I want to build a sort of robot arm that has the capacity to lift at least 20 pounds. I know that this is a very heavy load, and most likely exceeds the limitations of the typical hobby servo. I'm curious as to whether anyone knows of a way to lift such a load (efficiently as well). I'm not sure if a gearbox by itself will be enough; there may be some potential in DC motors but I honestly haven't done too much in-depth research on them, nor do I know exactly what I would need to program them to act like a servo.
Does anyone have any information I could perhaps work from? Thanks so much! :)