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Autotune works only after stick inputs (7kg Octo)

Hello,

I have some issues with autotune and hopefully someone can help me solving this :slight_smile:

I have build an octocopter with a total weight of 7kg with 1855 props and 340kv motors and a rtk system. There are 2 batteries (6s) mounted on a rail system on the front and back of the frame.
During the first test flights there are 25-31 sattelites available while having wind speeds with about 10-15 km/h.
With the default PIDs the copter is stable enough to perform max stick inputs in stabilize and alt hold flight mode. The Loiter flight mode is still working but the copter is oszillating about 10cm on each side of the motors up and down while this could be an issue with the pids while using a precise gps. The initial tuning instructions were applied but no PID tuning until now.

To perform the autotune process I was taking off in stabilize flight mode. After I have reached my position I switched to AltHold and after the copter was looking pretty stable I was switching to Autotune with the flightmode switch and not with a AUX channel.

A little bit before and during the autotune process I was trying not to touch the remote to let autotune do its job. I have also increased the deadzones of some channels that are sometimes sending offsets while they are centered.

The problem with autotune and my setup is that it will only perform one roll or pitch action directly after entering autotune and when I was sending pitch/roll corrections with the remote. Autotune wont do any further actions until I interrupt the process with my corrections.

During the previous Autotune flight I had some anomaly errors while taking off and abourted the flight. I have added some shielding to the power cables and this error was gone for this flight I am talking about.

Does someone have an idea what is going wrong here?

During the flight I was taking off and landing serval times and autotune was started somewhere in between :sweat_smile:
You can download the log here: https://www.file-upload.net/download-14311002/2020-10-0312-33-17.bin.html

Before you do an autotune, you need to follow these instructions:
https://ardupilot.org/copter/docs/tuning-process-instructions.html
https://ardupilot.org/copter/docs/common-imu-notch-filtering.html

And you do need to do position correction when doing autotune. If you do not manually correct the position and yaw relative to the wind direction you will get a bad autotune.

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