We are operating a few large hexa copters, T1500, which is being sold by T-drone.
Please refer to her specs underneath but they can vary a bit (motor, ESC) depending on versions.
motor: MN8017 KV120
prop: NS30*10
ESC: Flame 80A HV
size: 1600x1600x950mm
AUW: 23kg
Currently, we are facing an issue that one of the drones is getting unstable whenever she is flying INTO wind. She starts to move its head up and down and the vibration sometimes gets worse unless we slow her down. No harmonic notch filter was applied. (Is harmonic notch filter helpful to large copters like ours too?) Autotune done with aggresiveness as of 0.1 and FC(cube orange) is dampered.
Someone adviced me to modify PSC_VELXY_D down to 0.07 and it seemed to have worked at that time but the symptom is back again. ( or it was always there but I havenāt noticed it)
A hover flight would be interesting to see as it looks like the outputs are oscillating. You do want to configure the Notch filter and a couple other parameters:
INS_LOG_BAT_MASK,1
INS_LOG_BAT_OPT,4
PSC_ACCZ_I,0.44
PSC_ACCZ_P,0.22
I would set this back to default PSC_VELXY_D. and then come back to it possibly.
Was this determined from Setting the Motor Ranges? Setting Motor Ranges
MOT_SPIN_MIN,0.15
OK. I set PSC_VELXY_D to default value 0.5. Also, these values are adjusted as you suggest.
PSC_ACCZ_I,0.44
PSC_ACCZ_P,0.22
MOT_SPIN_MIN,0.15
Yes, It was 0.15 is default value for our drone. Is that what youāre asking?
Setting up a notch filter didnāt look easy (I actually tried to go ahead with it a couple of times before) but I will give it a try once again if it is going to improve the performance a lot.
I found mot_spin_min value in the parameter uploaded is set as 0.04 and it was given from manufacturer.
I didnāt follow that Setting Motor Ranges guide. Btw, our dronesā mot_spin_arm and _spin_min are same as of 0.04. According to the guide, spin_min is to be 0.03 higher than spin_arm value. That means, for our case, spin_min needs to be 0.07 at least. (letās assume that spin_arm value is correct one) Am I right?
I couldnāt make time to test drone today but let you updated when I do. Thank you.
These parameters were fixed beforehand but I forgot to fix PSC_VELXY_D back to default value, 0.5. I might give it another try with that D value fixed if needed.
The flight seemed OK this time to me.
BTW, MOT_SPIN_MIN was 0.15. I was too tired last night and probably had things mixed up. Mot_spin_arm 0.03 and _spin_min 0.15. I might have to make some time to do the proper motor range setting ASAP.
First one, with all those HNTCH parameters and ATC_THR_MIX_Man adjusted as suggested. There was no notable shaking in pitch and roll axis.
Second one, I modified PSC_VELXY_D from 0.07 to 0.2. When we pushed her up to max loiter speed and put pitch stick in to middle she stopped but became unstable a lot. After that, we landed her immediately.
Few weeks ago, we had a bad crush breaking arms and legs when I modified PSC_velxy_P,I,D back to default value. At that time, when she took off, she was moving like a falling leaf in the wind and I couldnāt get a control of her at all. After that crush, parameters were returned back to how it is now.
Autotune is going to be done when the wind subsides a bit.
How is the notch filter working? I am (have been several times actually) looking into the manual again in the ardupilot but it might take some time for me to understand properly.
I also noticed in the log that drone location while on the ground before launch was keep changing. Could it indicate any fault in any sensors like GPS or IMU?
While I was downloading Logs from drone after flight in the office, I heard EKF something (I canāt remember clearly) Kept changing. Is it normal?
FC is quite old, over 1.5 year, and so are GPSs. Iām worried they could have deteriorated not functioning as it is supposed to be.
Sorry for all these noob questions. If itās not appropriate asking here, I will make another thread.
Looks like there is some compass interference. I see you have not run Magfit for compass calibration and motor compensation. This should be considered a mandatory process in my opinion and itās easy to accomplish Magfit Donāt worry about the āPython environmentā use MAVExplorer as per the guide. Make a flight with a few figure 8ās and some throttle changes and then use that log.
There are also GPS switching messages. This is normal when using āuse bestā.
I think the Flight Controller in fine. Update to current Stable.
Our hexa is flying beautiful after we applied all your suggestions.
I also modified āATC_THR_MIX_MANā parameter to 0.5 in our other drones (same model) and they also stabilized a lot.
MAVExplorer program was not easy to start with but I am going to keep trying and setting up notch filter on other drones might be my first goal for now.
The filter attenuation of 40 dB has been found to be the best maximum to use in most cases. The Ratio drops the low side of the notch by that multiplier. It can be used to broaden the notch. A harmonic value of 3 is not the 4th harmonic itās a bitmask value that means 1st and 2nd harmonic.
