In an attempt to kill off the giant rad scorpions and the like, the U.S. army unleashed waves of robots; the army collapsed afterwards and the robots' memory circuits are damaged, from lack of that maintenance type. Some robots can crudely repair themselves, and some humans repair and control robots(like the Mechanist); some robots can repair and build other robots, too.

Nah, the US army was no more way before the Radscorps (or any other nice friendly creatures) appeared. The thing that caused the scorps is the same thing that caused the army to be no more

Robotics was of interest to the army though (spoiler alert!), and, the house robots were in use before the war, and yes, able to repair themselves. There are some design documents, look 'em up (me's too lazy to do it)

I was thinking the Op was maybe being sarcastic? Making a point about the Yao Guai thread....

With all of the Maintenance robots everywhere, in so many of the tunnels, and in stores, and so many in Private homes (not to mention a massive robot factory), most of them art probably survivors of the war that are simply undertaking their duty which seems to be Pest Control and Security.

Thus they attack "Unauthorized Personnel" and any kind of creatures on sight.

That is my theory too, and when they see you, since they do not recognize you as authorized personnel, they attack you as an "intruder", that at least explains the ones in metro tunnels and pre-war buildings, I'm not sure where the ones wandering about the middle of nowhere could have come from.

Lots of well to do family's probably had Robots, you could obviously see that Robots were marketed to citizens (remember the loading slide for the Robotic Pony?) so a significant amount of people probably had Robots in their homes.

They might have been in their tubes recharging when the bombs went off and thus survived, and have been wandering around fulfilling their duties.

Not to mention that I imagine that a bunch in the Metro tunnels most likely found a door out and wandered outside.

Also lots of people like the Machinist or Tinker Joe who have probably refurbished some Robots they found so they could have them as companions.

Considering the Robots run off Fission batteries, I would imagine they are a little bit more hardened to radiation / EMP, then say your average human / ghoul.

how about a conceince of robots, i did see a robot in one of this pulaski peserver shelters in washington.