Fine Structure

A Special Inverted Pendulum

Check out this video where a student at the University of Stuttgart shows off his impressive work creating an inverted pendulum for his "engineering cybernetics" program (best title ever?).

The impressive part comes about half way through when he balances a double inverted pendulum by using a brilliant bit of physics: by constraining the amount of energy in the system to just enough to get both pendulums standing straight up, he prevents the normally wild swings of a double pendulum. It seems like this method would require both a method of driving the base and an encoder for measuring the push and pull of the pendulum on the base but details are very limited. If anyone could provide some more information, I would appreciate it. ]