Double Inverted Pendulum

A double inverted pendulum (DIP) consists of two masses connected in series by rods to a pinned base. Without some form of control at the base, a DIP system is unstable. Consider the DIP shown below in the upright (inverted) position. The DIP is controlled by vertical base excitation, e.g., imparted by a motor with … Continue reading Double Inverted Pendulum →

Parametric Oscillator

I sometimes ask collaborators for post ideas. At the end of our meeting this week, Prof. Mark Denavit suggested modeling a parametric oscillator in OpenSees and referred me to the following video. https://youtu.be/MUJmKl7QfDU OK, if you didn't watch the video, the response of a parametric oscillator is modified by some frequency-dependent parameter of the system. … Continue reading Parametric Oscillator →