AltHold: rises up like a rocket

ArduCopter
1

APM.zip (430.7 KB) My Tyro129, firmware MatekF405,

with INS_GYRO_FILTER=60 flyes in STABALIZE - Perfect.

In ALTHOLD can not hold altitude and rises up suddenly.
I modified some params as from: https://ardupilot.org/copter/docs/tuning-process-instructions.html

MOT_THST_HOVER = 0,21
PSC_ACCZ_I = 0,42
PSC_ACCZ_P = 0,21

But the problem is not solved.

My logs in google drive

Or my logs direct download:
APM.zip (430.7 KB)

1 Like
2

Vibration failsafe was activated. More about it here.
https://ardupilot.org/copter/docs/vibration-failsafe.html

Vibe FS
Vibe FS1655×599 78.9 KB

3

Thanks for the quick reply.
In STABALIZE it flyes very smoothly (because of INS_GYRO_FILTER=60)
and seems to have no vibrations.
What is the best approach in that case ?

  1. To disable the vibrations failsafe ( FS_VIBE_ENABLE = 0 )
  2. To flash older firmware (Arducopter 3.6.X)
  3. Try with higher INS_GYRO_FILTER, may be 80
  4. To try to reduse that invisible for me vibrations ( some other filter Notch, soft mounted FC …)
4

You are not the 1st to report this problem. Better Vibe isolation would help but I think I would disable the failsafe.

5

Just add rubber Padding and find function downwash and enable I guess this might solve your problem .

6

Today I changed:
INS_GYRO_FILTER=80
FS_VIBE_ENABLE = 0
But the problem is not solved.

I rise the quad at about 5m in STABALIZE,
I switch to ALTHOLD at mid throttle.
The quad falls about 2-3 meters, after that suddenly rises up ( more than 10m) after that I switch back to STABALIZE.

When I arm in ALTHOLD on the ground it starts spinning the motors, but does not lift up at about 75% throttle. After that rises suddely.

7

Send me long file

And just try this actions

Try to takeoff in position hold mode

Then shift to stabilize mode.

Dont forget keep kill switch handy

And send what hardware your using including some images of it.

Thanks and regards

Omkar

8

crazy vertical shoot up in pos hold and alt hold is due to excessive vibrations every time. usually with a hard mounted FC.

on params front - review your PSC section, i copied it below. freq of filters in there have direct implication to that issue.
second, if you cannot suppress vibrations mechanically - use the notch filter. there is a whole tread about it on this forum. for medium 450mm drone i also give you sample params to use, but you will need to read it up and tune it properly as explained in the documentation.

PSC_ACC_XY_FILT,2
PSC_ACCZ_D,0
PSC_ACCZ_FF,0
PSC_ACCZ_FLTD,0
PSC_ACCZ_FLTE,40
PSC_ACCZ_FLTT,0
PSC_ACCZ_I,1
PSC_ACCZ_IMAX,800
PSC_ACCZ_P,0.5
PSC_ANGLE_MAX,0
PSC_POSXY_P,0.25
PSC_POSZ_P,1
PSC_VELXY_D,0.5
PSC_VELXY_D_FILT,40
PSC_VELXY_FILT,40
PSC_VELXY_I,1
PSC_VELXY_IMAX,3000
PSC_VELXY_P,2
PSC_VELZ_P,5

INS_HNTCH_ATT,40
INS_HNTCH_BW,70
INS_HNTCH_ENABLE,1
INS_HNTCH_FREQ,140
INS_HNTCH_HMNCS,3
INS_HNTCH_MODE,1
INS_HNTCH_REF,0.38

9

it also may be prop wash in your baro, but, usually it is all due to vibrations.