THE CRITICAL CONTACT
While there are different styles of omni wheels, most notably single and dual row wheels, the best performing wheels induce the least vibration as the wheel rotates to deliver the best ride quality.
To do so, the contact patch switches from one roller to the next as the wheel rotates.
In the event the wheel rotates as part of a change in the orientation of the payload or the direction of movement, the rollers in contact with the ground or the payload (in the case of a conveyor) freely rotate, making the movement efficient with the least amount of friction and scuffing.
A critical benefit both when in use as a downward facing floor- or upward facing conveyor wheel.
Another critical aspect of optimising the ride quality and performance of omni wheels is to assure they run perpendicular to the contact surface.
Even a few few degrees off, diminishes ride quality significantly.
The easiest way to assure perpendicularity to the running surface, especially real world surfaces, which are rarely perfectly level is to mount the omni-wheels onto a common axle.
This naturally optimises alignment and halves the angle of difference, splitting it between both wheels.
If you want to know more or have any questions, please let me know.