Caster on robot can hang on the edge of the mat

[tcorbly]

[ronperris]

As a novice, I see a couple ways to fix this.

1. Lower the robot chassis friction here.

2. Lower the surface friction here.

Is this what you were thinking of @tcorbly?

[chrismbirmingham]

In my testing, changing the friction doesn't make a difference for either 1. or 2., I think the solution is more likely to change the geometry. Either by decreasing the thickness of the mat, sinking it into the floor, or modifying the geometry of the caster.

[chrismbirmingham]

Changing the mat height to -7.1 appears to solve this issue.