I had strange issue yesterday. While in ALT_HOLD mode, quadcopter suddenly starded climbing like a rocket. Did not respond to my throttle input until I switched to STABILIZE. Then it got controllable again.
I'm not a big log expert yet, so would appreciate any help investigating my log:
https://dl.dropboxusercontent.com/u/31684304/2014-05-24%2002-03-41_12.log
The climb starts at around line 17450 with full throttle, and stops after 17724 When I switch to STABILIZE. Thare is also switches to LOITER and back to ALT_HOLD during the climb, that gave no effect.
Strange thing I noticed - is during climb BarAlt increases, as actual altitude did (gained about 50 meters during that jump), but GPS.RelAlt decreases. Could that cause this jump?
Here is how it looks on graphs:
I did not increase throttle on my Tx. And it looks like ThrIn did not jump, but only went down trying to compensate sudden climb, so does not look like a Tx glitch as well.
b.t.w. 2 flights before this issue I have replaced ESCs on this quad (with faster BLHeli ones) and did AutoTune, that seemed fine. I don't think ESCs could cause that jump, but nothing else was changed recently.
Also, it was pretty hot (and sunny) outside when I flew. But don't think sun could cause this 50m clibm as well - at least baro alt log looks more or less like truth.
Replies
Ha!
I've just notice, that whenever vibrations increase, CRate drops. (See image), but!
As per Docs:
So how can CRate be negative, when RelAlt increases?
Screenshot 2014-05-27 00.35.56.jpg
I was able to replicate thisseveral times. And Now I'm certain, that this relates to increasing vibrations in some conditions.
However, here is interesting part of today's log:
There is clear increase in vibration, as I tilt copter forward and speed up. BUT:
Both BaroAlt and RelAlt increase, and even though RelAlt grows slower, than BaroAlt, none f them is decreasing. But AP still adds throttle up to 1000 (full throttle) and keeps it there.
Why could that happen? With all vibrations, there was no reason for AP to throttle-up.
Screenshot 2014-05-26 23.29.43.jpg
Can't find any reason other, than RelAlt dropping down... Will do more test flights next week to see it that happens again.