Vroomba!

Square-cube scaling being what it is, I think it'd be much more reasonable to use propellers (like quadcopters) than try to scale down COPV's to a Vroomba! size. That's actually an interesting product idea. A small flying vacuum cleaner could clean a variety of surfaces; not only floors.

(And you could even mount the charging station on the ceiling, so it doesn't take up floor space).