Stuck robots
I'm sure it will get stuck and be a disaster, but devil's advocate: If it gets stuck, so what? Page a zero-hours flesh-drone to go get it unstuck. More expensive, but without the trundle-bot you'd have had to pay the flesh-drone to go the same distance anyway. If it works, say, 90% of deliveries, you're ahead of the game.
That of course is the same strategy used for automated check-out tills.
Also, the wheel configuration seems very reminiscent of the various Mars rovers, so I bet NASA's got a bunch of surprisingly clever algorithms worked out. This is exactly the kind of thing that's supposed to justify all that messing around with rockets. (If it works.)
Biting the hand that feeds IT
