Servers by jDrones

PERIODIC VIBRATIONs


(moonmotor) #1

I’m getting vibration warnings, especially in the Z direction and looking at the logs, they appear to be periodic in nature. It’s very odd to me and I’ve been struggling for several days trying to isolate the root cause. Has anybody else seen anything like this or have any ideas on what might cause time-related vibrations?
This was during an auto mission, imaging field crops, so it may have something to do with acceleration (positive and negative) at the end of each row in the “mow the lawn” pattern.
LOG file too big to upload here, but can be downloaded from Google drive here: https://drive.google.com/open?id=0B0OMLBwWNbKjal9NNjJPU1l5eW8
Thanks in advance for any thoughts on this topic.
MM


(moonmotor) #2

more info…this is a Pixhawk 2, running Copter 3.5 on a 700mm quad


(Mike Boland) #3

Although your Z Vibes are not excessive, being under 70 at peak, they do vary greatly during manoeuvres.

What was interesting is the reduction in Vibes with yaw and pitch and the increase in Vibes in level flight.

These Vibes seem to relate to your forward speed.

So I would be looking at aerodynamic vibrations, especially blade flex, frame flex, something loose and rattling in forward flight, that sort of thing.


(moonmotor) #4

Thanks, will have a look at that.


(moonmotor) #5

BTW, what did you use to generate that plot?


(Mike Boland) #6

The program is APM Planner 2 and it has the best graphing options out there.

I do also use Mission Planner but it is not compatible and the graphing is nowhere near APM Planner 2’s which follows the Macintosh interface quite closely.