Mecanum needs a flat floor

[Lesman]

We were driving our recently assembled mecanum robot around, and have noticed that even a slightly uneven floor can result in problems maneuvering (going straight tends to work well everywhere). Even with the large number of mecanum drives this year I haven't seen anyone voice any concerns about this. Do you guys think that this will be a problem?

[Dan Petrovic]

There have been many threads about mecanum drives and their need to have all four wheels contacting the ground.

They have basically been discussions about the importance of a suspension to ensure that imperfections in the chassis or the floor don't screw up the driving.

Just a small bit of movement with a suspension should be good considering how the carpet flattens a bit under the robot.

We used a mecanum drive last year with rubber dampers acting as a sort of "suspension" and had no problems. The wheels moved about 1/8th of an inch or less.

[The Megan 2207]

While testing our mecanum wheels, we decided to see if they can handle bumps. One of our team members threw his shoes in front of the robot. Apparently, our robot can drive over shoes. The same team member then decided to see if the robot can drive over him. It couldn't.

Anyway, I don't think an uneven field will be a problem (for driving, anyway... line sensors are another story).

[Joe G.]

Unfortunatly, as you have discovered, mecanum and holonomic drives need a level surface to function properly. Some kind of suspension is usually used. I'm not sure how your's is set up, so this probably won't work, but this is the simplest way I could come up with:

have pillow blocks holding up your shafts. Put them offset from the chassis by about an inch, and have the screws used to offset them on springs. They will be normally compressed, and uncompress when weight is taken off of them

[Cow Bell Solo]

you do not need an flat even floor for mecanum wheels, yes a flat floor is ideal but the bumps in the field will be no problem for the mecanum wheels

I know that the wheels are slightly different (at least from our robot) and are alot bigger but check out http://www.airtrax.com/video/Obstacle_navigation.wmv that video from airtrax

[llama]

Originally Posted by Cow Bell Solo

you do not need an flat even floor for mecanum wheels, yes a flat floor is ideal but the bumps in the field will be no problem for the mecanum wheels

I know that the wheels are slightly different (at least from our robot) and are alot bigger but check out http://www.airtrax.com/video/Obstacle_navigation.wmv that video from airtrax

in the video they even mention that the wheels are cushioned so they do in fact need four points of contact at all times...

[Cow Bell Solo]

ya and they are slightly different, but we have had our robot run over shoes(yes it was my shoe) and other items and it has had no problem going over and we have the mecanum wheels from andymark plus all types of wheels idealy want to have all wheels touch the ground