Betaflight tuning glossary
The terms behind a Betaflight tune, in plain language — and how PIDoctor spots each one in your blackbox log.
PID controller (P/I/D)The PID controller is the algorithm Betaflight uses to hold your quad on the commanded rate: P reacts to the current error, I removes steady-state drift, and D damps oscillation and overshoot.PropwashPropwash is the low-frequency oscillation and jello you get when the quad flies through its own turbulent prop wake — typically during fast descents and hard direction changes.D-term noiseD-term noise is high-frequency noise amplified by the derivative (D) term — it drives the motors hot and can degrade tracking.Motor noiseMotor noise is vibration from the motors and props (imbalance, bearing wear, frame resonance) that shows up in the gyro signal as peaks that move with motor RPM.Dynamic notch filterThe dynamic notch is a Betaflight filter that automatically tracks the strongest noise peaks in the gyro FFT and notches them out, following motor RPM as throttle changes.RPM filterThe RPM filter uses bidirectional-DShot motor RPM telemetry to place precise notches on each motor's rotational harmonics, removing motor noise at the source.Gyro lowpass filterThe gyro lowpass (LPF1/LPF2) attenuates high-frequency noise on the raw gyro signal before it reaches the PID controller.D-term lowpass filterThe D-term lowpass attenuates noise specifically on the derivative (D) term — the noisiest part of the PID loop.Step responseThe step response is how the quad's actual rotation rate reacts to a sudden change in commanded rate — the core measure of tracking quality.OvershootOvershoot is how far the quad rotates past the commanded rate before settling — visible as a bump above the target in the step response.Rise timeRise time is how quickly the quad reaches the commanded rate — a measure of how responsive and sharp the tune feels.FeedforwardFeedforward adds control output based on how fast your stick is moving, so the quad follows rapid stick inputs without waiting for error to build up.TPA (Throttle PID Attenuation)TPA reduces the PID gains at high throttle, where the extra authority would otherwise cause oscillation and hot motors.Phase marginPhase margin is a control-theory measure of how far your tune is from instability — how much extra phase lag (delay) it could tolerate before it starts to oscillate.Blackbox debug mode (unfiltered gyro)The blackbox debug mode selects extra data to log — crucially the unfiltered (raw) gyro, which is what makes deep filter analysis possible at all.