Unstable wobble on auto mode

This our 24 kg quadcopter without payload. I have made all calibrations except autotune. İt’s quite good tuned in stablize and althold modes. The problem is when we try take off or loiter modes it makes this wobbly movement. M9N GPS status are 28 sat. and status 4. I thought it’s about compass calibration according to datalog and made iron calibration and it got better but not enough. You will see in the video after the take off we changed to althold and it’s hanging in the air directly.

Main Hardware:
44.4V 22000mAH battery
T-Motor BLDC’s


On such a big copter, did you tune it professionally? Did you bring a consultant to do it? How exactly did you tune it?

Thanks for the reply.
I applied this guide you posted step by step.
IMU temp calibration
IMU And GPS orientation
ESC Calibration
Initial Tune according to drone
Simple accel calibration
Compass iron calibration done after first guided take off
Hardware report

16_notch_filter_setup.param (4.9 KB)

After first flight test in stablize and althold modes it looked good. No hot motors.
Notch filter Calibration

updated param file for notch
17_notch_flter_results.param (338 Bytes)
updated throttle control file. Hover throttle appeared 0.4
18_throttle_controller.param (971 Bytes)

Last step for me was magfit. Before doing the script we wanted to take off in guided but it appeared we have problems in guided mod. I’m not sure what parameters to check when the problem is in only guided mode.

I’ll have a look on Tuesday at the office. I’m doing a workshop on tuning drones for professionals on the 16 of April. Want to join?

I’ll also be presenting the ArduPilot methodic configurator GUI software:

For big drone, these two steps helped me. But, before that, Autotune first and must sure is a low noise and low vibration drone frame.

1 Like

Hello again. I can’t get a visa soon but thanks for the invite.

I have made a few changes and corrected some mistakes. There is definitly a problem with the compasses. I disabled orange cubes compass and fixed GPS Compass 45 degress (yaw270) cause magfit tool shows 45 degree even the gps looking forward and it got better.

Here is the filter graph

İn datalog rate.out values below 0.1
Vibrations below 15.
I’m not sure if ATT roll-des.roll values are okey.

Here is the last auto flights video, parameters and datalog.
I lowered waypoint speed for safety.
It’s still not good enough.
quadcoper - Google Drive

We are doing magfit calibration with script today. I will update here the results.

We suppose found the main problem. Inaccurate gps position causing the quad to going that direction and powerful motors reasoning overcorrecting itself.
I lowerd PSC_POSXY PID parameters to reduce that overreaction and it’s stable right now.
The problem to solve right now is 1m accurisy so travelling 1m radius around even we have 30 sattelites, 0.5 HDOP GPS and 16 sat 0.9 HDOP RTK FIX.

1 Like