Exocomp

Exocomps are a type of of maintenance robot seen once in the TNG episode "The Quality of Life". They were prototypes that developed a limited degree of sapience.

Exocomps were small machines that could easily fit inside a 1 meter cube. They had anti-gravity devices for locomotion and a small replicator mechanism that could generate an assortment of tools. Their purpose was to fly through the ductwork (Jefferies tubes) of a small space station to conduct maintnenance and repairs. They were built with enough artificial intelligence to diagnose problems and determine how to correct them, but they developed sapience as an unforeseen side effect.