Assume robots are the same as humans. Robots can do all the work that humans can do. Robots need the same amount of energy/food to stay functioning as humans do, but robots themselves can produce that energy/food just like humans can. Robots will need maintenance and training as humans do, but robots themselves can produce that maintenance and training just like humans can. Robots can produce other robots, just as humans can produce other humans.
The only difference between robots and humans is that robots are owned by humans. Robots are just like human slaves. Robots will earn the same wages as humans, but those wages, minus the costs of the robots' subsistence, will go to the robots' owners. Just like slaves.