We set up a test to look at 2 things: 1) what the contact point of the rollers on the ground looks like while moving and 2) whether the rollers roll when moving forward. We utilized the phenomenon of FTIR: Frustrated Total Internal Reflection to highlight the contact point of the rollers. A piece of polycarbonate was placed across 2 tables with a few high power lights placed on their edge. This creates a lot of light passing through the polycarbonate via TIR. When the roller comes into contact it “frustrates” the TIR which causes light to be scattered from that point and essentially makes it look lit up.
We then rolled the wheel by holding it tight against the poly and applying torque while pulling the wheel toward us and allowing the friction to pull back—basically recreating the driving situation. We did NOT just roll the wheel along. This is hard and takes some practice…
And yes, all the rollers CAN freely spin. We are a bit obsessive about them actually.
