Examples of wide-based robots using traction and omni wheels

[Andrew Lawrence]

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!

[ttldomination]

http://www.youtube.com/watch?v=Ge8AAtj8qa8&list=UU4BdKshCs-JC8HanT-9EMbA&index=9&feature=plcp

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.

[Andrew Lawrence]

http://www.youtube.com/watch?v=Ge8AAtj8qa8&list=UU4BdKshCs-JC8HanT-9EMbA&index=9&feature=plcp

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! :D

[EricH]

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.
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.

[Andrew Lawrence]

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.

[PayneTrain]

Exxperiment with omnis and tractions in opposite corners.

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

[Andrew Lawrence]

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.

[PayneTrain]

The benefit will lie in turning.

[ttldomination]

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

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.

[Andrew Lawrence]

The benefit will lie in turning.

Your wording makes we want to test that right now. :D 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.

[Akash Rastogi]

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!


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.

[Andrew Lawrence]

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.

[Squeakypig]

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.

http://www.youtube.com/watch?v=_hTyXQUgYLE&feature=related

[Andrew Lawrence]

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.

http://www.youtube.com/watch?v=_hTyXQUgYLE&feature=related

I love that robot. :D 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!

[IraJason]

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.

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

[thefro526]

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.

[Andrew Lawrence]

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!

[Tom Line]

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.

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.

[Donut]

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:
http://www.youtube.com/watch?v=7ZRYYIMcnYg&feature=plcp&context=C3e2ba71UDOEgsToPDskJ-2pHL7knCcI2E3HOLmYKZ

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

[Andrew Lawrence]

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!

[EricH]

I think the post right above yours answered your question...

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 [...]
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:
http://www.youtube.com/watch?v=7ZRYYIMcnYg&feature=plcp&context=C3e2ba71UDOEgsToPDskJ-2pHL7knCcI2E3HOLmYKZ

[Andrew Lawrence]

I think the post right above yours answered your question...

Oh. I didn't see the part about spinning our of control. Thanks!

[PayneTrain]

Note when I say "traction wheels," I'm not talking about the kitwheels. i'm talking about aluminum-cut, 2 inch wide IFI roughtop wheels. The definitive stock traction wheel (We used to make some killer custom traction wheels until 2008).

Those things invented wheel scrub.

[Andrew Lawrence]

Note when I say "traction wheels," I'm not talking about the kitwheels. i'm talking about aluminum-cut, 2 inch wide IFI roughtop wheels. The definitive stock traction wheel (We used to make some killer custom traction wheels until 2008).

Those things invented wheel scrub.

We're using Andymark Plaction wheels, not the kitwheels.

[PayneTrain]

We're using Andymark Plaction wheels, not the kitwheels.

Wedge or rough?

[Andrew Lawrence]

Wedge or rough?

Roughtop all the way.

[Garrett.d.w]

Have you guys thought of a six wheel drive wide base? I modified a kitbot at the start of the season to do this (1/8th in drop on the center wheel). I haven't gotten to drive it extensively, but it seems to work.

As for four wheel drive. We have successfully gone two traction wheels in the back (or wherever most of your weight is), and omnis in the front. I can't find a vid anywhere, but those at bunnybot 2010 can attest to the fact that it was quite strong and fast (we were able to tow a goal that was made out of rough plywood on uneven carpet and win a few pushing matches). It was also very easy to drive (we managed to deliver coffee without spilling it :P).

If you don't want to modify your bot to try it out, you can build spacers that allow you to put two omnis on one hub, allowing you to simulate a full width wheel.

[Andrew Lawrence]

Have you guys thought of a six wheel drive wide base? I modified a kitbot at the start of the season to do this (1/8th in drop on the center wheel). I haven't gotten to drive it extensively, but it seems to work.

As for four wheel drive. We have successfully gone two traction wheels in the back (or wherever most of your weight is), and omnis in the front. I can't find a vid anywhere, but those at bunnybot 2010 can attest to the fact that it was quite strong and fast (we were able to tow a goal that was made out of rough plywood on uneven carpet and win a few pushing matches).

If you don't want to modify your bot to try it out, you can build spacers that allow you to put two omnis on one hub, allowing you to simulate a full width wheel.

We thought of doing a 6WD drop center, but that would make us even less stable than we are now.

[Mk.32]

http://www.youtube.com/watch?v=AnIGjPHzkBk

2012 KOP Wide base, completely stock and it turns perfectly.
Though with another 80 or so lbs of weight it might get a bit tricky.
Omins in the front or back will help for sure, we ran them with our 2011 robot and that was LONG 4 wheel drive.

http://www.youtube.com/watch?feature=player_embedded&v=3RnBf0_tKAg

[Garrett.d.w]

We thought of doing a 6WD drop center, but that would make us even less stable than we are now.

With a very small drop, it is very stable (the kop drop is huge, 1/8 is about a fifth of the kop drop). Fully loaded and on carpet, the drop is barely noticeable. It also helps that we are using small wheels. Four wheel drive will always have an up on stability.

I'll post a "drivers review" about it when we start practicing next week.

[Hawiian Cadder]

Our 2012 robot was 6wd tank with no drop center and omni wheel corners, our 2008 was 2 omni, 2 pneumatic, and our 2009 was 4wd. I can say that of all of these the omni corner robot handled the best. The "shopping cart" effect that occurs with any type of asymmetric wheel layout causes drivability to suffer greatly. One Thing I might suggest is to file the kit wheels into a rounded profile, they seem to slide sideways better that way.

[Andrew Lawrence]

Our 2012 robot was 6wd tank with no drop center and omni wheel corners, our 2008 was 2 omni, 2 pneumatic, and our 2009 was 4wd. I can say that of all of these the omni corner robot handled the best. The "shopping cart" effect that occurs with any type of asymmetric wheel layout causes drivability to suffer greatly. One Thing I might suggest is to file the kit wheels into a rounded profile, they seem to slide sideways better that way.

Nice to know what your 2012 bot will look like now! You probably meant 2011, though. :) Do you know the spacing of the wheels on your 2011 6wd tank? And what size wheels did you use?

[Mr. Rogers]

Just remember, you will be easy to push with only two wheels providing traction. Consider making your traction wheels wider. (IFI 2'' wheels)
http://www.vexrobotics.com/ifi-wheel.html

[Andrew Lawrence]

Just remember, you will be easy to push with only two wheels providing traction. Consider making your traction wheels wider. (IFI 2'' wheels)
http://www.vexrobotics.com/ifi-wheel.html

1) What exactly will IFI wheels do for us?

2) Our strategies are to be fast, maneuverable, and for the most part stay away from opponents/areas where we get penalized. However, we do have a strong defensive strategy which will be useful no matter the opponents we go against.

[jwfoss]

Back in 2006 FRC322 had a wide chassis and the traction/omni combo you are looking for, they seemed to move on the field rather quickly:

http://www.chiefdelphi.com/media/photos/23148

http://www.thebluealliance.com/team/322/2006

[IKE]

In 2010, 2619 was a really great wide bot that did not get the attention it deserved. Here you can see t participating in a 12 to 13 match that was really a nail biter.
http://www.thebluealliance.com/match/2010gl_qm45

They are the blue wide bot that starts deep and works their way forward.

That year they used KOP (gray rubber) in the front, and lunacy wheels in the back (if I remember right). This robot was a lot scrappier than its relatively low traction system would have you believe.