Hi,
Thanks for the info.
After seeing part of your drone picture, i realize that you are using a spring loaded folding arm… If this is the case, its 100% the spring is giving the drone a lot of vibrations.
Using a dampner on that folding adaptor may resolve your vibration issues.
They aren’t spring loaded arms. It is a clamped based design. The 80 Hz resonance is just from the cantilever carbon with a mass at the tip.
Does PX4 offer any accelerometer filtering other than IMU_ACCEL_CUTOFF? My value is set to the default of 30 Hz which is well below the 80 Hz issue I seem to be seeing. That parameter says it only affects the acceleration data sent to the controllers but not the estimators. The filtering discussed for the gyros makes no mention of the controller vs. estimators.
Arducopter has a low pass filter on the accelerometer (INS_ACCEL_FILTER) which might explain the better performance I’ve see when using that firmware.
@mwshafer I’m interested to understand why those vibrations issues are not visible on Ardupilot. Could you please share an Ardupilot log of the drone that flew well on APM or at least the tuning gain of the rate controllers and the IMU filter settings.
Especially:
INS_GYRO_FILTER
ATC_RAT_PIT_FLTD
ATC_RAT_PIT_FLTT
ATC_RAT_RLL_FLTD
ATC_RAT_RLL_FLTT
ATC_RAT_YAW_FLTE
ATC_RAT_YAW_FLTT
They have a slight different signal processing chain and I’m wondering if we’re missing something in PX4.
Thanks in advance.
@bresch I’ll be able to do this testing with Arducopter with my current vehicle but not for a couple of weeks. I’ll mention you here as soon as I can get this test done.
Thanks, but it you already have an APM log of the previous drone it could be enough.
I’ve done a rather vanilla X500 build with the orange + and am experiencing very similar symptoms. I am wondering if some of this is due to the frame design, so i will build a damping support for the 2 landing gear arms and see if it has any impact.
EDIT: Found there is a provided landing gear reinforcement STL file, so I’ve added it. I suspect holybro knows about this vibration issue and this is probably a fix. I’ll log it again tomorrow. For the others on the X500 frame, was this with or without the support installed?
Here is the vibration with the support installed.
It thought it sounded better, but the data doesn’t seem to support this. I will try mounting the cube differently and retry.
