This Bots will be drones that will build Buildings and other Structures ( This to the Theory that we can create Matter from Energy as also the Opposite; https://www.sciencedaily.com/releases/1997/09/970918045841.htm) and produce as also help clean up streets.
With using Plasma generators to create a Gravitation field around them.
They will fulfill all functions in second. Do to the nano-computers inside them.
I take this Picture as a Example.