It's going to take about 40-50 years to reproduce what humans can do in a restaurant today with robots. More likely, the food preparation process will be altered to allow for easier automation. With the exception of a supervisor/engineer (that position won't be automated for at least another 100 years) - I think we'll see a fully automated fast food restaurant in about 20-25 years - though some elements of the restaurant business (Cleaning, French Fries, Order taking) - will likely be automated sooner - there will be demonstration restaurants with 50% automation in about 10 years.
[note: And yes, I do realize that the above predictions will require radical advancements in automation that are not easy to predict - call me an optimist. :-) ]
[note: And yes, I do realize that the above predictions will require radical advancements in automation that are not easy to predict - call me an optimist. :-) ]