Unlike the left arm, the robotic arm has no joints in it whatsoever. This arm is a piece of machinery, and was required to act accordingly. Therefore this arm would move with a very straight, pivotal motion as opposed to a more organic motion.
Here is a basic animation I did to show the robotic arm in action.
When it came to binding this arm to the rest of the body, I was faced with several problems. I had initially only parented the curves to the chest controller, meaning that when I rotated the body (after binding the rig to the model, the robotic arm would move out of it's socket. I tried to solve this by combining the shoulder with the rest of the model and keeping the rest of the arm separate, but I was faced with the same problem.
I solved this problem, by trying out an idea, which was to create a new joint from the chest that would go to the right shoulder. I then constrained both the first curve of the arm and the arm itself to the new joint. Now when I rotated the monster's upper body, the arm kept in place.