Quick change interface for low complexity rotary actuator

A rotary actuator, comprising:

• a first interface surface with a plurality of apertures defined therein;
• a second interface surface which releasably mates with said first interface surface and which has a plurality of surface features thereon;
• a plurality of interface modules, wherein each interface module includes a first interface module portion which releasably engages one of said plurality of apertures on said first interface surface, and a second interface module portion which releasably engages said plurality of surface features on said second interface surface;
• and
• a gear train which rotates said first interface surface about an axis;
• wherein the second interface module portion of each of said interface modules has at least one contact flat and a first set of mating features which releasably mate with a second set of mating features disposed on the second interface surface.