[patrickrd]

Originally Posted by mzitz2k

Interesting! What did the neoprene look like? There are so many different types... What was the hardness rating and did it have "teeth" or was it just a flat sheet of material??? If you have a picture of part number, even better!

The neoprene had Durometer = Shore A: 70. We used rubber o-rings as the test specimen, 1/2" outer diameter by 3/32" thickness (purchased from McMaster). This is a much smaller scale than used in FIRST. The o-rings were used for contact with the carpet on each roller of our omni-wheels.Testing each material was simply a matter of replacing the o-rings in the wheel. I've attached photos of the wheel and the test setup. In short, the weight of the setup provided a constant normal force, and a voltage was applied to the motor. The voltage was increased until the wheel slips. From this data it is easy to find out what the coefficient of friction is. The uncertainty is less than 5% for all the data.

- Patrick