View source for Altitude PID


==Requirements==
Here are some notes for achieving a good altitude hold :
* protect the [[Hardware#Barometer_.2F_Altimeter|barometric]] sensor from light and air turbulence (a black plastic tube glued on the pcb with some foam inside or anything else).
* tune your multirotor with proper [[Calibration_Accelerometer| Acc calibration]] , radio and Acc trims
* consider that you should activate baro only when a stable hover is reached
* Once you activate the baro DO NOT touch anymore throttle
* Once with baro on you should not notice any differences in behavior between Acro and Acc mode.
* When changing PID values begin with I and D values at zero,
* If copter goes up and down with an incremental sinuosid from altitude point (point when you activate baro) decrease P value little by little, when you reach a good result increase D parameter.

== Altitude PID tunning==
* Set P and I to 0.
* Slow increase D from 0 in 0.2 increments until you start to get a slow yo yo movement. 
* Reduce D a littleuntil yo yo movement stops.  
** At this point the multicopter will start to hold altitude with drift
* Increase P slow now, and you will find that the multicopter will start to hold, until it starts the yo yo movement, 
* reduce P until yo yo movement goes away. The multicopter will now hold altitude with less drift.

*I is now increased to reduce the drift when the battery runs down and the throttle needed to keep the copter at hover changes.


[[Category:Configuration]]