Swinging around while hovering low

[microlinux]

I had a new thing happen when I tried to land last night. I normally hand-catch my drone, so I brought it down to about 5 feet above cut grass. Normally, it it hovers pretty rock solid. However, it was slowly swinging all over the place - about a 3 to 4 foot area. It would be stable for a second or two, then start swinging around - rinse repeat.

I allegedly had good GPS, 16 satellites. Tried switching from ATTI and back to GPS, same behavior. I was eventually able to catch it during a "lull". I didn't have the presence of mind to try switching VPS off, so maybe something funky with that. Has anyone else experienced this?

 

[ChrisRL]

Redo your IMU calibration, and also your compass calibration, then try again.

 

[Fly Dawg]

VPS will do that. Personally I leave mine off.

 

[microlinux]

I don't think it's IMU or compass, it otherwise flew like a dream. But, I did re-calibrate the IMU when I got home, for good measure. If it happens again, I'll trying switch the VPS off.

I imagine somebody got a good laugh watching me try to catch it. Cue the circus music.

 

[ChrisRL]

Oh yeah, that's right, +1 for Fly Dawg.
I have my VPS turned off mainly, since I'm more often called to fly in tight spaces than not, so for me it isn't a factor - but yes, certainly VPS calibration etc will play a part.
There's some fairly decent Youtube footage these days about how to get a decent sensor calibration going quickly and easily.
Best
C

 

[Meta4]

I had a new thing happen when I tried to land last night. I normally hand-catch my drone, so I brought it down to about 5 feet above cut grass. Normally, it it hovers pretty rock solid. However, it was slowly swinging all over the place - about a 3 to 4 foot area. It would be stable for a second or two, then start swinging around - rinse repeat.

It's all due to VPS which needs a clear pattern or texture that it can lock onto and good lighting.
Poor light and grass is going to cause it to search.
Next time, try climbing above VPS height (10 metres or 33 feet) and see if that makes a difference.
Then disable VPS and bring it back down low again.
If it's stable in hovering, that should show you why.