Replies to This Discussion

Permalink Reply by Jonathan M on April 2, 2012 at 8:30pm

Also, this may or may not be related, but I had a long flight today with the go pro.  Looking at the log file, the mag seems to drop out completely randomly.  It flew pretty well, and only a few times did yaw feel sloppy.  I tried loiter (needs tuning) and alt hold (ch6 tuning attempt) but mostly flew stable and simple.

Another oddity of this flight happens about a third of the way in, my quad had a uncommanded roll which ended in a crash.  Fortunately, I was about 3 ft above the ground and did not damage anything.  I flew fine after this with no issues.  Any thoughts as to what caused this?

Attachments:

• 4-2-12_goproflight_long.log, 2.7 MB

• ▶ Reply

DeveloperPermalink Reply by Adam Rivera on April 2, 2012 at 8:53pm

Jonathan... I don't see any flying in that tlog. That is most likely the problem.

• ▶ Reply

Permalink Reply by Jonathan M on April 2, 2012 at 9:50pm

Hmm.. well that would be the a big red flag!  I was sure that was a flight tlog.. hmm.

Are tlogs generated for each flight, like the .log files?   I don't have wireless telemetry, so i have to download files after each flight. 

• ▶ Reply

DeveloperPermalink Reply by Adam Rivera on April 2, 2012 at 9:56pm

tlogs require that telemetry is enabled. If you are feeling courageous you could pull the latest from git trunk and use the new in-flight compass calibration. People who have tested it thus far have had very good results.

• ▶ Reply

Permalink Reply by Jonathan M on April 2, 2012 at 10:00pm

Gotcha.  That makes sense.

I was thinking about it.  Maybe tomorrow :)

What do you think about that other log i posted (2.7 mb one)?  The mag seems to drop out completely randomly.  I haven't seen that before.  Yaw didn't seem affected much though i did have an uncommanded roll.  Not sure if that was related.

• ▶ Reply

DeveloperPermalink Reply by Adam Rivera on April 2, 2012 at 10:04pm

I didn't have time to take a look at the longer log, but with an uncalibrated compass as yours was, all sorts of strange things can happen. The heading and attitude solutions are intertwined so the uncommanded roll doesn't surprise me. Good luck!

• ▶ Reply

Permalink Reply by Jonathan M on April 2, 2012 at 10:44pm

Good point.  I will look into a bit more.

About your in-flight compass cal, does it help with magnetic interference we are seeing form the motors?  I know that with the 2.5+ firmwares, the DCM is more sensitive to magnetic interference when it comes to yawing (at least that's how i understand it).  I am assuming that the in-flight cal takes looks at the motor induced offset as well, correct?

Thanks for all of the help!

• ▶ Reply

DeveloperPermalink Reply by Adam Rivera on April 3, 2012 at 6:59am

The in-flight compass cal is thanks to Bill Premarlani and Andrew Tridgell... It attempts to model the offsets for the amount of motor noise that your frame has. So in a way, yes.

• ▶ Reply