pic: 1683 30-Point Climber

[Nuttyman54]

Originally Posted by John Sabath

I've seen similar configurations before, so I'm assuming this one is no different.

The omni-wheels in the center are slightly lower than the traction wheels in the front and the back. The bot doesn't use all 6 wheels simultaneously. Personally, I don't see the advantage over a basic 2 omni 2 traction drive, because they'll both end up handling the same way.

The configuration you're describing is typically done with all traction wheels, colloquially known as dropped-center 6wd. The purpose of lowering the middle wheel is so you can use all traction wheels while still being able to turn.

The issue with putting all the wheels in the same plane is that it becomes very difficult to turn, because you are trying to drag the corner traction wheels sideways along the ground while you turn. The traditional method of doing 6wd with omnis is to put the omni-wheels in the corners, so that they roll side to side when turning.

Putting the omni-wheels in the center only hurts you. If you don't drop the center wheels, they would never scrub sideways so you get no benefit, and only lose traction. If the center pair of omnis is dropped, the turning center of the robot will change drastically depending on which set of traction wheels are in contact with the ground at the time. This would probably be very hard to control.

I would strongly suggest that 1683 test this on their carpet at the full robot weight to see how it performs. If the center omni is not dropped, I suspect you will find it very hard, if not impossible, to turn. If the center omni is dropped, I suspect it will drive pretty erratically.