PID Controller for Quadrocopter
https://aeroquad.com/content.php?s=eae2a44ea610f496459851719b83d95d
https://aeroquad.com/content.php?1-open-source-quadcopter
https://polakiumengineering.org/?page_id=1989
https://www.geek.com/articles/gadgets/review-heli-max-1sq-quadcopter-2012125/
https://www.geek.com/articles/geek-cetera/diy-kit-appears-for-3d-printed-quadcopter-20121123/
https://www.aeroquadstore.com/
https://code.google.com/p/aeroquad/downloads/list
https://www.hoverflytech.com/aeroquad.com/showthread.php?6985-First-full-Aeroquad-video
Matlab Toolbox on Particle Swarm Optimization