pic: A mechanum wheel that shouldn't bump around at all.

[exprg:melonhead]

Originally Posted by Ether

No, that's not what I said (not even close). I'm not sure how you concluded that from what I wrote. Help me understand what part led you astray.


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ok. here's what confuses me. if i want a robot that drives just as easily sideways as it does front and back, would it be best to have a 45. because the way i see it, the more you get away from that angle, the more energy it will take to move it sideways. correct me if i'm wrong because i feel like i'm missing a huge part of the puzzle here. but i think i understand the most part. it's basic physics really.

sorry for the mis-wording on my last post. i was pressed for time. i meant to say "easily move forwards and sideways". it's not that i don't understand it, because i do. i just need it explained how it would be advantageous to set it at any other angle.

[Ether]

Originally Posted by exprg:melonhead

ok. here's what confuses me. if i want a robot that drives just as easily sideways as it does front and back, would it be best to have a 45.

Yes, that's probably a pretty good rule of thumb. You're on the right track. The important thing is to try to make the roller bearing friction as low as possible. For "zero" roller bearing friction, 45 degrees will make fore/aft and sideways motions equally easy. But since there is always some roller bearing friction, you might need to increase the roller angle slightly (make the roller axis closer to the wheel axis) if you want to make both motions equally easy.

Originally Posted by exprg:melonhead

the way i see it, the more you get away from that angle, the more energy it will take to move it sideways. correct me if i'm wrong because i feel like i'm missing a huge part of the puzzle here.

You've got the right idea Justin. The more you get away from 45 degrees in one direction (i.e. smaller angle - roller axis becoming parallel to the plane of the wheel), the less efficient the sideways motion becomes. Moving the roller axis the other direction makes sideways motion more efficient - up to a point, depending on the roller bearing friction.

Take a careful look at posts 39, 41, 43, 44, and 45 in this thread - there's lots of good detailed explanation there. Ask questions about anything that's unclear.


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[exprg:melonhead]

Originally Posted by Ether

You've got the right idea Justin. The more you get away from 45 degrees in one direction (i.e. smaller angle - roller axis becoming parallel to the plane of the wheel), the less efficient the sideways motion becomes.


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thank you so much for helping explain this. i know it's hard to explain this through writing, and i know i don't usually learn well this way. you helped so much on clearing this up for me. i appreciate it.