I've created a race of nomadic robots, but am having trouble finding a culture to base their language off of. They're peripatetic nomads, meaning they travel around offering goods and services to any friendly people they come across, but most nomadic peoples of this style either use the languages of their country, or the language is too fluid and natural to be suited for machines.
Humans in such kind of situation devolop a Pidgin specifically for trade. It is arguably easy not only for humans but also for robots: no complicated ingredients in syntax nor morphology, and also usually a simple phonology.
How about Polynesian languages? The people travelled far distances, their culture was very spread out, and they don't really have a country that 'owns' the language.
A further positive aspect is that you can pick up basic Hawai'ian on Duolingo; this quickly gives you a feel for the language. It's VSO, so sounds unusual enough to Western cultures who are more used to SVO. It would also be very plausible for machines who might process knowledge in predicate calculus (as in
The vocabulary has a strong English influence, due to the colonialisation by the Americans, who made teaching the language illegal, but you will probably adapt that anyway to choose your own words.