[Andrew Blair]

Originally Posted by Joe Johnson

At the time, I thought, how much load can those crumby mecanum wheels be putting on the transmission? But now I see that in fact, it must be a lot because you showed more wear than the 2-CIM test we ran.

I believe that the reason that the mechanum transmissions bowtie more readily than in a standard drive train is the dynamics of their control. Where as in a regular drive, in order to put large forces on the transmissions, you must actually change the direction of the robot. Each shift is noticeable and easily documented as a fatigue cycle.

With the mechanum setup, you are likely not putting the transmissions under the massive load of decelerating/accelerating the mass of the entire robot, but with every sort of direction change, and to a lesser extent, slight adjustments course, you are fatiguing that connection.

So, the actual loading on the transmission may be half or less that of a traditional setup, but the number of cycles experienced could be a magnitude higher or more. So long as that yield is reached, it'll go, and a greater number of cycles would account for the greater amount of bow tie. Maybe anyway! Side loading could possibly account for something too. An axial misalignment between the shaft and the carrier plate created by an improper mounting setup could potentially increase the bow tie effect.

Regardless, I am relatively surprised at the amount of strength that the connection retains, even increases, as the bowtie widens. Work hardening is the only thing that I can imagine is occurring, though it is still quite astounding. I was quite sure that teams would be reporting near or actual failures by now. Something's happening in there...