Requesting feedback on tune of a 6 kg T-motor M1000 UAV

ArduCopter
1

Hello community members,

We have assembled a T-motor M1000 UAV and have done some tuning. The drone is flying good, but as certain points it becomes unstable, especially when there is a coupled input (roll and yaw together or other combination) and also when there is wind (4-5m/s). Vibe goes to 25 sometimes but remains under 30 with no clippings.

We are planning for deploy it for aerial mapping missions but are not very confident whether it will be able to handle complex mission (although we have done mission of 5 mins in terrain follow mode)
I request all the experienced member of this community their feedback on the tune of this aircraft. It will certainly help my team and other members in tuning their aircraft.

Please find the log attached.
Flight log

My ultimate question is whether it is safe to fly this drone and if not where should I focus on?

2

You can safely set these and there might be a slight improvement to stability
ATC_THR_MIX_MAN,0.5
INS_ACCEL_FILTER,10

Improve the logging without going crazy:
LOG_BITMASK,174078
and set your battery failsafe actions
BATT_FS_CRT_ACT,1
BATT_FS_LOW_ACT,2

These look suspect, anything special reason for these values?
MOT_PWM_MAX,2000
MOT_PWM_MIN,982
MOT_THST_EXPO,0.12

I think these would be more like all T-Motors other gear
MOT_PWM_MAX,1940
MOT_PWM_MIN,1100
MOT_THST_EXPO,0.4 ← reports of this being a good value for the integrated motor/ESC combos

And you will definitely have to redo these using the MissionPlanner motor test after changing those MOT_ settings listed above:
MOT_SPIN_ARM,0.15 ← probably about 0.10
MOT_SPIN_MIN,0.23 ← probably about 0.13 to 0.15

And MOT_THST_HOVER will need some time in ALTHOLD mode to relearn after all those changes.

There’s bit of a mess of frequencies there. I think you can trim down all your HNOTCH settings to these:
FFT_ENABLE,0
INS_HNTC2_ENABLE,0
INS_HNTCH_REF,0.20 ← start with this
INS_HNTCH_FREQ,40
INS_HNTCH_BW,20
INS_HNTCH_OPTS,0
INS_LOG_BAT_MASK,1
INS_LOG_BAT_OPT,4 ← my new favourite

INS_HNTCH_REF can be checked against MOT_THST_HOVER later, the new value should be about 0.7 x MOT_THST_HOVER.
For example if MOT_THST_HOVER is 0.25 then INS_HNTCH_REF = 0.7 x 0.25 = 0.175
This is a bit rough but can be refined later.
The real formula is
INS_HNTCH_REF = hover_thrust * (min_freq / hover_freq)^2

I always set an RC channel to Emergency Stop, especially with these big expensive/dangerous props.
RCxx_OPTION,31

Do a test flight in AltHold with mostly just hover and some gentle movements, see how that goes.
Obviously if there’s oscillations or any bad instability land immediately.
If everything is OK then try some Loiter too.
Let’s see that .bin log file :slight_smile:

3

Also I noticed you’ve got everything selected in GPS GNSS MODEs
Try reducing it to just two of
GPS
Galileo
Beidou
GLONASS
and see which gives you the best most stable HDOP
Usually select GPS + one other = 5 or 9 or 65

Be fully aware of the options for GPS_AUTO_SWITCH too. Sometimes switching GPS source mid-flight can have unintended consequences if their tracks were diverging. How you have this now appears to be working well, I just wanted to mention it.

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