Blind juggling robot

BB's secret software hacker Dean Putney spotted this neat "blind" juggling robot. Dean writes:
This machine bounces a ball without any sensory input. The surface it is bouncing the ball with is slightly curved, so that if the ball doesn't hit in the center it will be bounced at an angle and correct for the horizontal motion. The machine actually has no idea where the ball is though, since its feedback control system is purely mechanical. It's surprisingly robust, allowing the machine to be moved under the ball, swung on a pendulum and it works with several different balls, as shown in these videos.
Blind Juggling Robot