Here's a short clip of our
3-jointed arm from 2007. The controls were fairly simple, because for that game most of the joints could be slaved to the position of a master joint. So the arm driver just specified where the tip needed to go and the rest of the arm followed.
There was a tightly constraining 80" cylinder written into the rules that year, so the software managed all the joints to keep the whole arm within that imaginary cylinder.
The arm was modeled and controlled in Vex first to test the control logic.