We used three pneumatic cylinders to move the lift between three different positions. The cylinders were only fed in one direction to save air, gravity pulled the lift back down. The back part is attached to the base. There are two stages attached to it. The stage towards the front has the manipulator attached. We didn't use COTS slides, the stages were attached using rollers. I am sure Raul can give a better explanation, but heres some pictures. They don't show the best view, but I suppose there better than nothing. The full resolution photos can be found
here.