Trex 800e and pixhawk oscillating in loiter

Greetings to all
sorry for my English…

I have finally been able to blow my trex 800e with pixhawk.
after many vibration problems, finally resolved repositioning batteries (12s 10000mah).

now finally flies in the stab and hold alt modes, but loiter begins to oscillate in a circular
(reminds me of my Quadcopter when compass was misguided.

compass this (in my opinion) well oriented compass indicator planner suggests me well,
but no way to find the problem,

I will leave a log of flight if anyone is encouraged to take a look. … XJkTVIzRFU

A greeting and thanks for the help.

1 Like

Did you ever get this “TBE” issue resolved??

This should help.

You should be able to start at 0.100, and go from there, maybe up to 0.500, some people even go up to 1.0. But 0.038 is certainly too low. Also increase the IMAX to 2500. This will all help with the above issue.

Typically you would run the I-term at 1 or 2 times the level of P-term on a quad. But on heli, the spread is much more. P tends to be very low, and I-term tends to be very high. This is because of the very different response characteristics of the two systems.

Loiter can also oscillate if the Rate PID is not tuned up well enough, and the helicopter is not responsive to the angle requests from the Loiter controller. I’ve seen this a few times, when there’s not enough P and FF, and the copter is basically flying on I-term.

Hello Alainrc

could you solve your Problem?
I think i have the same issue / mistake in my params.

best regards

still I could not fix the problem, because other tasks I had to park the project. in a couple of weeks I hope to get back with the new update 3.3
thank you all for the help, in short I will keep you informed.


pd: I leave an image of the helicopter

Try lowering HLD_LAT_P and HLD_LON_P using the channel 6 tuning. At value of 1 I was getting this gyration, tuned down to 0.7 and it was almost eliminated.

When you say circular it brings to mind the “toilet bowl effect” that occurs on multirotors, as caused by interference of the GPS, I’ve had it occur on a tricopter build and once I moved the GPS higher, on a mast, it went away.

The main problem is what has happened in the Rate PID is not adapted, and interference magnetic compass leads, please check the patient

Well, I tried adjusting everything in RATE_PID, still got this oscillation which I call the Bill Haley Effect (Rock Around the Clock ;> Much nicer name than referring to a toilet bowl, not all of which have circularly flowing water in any case - check out a Dutch toilet for example…)

But I’ll try on your recommendation a shielding of the compass leads.