What is a word that means "like a machine"? By this, I don't mean "robotic", nor "mechanical"—that implies stiff and repetitive, and I'm thinking more along the lines of how one would behave and carry themself. I want a synonym for "machine-like" that can be used to describe someone who is precise, resolute, and stoic. For describing something like, say, an army.
Example sentence: "He was so incredibly disciplined, many described him as [x]."