Question to Position Hold Mode

ArduCopter
1

Hello,
ich have a Octocopter and I have a question to flying in PosHold Mode. As far as I understand this mode holds altitude, GPS-psition and the heading. My question goes to the heading hold. I expect that the copter holds the heading if I do not give a RC-command, right? So I made an experiment:
I hover in front of me (no wind at all) with for ex. heading 0°. Than I go to the hovering copter and turn it with my hands (not with RC-command!) to heading 90° and let it go again. Then the copter goes a little bit back in the direction of 0°, but only a little. Something about 10-20°. I expect that it goes back to heading 0°. So, do I expect the wrong thing or is something wrong with my setup. Can anyone explain this to me?
Best regards
Andreas

2

Use loiter instead, it should behave like you want.

3

Hi,
thank you for your advise. I was just outside and gave it a try in loiter mode. But it is still the same. The copter does not go back to the origin heading. Any other idea?

Andreas

4

Which FW version? update to the latest stable before continuing.

5

V4.3.2. just trying to update it, but I’m struggling with this…

6

OK, now I updated to V 4.3.7, but nothing changed. The copter goes back about 10-20° but not to the origin heading.

7

So you are manually grabbing the copter and turning it? I do not think it will behave like you are asking as this would be a very odd flight characteristic. what in your mission profile would exert that kind of yaw force not commanded via the rc/gcs?

1 Like
8

I want to mount a Payload on the top of the copter. But this payload can not be placed in the Yaw-center of the copter. So if a windgust appears it will not only push the copter to the side but it will also turn it arround the yaw-axis. …and then it looses the heading if the copter does not have enough torque for only a small moment of the gust.

9

Has this copter exhibited the described behavior inflight without the user physically turning the copter. post a log file of it in normal flight that will help.

10

Hi, Thank you that you will help me. For a better understanding some statements:

  1. I’m not experienced. This is my first copter
  2. It is an Octocopter with EDF
  3. FC is an Pixhawk
  4. The EDF’s have very little torque, so I mounted them with an angle of 5°. After this I was able to control it.

The copter flies not to bad, but with an excentric payload on top the YAW does not work good enough. So I tried to tune the PID and when I did this I found that the copter does not turn back completely to the origin heading when I turn it by hand. Here is the link to the logfile for turning by hand:

And here is a Link to a logfile with 3 short files. The first 2 flights were made with the Payload. The 3rd without.

With payload I was not able to control the copter. Without it was OK.