Altitude PID

Requirements

Here are some notes for achieving a good altitude hold :

• protect the baro 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 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.