Three joint arm

[IKE]

Team 33 2005 was a double jointed arm, and 2007 was a triple (shoulder, elbow, and rotating wrist). There is a lot of good documentation on the 2007 arm in the Behind the Design book from 2007.

Most FRC games I have seen can effectively be played with the 2 joint arm. The third joint adds more complexity than it would likel be worth for many games, but it would be a good learning exercise.

I think it is wise to protype an arm as the likelihood for a pick and place game is pretty high this next year. Also important to any arm design is the object manipulator. Instead of doing a 3rd joint, I would focus some effort on trying to pick up an odd shaped piece like a cone, cylinder, or some other non-ball shaped piece (inner-tube, tetra, box...).