Vibration & APM:Plane performance

Archive
1

Hi Everyone,

Coming from APM: copter, vibration was a major thing. I’ve kind of put it aside on this plane build but today I checked some logs and they are not all within the specs listed on the wiki… but the wiki talks about copter, not plane. Should the same considerations be taken with APM: plane? are my vibration out of wack to the point of an imminent failure in assisted modes?

Here are graphs of the IMU:
X

Y

Z

and a log:
LOG

plane is flying great so far - loiter makes nice circles, stab is smooth. Just want to avoid issues in the future.

Thanks!

2

I’ve asked this question in the past and Tridge assured me that APM: Plane is not vibration sensitive. You shouldn’t be concerned unless you have a big gasser or something.

3

Vibration sensitivity on plane is about to change in a big way: the EKF will do navigation using the accelerometers in the same way copter does. If you’re using an APM2, then you’re fine. If you’re using pixhawk, you might not be soon.

4

thank you iskess and jschall for the clarification. It’s nice to have one less thing to worry about :sunglasses:

jschall - I am using an APM2 , but I was planning on trying the pixhawk on the plane… I will hold off. Not sure if you can/want to elaborate, but I’m curious why the pixhawk will not be a good choice once these EKF changes are applied to plane.

thanks!

5

[quote=“raphh”]thank you iskess and jschall for the clarification. It’s nice to have one less thing to worry about :sunglasses:

jschall - I am using an APM2 , but I was planning on trying the pixhawk on the plane… I will hold off. Not sure if you can/want to elaborate, but I’m curious why the pixhawk will not be a good choice once these EKF changes are applied to plane.

thanks![/quote]

I don’t mean that things will get worse than they are or that it is a bad choice - I mean that if you want to get the best performance out of the EKF, you will want low vibration levels.

6

Hi Jon,
I’ve been testing the EKF code on my high vibration nitro planes and it has been no problem. The tuning parameters we will choose for the EKF in plane are designed to cope with lots of vibration.
We’re not trying to hover in a 10cm box in a plane, so we don’t need to level of tuning for inertial navigation that a copter uses.
I don’t use any anti-vibration mounting on my planes at all - just velcro straight to the wooden fuselage on a plane that vibrates a lot. It hasn’t been a problem.
Cheers, Tridge

7

This is awesome to know - I am almost to the point of mounting my electronics in my X8, and I also have seen different comments on vibration.

Brad