How much vibration noise is expected?

Flight Testing & Log Analysis
1

I’m troubleshooting my drone, and just wanted to know what the general consensus is for an acceptable amount of IMU noise from vibrations?

During flight, I’m observing IMU noise in the X and Y directions on the order of +/- 0.9 m/s^2, and in the Z direction about +/- 1.5 m/s^2.

Is this normal, or is this too high? My PX4 is mounted in such a way that it would be time consuming to remount with foam vibration dampers, so I wanted to see what people thought about this before I go through the effort to try it out.

I’ve also had a couple minor crashes on this drone and the propellers are less than perfect. I’ve heard mixed beliefs on how much the propellers effect the performance of a drone. Is it worth always making sure the propellers are new and flawless?

IMU_Noise.png1024×768 114 KB

I’m experiencing jitter in Altitude hold, and thought this might be the cause.

Thanks.

2

Hi,

It depends on the frequencies in the noise. Here is a flight with a drone without issues from vibrations but with significantly higher magnitude of noise.

image.png1302×779 186 KB

However, as soon as you have noise with higher frequencies it might very well cause issues

3

What is the easiest way to do a frequency analysis of the noise? I’ve been using FlightPlot to view my log files. I didn’t see a Fourier Transform option in FlightPlot. Am I missing something that can do this for me? Or is there a different tool I should use? Or should I just use the provided python script to convert to a CSV and then write a script to plot the FFT in Python.

4

As far as I know Matlab or (as you said) Python are the easiest options.