written by Wolfgang Christian and Dan Hampton

The Double Pendulum model displays the motion of a two-part pendulum and its Poincare map. A double pendulum is a simple pendulum with another pendulum attached to its end and the state of this dynamical system is specified by two angles and two angular velocities.   Because there is no friction, the double pendulum is an example of a Hamiltonian system and energy is conserved.  This EJS model simplifies the system by using equal length arms and masses.  Clicking in the Poincare section sets the initial conditions of the rotor.  The user can examine and modify this simulation if EJS is installed by right-clicking within the plot and selecting "Open EJS Model" from the pop-up menu item.  

The Double Pendulum model was created using the Easy Java Simulations (EJS) modeling tool.  It is distributed as a ready-to-run (compiled) Java archive.  Double clicking the ejs_lagrangian_DoublePendulum.jar file will run the program if Java is installed.  EJS is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models.

• Download ejs_mech_lagrangian_DoublePendulum.jar - 2784kb Java Archive File

Published August 20, 2009
Last Modified June 3, 2014

This file has previous versions.

Poster presentation at the 2009 Davidson College student research symposium.

• Download HamptonpendulumPoster.pdf - 465kb Adobe PDF Document

Last Modified January 11, 2010

The source code zip archive contains an XML representation of the Double Pendulum model.   Unzip this archive in your EJS workspace to compile and run this model using EJS.

• Download ejs_mech_lagrangian_DoublePendulum.zip - 480kb Compressed File

Last Modified August 20, 2009