I’m trying to tune my small octaquad and I have some issue with Altitude hold function.
It is a 7 inch octaquad running at 4s with a flight time of 26 min. As you can see from log, it is a bit overpowered.
aircraft use an old VR Ubrain 5.1 running AC 4.0.7.
I recently enable notch filter and I think/hope I configured it correctly.
The issue is that in alt hold, it is not stable and move up and down for about 2-3m minimum and while moving forward I can hear motors increasing and decreasing quite rapidly.
Attached also the full parameter list octaquad.param (17.6 KB) 2021-04-11 17-30-05.bin (1015.1 KB)
no one can help? Do you need more info?
The 1st thing to notice are these parameter values.
These are off by a factor of 10 so essentially it’s unlimited. Your filter values are too low for a 7" craft. Run the Mission Planner Plug-in from Alt>A and reconfigure.
Also MOT_SPIN_MIN is higher than MOT_THST_HOVER.
Never heard about ALT>A, what it does?
Connect to Mission planner and hit Alt>A. It’s the Initial Tuning Guide plug-in.
performed the Alt+A function and now copter looks a bit better. I got another strange issue. During translated flight or forward, quad is “vibrating” on the Z axis. It look like that throttle control is too aggressive.
Once again attached parameter filed and log octaquad updated.param (17.7 KB)
You can try setting these:
PSC_ACCZ_I to 2 x MOT_THST_HOVER
PSC_ACCZ_P to MOT_THST_HOVER
It needs tuning. Run Auto Tune.
can it run autotune for altitude?
No but when it tunes pid settings correctly it removes vibration slightly and makes the altitude hold more accurate
After setting :
PSC_ACCZ_I to 4 x MOT_THST_HOVER
PSC_ACCZ_P to 2x MOT_THST_HOVER
with MOT_THST_HOVER= 0.12
I had to increase PSC_POSZ_P from 1.0 to 2.0
Yeah, dropping PSC_ACCZ_P and then set PSC_ACCZ_I to 2x the value will stop the motor pulsing, I’ve not figured out how to increase the ALT hold strength Yet - seems my baro bounces about in MP (like most do)
usually the ardupilot system that I setup are not that overpowered.