A few users, myself included, appear to be having issues calibrating accels and/or arming when using APM 3.2 on a Pixhawk. I see posts here and there, but thought it may be best if those having the issue could all 'check in' to one post so that the developers can see how widespread the issue is and gather data.
My Pixhawk will arm occasionally, and will even fly successfully. Occasionally however it will not arm and I will receive the pre-arm error "Accels not healthy". A few days ago I was able to arm and fly thorugh one lipo, then after landing and swapping batteries I could not arm due to this reason. I have attached the logs from the successful flight, as well as the failed pre-arm logs, to this post.
As you can see from these images there is something amiss with IMU2. This is a snippit from the good flight, showing values for AccX on IMU1 and IMU2:
and here are the same values on the second attempt, pre-arm.
In the 3.2 release thread a few users had mentioned the issue and Randy advised to set the log_bitmask to "131070" so that it will log everything including the pre-arm checks. I encourage others having the issue to do the same and share the logs and experiences here so that we can find out what is going on here - is there a bad batch of Pixhawks in the wild that only now show the hardware errors due to something new in 3.2, or is there an issue in the APM software?
Replies
I think I also suffer from bad gyro problem. To me, the vibration/IMU value can be increased sharply at any moment and then cause the crash or full throttle out, no matter how good you damp the vibration. When I restarted the system, the quad will fly fine again. I know we have nothing to do in this moment other than replace a new board and hope the new board get a good gyro and accelerometer . I attached the log if you guys interest to investigate what is the problem. I was used PX4 and AC3.2. In the log, the first 5mins is under autotune. At the end of the log, the IMU value suddenly increased and cause crash.
Been following this thread but still learning so excuse me if this is a stupid question(s).
Does this phenomenon occur if EKF is disabled in 3.2?
Are both IMUs utilized when EKF is disabled?
I was just wondering after reading an EKF explanation in the Arducopter wiki.
mp.
Hi,
I can confirm I got today a bad pixhawk card (bad gyro health, general erratic behaviour, impossible to callibrate the accel) that was bought end december 2014. That reinforce the idea suggested in this thread that a batch of bad pixhawk cards were produced end of 2014.
I lost my whole day troubleshooting this and was very embarassed in front of my customer. Please 3DR, you need to take quality control to the next level because this is scary!
Hi All, first post so let me know if anything is out of order.
I have a Pixhawk running 3.1.5 and it seems fine, flies well, vibration levels shown in the logs are well within the recommended range.
Update to v3.2 and the fun starts. Upgrade process works fine, radio, accel and compass calibrations all seem to be OK.
Set the craft on level surface, plug it in wait a few minutes for everything to settle. Arm the craft (no pre-arm errors) and take off.
The craft will roll to the right roughly 20 degrees, requiring full left stick to maintain a stable hover. When the craft is on a level surface the artificial horizon shows in MP the correct output and when moving the craft around all seems well.
I have formatted the SD card and done an eeprom erase from the CLI in 3.1.5 prior to each attempt.
Reload 3.1.5 and the craft returns to a flyable state.
Haven't tried 3.2.1 yet to see if there is any difference.
Let me know if there is any further information I can provide especially which logs may be of use.
Cheers
Justlookin,
Dataflash logs from a problem flight would be great.
Thanks Randy.
This is from a 1 minute flight from yesterday. The craft starts to drift after that and it is just not flyable.
2015-02-03 11-26-41.bin
After a bit more fiddling it turns out this is a weird channel mapping issue.
Not sure if it is the same, but I logged a similar issue on the support forum here, with logs:
http://ardupilot.com/forum/viewtopic.php?f=80&t=11076
It isn't failing pre-arm checks for me, but IMU+IMU2 have a high degree of variance, and on one flight it lost its sense of horizon by about 15-20 degrees during the flight. The Pixhawk is direct from 3DR.
Hi Andrew,
That looks like vibration induced aliasing to me, not sensor failure. You have an awful lot of vibration, and probably a significant amount of vibrational energy at the 800Hz sampling frequency of the lsm303d.
Once you fix your vibration issues I think you'll find it will behave a lot better.
Cheers, Tridge
Thanks for looking Tridge -- I'll take another look but with vibes generally under 0.1g I would have thought I'm in the clear, do you think it is because of the frequency rather than the amplitude?
Also, I swapped out the Pixhawk for another one and the issue seems to have gone away. I'll keep testing and keep an eye one it, but good to rule out any link to this specific issue.
-
30
-
31
-
32
-
33
-
34
of 46 Next