As you’ve said, you can’t get the P gain as high as you did with FILT at 4. So going to FILT = 10 will not help getting a higher P gain. The reason FILT =4 is helping you is the fact that your oscillatory frequencies are above 4 hz. If you set FILT to 10 hz, it would have very little, if any, affect on a bad oscillation at 5 hz. Remember that FILT is the Frequency below which the low pass filter is allowing to pass through. Now it is not a direct cut off at the FILT frequency. It’s attenuation effect ramps up as the frequencies go beyond the cut off frequency. [quote=“timbaconheli, post:536, topic:16800”]
A thought, so ive heard from many sources Pixhawk tends to get swamped with 3d flight, like flips and rolls tic tocs or whatnot, so i was thinking. In “stabilize” it is using accellerometers, and gyros if i understand correcrly? Does it use them in every flight mode? What im getting at is this, at times the EKF blows up for X reason and as Chris points out, with a flybar its not an issue because the flybar stabilizes it and you can fly around manually without issue.
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So the EKF uses accelerometers and possibly gyros too to determine attitude. And yes it is using attitude to control the aircraft in every mode because everything goes through the attitude controller (for Flybar_mode=0). So if the EKF blows up then there is not much you can do. The only way you might be able to save your heli would be to tune it with the ATC_ANG_ PIT_P and ATC_ANG_RLL_P to zero. This will cause the attitude controller to rely more heavily on the PID rate controller to capture the attitude in all modes but if the attitude solution is lost, it would allow you to switch to acro mode without the bad attitude solution impacting it. This was discussed some by Rob and Leondard in the unusual swashplate behavior topic.
I looked at some older ones last night. It appears the roll oscillation is around 5.5 hz. I have not seen a case where I could see a bad oscillation in pitch. You might have to raise that P gain by itself to see what the frequency is in pitch.