My dog barks at and even attacks a vacuum cleaner, I know because I, not a maid, am operating the vacuum cleaner. I have seen this before, dogs barking or even attacking noise, or maybe just a broom. I recall a dog that went "nuts" if he saw someone with a garden hose (If you know what I mean) watering flowers.
I don't recall any of these animals being broken of those habbits, but I can say if I just keep working with the vacuum my dog gets distracted and goes to another room and the confrontation is all over.
Is he barking at them or the thing they are using to clean? Are they there every day? Some obedience training might help.
Getting him to interact with the maids might help. They can try giving him treats, tossing toys, etc.
Try gating him off in another room? If he is crate trained, put him in the crate when they are there maybe.