# Can a robot or mechanical part be programmed to exert a specific force

So I was thinking about projectiles that don't need a propellant like gunpowder I've seen coils gun but that's a little out my way. I was wondering if I know the force required to propel a object could I program a robot to exert that force to propel the object the same way (in a linear propelled fashion).

Yes you can. People built robots doing exactly that for several hundred years.

• In what way is a trebuchet programmed to apply a specific force (as opposed to range and loft being adjusted by providing force for longer or shorter time or the same force applied to a greater or lesser mass)? Jun 28, 2016 at 12:21
• @PeteKirkham I'm not sure if I understand you correctly, the specificness of the force is the duration, amount and direction it is applied to the projectile. The trebuchet can be programmed by changing the counterweight, sling length, its base (wheeled or not), arm length, projectile weight, etc...most of it happens in some cruel mix of templates and macros that is commonly referred to as "mechanics". Jun 28, 2016 at 18:23
• Although you can make programmable mechanical devices - Jacquard looms and the Jaquet-Droz automata - they all all have some means of representing information and actuating effectors based on the representation. Putting another rock in the counterweight does not constitute programming. Jun 28, 2016 at 20:18
• @PeteKirkham you seem to be interested in nitpicking about some definition of programming. That's fine, go ahead. I think inserting a different punch card in the loom is just the same as inserting a different counterweight in the trebuchet. Both machines are programmed with some application specific language, holes in the card and mass of the counterweight. Jun 30, 2016 at 12:57
• The idea that you program a rock to fall by lifting it up makes the concept of programming so wide to be useless. There is no flow of control. There is no separation of information and effector. Jun 30, 2016 at 20:45