EZ-Tune

EZ-Tune is a simplified tuning framework for multirotors. Instead of setting every PID gain, rate, expo and filter value by hand, you work with nine values and the firmware derives all the underlying settings from them. For example, instead of setting several filters with individual cutoff frequencies and types, you set one base frequency and INAV configures the whole filter chain around it.

When EZ-Tune is enabled, it takes over the settings it manages, so the manual PID, rate and filter controls of the Configurator's Tuning tab are hidden while it is active. That also makes it hard to break a working EZ-Tune setup by editing a value it would overwrite anyway.

warning

EZ-Tune applies to multicopters only, because it writes the multicopter PID bank and nothing else. If you set the platform type in the Mixer tab to anything other than multirotor or tricopter, the Configurator switches ez_enabled off for you.

note

The Configurator still labels EZ-Tune experimental. It is not guaranteed to work on every frame, and the way the values are computed can change between INAV versions. EZ-Tune values are stored per control profile, so switching the control profile switches the EZ-Tune values with it.

Where to find it

In the Configurator, open the Tuning tab and stay on the Main PID Gains page. The highlighted box at the top of the page holds the Enabled switch, and the nine sliders below it appear once EZ-Tune is enabled. The right-hand side of the page shows a PID preview and a Rate preview that update as you move the sliders, so you can see the gains, rates and expo curve that will be written before you save.

The same values are also reachable from the flight controller itself through the in-flight OSD menu under PID TUNING > EZTUNE, with the exception of Snappiness. Everything can be set from the Configurator or the OSD menu, so the CLI is only needed if you prefer it, or for backups.

Before you change anything

Save a copy of your current configuration with diff all in the CLI and write it to a file. If a tune turns out worse than what you had, that file is the fastest way back.

The nine values

Slider	CLI setting	Range	Default	Acts as
Filter Hz	ez_filter_hz	20 - 300	110	base cutoff for the gyro and D-term filter chain
Axis ratio	ez_axis_ratio	25 - 175	110	pitch gains as a percentage of the roll gains
Response	ez_response	0 - 200	100	P-term
Damping	ez_damping	0 - 200	100	D-term
Stability	ez_stability	0 - 200	100	I-term
Aggressiveness	ez_aggressiveness	0 - 200	100	Control Derivative term, called FF in the preview
Rate	ez_rate	0 - 200	100	rotation rates and RC expo
Expo	ez_expo	0 - 200	100	RC expo shown in the preview
Snappiness	ez_snappiness	0 - 100	0	D-Boost

EZ-Tune itself is switched on and off with ez_enabled, which is OFF by default in the firmware and set to ON by the multirotor presets described below.

Moving a slider from left to right increases the effect it describes, typically from sluggish, through the value that suits the craft, to unstable. Damping is the exception and is best left alone until the final test flights.

• Filter Hz sets the base cutoff frequency for the gyro and D-term filters, so higher values mean less filter delay and better stabilization, but also more noise reaching the motors. The goal is the highest value that shows none of the usual side effects: hot motors, audible oscillation, rapid shaking, or the craft climbing by itself.
• Axis ratio describes how the mass of the craft is distributed. A perfect X frame is 100, and most modern frames land somewhere between 110 and 130 because they carry more mass along the front-to-back axis.
• Response defines how quickly the craft reacts to stick movement and gyro signal. Increase it if the craft feels sluggish or has a slow wobble, and decrease it if motors get hot, it overshoots, or it feels nervous. Most modern quads with strong motors fly best with Response below 80.
• Damping opposes any change of rotation speed and makes the flight smoother and more stable. Raise it until the first side effects appear; most modern quads accept 150 to 180.
• Stability is the long-term stabilization strength and usually needs no tuning at all. Most modern quads tolerate 120 to 130, and lowering it can help with heavy propwash during vertical descents.
• Aggressiveness defines how hard the controller pushes on fast stick movement. It changes stick feel rather than stabilization.
• Rate sets the rotation rate for all three axes, where 0 is 300 dps, 100 is 600 dps and 200 is 900 dps. Yaw is always set 100 dps lower than roll and pitch.
• Expo shapes the RC input curve, with lower values making the sticks more sensitive around centre.
• Snappiness accelerates the reaction to fast stick movement, both when you start and when you stop a manoeuvre. It is 0 by default, so it does nothing until you raise it.

Filter Hz starting points

Propeller size	Filter Hz
3 inch	90
5 inch	110
7 inch	90
10 inch	75
12 inch	60

These are starting points, not final values, and the sequence is deliberately not a straight line. Use Blackbox logs and your own judgement to find the value that suits your craft once you have flown it.

tip

For propellers of 10 inches and up, expect to reduce Response and increase Damping compared with the smaller sizes. The values in the preset table below show the same trend already between 3 and 7 inch quads.

What EZ-Tune writes

The values above are not stored as PID gains: the firmware recomputes the affected settings every time EZ-Tune values or the control profile change. Knowing the formulas makes the preview panel easy to read.

PID gains

EZ-Tune starts from its own base gains, which are P 40, I 75, D 23 and CD 100 for roll and pitch, and P 45, I 80, D 0 and CD 100 for yaw. Roll takes those base values scaled by the matching slider: P by Response, I by Stability, D by Damping and CD by Aggressiveness, each as a percentage. Pitch takes the same result multiplied by Axis ratio, so the default 110 gives pitch gains 10 percent above roll. Yaw is scaled more gently, at half the deviation from 100 that roll and pitch get, so a slider at 150 gives 125 percent of the yaw base gain.

The results are written to mc_p_*, mc_i_*, mc_d_* and mc_cd_* for the active control profile.

Rates and expo

Rate is mapped linearly onto roll_rate and pitch_rate, from 300 dps at 0 to 900 dps at 200, and yaw_rate is set 100 dps below that. This is why the Rate preview table reports values in dps rather than in the deca-degrees used by the CLI settings.

note

In INAV 10 the firmware computes the applied rc_expo and rc_yaw_expo from the Rate slider, while the Configurator's expo preview and curve are drawn from the Expo slider. If the stick feel around centre does not change the way the preview suggests, this is why.

Filters

Filter Hz drives the whole filter chain, and this is the part of EZ-Tune that replaces the most manual work.

• gyro_main_lpf_hz is set to the Filter Hz value.
• dterm_lpf_hz is set 5 Hz below it, never below 50 Hz, and dterm_lpf_type is set to PT2.
• The dynamic gyro notch is enabled in 3D mode with dynamic_gyro_notch_q at 250, and dynamic_gyro_notch_min_hz follows two thirds of Filter Hz, never dropping below its own default of 50 Hz.
• setpoint_kalman_enabled is switched on, and setpoint_kalman_q sits at 200 below 150 Hz and rises towards 400 as Filter Hz approaches 300.
• smith_predictor_delay is set to the PT1 filter delay at that cutoff, which works out at roughly 1.5 ms for the default 110.
• gyro_anti_aliasing_lpf_hz is returned to its default, gyro_filter_mode is forced to STATIC, and rc_filter_auto is forced ON.

Snappiness is applied through d_boost_min, from 1.0 at 0 (no D-Boost) down to 0.0 at 100.

Recommended starting values

The Configurator ships complete EZ-Tune presets for three quad sizes. They are applied by the defaults dialog that appears after flashing, and can be applied again later with Select New Defaults on the Tuning tab. All three enable EZ-Tune, which is why a freshly set up multirotor arrives with EZ-Tune already active.

Setting	3 inch	5 inch	7 inch
ez_filter_hz	90	110	90
ez_axis_ratio	116	110	110
ez_response	71	92	101
ez_damping	103	108	115
ez_stability	105	110	100
ez_aggressiveness	100	80	100
ez_rate	134	134	134
ez_expo	118	118	118

There are no presets for larger quads. For those, start from the Filter Hz table above, follow the trend the presets show, and expect to test and adjust.

warning

Presets cannot account for your frame, motors, propellers and battery, so treat them as a stable place to start and nothing more.

Tuning procedure

1. Enable EZ-Tune and set the values recommended for your craft, either by applying a preset or by working through the sliders.
2. Press Save and let the flight controller reboot.
3. Test fly and note what needs changing.
4. Change one value, save, and test again before changing anything else.

Look for a responsive setting that is still stable, then go back a little, or raise Damping at the end until the craft feels reliable. The values interact, so a change that looks harmless on its own can shift the result of an earlier one.

tip

Share results and ask questions in the #ez-tune channel on the INAV Discord.

Coming from Betaflight

The slider concept resembles the Betaflight slider tuning, but EZ-Tune covers more ground. It does not only scale the PID controller: it also sets the rates and expo, configures the filter chain, and enables the functions that go with it. Instead of twelve PID values you set four, and instead of a set of individual filter settings you set one frequency.

If you are moving over from Betaflight, INAV for Betaflight users covers the wider differences between the two firmwares.