Short:
Quad has been flying beautifully for months. Updated firmware, had issues, went back to older versions, still have issues. Have logs but not able to diagnose.
Long: (What I see as important details are bolded.)
I have a fairly stock 3dr quad which has been working well without much maintenance since late March. I took it on a road trip and upon returning, upgraded Mission Planner and the firmware. After one successful ~6 minute flight with the new firmware, I had my first issue. I was flying low to the ground and within a minute the quad started drifting backwards. I compensated by pushing forwards, without seeing much pitch. It continued moving, so I kept pitching until I realized I was at full pitch input. Since I was still moving backwards (and visibly around zero pitch) I dropped throttle and took a 1.5 m hard landing (no notable damage).
I then tried moving to an older firmware (2.9.1b), thinking it might have been a compass issue with 3.01. After moving I did a full recalibration and check over the components. During my first test flight the copter did a similar thing to what it did before, except moving to its right instead of backwards. I was ready and managed to land softer, but still had to bring it down quickly. After bringing it down I noticed that my gimbal was jumping all over the place, as though the accelerometers were reading radically different orientations.
I then reinstalled mission planner, restarted the computer, reinstalled firmware and recalibrated. During the test flight after this it started well, though it felt a bit different (maybe sluggish?) from normal, and I had to hold a higher throttle position for neutral than I was used to. 3-4 minutes into a ~6 minute battery life, the quad started losing power, and I somehow managed to land softly with full throttle input. After disarming I checked the batteries to see plenty of voltage. I them re-armed to check, and the motors spun up normally. The logs from this are the first from the two attached. Despite my lack of practice reading logs, I think there is a pretty evident throttle issue near the end of the flight (6070), but that's all I've been able to gleam from it.
I then tried an older firmware (2.9.1) (while cursing myself for not noting what I was running before upgrading). I then recalibrated, and took another tentative test flight. First ~3 minutes were fine, with a little drift to the right. Then as I was going the rightward drift became more pronounced. I was more prepared for it than I was previously, and managed to hold a level hover as the drift increased, by increasing my roll input. The logs from this flight are the second ones attached. Again, I can't read into them much, though it seems that the quad is registering a large roll in, AND a large roll angle. Since I was holding it in a hover, I suspect this roll angle isn't reading correctly. Of additional note, the gimbal was freaking out in a similar manner to that which I mentioned earlier. This second log also has the IMU readings, if that's of interest.
Based on what I've seen I feel like it might be an accelerometer issue, but one that's starting during flight, and inconsistent. I don't know what else I can do to narrow this down, or what steps I might be able to take to correct it. I would love any advice or direction that I might be able to get. Thank you very much, and I'm sorry for the long write-up, I figured completeness might be of service in case there are some thing which I'm not putting together!
Replies
Update: I have upgraded to 3.0.1, remounted the APM so as to reduce compass interference, and checked to make sure compass and vibration issues are under acceptable levels (they are).
I took some test flights today, and got two issues, both of which seem to be the same as those I've seen before (thus not firmware related). First was a crazy disorientation of the quad, which I was watching live via my computers telemetry. The quad was disarmed on the ground, while the virtual horizon was spinning randomly and out of control, which the telemetry logs clearly show.
I then disconnected the battery for 10 seconds, and reloaded to find the quad was registering as level again. I took a very cautious test-flight, and the quad flew fine for most of its battery life (though it was pulling slightly to the left). The quad suddenly pitched back and rolled right, and I was not able to correct with just inputs. I had to drop throttle and take a bit of a bouncy landing (all seems fine).
I have telemetry logs for the on the ground crazyness as well as the most recent flight with the sudden pitch/roll. I am getting better at reading them, and it seems as though I'm having some large board voltage fluctuations (Vcc drops from 5.1 to 4.2 V repeatedly). Otherwise I can't gleam much other than confirmations of the issues I saw. I'm still hoping someone who understands these things better might be able to help me.
For now I'm going to see if I can normalize my board voltage by disconnected my gimbal (currently drawing power from A3 and A4, with signals from A10 and A11), and see if that changes my power issues.
2013-07-28 11-45-18.tlog
2013-07-28 11-51-56.tlog