Quadcopter Flight Instability (Need Help)

ArduCopter Copter 4.3
1

I am using Pixhawk Cube with Firmaware 4.3.6 Official, MN5208-320KV Motors, T-motor Air 40Amp ESCs and T-Motor 18 Inch props with a 6s battery. But was using a custom quadcopter frame, Drone was suffering from high levels of vibration, which may affect the flight controller feedback loop.
I used the initial parameters calculator to find and update parameters for the Quadcopter. Selected Flight modes were Stablize → Loiter → Land. We flew it in Stabilize, then shifted it to Loiter, and then on Land, It oscillated a lot in Landing Mode.

It is requested to kindly review log files in the given link for analyzing the behaviour of Quadcopter.

Thanks in Advance.

2

Forget the video, post a .bin flight log. In fact you should review the flight log 1st and try to determine why there is oscillation based on details in the tuning wiki.

2 Likes
3

I enjoy the videos, they don’t offer much in the way of data to analyse, but they are very entertaining :smile:
If there is a lot of vibration it would be wise to sort that out first before working further on flight tuning

1 Like
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Thanks for replying,
below is the link of the log file.

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:+1: Thanks for suggestion, We have changed the frame aswell.

6

The oscillation is strong with this one.

The oscillations were just getting worse as time went on, rather than being related to Land mode.
Y axis vibrations are getting a bit high, you might want to investigate that.

Try setting these before the next test flight

ATC_RAT_RLL_P,0.10
ATC_RAT_RLL_I,0.10
ATC_RAT_RLL_D,0.005
ATC_RAT_PIT_P,0.10
ATC_RAT_PIT_I,0.10
ATC_RAT_PIT_D,0.005
INS_ACCEL_FILTER,10
INS_HNTCH_ENABLE,1  // set this then refresh params to see the rest
INS_HNTCH_MODE,1
INS_HNTCH_REF,0.2
INS_HNTCH_FREQ,50
INS_HNTCH_BW,25
INS_HNTCH_FM_RAT,0.7
INS_LOG_BAT_MASK,1
INS_LOG_BAT_OPT,4
MOT_SPIN_MIN,0.13

A few of the HNOTCH settings and some other parameters will need adjustment once you have stable flight and hover is learnt.
Just try to take off and hover, use Stabilise (because we should all practice more using this mode) then AltHold for a while. Use Loiter if everything is going OK. If the oscillations aren’t so bad it will still take a while for the hover thrust to be learnt.
You can put Land on another two position switch.
Use the tuning guide to reduce the oscillations further.
https://ardupilot.org/copter/docs/ac_rollpitchtuning.html#manual-tuning-of-roll-and-pitch

Let’s see the log of your next flight.

7

Many Thanks xfacta
I’ll definitely give it a try before next flight.