Multirotor not stable in Loiter mode

1

hi good day all

im facing issue in quad 825 mm size motor to motor , the quad flies good in loiter for few min all of sudden tends tp pitch forward and hd to take to alt hold and recover

tried manual tuning & autotune , tuning goes well but after tuning same issue persists in pitch axis

Quad X, cube orange plus

Tmotor Antigravity MN 6007II 320KV with 22*6.6 Prop,
ESC hobbywing Sky walker 60A v2
here 3+ GPS

iv attached logs of the previous flights ( Logs – Google Drive)
hope to resolve the issue soon with the help of the community

2

There’s a lot of logs there - please point to just one where there issue occurs, and is NOT an Autotune log.

3

almost all flight had same behaviour, post tuning & would request to look into all to know this issue

4

Motor 3 is working consistently harder than all the rest, so there is a noticeable weight bias towards that arm. Improve the COG/weight balance a bit. Try to correct this before anything else.

Periodically the other motors are hitting their minimum, so this wont be helping stability at all.

Those ESCs are really Plane ESCs and there’s limited information about them. Clearly they work but I wouldnt have put them high on my list of ESC choices. You will be better off with good BLHELI32 / AM32 ESCs, or something more professional like an APD or similar - when you are looking around for the next upgrade :slight_smile:

There are quite a lot of default values for important parameters, so you have not done the “Initial Parameters” and autotune must never have completed.

Go into MissionPlanner / Setup / Mandatory / Initial Parameters.

  • Put in 22 for your prop size and 6 cells for the battery section (dont change anything else)
  • Select the “Suggested settings”
  • Accept all the changes offered.

Now also set these:

ATC_INPUT_TC,0.20
MOT_SPIN_MIN,0.13
PILOT_THR_BHV,7
PSC_ACCZ_I,0.4
INS_LOG_BAT_MASK,1
INS_LOG_BAT_OPT,4
LOG_BITMASK,180222
FFT_ENABLE,1
INS_HNTCH_ENABLE,1

and reboot the flight controller, or at least refresh all the parameters.
Then set these:

FFT_MINHZ,30
FFT_MAXHZ,300
FFT_NUM_FRAMES,2
FFT_HMNC_PEAK,2
FFT_WINDOW_SIZE,128
INS_HNTCH_MODE,4
INS_HNTCH_FREQ,30
INS_HNTCH_BW,15
INS_HNTCH_FM_RAT,1
INS_HNTCH_REF,1
INS_HNTCH_OPTS,2

Now do a test flight and let’s see that log.
Be aware the throttle control will be from mid-stick, and the copter is now assuming the throttle stick is self-centering (which I figured out from your log). The controls will also be a little smoother, instead of “racing qaud” nervous.