Attach it directly to the base plate
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if we attach the cube to the main base plate, where we attach the main pdb and the power wires of the motors?
its a solution we think time ago
Right. This is what was done on the X8 with the same problem.
hard mounting on the main base?
Yes, try hard mounting. If that doesn’t work use one of the vibe mounts designed for the Cube carrier.
If you don’t want to do this you could try a much thicker mount plate and put a stand-off in the middle of the plate. I just took a look at the last log you posted and with X/Y vibes peaking ~25 this might be good enough.
the first attemp will be to replace these original thin carbon plate to a more rigid about 4mm thickness with more robust spacers to attacht the plate to the main base. replace the original m3 alu spacers for m5 robust spacers with more contact surface…
I feel these 3 wires are potentially the cause, hitting the cube+ and anti-vibration stand.
Alternatively, you could cut a bigger FCU plate and place it on top, a bit further away from the PDB mounting. Consider printing a cover to reduce vibration induced by propeller wash, it helps. It also helps mitigate atmospheric drastic change to the barometer. Example.
This frame already have its own canopy/cover. its removed to make a picture of the electronics.
respect to the loosen wires, there are the softest wires i can.
the main problem came from the flight controler carbon plate on the frame main board, its very thin and could be amplify the vibrations on the frame.
next step are changing these plate to a new one much more rigid
Our next step are to test the new one flight controller plate.
4mm thick, much more rigid than the original one o 1,5mm
10mm alu spacers with much more contact surface.
the system now is much more rigid than the original one.
i try to mount the cube hard mounting with 3m doubled foam adhesives and make a new test flight
thanks very much Dave for your advices
I hope your approach works.
Our experience and observation shows that our base plate the root cause, as the arm lift the base plate flex. When throttle up and down, pitch and roll, the base plate flex. To resolve the flex, we redesign to have a square or rectangle “bones” between plates to prevent it to flex when lifting. Our drone is 1.88m.
Happy flying.
We have test flight today.
with the thick 4mm, flight controller carbon plate and the cube orange plus hard mounting on it with 3m double sided foam (the thicker one)
we have removed the fc vibration mount.
the vibe test are the following
X:
Y:
Z:
i think that these vibe results are acceptable and safe to flight
what doo you think?
the drone flies very smooth.
They are higher than I would like to see them. Try with the mount back on. Which mount is it?
And you want to review the notch filter again with higher rigidity in the mount plate with or without the vib mount.
Thanks Dave for your comments.
Are a litlle higher but more stable, without spikes like previous test with the standar carbon plate and 3d print vibration mount.
please note that this flight, was a auto mission with 10-12 m/s gust winds. previous test was with very calm days.
and a very curious thing
with this thick and rigid plate, the vibrations behave in an expected way, the undamped imu registers high values than isolated imus.
with the standard thin plate, the non isolated imu have a lower values, this was contrary to what was expected.
the rigid plate in my opinion helps to moderate and control the vibes.
In this flight 0 clippings an 0 “orange” warning vibes in MP.
if you want, i will send you these log to setup the notch filter. i turn off the filter
since with the new rigid plate the previous frequencies would change
Sure, post a link to it and we’ll check it out.
This looks good to me. It is much cleaner than the previous configuration which had a mode ~32Hz apparently from the thin plate flexing.
Thanks for this review Dave,
i will setup the notch filter with these values and make more test flights a day more calm without wind.
Have you see in the log, we have a “secondary” issue with the GPS units. we use dual here4 and have a lot of issues on cold starts with both gps (gps bad fix) and the second gps never reach their correct gps sats, (about 30).
we use an external power 5v to power can splitters and gps in each can port.
both gps modules updated to latest by dronecan in MP.
do you see anything bad in the params?
I see the problem but I don’t see anything in the parameters to explain it.
maybe faulty gps modules?
i have send various gps modules of here4 of our fleet, to warranty service on my reseller
due to the magnetometer issue.
but in this case, the compases are ok, but the sat number dont reach correct values.
the external power of the modules maybe an issue? i have setup the castle creations bec to 5,3V
Vibrations are definitely too high, particularly for the non-damped IMU.
I would set these:
ARMING_CHECK,1
GPS_GNSS_MODE,5
GPS_GNSS_MODE2,5
INS_GYRO_FILTER,15
Can you put the two different GNSS units each on a different CAN bus?
Since it is a Cube Orange+ I would enable the FFT and set the harmonic notch filter accordingly. That way it should not need adjusting as you make improvements or change the payload.
FFT_ENABLE,1
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_REF,1
INS_HNTCH_FM_RAT,1
INS_HNTCH_OPTS,0
This should just work, but may need a slight adjustment after the next test flight.