Repairbots are a class of semi-intelligent robots that whizz around inside the Centauri Princess, doing housekeeping duties for humans. They are of two types:
The term "repairbot" was originally coined to describe the main duties of these robots as entities whose job was primarily to 'repair' and replace various bits of mechanical hardware throughout the Centauri Princess interior. Even though later on into the voyage they became capable of doing a lot more elaborate tasks, the name repairbot remained as the generic way of referring to them.
Each repairbot has a unique numbered designation, and typically one would refer to them simply by their numbers: example "Number 232" that was serving Shirin's home on Midsummer Crescent at the time of Operation Energy Barrier (Chapter 9 of First Ark to Alpha Centauri) . In some cases, when people got really affectionate with their pet repairbots, they give them real names. Example: Caroline and Haroon called theirs "Felix" (chapter 2, page 51 of The True Price of Immortality) as it was very much a part of their family.
The domestic repairbots in the main, are much like cute pets. They have a humanoid appearance, with a silver metallic head, glassy photosensitive eyes, wiry arms and legs. They have the ability to talk to you and engage in basic conversation. They are also flight-capable, having retractable propellers with which they can hover and glide in the zero-g environment inside the Ark, once airborne. They can help you with physically demanding tasks, such as carrying heavy shopping and even clean and dust your house for you, or mow your lawn or dispose of fallen autumn leaves (as in chapter 2, page 51 of The True Price of Immortality).
The industrial repairbots are much larger by comparison and they are used for bigger jobs, like when people have to go outside to fix a part of the ship, or when the sun-simulating light bulbs arranged in clusters ('miniature suns' in the novel) on tops of their transparent pedestals burn out and need replacing, or when weatherbots need to have their batteries replaced, etc