Pic: Easy to make mecanums..

[Madison]

Originally Posted by Alex.Norton

Its not that 45* is most efficient. It is that 45* results in the max speed to the side is equally to the max speed forward. They are actually less efficient than say 30* because the rollers need to turn faster when moving in a direction other than forward. Of course 30* also means that the max side speed is lower than the max forward speed and the pushing power is greater.

By 'most efficient,' I meant simply that a 45* offset allows for the fastest perpendicular drive speed. It's true that you can optimize the offset angle to better suit the conditions under which the drive will operate.

[Dillon Compton]

Question:

Most mecanum wheels have the rollers at a 45* angle on 2 axes (I think you all know what I mean, at least, I hope it's clear: the rollers are at a 45* angle to the wheel and then angled upwards, correct?)

Is this necessary, is it simply for increased traction, or could one theoretically design a mecanum wheel more in the style of an omni wheel, simply rotating the rollers to a 45* angle instead of a 90* angle?

[Simon Strauss]

Originally Posted by Dillon Compton

Is this necessary, is it simply for increased traction, or could one theoretically design a mecanum wheel more in the style of an omni wheel, simply rotating the rollers to a 45* angle instead of a 90* angle?

Yeah, take a look at this report (where i got most of my Mecanum information from) specifically the image on the first page titled the conventional Mecanum wheel. I think that is what you are talking about and although not as cool looking as the others, probably the easiest Mecanum to build if you don't have a CNC mill or, mill master and don't want each wheel to be a multi piece wheel.

[Dillon Compton]

Originally Posted by nycpunk

Yeah, take a look at this report (where i got most of my Mecanum information from) specifically the image on the first page titled the conventional Mecanum wheel. I think that is what you are talking about and although not as cool looking as the others, probably the easiest Mecanum to build if you don't have a CNC mill or, mill master and don't want each wheel to be a multi piece wheel.

Is the oblong roller necessary as well, or could one do something more along the lines of an AM trick wheel with the roller at a 45* angle?

[Alan Anderson]

Originally Posted by Dillon Compton

Is the oblong roller necessary as well, or could one do something more along the lines of an AM trick wheel with the roller at a 45* angle?

The shape of the angled roller is intended to make the overall profile of the wheel a smooth circle. If that's not done, the wheel will be somewhat "bouncy" in operation, and it won't have consistent traction as it turns. If the inconsistency is severe enough, it will be difficult to maintain a desired direction of travel.

[rachal]

The finished mecanum! (Sorry about the glare)


A comparison with the spares.


Much lighter now

[techtiger1]

Excellent job 1072 very nice machining process. I also love what you have done on being able to lighten the wheels. I like the fact that 1072 makes most of the stuff they design and has some great initiative about things like that. Finally, amazing pictures.

-Drew

[rachal]

Wow...we've been extremely busy with other things for the past few months, but we're finally getting close to wrapping this project up (the mechanical aspect, at least...)


Looks just like the CAD, doesnt it?


We're using a kitbot to test the wheels for now. (two of the wheels are still uncheeseholed, which is why they're hiding in shame under the other two =P)

[Kingofl337]

Team 40 used these last year. The biggest thing I can stress is make sure the chassis is a square. If the chassis is rectangular you will have a difficult time turning. If you check out checkmate40.com we have some video's of the robot running. It looks like its floating when it drives but doesn't stand up well to being pushed.

Bottom line, if you are looking for a robot that will push well or stand up well to being pushed you are looking at the wrong type of wheel. See the 6 wheel drive thread.

We do not plan to use them again this year unless the game dictates we should.