Very agressive oscillation in Position mode 2019 1.9.1

I am using px4 v1.9.1 stable hexacopter, I have a big problem in position mode. when I brushed the stick and returned it or had a strong wind blowing, the plane vibrated and swayed very hard at the initial return, anything could help me, thank you, below is the log:file:

I have encountered this problem for 2 months and have not been able to solve it, anyone who has similar problems can help me,
I fly Pixhawk 2.1 with arducopter fw 3.6.8 with the same configuration, I don’t see this phenomenon

Are you talking about the oscillations after the large yaw input just before 2:30 ? If yes, you can reduce the yaw stick sensitivity by changing MPC_MAN_Y_MAX

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I encountered fluctuations when flying in position mode. When I moved the plane and let go of the stick, the plane was constantly shaking and then stood still

I am trying to explain to you understand my problem. Below is a video that simulates my problem:

This is the video I just checked this afternoon, I feel too much feedback in position hold mode … can you see the clip and evaluate it to help me?

Hi @Tan_Ph_m ,
What do you mean by “too much feedback”? Is the drone too sensitive (stick feeling)? I don’t see oscillations in this video, so I don’t thking that the feedback gain is too large.

Yes, I noticed that the drone’s response level was too great, and the shaking phenomenon I had overcome, thank you.

Hi @Tan_Ph_m @bresch @LorenzMeier
I am facing the exactly same issue with my hexacopter (20kg AUW). which @Tan_Ph_m has tried to explain through the simulation.
i am using firmware version 1.11.0rc.

i tried reducing the gain MC_ROLL_P and MC_PITCH_P to 5 from 6.5 and MPC_XY_P to .8 from .95
still when i give roll or pitch command entire vehicle starts oscilating instead of moving in X or Y direction.
please let me know how you have resolved the issue.

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@Ramdg You first need to find which loop is creating the oscillations. Is is rock solid in attitude controlled mode (i.e.: no velocity/position loops involved)? Is it shaking in while moving in position control? Or only during hover?

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@bresch Thanks for the reply.
When I am flying in manual/stabilize mode, its stable and there is no oscillation at all…
when i am switching to position control mode it is hovering just fine…However, when i try to give roll or pitch input (in position hold mode) it starts oscillating in roll/ pitch (depends on the stick input)… even a disturbance due to wind gust is making it oscillate (and once vehicle start oscillating the oscillation amplitude keeps on increasing )

Please suggest me which parameter needs to be tuned !!!


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Ok, so this is most likely due to the velocity gains being too high for the roll/pitch response of the drone or a poor velocity estimate. A few possible solutions:

  • decrease the MPC_XY_VEL_[PI](_ACC) gains and the MPC_XY_P gain
  • tighten up the rate/attitude loops (if possible)
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Thanks for the suggestion …
i ll try that and see the response

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Hi @bresch
I adjusted the parameters that you suggested and the hexa seems stable…However, when i leave the Hexacopter in position hold mode. It starts circling (Toilet Bowling ) . Also, sometimes i face continuous short jerks in roll and pitch…when i give some roll and pitch command and leave the sticks at center… I have disabled internal compass and using here2 external compass.

Please suggest me what can be the possible solution to remove TBE as there is no effect of magnetic interference which i checked through the log data !!!

Logs or didn’t happen.

Hi @bresch
Here is the log

I am using Firmware v1.11.1 and here2

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