Each settlement could have an Assaultron or Sentry Bot guard or both, it would be fun

Yea. I want Liberty Prime around my hood.

Mysel do have Assaultrons and Sentry Bots in a few settlements. They are today turn off, since I don't need them. Btw, this ain't sure of, but wiki says that having robots/Gutsies do decrease happyness, not sure about Sentry and Assaultron bots since in settlements where I have these, not going to have very high happyness. I had one police robot once, but something went wrong (he was activated) so he fleed. Never seen him again. Scripted robots (robots you should not have) do behave strange.

Cheers,

-Klevs

Gutsiest when counted as settlers (in Graygarden for example) have fixed happiness (either 50 or 60%, don't remember anymore). Therefore in a mixed settlement, they can either increase or decrease happiness depending on if happiness of human settlers is less or more then that of robots.

Some settlements do have default robots, but unless they count as settlers, they don't influence happiness. At last I am not aware about it.

I believe it refers only to Greygarden robots. They decrease happiness. With 1 settler and 6 robots, (without any shop or dog bonus), happiness will stop at 54-55%. The system counts it this way : (6*50+1*80)/7=54,2 . So yes, their happiness is 50%.

Well technically it does not decrease or increase happiness, presence of robots do not influence humanoid settlers. But since they are part of the settlement, their happiness counts to total average (as per your calculation). Of course if humanoid settlers are unhappy (below 50%), then presence of robots will increase average.

You are right and you explained it in a better way. My language is a bit limited as I`m not a native English speaker so I used the simpliest way to describe it.