In 2077, after the bombs fell, the survivors found themselves sealed inside the Vault with around 100 robots (one for each resident). At first, they were delighted by this prospect, given that the robots could potentially serve as robotic butlers and do all of the work for them, however, upon trying to interact with them, they got quite the response.
Many of the robots were rude, spoke only in vulgarities and refused most demands made to them by humans. The machines weren't hostile, nor did create problems (most of the time) and so the Dwellers decided to simply play 'live and let live' with the machines.
For unknown reasons, several machines have been exiled over the years, Gerald is one such example, who barely remembers the circumstances behind his exile but remembers telling the Overseer to 'fuck off.' Forky is another machine, who was exiled, along with several of his bretherin, apparently because they were damaged or broken or proved too unruly to keep around the Vault.
The Vault is still operational to this day, little else is known about it at this point in time.