Vibration analysis

PX4 Autopilot Flight Controllers đź’»
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Hover test: Here is a plot of the spectrum of accelerometer data logged at 1KHz. Data collected using a slight modification to PX4 master (Pixracer/250 FPV quad). Props are 5x4.6 and are dinged up a bit; definitely not perfect balance. Largest vibration amplitude is on Y axis (green) smallest on Z (blue) as expected.

hover.png1200Ă—941 51.1 KB

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Fidelity test: 450Hz sine wave excitation aligned roughly along Z axis

test_450.png1200Ă—941 51.6 KB

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Fidelity test: 180Hz sine wave excitation aligned roughly along Z axis

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Spectrum of gyro signals from 10 seconds of active flight with rapid roll/pitch inputs:

gyro_flight.png1200Ă—941 34.8 KB

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What is the purpose of this vibration analysis?

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The vibrational characteristics of the flight environment are of interest to IMU and attitude control system designers. It’s also a good quantitative measure of RPM and prop balancing :slight_smile:

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Is there a branch with the modifications to do this test myself?
Just wondering, thanks!

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This is still “Work In Progress”, and could easily break the attitude controller, so I don’t recommend trying it yourself yet. I’ll post a link to my branch when/if I think it’s safe for others to fly.

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@Mark_Whitehorn Impressive work. I’m excited to use this on my gas powered vehicle when it’s ready.