Hi Leonard,
Sorry to bug you, but can you please suggest the settings for a Flamewheel F450 Quad and for a F550 Hexa of the following parameters:
INS_GYRO_FILTER -?
INS_ACCEL_FILTER -?
MOT_THST_EXPO -?
and the limit for these parameters
ATC_ANG_PIT_P -?
ATC_ANG_RLL_P -?
Is 15 to high?
Thanks
Henry
Thanks all for the buzzer issue. The first time we saw this it was on a iris where the buzzer caused both IMUâs to go bad. Here we are obviously getting just one because that one is in just the right spot on the board.
Great info, thank you!!!
Hi Henwilsch,
I would go with:
NS_GYRO_FILTER -40
INS_ACCEL_FILTER -40
MOT_THST_EXPO -0.65
and the limit for these parameters
ATC_ANG_PIT_P -10
ATC_ANG_RLL_P -10
As safe parameters. I would consider dropping the filter frequencies to 20 and 10 on the D filters if you find you have excessive noise issues.
Sorry for the slow reply I have had a crazy few months.
Hi Leonard,
I would suggest to move core recommendations from this thread straight into the wiki for arducopter into a separate section on how to setup pids for a small racer pixhawk based model.
i went into almost week long ordeal fighting same exact issue and found this thread just thx to pure luck.
https://discuss.ardupilot.org/t/need-help-severe-shaking-on-roll-axis/29823/9
Your recommendations were the key - on filtering and startup pids. as i only dealt with large and medium models before i could not figure out at all what was the issue with oscillations and jigsaw output on RCOU.
Thanks again for your help and support!
The key was lowering P gain, But and a big but, the mission planer extended tuning does not allow it to be lowered any lower than 0.080, and it needs to be around 0.050.
Go in to full parameter list and tune these:
ATC_ART_PIT_P 0.05
ATC_RAT_RLL_P 0.05
INS_ACCEL_FILTER 30
INS_GYRO_FILTER 60
I could tell but the fast oscillation it was too high P-gain. This is on a 4 year old 6G quad (thrust to weight ratio measured on filtered ACC Z axis in BF, hover to punch out), my normal quad is 9G and its considered a tanker, the new stuff is +13G. Can someone tell mission planner dev(s) to open up the tuning range, a low of 0.080 is probably fine for AP rigs, but nowhere close for the new mini quads requirements. I recommend 0.020 as a new low setting in âextended tuningâ page.
it is correct. also, as i posted in rcgroups - the PSC_ACCZ_FILT parameter can also be causing âup and downâ jumping syndrome on small 6" and smaller models, and needs to be set to 40 or 80 Hz as well. as of to use 30, 40, 60, 80 - it really depends upon level of vibrations and desired agility.
May I ask the meaning of increasing ATC_RAT_PIT_FILT from 20(default) to 40? I did not fully understand the description in doc about ATC_RAT_PIT_FILT.
And why increase INS_GYRO_FILTER from 20(default) to 40. but decrease INS_ACCEL_FILTER from 20(default) to 10? the doc states âThis can be set to a lower value to try to cope with very high vibration levels in aircraft.â I think small quad has higher vibration than big quad?
Thank you very much
I have a discussion here that would be a good place to make recomendations for parameter limit changes and defaults feedback.
I organised the new wiki tuning page to try to cover most of the introductory tuning questions.
hi @Leonardthall thank you very much. Your tuning instruction guide really saves my life (and many other people, I am sure)
Would you mind further explain the reason of increasing INS_GYRO_FILTER? Look into the source code, I think it is the cutoff frequency of low-pass filter for gyro. But I do not understand why increase it for small quad. I think increase it will let more noise enter EKF? And small quad usually has more vibration.
I do not understand what ATC_RAT_RLL_FILT do, too. I still not get it after dig into the source code. Would you mind giving me a little hint?
Thank you very much
The filters reduce noise but increase latency. The smaller and faster the aircraft the more important it is to minimise the latency. So this means we must increase the filter cut off frequency. To help with this these small aircraft have noise that is also a much higher frequency than larger aircraft.
The other thing to mention is the INS_GYRO_FILTER does not have any impact on the EKF.
ATC_RAT_RLL_FILT is the D term filter. If you look at some PID loop videos you will see that the D term needs to be filtered because it tends to increase gain at higher frequencies.
@Leonardthall Thank you very very much. Your explanation really helps me a lot.