Mecanum in FRC2020?

There are boundaries (3 in wide and 1 in high) around shield generator. here are boundaries (3 in wide and 1 in high) around shield generator. Robot will need run across-over them frequently. Do you think we can still use Mecanum wheels design?

I think 6 inch mecanums would certainly cross over the bump but it would be a rough ride over. Since mecanums are usually a 4 wheel drive if you cross at an angle you may get stuck.

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A quick search of this forum will lead you to several other threads discussing the pros and cons of use of mecanum wheels in the 2020 game.

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Mecanum wheels work great for flat ground applications, but in my experience I have been able to break them very easily on bumps, even steel 6" ones. I would anticipate that the steel tubing in the rendezvous point would absolutely destroy mecanum wheels if you hit them at any reasonable speed.

Honestly, I don’t see mecanum being a good choice this year. Our team is very fond of our mecanum drives and have used them with good success, but we’ll be going for a 6-wheel WCD this year. With the shield generator boundaries and not much need for lateral movement, combined with a need for high speed and strong pushing capabilities (for defense) it just doesn’t make sense to use a mecanum drive.

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If you are a quick low robot that intends on using the protected zones I could see mecanums being effective. But if you plan on contending with the rendezvous point in the center in the field for anything other than end game I would recommend against the use of mecanums.

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Build a tank drive and get tons of drive practice. It will be more effective than a mecanum drive 100% of the time.

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You can use them, but I would be concerned about them breaking if you move too quickly over the berms in the center of the field.
Honestly, I’m even a little concerned about Omni going over it. We have had berms in the past, but never in an area that robots would be moving with so much speed.

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One idea that was proposed on saturday was installing “skid plates” in front and behind the wheels that would take most of the force from slamming into the iron bars

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If you have a strong enough strategy or reason to do it that outweighs the problems you recognize go for it.

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As @JVN would say “Try then iterate” It won’t take long to build a kitbot frame, slam 4 mecanums on it, add weight to get to 120lbs, build a hump and then spend two hours driving back and forth over it until something breaks.

That way you move from the "I think … " to “Hey we have data”

Let us know how your testing works out.

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Please ensure that if (when) your skid plate fail that they don’t violate R7.

Thanks for the feedback

Thanks for the feedback.

I was wondering the same thing so after running the battery down quite a bit I stuck a piece of 1x3 to the floor to see if I could get the robot stuck going as slow as I could throttle wise. Seems that you won’t get stuck on it no matter what you do and how low your battery is. Strength wise my local team jumped off of hab 2 every match last year with mecanum with no issues. I know the post is already solved and there are plenty of strategic reasons to go with something else but I already had the footage and figured it would be good data to share.

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Did you do any testing of a robot driving into it full speed?

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Not yet as I was out of charged batteries by the time I thought to do this. The drive base is still together so I’ll take a video tomorrow of some high speed hits. The vex mecanums in my experience are fairly robust and I’ve never had an issue with them.

Frankly mecanum wheels this year might only prove troublesome. They are not as fast as tank wheels, and can therefore reduce your efficiency, but they are also not very resistant to shock, and with defense, the boundaries, and other potential issue-causers, I do not see much advantage. And I used mecanum last year lol.

I don’t know how you jumped off hab 2 last year without breaking a wheel.

We broke 6.

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Please also add weight to the chassis to simulate a typical robot.