Hey, My team is going to be using mecanum wheels and I was wundering if there was any good advice about there grip. I am conserned that they might not be able to clim the bord at the end. Another problem that I am seeing is the rings. Is there a way to get over them that will work and not use to much space? Please tell me if you have an answere.
There seems to be two ways teams approach the problem of getting stuck on rings. You can either build your robot with high enough clearance that rings can just pass through between the two sides of your drive under your bot. Or alternatively you can build the drive low riding enough so that rings just get pushed, not slip under and get stuck. But as far as I know there is no way to guarantee you’ll never get stuck on a ring, it just seems like something that happens if your bot lands on one in just the wrong way.
as far as using mecanums go, see this post discussing their traction in comparison to omni wheels: Omni wheel vs Mecanum - #13 by technik3k
to summarize it, mecanum wheels have significantly less traction than omni wheels both on foam tiles and on a plastic surface like the platform. This doesn’t mean mecanum wheels won’t be able to climb the platform, that depends on a number of factors, not just traction, but it might mean that you’ll have a harder time climbing than if you were to use omni wheels.
11 Likes
My team has a robot with a four bar. That makes the robot top heavy do you have a good way to stop tipping and not use a motor? Also I am wandering what compition you used the mecanum wheels in.
I find it useful to look to real world inventions that may already solve the problem that I’m encountering.
Say I wanted to lift something up really high. I might look at a SKYJACK, or a Forklift, or a Boom Crane.
In your case… I might look for something like:
6 Likes
That is very smart. I did not know that somthing like that was real. I guess that somthing like a bike kickstand is like that but still it is smart. That looks like it will work with the bord. Most of the anti tipping mechanisms that I have seen do not work with the bord.
Thanks
One of my students put together a basic mecanum base, and can confirm it easily climbs the ramp. In fact, with a tiny bit of added weight it easily strafes up the ramp. (As it is only 5 pieces of structure atm, it is very light.)
1 Like
this might work for you. This iteration had the axle come up with the lift, but I had a method which would keep the axle in the base and keep it up. If you wanted to still climb the ramp you could try to make a reset feature where you push into a wall and a different set of things keeps the anti tips in while you climb. There is probably a thread out there on VF which goes into anti tips for tower takeover.
Some teams also had extensions to their drivetrain which folded around the outside of their base, tensioned with rubber bands, which have enough ground clearance that they could probably work for your need.
Some teams had a set of parallel bars which would flip out behind their lift, tensioned upwards, which would prevent them from falling back like the gif Sidoti sent. This would likely work well as well.
2 Likes
Are any teams useing mecanums. I am confused why I can not very many teams that are using them. There are some not true thoughts about there grip but it is still a small amount.
I’m having trouble extracting anything coherent from this
5 Likes
Are any teams useing mecanums. I am confused why I can not find very many teams that are using them. There are some inaccurate thoughts about there grip and I do not know why.
P.S. sorry for the poorly writen commint.
3rd grade English does wonders.
My take is you want to know:
-Are there other teams using mecanum wheels
-Why are you unable to find other teams using mecanum wheels
-There are inaccuracies regarding mecanum wheels’ grip on the platform and you’re unsure as to why.
Are there other teams using mecanum wheels? Probably. Are there a ton of other teams using mecanum? Probably not. There’s a lot of different options available for drives this year, with one of the most popular being a 6 motor, and mecanum drives feel inefficient compared to other options (though don’t let that stop you from trying it out.)
Most of the teams that have made reveals of their robot also opted not to use a mecanum drive, which would be explain why you’re unable to find anything regarding how a mecanum drive would do this year.
As for the grip inaccuracies, that’s a little more tricky. I know Doug had mentioned above that he had a team build a bare-bones mecanum and it was able to climb no problem, however I’ve seen a mecanum that, while it wasn’t bare-bones, it didn’t have a ton of extra stuff on it either, and it wasn’t able to get up the platform at all. I think all the inaccuracies stem from hardly anyone actually attempting to build a mecanum drive, and those that do build one getting different results — it’s one of those things you’ll just have to build and test for yourself.
6 Likes
I agree that 3rd grade English does do wonders.
We use mecanum wheels, they let us have mogo lifts on the side to be able to have an intake put rings on both.
1 Like