Elastic Pendulum is a bot that generates and posts videos of double elastic pendulums to Twitter twice a day. A double elastic pendulum (or double spring pendulum) is a variant of a common system in mechanics known as the double pendulum, which is essentially a pendulum attached to the end of another pendulum. These types of systems are particularly interesting because their motion is complex and cannot be solved for using standard Newtonian mechanics. The main difference between a double pendulum and a double spring pendulum is that the fixed rods commonly seen in double pendulum problems are replaced with springs. This minor change leads to even more chaotic behavior than the standard double pendulums. The gif above shows 5 double pendulums simulated with slightly different starting angles leading to different simulated trajectories.
The bot works by integrating the Lagrangian equations of motion for a two-dimensional double spring pendulum using scipy.integrate. Videos can be quickly generated and simulations flexibly allow a range of parameters for the double pendulum system and customizible pendulum and background colors.
To install the bot simply clone this repository and run the following commands in the terminal
git clone https://github.com/tyler-a-cox/elastic-pendulum
cd elastic-pendulum
python setup.py install
or you can install directly from the git repo
pip install git+https://github.com/tyler-a-cox/elastic-pendulum
This package can either be run to post videos to twitter given the proper credentials or you can simply simulate a pendulum and save the video like so
from pyelastic.animate import Animation
anim = Animation(fps=60, tend=10, filename='example.mp4')
anim.animate()
For more information on the physics involved in the simulation, check out the blog post or you can follow the bot on Twitter at @springy_bot.