have any videos/pictures (vids preferable) of robots that fit this description?

I already searched on CD and Google for a while and found nothing, so I’m hoping some teams know of some.

Thanks!

We had a long base 4wd with a set of omnis in the back. Obviously if it worked with long, then it’ll turn fine on a wide drive base.

  • Sunny G.

Thanks! :smiley:

Too well, possibly.

A wide wheel base won’t have nearly as much trouble turning as a long base anyway. Just go with 4 tractions/lunacy wheels if you’re doing a wide base; adding omnis could result in too much turnability.

Our problem is we want to extend the wheels out a bit farther, and our wide robot already has a larger wheel base than our long 6 WD.

Exxperiment with omnis and tractions in opposite corners.

O---------T
l----------l
l----------l
T---------O

This seems interesting, but I don’t see why it’s any better than tractions in front and omnis in the back.

The benefit will lie in turning.

One thing that the team felt in 2010 (the video above) was a significant amount of fishtailing. With the wide base, perhaps you’ll feel a significant amount of that compounded with increased sensitivity.

With the setup that PayneTrain has suggested, notice that there is no real point about which the robot can fish tail. It forges stability into a potentially unstable design all while distributing the weight over omni wheels and traction wheels.

  • Sunny G.

Your wording makes we want to test that right now. :smiley: I think we’ll possibly stick to using gulp Lunacy wheels. They fit our needs, and we’ll be able to keep our bot the way it is without changing too much right now.

This is probably wrong actually. If you have a wide base robot, and you’re powering all wheels, you should have 0 issues with wheel scrub while turning.

We are currently using the new 6" wheels in the kit, and using the spacing provided. While we turn, we don’t maneuver/turn as well as we’d like to. FURTHERMORE, the main reason we’re looking into this is because we want to move our wheels out a bit more so we have a bit more stability for the robot, thus making it even harder to turn, especially with the 4" AM plaction wheels we will be using as of tomorrow.

Officially, I can’t say it’s bad, since we didn’t test on carpet. However, we tested on pretty slick concrete that may have been even easier than carpet, and that’s what scared me. We will test on real carpet tomorrow.

1 set of omnis and 1 set of tractions…after seeing other people’s comments, I have further understood what you have meant…

But I had to post what I was thinking - I introduce to you, the magic of Nanodrive.

I love that robot. :smiley: It’s one of my favorites on my playlists (Anything 148, really). While I love the drive, it’s a little complex for us right now, and especially for this late in the season.

Thanks for the post, though!

Make sure to report back once you do test on carpet… it really can make the difference in how your drivetrain performs

Check out this video of 1918 in 2010: http://www.youtube.com/watch?v=YGTwp3hjVI8&feature=related

Some of their other videos show them using standard 2008-ish Kit wheels on the end instead of Omnis. I’d contact someone on their team and see if they’re willing to share their experiences with you.

Thanks a bunch!

Not true. In fact, we went through a design change already because with a well balanced wide robot with pneumatic wheels at the corners inflated to max pressure, the robot had a very hard time turning.

My team used a wide robot with kit wheels in the front and omni-wheels in the back for the 2008 season, after doing this in a long configuration had worked out well the year before. In the end I think the robot ended up turning too well as we only had one or two students who could actually drive the thing and it still fish-tailed or spun out on occasion during matches (we were also geared for 13 fps which didn’t help matters). Since then we’ve gone back to the long configuration with omnis every year since because it gives us good turning without going overkill like the wide base did with it.

I found a video of ours with some of our practice driving, skip ahead to about 1 minute in to see the robot actually driving around:

I’m sure the blue alliance has some match footage as well but that will probably be far away shots of the field.

When people say “turn too well” when referring to omnis, what exactly do you mean by that? Do they turn more than the controlled angle? If there were other options to ease in turning, would you suggest omnis over them, or no? If no, then what “them” would you suggest? We are hoping on using 4" wheels for our robot.

Thanks!