From Starfleet Commander
The Lab Droid is a type of droid assigned to the Research Lab to help out your scientists. Other than human Scientists, they are the only type of workers that can be assigned there. You are allowed one worker for a level 0 Research Lab, and then another 1 worker for every 3 levels. So for instance a level 3 Research lab can have 2 workers, a level 6 can have 3, and so on.
Each Lab Droid increases the speed at which you can research the new lab by a set amount. The default Lab Droid gives you a 2% speed boost.
Lab Droids are produced at the Factory.
Factory Level 4
AI Tech Level 6
Energy Tech Level 5