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.D_min / D_max (dynamic D)D_min and D_max let Betaflight vary the D term dynamically: low during calm flight for less noise and cooler motors, higher during fast moves for more damping.Anti-gravityAnti-gravity briefly raises the I term during fast throttle changes, so the quad doesn't sag or pitch when you punch the throttle.Dynamic idle (dyn_idle)Dynamic idle holds a minimum motor RPM via a governed lower RPM limit rather than a fixed throttle value — so the motors don't spin down too far during fast descents.Thrust linearization (thrust_linear)Thrust linearization compensates for the non-linear thrust-to-throttle curve of props by raising effective gains at low throttle — for more consistent behaviour across the throttle range.Bidirectional DShot (RPM telemetry)Bidirectional DShot lets the ESCs report each motor's actual RPM back to the flight controller — the foundation for the RPM filter and dynamic idle.SetpointThe setpoint is the rotation rate your stick input commands — the target value the quad is supposed to follow.PIDsumPIDsum is the sum of the P, I and D terms per axis — the control output that (together with feedforward and the mixer) ultimately drives the motors.Mid-throttle oscillationMid-throttle oscillation is a wobble that appears only in a mid throttle band — usually from motor/frame resonance the filters don't cleanly catch there.I-term relaxI-term relax slows the buildup of the I term during fast stick moves, so error doesn't accumulate and cause a bounce-back afterwards.RC smoothingRC smoothing filters and interpolates the radio signal so stepped RC data doesn't create visible jumps in control.Bode plotA Bode plot shows how a control loop responds across frequencies (gain and phase) — the standard tool for judging stability and margin.Throttle boostThrottle boost sharpens the response to fast throttle changes by briefly adding extra throttle authority — for snappier punch-outs.AirmodeAirmode keeps the PID control active even at zero throttle, so the quad stays controllable at low or zero throttle instead of losing control authority.Gyroscope (gyro)The gyroscope is the sensor that measures the quad's rotation rate per axis — the basis of all control and all blackbox analysis.Looptime / PID loop frequencyThe PID loop frequency is how many times per second the control loop runs (e.g. 8 kHz) — higher means finer, faster reaction but costs processing power.DShotDShot is the digital protocol the flight controller uses to send motor commands to the ESCs — precise and noise-resistant, with a bidirectional variant for RPM telemetry.Motor timingMotor timing is an ESC setting that affects when the motor windings are switched — it influences smoothness, efficiency and motor heat.Soft mounting (gyro isolation)Soft mounting mechanically isolates the flight controller (rubber grommets, soft dampers) from the frame, so less vibration reaches the gyro.Prop balancingProp balancing corrects imbalances in the props that would otherwise reach the gyro as vibration at the prop's rotation frequency.Integrated yawIntegrated yaw is a Betaflight mode that integrates the yaw control output, giving smoother, more precise yaw control.Absolute controlAbsolute control is a Betaflight feature that adds extra correction so the quad follows the commanded setpoint more tightly instead of slowly drifting off.I-term windupI-term windup is the unwanted buildup of the integral term when the quad can't follow a command — it causes overshoot and bounce-back once the error drops again.VBat sag compensationVBat sag compensation counteracts the battery's voltage drop so the tune feels the same on a full and on an empty battery.Rates & expoRates and expo define how stick movement translates into rotation rates — the maximum rotation speed and how sharply it reacts around center stick.Static notch filterA static notch filter removes a fixed, known interference frequency (e.g. a frame resonance) that doesn't move with throttle.Center of gravity (CG)The center of gravity is the quad's balance point — if it isn't centered, the controller has to constantly compensate, loading roll and pitch differently.Throttle limitThe throttle limit caps maximum throttle — as a percentage scale or a hard limit — to protect motors, ESCs or over-powered setups.