I am building a robot arm on my own. My main problem is the mechanical transmission. I plan to use pulleys and metal strings, but when I bought it I realized two things: they weigh more than the metallic structure and are not accurate.
I think the most convenient thing is to use hydraulic pistons powered by a steppeper motor with a screw (linear movement), but, I'm still not quite sure.
Do you recommend that one or another better?