Loiter fine tuning help needed

Good day everyone,

I'm building a new quad which is Steadidrone Qu4d 2014. I've divided a build process in three steps: 1) Build the frame without the gimbal and achieve a nice flight performance; 2) Install FPV gear; 3) Install gimbal.

Quick specs:

  • Steadidrone 2014 Qu4d frame
  • T-Motor 3506 650KV
  • 11' APC MR props
  • 4500mAh battery
  • TBS bulletproof ESC's (SimonK firmware)
  • AUW is about 4 pounds
  • Pixhawk with 3.1 firmware
  • Everything is calibrated according to the manual, vibrations are minimum

I've recently finished the frame and going thru the process of PID tuning. 

As the default I'm using basic 3DR quad settings except couple of changes to the roll and pitch rate P values.

I've successfully done the autotune procedure but result is worse than that I've done manually.

Quad flies great in stabilize, also Alt Hold works acceptable. But my problem for now is liter.

So, the problem:

When I switch to liter the quad hold the position very well, even in the wind. Smooth corrections and no sharp movements or sounds. But when I give a stick input the quad reacts very "softly" and "lazy", drifts 5-10 feet once stick is released and then slowly drifts back to the position where stick was released. I've tried to knob-tune rate P of the loiter settings from the Loiter Mode page of the wiki, but didn't see much difference. Also, wiki says if vehicle flies good in stabilize, liter should be more or less OK and not tuning necessary.

The reason I'm concerned is because I had another drone before based on the APM 2.5 and loiter was "better".

Any help or advise is really appreciated because I'm in the dead end now. Don't want to proceed until this is figured out.

Please see the attached log file (number 8 is the one from the video, number 7 is with autotune) for system report and a video with the test flight demonstrating the issue.

https://www.youtube.com/watch?v=FSFulL9Q5_c

Thank you!

8.BIN

7.BIN

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Replies

  • Hi,

    Your video is private. I am also trying to get something good with loiter. If it feels lazy, I believe it may be related to the Nav Speed parameter. If I understand how it is supposed to work, your stick gives a speed value (full stick = 100% nav speed?). In the wiki they say that acceleration is 50% of the loiter speed, which I am not sure to understand. Does it means that 5m/s nav speed will give a 5 m/s/s acceleration?

    My personnal problem is that my quad oscillates a lot, so maybe I need to decrease the rate parameters. It fly perfectly in stabilize or althold with no oscillation at all, just having trouble in loiter...

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