[Ianworld]

From my experience almost every rookie team has to build their one scissor lift to learn firsthand why they're a tough choice for FIRST. In almost every robot situation a different mechanism will be just as effective and really the key point easier to make. A scissor lift requries a large amount of careful machining and has certain issues such as how to start it and stability when fully extended.

I'm a big fan of keeping things simple. This year the object is spherical, a 4 bar linkage on the arm isn't necessary. The main advantage of sucha mechanism is that it keeps an object at one end level throughout the whole motion. A ball is a ball no matter which way you rotate it.

Anyhow think simple and functional. I'm a big fan of just simple rotating arms. You just need to think of the torques and the power necessary to move a ball at a distance.