Bad IMU vibrations in z-axis, possible causes?

Hardware Multirotors
1

Hello,

I have just completed my first flight with the pixhawk running AC3.1 and have been learning how to analyze the logs.

Here are the IMU vibration levels graphed in mission planner (logs downloaded via USB).

[attachment=0]smart-drone-log-1-18-06-2014 (2).png[/attachment]

As you can see the vibration levels for the y-axis are going above ±3. What would cause vibrations in only one axis? The x-axis vibrations are well within the acceptable range and I would have thought that the two would mirror one another?

What can I do to reduce the vibrations to withing the acceptable ±3 range?

Best regards,

Jethro.

2

[mf]Copter/Log analysis[/mf]
My guess would be one of those:

  • Mistake in the design of your vibration isolation OR
  • Something touching your controller from one side, transferring vibrations in one axis
3

Ok, that’s a good point I will check if anything is touching the Pixhawk. As for mounting I simply mounted the Pixhawk with the provided foam from 3DR.

Thanks for moving my post Stefan.

4

Did you cut the foam or use it as it is?
When the pieces are rectangular, its possible that they dampen more in one axis than in the other.

5

Thank you Stefan, this is really helpful. Here is a diagram of how the Pixhawk and foam rectangles are mounted…

I have some stuff to work with now! Thanks!