Your thoughts on Mecanum wheels....

[DB_UPS]

Originally Posted by BigJ

also, your programmers will need a lot of time to develop and test (also trig skills)

1675 used mecanum fro the first time last year, and although it was hard, I had fun learning all the vector theory to program it.

Like josh said, Our progrem team did have fun programing it. Its wasn't really hard to build, we had a rolling chassic by week two last year (it wouldn't been soon by due to the shortage of AM mecanum we get done a little later) it was on the KOP chassic with the wonderful BaneBots transmissions.

The only problem we truely had was it wasn't encoded. It was open loop.

Would i do it again, sure if we make a custom chassic so the wheel are perfectly squared and encoded, i would do it in a heart beat.

[yoshibrock]

Some cons to Mecanum wheels are fragility (they break rather often) and drift (which can also be a pro). With any wheels that are omnidirectional you get pushed around a lot easier (which isn't too much of a problem this year, but still something to consider). Also, if you don't use a suspension, they're very bumpy. Some pros are mobility and a unique experience for your drivers.

[Jared Russell]

One unavoidable problem with both Mecanum and Kiwi-style omni drives are that you are essentially throwing away 30% of your speed. For every rotation of the Mecanum wheel, the robot only translates 1/sqrt(2) = 70.7% of the wheel's circumference when driving straight. Driving diagonally (with two wheels driving and the other two fixed) alleviates this problem.

This is why 341 changed our 2007 kiwi drive from this:

/ \

\ /

to this:

| --

-- |

last year.

[GMKlenklen]

what would be a good encoder choice? banebots is our first choice because we are considering using the banebots 56mm tannie... (worked great last year... already have all the parts). we'll probably be using the kitbot chassis, so as to aliviate as much cost from the drivetrain as possible.

[Zyik]

From what I've seen the benefits of having Mechanum wheels are:

• Allows for good freedom of movement
• Amazingly agile
• They look cool

I don't know how they are for speed or if having them effects that at all. However I have seen my teams robot push mechanum wheeled robots almost anywhere. There doesn't seem to be anything you can do once we come up behind you, if we wanted you to go away from the rack then thats exactly where you were going.

[kE7JLM]

I would not do it, not traction at all.

[GUI]

Originally Posted by Abwehr

One unavoidable problem with both Mecanum and Kiwi-style omni drives are that you are essentially throwing away 30% of your speed. For every rotation of the Mecanum wheel, the robot only translates 1/sqrt(2) = 70.7% of the wheel's circumference when driving straight. Driving diagonally (with two wheels driving and the other two fixed) alleviates this problem.

This is why 341 changed our 2007 kiwi drive from this:

/ \

\ /

to this:

| --

-- |

last year.

This is not a- much of a problem with mecanum, because the rollers don't spin when driving forward or backward you only lose speed going sideways/diagonally.