Questions on Mecanum wheels

[NinjaCat]

I'm from a second year team, and this year we are looking to use Mecanum wheels. Can we use the frame we got in the starting kit? How are the wheels installed on the frame? How are the motors for the wheels installed and programmed? Thanks for posting!

[IronicDeadBird]

Originally Posted by NinjaCat

I'm from a second year team, and this year we are looking to use Mecanum wheels. Can we use the frame we got in the starting kit? How are the wheels installed on the frame? How are the motors for the wheels installed and programmed? Thanks for posting!

I'm not sure the kit frame is optimized for mecanum so you might need to pull out a calculator. Make sure you know all the technical data behind how mecanum works before you start mounting stuff willy nilly. Mecanum works when done right and is as loose as a clowns pocket when even slightly off.

[pfreivald]

I highly recommend direct-driving mecanum wheels off of Toughboxes or Planetary Gearboxes (like Banebots P80s). Any gear ratio from 9:1 (probably too fast for this game) to 14:1 (perhaps just a tad too slow) should work well.

Support the shaft on the other side of the wheel (which will protect it from impacts, too.)

That's about as foolproof a mecanum setup as you're going to get, and while it might not work straight out of the AndyMark box, it's something you can whip up with some aluminum from the local hardware store without too much effort.

[NinjaCat]

I also see many teams say to get suspension on mecanums and they need to be well balanced and precise. Any advice on how to do that?

[efoote868]

Originally Posted by NinjaCat

I also see many teams say to get suspension on mecanums and they need to be well balanced and precise. Any advice on how to do that?

Flex in your frame can work... spring loaded mecanum wheels are another possibility. Search the web to see what teams have done in the past, or try and put together your own solution.

Do your best to balance your robot to keep the normal forces on each mecanum wheel roughly the same, then use other parts to aid in balance (battery for one, electrical components, compressor and air cylinders if used). Also keep in mind dynamics, how will your robot behave when lifting 1, 2 or 6 crates?



However, I would caution you on trying something new (like a holonomic drive train). Ideally your team would pick a realistic strategy of what you want your robot to accomplish, then design around that strategy. How much will the added complexity benefit your team, instead of maybe an extra week of driver practice?

Best of luck this year!

[Sperkowsky]

Last year was the first time my team used mecanum wheels and in all honesty they ended up being a huge learning curve and a giant waste of time. This years objective does change stuff a bit. We went mecanum wheels again and they are just about installed. The thing is remember you need double the gear boxes and double the moters. It's also a much bigger stress on your coder and will easily take a full day to dial in correctly. The other thing is this year's chassi doesn't natively fit 4 tuff box nanos or tuff box minis(ones included in kop) the way the chassi is made also makes it impossible to mount 4 minis so you have to buy 4 new gear boxes (assuming you don't have them around) then at that point you have to drill holes to match the nanos. It also means 2 more talons or jaguarsso more on the wiring.. Think about whether it is worth the stress. Anyway happy building

[Amar Shah]

Originally Posted by Sperkowsky

It also means 2 more talons or jaguarsso more on the wiring.. Think about whether it is worth the stress. Anyway happy building

Unless you previously had a two motor drivetrain, wouldn't it be the same number of motor controllers?

[asid61]

The wheels themselves are installed in the same way as others, but you don't chain them together. You need a seperate gearbox for each one.

[Sperkowsky]

Originally Posted by Amar Shah

Unless you previously had a two motor drivetrain, wouldn't it be the same number of motor controllers?

Well yes but this year's kop uses a drive train that can be configured with 2 or 4 moters come to think most people will just do 4 from the beginning but you never know.

[pfreivald]

Originally Posted by NinjaCat

I also see many teams say to get suspension on mecanums and they need to be well balanced and precise. Any advice on how to do that?

Having used mecanum and then octocanum for five years, I've never found it necessary.

[rj.nyguy]

Originally Posted by NinjaCat

I'm from a second year team, and this year we are looking to use Mecanum wheels. Can we use the frame we got in the starting kit? How are the wheels installed on the frame? How are the motors for the wheels installed and programmed? Thanks for posting!

My team has used macanum for the past two years and have luck using the andymark nano tube gearbox.

[GeeTwo]

I agree that trying to mount mecanum on a KOP drive system is likely to be far more trouble than it's worth. If you're doing mecanum, save this chassis for an off-season project, or next year. We did mecanum last year, and our construction was rather simple. We used two lengths of 1-1/2" x 1/8" aluminum angle with some notches for the axles on a TB mini, and bolted the TB inside the angle using its existing holes both at the bottom and through the axle plate. We then mounted the hubs "inside" the wheels, and mounted them as close to the gearbox as we could without anything rubbing. We did not support the end of the shaft, and did not have any camber problems. With the extra weight you may be carrying this year, it might be prudent to use taller angle, press a flanged bearing into it, and stand the gearbox back a half inch or so. In that case, I'd use spacers and mount to the holes outboard of the axle plate screws. (We're on a budget and try to never modify a COTS part if we don't have to.)