* PID tuning 101 http://iflyquad.com/2016/03/11/the-pid-tuning-guide-short-version/
* PID on Betaflight/Multiwii(Rw): https://www.youtube.com/watch?v=QXu35kvMT_8
* http://www.airsanglier.com/2016/04/tuning-pid-pousser-votre-machine-aux-limites/
* https://github.com/betaflight/betaflight/wiki/PID-Tuning-Guide