I'm designing a 3D printable prosthetic hand.
Each finger has 3 joints. The first 2 joints let the finger only move in the vertical (y) direction. The final joint is like a ball and socket joint (connects finger to palm) and lets the finger rotate Up/down & left/right about 30 degrees in each direction.
Summary of 3 joints: 1 joint = finger moving in vertical (y) direction + 1 joint moving in vertical (y) direction + 1 joint rotating in vertical (y) and horizontal (x) directions
From a mechanical engineering perspective, can someone help me here by telling me how many degrees of freedom are on each finger here? How would you calculate it based on the motion I have stated above? Thanks!
I'm guessing 1 degree of freedom for the 2 vertical joints each because they only move in one dimension =2 DOF so far + 2 DOF for the rotatable joint ? = 4