Hi Glor
Current functions of the arm include only positioning on a certain point in 3D space. No object grabbing yet.
For object grabbing, there should be some kind of visual feedback - "object-arm distance control loop".
What i did is similar to this project on instructables: http://www.instructables.com/id/Intro-and-what-youll-need/
Then, on top of that, there is another layer of control loops that coordinates lower levels, like in the link I posted in the first post.
best
amatic