Can someone help me analyze the flight log of my octaquad? I’ve seen a lot of documentation, but sometimes I get confused with so much information.
I’m following the methodical configuration and now I’ve stopped at the first part, adjusting the notch filter. Looking at the drone in flight, everything seems fine, but I still see that the PIDs are slow, maybe I could increase them a little more. However, I would like to be sure that the vibrations are within the limit to continue, but I can’t see excessive vibrations looking at the logs, am I right? Is it possible to improve it even more?
Can someone analyze it and tell me if it’s okay, or if I should change something?
Thank you very much for the feedback, Amilcar.
I’m following the steps. I’ve done a few more flights and it seems quite stable, I’ve done the autotune, but I’m having problems with my power module. I’ll fix it and continue testing and configuring.
By the way, congratulations on the methodic configurator tool, it helped a lot.
Your fundamental frequency is 39hz and 78hz you are currently filtering at is 2nd harmonic, although it’s low in power it still have some feedback in PID regulator. Not sure if you should address it if the tune is acceptable.
It might be wise to try switching to 3rd hard mounted gyro, it gives much less noise in lower range - 13db, maybe you will not need dynamic notch at all with it.
Be aware that the 3rd IMU (hard-mounted) has less resolution and a more narrow range of measurement - this makes it appear to report less vibration. That could be useful, particularly as a last line of defence, however the better solution is to rely on the 1st and 2nd IMUs and fix any physical vibration issues.
I had a look at Log 62.
Vibrations look OK.
You already had the notch filter working great and the settings are optimal.
Do not change any IMU or EKF selection or “primary” settings, the default IMU selection is the correct configuration.
You could safely set:
INS_LOG_BAT_MASK,0
INS_LOG_BAT_OPT,0
There’s some other tuning and parameters that could be improved, but vibration and harmonic notch filter is a PASS.
For these large copters I strongly recommend setting FENCE_ENABLE,1 and checking the other fence parameters. This will prevent arming in any mode until HOME can be set. This can take longer than expected, so just wait. Use the time to consider the pre-flight checks and planned flight.
I wasn’t going to go into the rest of the tuning unless a specific issue was raised, but I checked anyway just in case there was anything related to vibrations.
What I see:
Motor outputs are excellent and no oscillation.
Attitude control is great for a large copter, no oscillation, no significant overshoot or undershoot.
Yaw just needs a bit of work, some overshoot.
..and some parameters can be adjusted to suit large copters:
Other: ATC_THR_MIX_MAX,0.8 may not be needed, try the default 0.5 unless you’ve had issue with it. WPNAV_JERK,5 might be a bit much, I normally use 2 for larger copters = smoother turns. WPNAV_SPEED,2000 is probably not achievable, set something sensible in case a mission doesnt set a valid speed. Same for the other WPNAV ACCEL settings, check they are achievable and not going to snap the arms off the copter.
I followed all the instructions up to number 21. Now I need to activate quick tuning, but I couldn’t get it to work using a button on the Herelink controller. So I ran autotuning and stopped at that point; I didn’t have any more time to fly.
Yes, Amilcar. I followed the instructions and it worked perfectly on the first flight, requiring only a few adjustments. The tool is very good, I really liked it. Thank you for that.
