Robots fill many roles, and have a wide array of functions here are some examples:

Cargo robots are designed to carry heavy loads.

General-purpose robots could perform most of the functions of a human worker, but were generally limited to a single function.

Power Utility robots store and dispense large amounts of energy.

Superstructure Maintenance robots repair the outer hulls of space-craft and space stations.

Virobots are parasites on intelligent life-forms.