I have successfully created an assembly model of a robot similar to the video shown. It animates as expected. In the video the user appears to be moving a box which is a target. The robot then moves to maintain constraint when updated. In my case, when I update, the target object goes back to the arm, instead of the arm moving to the target. Seems like some kind of hierarchy? I must be missing a step.
Thanks for the help, and for the plugin. Looking forward to how it develops.

constraint to the target box. It will prevent the box from being moved by Rhino Assembly, the arm should move instead.