A Peanut-Shaped Oscillator

A small ball-bearing rolls within a contained peanut-shaped tunnel. This is a somewhat unusual nonlinear oscillator since the ball is constrained to follow a specific path, however, its velocity provides the other important component of phase trajectories.

It's motion is tracked by a video camera that is attached to the frame as it is subject to periodic shaking and tilting. A couple of slides are contained here.