I have a F450 quad with APM 2.6 AC3.2. Recently I'm getting BAD DCM Heading error and the copter goes into LAND mode. This is happening very frequently. I have mounted my GPS Compass on a mast. I didn't face this problem earlier. Compassmot showed mag interference of 3%. So what is causing this? Pls help me in identifying problem.
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It's probably worth checking simple things like prop balance, motor alignment - I think those things will remove normal high frequency vibs but not more pathalogical mechanical vibs
Hi Andy,
Indoor test just now.
How are the IMU params looking? esp. AccY
TIA
2015-05-07 12-13-07 1.bin.log
AccXYZ.png
Looks great!
Some time ago I had problems with little bolts inside the cage, they were magnetized by a screwdriver and give me many headhache up I discover, here You have a compass discussion look if something is usefull for you. http://diydrones.com/group/arducopterusergroup/forum/topics/compass...
Hi Cala - Let me check on the bolts also but I have secured the caddy using just two ( using M3x10 ) . Maybe I will heat them to get rid of any magnetism since I may not have nylon ones. Will use a compass to check for any magnetic field.
Will report back.
Phani, were you able to solve this. I too am getting DCM Bad Heading every now and then and quad looses it's orientation.
I did a compassmot and my interference was also roundabout 3%.
Sorry for replying late. Yes! I have solved the problem by raising the height of GPS by few inches and with proper compass & compass mot calibration. Now it flies fine.
No such luck for me... I am out of ideas!
I also which I knew what caused your flyaway. I had a similar thing which resulted in a nasty crash. I'm guessing in my case that perhaps it gave up on the compass heading and switched to the GPS, but who knows...
So I had a look at the code, as your situation is fairly similar to mine. ErrYaw is determined by comparing the compass heading with the inertial solution (unless you are going over a certain speed in which case GPS might get used). Ergo ErrYaw increasing is either because your compass is giving bad readings or because the inertial solution is wrong (determined via IMU readings). So the things to check are compass interference and vibrations. Neither of these look bad to me from your logs, so I'm not sure what to suggest. I would definitely try 3.1.5 to see if that's any better and I would definitely look at the mounting of your APM - is it mounted suitably? I wish there was an easy way of determining what's wrong! I had a patch accepted for 3.3 which allows you to see the compass health - which would have caught my issues, but I'm not sure what else could be checked.
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