Flight Parameter Tuning

When tuning a multirotor, the first goal is a stable airframe with no oscillation — everything after that builds on it.

• Put the aircraft in STABILIZE.
• Raise the throttle slowly until it lifts 2~3 m, and watch how pitch and roll respond.

WARNING

Tuning flights are dangerous. They are for professionals only, and the operator carries the risk; this page is technical reference, nothing more. If you cannot accept that risk, buy a ready-built drone instead.

If the airframe starts shaking or vibrating during the process, cut the throttle immediately and abort the takeoff or land. Finish the pre-tuning setup before you touch the PIDs.

Default PID experience notes

NOTE

The Stabilize (angular rate) P sets how fast and how hard the attitude is corrected; the rate P sets how steady it flies. Stabilize P strongly affects the rate P. Unless you need more agility, want a different feel at the sticks, or the rate P has hit the system's limit, leave the angular rate P alone. The larger it is, the better the wind rejection. In ordinary tuning you work on the rate PID in the red box first.

TIP

The defaults suit small aircraft. Micro and light machines need a lower rate P; mid-to-large machines usually need a higher one. Within one airframe class: more power means a lower rate P; softer arms or wings mean a higher D to suppress the vibration; a higher angular rate P means the matching rate P goes down.

1. For wheelbase 250 and below, if it shakes as soon as it leaves the ground, start from:

Axis	Parameter	Default	Suggested start (lower P to cut the shake)
Roll	ATC_RAT_RLL_P	0.135	0.07
Roll	ATC_RAT_RLL_I	0.135	0.07
Roll	ATC_RAT_RLL_D	0.0036	0.0016
Pitch	ATC_RAT_PIT_P	0.135	0.07
Pitch	ATC_RAT_PIT_I	0.135	0.07
Pitch	ATC_RAT_PIT_D	0.0036	0.0016
Yaw	ATC_RAT_YAW_P	0.180	Adjust to suit
Yaw	ATC_RAT_YAW_I	0.018	Adjust to suit
Yaw	ATC_RAT_YAW_D	0.000	Adjust to suit

2. On large heavy-lift drones, tilt the motors outward by 3° for better yaw stability, or more if the airframe needs it, so the heading does not drift on takeoff. (Rule out magnetometer and transmitter stick issues first.)

Axis	Parameter	Default	Suggested start (raise it)
Yaw	ATC_RAT_YAW_P	0.180	0.5 or higher

Multirotors with a low thrust-to-weight ratio and weak power need higher default PI values:

Axis	Parameter	Default	Suggested start (raise it)
Roll	ATC_RAT_RLL_P	0.135	0.25
Roll	ATC_RAT_RLL_I	0.135	0.25
Pitch	ATC_RAT_PIT_P	0.135	0.25
Pitch	ATC_RAT_PIT_I	0.135	0.25
Yaw	ATC_RAT_YAW_P	0.180	0.5 or higher

3. Airframes with flexible arms or wings

A soft airframe shakes at high frequency. Dropping P alone makes the attitude response sluggish and the body wobble. Raise D instead — it suppresses the vibration while keeping the response.

Note: the proper fix is to stiffen the structure.

Axis	Parameter	Default	Suggested start (raise D to cut the shake)
Roll	ATC_RAT_RLL_D	0.0036	0.0040 or higher
Pitch	ATC_RAT_PIT_D	0.0036	0.08 or higher

WARNING

These are values from experience, meant for the first test flight only. To match a specific airframe properly, work through the rate PID guide using how it actually flies.

Rate PID tuning guide

TIP

The order we recommend for those new to this: set rate P, then rate I (normally I = P), then adjust D for the conditions (lower D if the aircraft feels stiff, raise it if it buzzes). After the test flight, review the log and refine.

Term	What it does	When wrong	Which way to move	Step size
P (rate proportional)	Speed and strength of the error correction	Too small: slow rate response, weak feel, attitude lags Too large: high-frequency buzz, overshoot	Raise it if the body wallows or power feels weak; lower it if it buzzes	0.01~0.04
I (rate integral)	Corrects accumulated error	Too small: error is never removed and keeps building Too large: extra small corrections, bounce-back, low-frequency swing	It tolerates a wide range — normally keep it equal to P	Move gradually toward P
D (rate derivative)	Predicts and damps error, kills high-frequency buzz	Too small: buzz cannot be suppressed Too large: sluggish, stiff response	Raise it when it buzzes, lower it when it feels slow	0.0002~0.0004

Typical symptoms and what to do

Axis	Core parameter (ArduPilot)	Symptom and treatment
Roll / pitch	ATC_RAT_P (rate P)	Slow wallowing, weak response → raise P
Roll / pitch	ATC_RAT_P / D (rate P, rate D)	High-frequency buzz, overshoot → lower P or raise D
Roll / pitch	ATC_RAT_I (rate I)	In normal use set it equal to rate P
Yaw	ATC_RAT_YAW_P (rate P)	Yaw will not hold, spins, track drifts → raise P
Yaw	ATC_RAT_YAW_P (rate P)	Yaw too aggressive, oscillates → lower P

NOTE

Tuning is really about matching the ratio between P and D so the aircraft responds quickly yet flies steadily. In normal conditions the FLIT, FLTD and the gyro and accelerometer cutoff frequencies come from the parameters generated by the pre-tuning setup. If the motors screech, try lowering the gyro cutoff frequency.

Stabilize P (angular rate) loop

Outer loop (Stabilize): Stabilize P is your stick sensitivity — how much angular rate is commanded to correct an attitude error.

NOTE

Normally leave Stabilize P alone. If you want a livelier feel at the sticks, this is the parameter to change, because it strongly affects how rate P must be matched; the higher it goes, the lower rate P has to be, and too high makes rate P impossible to match.

If you do want more sensitivity, raise it in 20% steps until the airframe starts to shake, then back off 20%.

Vertical (throttle) PID tuning

• Set MOT_HOVER_LEARN to 2 to enable hover throttle learning.

TIP

If the aircraft bobs up and down in AltHold, halve the position and velocity loop gains: PSC_POSZ_P(PSC_D_POS_P) and PSC_VELZ_P(PSC_D_VEL_Z). If AltHold is steady with no bobbing, leave the altitude parameters alone — the defaults work for most airframes.

• Take off in STABILIZE, climb to 5 m, then switch to AltHold (be ready to go back to Stabilize if it loses altitude control).
• If the motors buzz or the throttle surges, lower PSC_POSZ_P and PSC_VELZ_P by 30% each time.
• Hover for at least 30 seconds so the hover throttle value converges, then land and disarm.
• Read MOT_THST_HOVER and set the parameters like this:

PSC_ACCZ_P（PSC_D_ACC_P） = 1.5 × MOT_THST_HOVER
PSC_ACCZ_I（PSC_D_ACC_I） = 2 × PSC_ACCZ_P(PSC_D_ACC_P)
ATC_THR_MIX_MAX = 0.9  // applies when MOT_THST_HOVER < 0.3

• Take off in STABILIZE again, climb to 5 m and switch to AltHold. Once altitude hold is working, you can take off directly in AltHold (it needs over 60% throttle output to lift off).
• Next, tune the Loiter control loop.

TIP

After the hover throttle learning run with no payload, set MOT_HOVER_LEARN back to 0 to disable it. Otherwise flying with a payload rewrites the value and the throttle starts surging.

NOTE

Most airframes need no changes to the altitude parameters at all.

Losing height in fast forward flight

This is mostly the controller's exposed barometer picking up airflow in flight, which makes the altitude reading wander. Options:

Option 1: fix the cause (physical shielding)

Approach	What to do	How	Cautions
Block the airflow	Fit a cover over the controller	Physically shields the barometer from direct airflow	1. Do not seal it completely — leave vent holes; 2. Keep the sensor ventilated for heat; 3. Do not block any other ports

Option 2: weight the altitude sources down

Approach	Parameter	What it does	Recommended	When to use
Add GPS altitude correction	EK3_OGN_HGT_MASK	When the primary height source is not GPS, uses GPS height to correct its offset and datum drift over time	Set to 1 when GPS is trustworthy (RTK, for example)	Barometric altitude has a slight offset and the GPS signal is solid
Adjust sensor weighting	EK3_ALT_M_NSE	The RMS noise of the height measurement — larger values lower the barometer's weight and raise that of GPS and the accelerometer	Raise it when wind disturbance is significant	Airflow through the barometer makes altitude readings jump

Option 3: change the primary altitude source (pick one)

Approach	Parameter	What it does	Recommended	Precondition
Switch the primary barometer	BARO_PRIMARY	Which barometer the controller prefers	Pick the one least exposed to airflow	The controller has more than one barometer
Switch the vertical position source	EK3_SRC1_POSZ	Sets the EKF3 vertical position (height) source	Set to 3 (GPS as the height source) when using RTK	An RTK module is fitted and its height data is trustworthy

Option 4: wind estimation compensation

Wind estimation compensation guide

Loiter parameters

Loiter (position loop) PID tuning

TIP

Finish the pitch and roll PID tuning before you start on the Loiter position loop. Some wobble and buzz that never showed in Stabilize or AltHold appears in Loiter. Most airframes need no changes to the position loop parameters.

Parameter	Core function	How it works	Tuning and troubleshooting
PSC_POSXY_P	Position loop P (horizontal)	Converts the gap between actual and target position into a desired horizontal velocity for the velocity controller — the core position parameter, setting how fast position error is answered	1. Too small: it will not hold position, drifts 2. Too large: correction too strong, it shakes or overshoots when holding a point 3. Regular circular drift is almost always compass calibration or GPS, not this parameter
PSC_VELXY_P	Velocity loop P (horizontal)	Converts the gap between desired and actual velocity into a target acceleration — sets how hard a velocity error is corrected right away	1. Too small: velocity lags, turns respond late, which shows up as position drift 2. Too large: over-aggressive correction, velocity overshoot, the airframe darts
PSC_VELXY_D	Velocity loop D (horizontal)	Damps short-term velocity changes during position control, smoothing the response	1. Too small: cannot damp velocity swings; gusty wind makes it shake or dart 2. Too large: over-damped, turns and speed changes feel stiff and lag
PSC_VELXY_I	Velocity loop I (horizontal)	Corrects long-term steady-state velocity error	1. Too small: a fixed velocity offset never goes away 2. Too large: integral winds up fast and overshoots

TIP

Order: PSC_POSXY_P first (the foundation), then PSC_VELXY_P (the core of the velocity loop), then match PSC_VELXY_D and PSC_VELXY_I.

Braking

If the airframe rocks badly or drops altitude when you brake in Loiter, check these:

Parameter	Notes	Remarks
MOT_THST_EXPO	Throttle curve thrust compensation	Lower values ease the rocking and roll-over risk when braking at low speed; 0~0.2 is suggested for power sets or FOC drives
Loit_BRK_ACCEL	Loiter braking acceleration	Higher values brake harder and faster in Loiter
Loit_BRK_JERK	Braking jerk	Higher values make the braking force change more sharply; twice Loit_BRK_ACCEL is recommended
Loit_BRK_DELAY	Braking delay	How long it coasts after the stick centres before braking; higher values smooth the transition and delay the brake
LOIT_ACC_MAX	Maximum acceleration for position error correction	-
LOIT_ANG_MAX	Maximum tilt angle in Loiter	-

Loiter handling

Parameter	Notes	Remarks
PSC_JERK_Z	Vertical jerk	Controls how fast vertical acceleration changes
PSC_ACCEL_Z	Maximum vertical acceleration	Controls how quickly vertical speed changes
PILOT_SPEED_DN/UP	Maximum manual climb and descent speed	-

Softer, smoother stick feel

Beginners, and anyone used to consumer drones, can keep the airframe gentle even at full stick by limiting the commanded acceleration:

Parameter	Unit	Notes
ATC_RATE_P_MAX	°/s	Maximum pitch rate
ATC_RATE_R_MAX	°/s	Maximum roll rate
ATC_RATE_Y_MAX	°/s	Maximum yaw rate

TIP

Set these to taste — the smaller the value, the gentler and slower the response. 30 °/s is the usual recommendation.

Tilt angle limits (optional)

For almost everyone a 30° maximum tilt does the job; change it if your work needs more.

Parameter	Unit	Notes
ANGLE_MAX	degrees	Maximum tilt for all modes
PSC_ANGLE_MAX	degrees	Maximum tilt in position-hold modes; 0 means use ANGLE_MAX
LOIT_ANGLE_MAX	degrees	Maximum commanded tilt in Loiter; 0 means two thirds of ANGLE_MAX

TIP

A larger limit makes turns and translational acceleration quicker, but holding attitude gets harder and it asks more of both the controller's algorithms and the pilot.

Throttle PID gain

Even a well-tuned multirotor can briefly lose attitude control when the throttle is slammed. Fast throttle-up or throttle-down easily produces pitch or roll excursions, and it shows up worst on high thrust-to-weight racing quads. ATC_THR_G_BOOST helps.

When ATC_THR_G_BOOST is non-zero, a fast throttle change adds dynamic gain to the PID loops, up to a maximum of 1. With it enabled, rate PID gains are doubled and angular rate PID gains rise with them; smaller values give less extra gain.

WARNING

This feature has not been fully tested. Enable it with care.