High vibration in Cube Orange+

Just did a test flight after setting the IMU_DGYRO_CUTOFF to 15 and 12. There wasn’t much difference as it looks like the higher frequency pitch oscillations are still there but their magnitude was reduced a bit. For some reason there was a low frequency pitch oscillation throughout the whole flight.

I am wondering if this is simply a tuning issue given the size (4.25 kg of my drone). Reading this makes me think I need to change my P and D rate values given the size of my drone. I’ve got both low and high frequency pitch/yaw oscillations and the vehicle does feel a little sluggish. Could it be that the high accel reporting is simply from bad tuning inducing oscillations? Right now I’m using the default rate PID parameters:

MC_PITCHRATE_D = 0.003
MC_PITCHRATE_I = 0.2
MC_PITCHRATE_K = 1
MC_PITCHRATE_P = 0.15

IMU-DGYRO_CUTOFF = 15:
https://review.px4.io/plot_app?log=9b0f2089-bd6f-4e47-82a4-71569abec817

IMU_DGYRO_CUTOFF = 12:
https://review.px4.io/plot_app?log=cbcc6223-2569-4b41-b5ca-32b88faa9f7d

After this I did an autotuning. The resulting parameters were
MC_PITCHRATE_D = 0.003 → 0.0004
MC_PITCHRATE_I = 0.2 → 0.25
MC_PITCHRATE_P = 0.15-> 0.21

MC_ROLLRATE_D = 0.003 → 0.0004
MC_ROLLRATE_I = 0.2 → 0.225
MC_ROLLRATE_P = 0.15-> 0.204

MC_YAWRATE_D = 0 → 0
MC_YAWRATE_I = 0.1 → 0.18
MC_YAWRATE_P = 0.2-> 0.15

The roll and pitch D terms dropped considerably and the P terms increased a little bit. The result test flight with these a parameters is here and still shows significant vibration, although I the vehicle did seem to fly better. https://review.px4.io/plot_app?log=25005f93-d26c-4bd9-b556-76338395feee
Still seeing those oscillations in pitch

I’m at a bit of a loss as to the source of these high vibes.

@sibujacob can you explain what you mean by better isolation of cables with aluminum foil?

@Hs293Go It looks like your logs and my most recent logs look similar with noisy pitch/rollrate values and setpoints.

@bresch Any ideas on this? i.e. why are we both seeing noisy pitch/rollrate values/setpoints? Thanks.

How is the Cube base board mounted to the frame? Is there any chance of that flexing? The Cube Orange’s isolator frequency is around 80 Hz but it doesn’t look like you’re hitting that, so I would exclude that.

I don’t think the mount is flexing. The cube is mounted to the Airbot Mini Carrier board. I have that mounted via some plastic standoffs to the frame of the drone. I can try to add some padding above the cube to more or less wedge it to the upper plate of the frame to eliminate this possibility but I really don’t think it is the mounting given that I have seen this on my other drone with a different mounting scheme. I’ll give it a shot though.

@mwshafer

it has been noted that while we place an aluminum foil all through out the plate where the esc and power cables pass through, the D_gyro and IMU_gyro graphs are indicating low noise .

Hi,

You can also check out my other link regarding distance sensor graph plots accurately the altitude without having a sensor connected.