PID tuning basics with step response
The step response is the most honest view of a tune: it shows how the quad actually reacts to a control input. Read it well and you tune deliberately instead of guessing.
Read the step response: rise, overshoot, settling
Rise time shows how fast the quad reaches the target rate; overshoot how far it goes past it; settling how cleanly it lands. The ideal is a fast response with little overshoot and no ringing.
Tuning P and D
More P sharpens the response but eventually brings overshoot and oscillation. D damps overshoot and oscillation but amplifies noise. Raise P until just before oscillation, then add D to damp — both in small steps.
The I term and drift
The I term holds the axis against steady-state drift (wind, center of gravity). Too little feels vague and drifts; too much bogs the axis down and makes it sluggish. Usually I needs only small changes.
Feedforward for stick response
Feedforward acts on stick speed and lets the quad follow fast inputs directly, without waiting for error to build up. It makes a tune feel direct without overdriving P. PIDoctor scores tracking and overshoot per axis and derives concrete values from it.