I wanted to start a conversation around the roll and pitch of Arducopter drifting as you fly.
The reason is I just assembled new hardware and problems that weren't there before have now shown up in a bad way. Flying indoors in a 5ft space I was able to get up to 30° error in roll and around 10-15° in pitch. I was able to control it and it flew perfectly level the whole time, I just had to hold the stick into the corner of the radio. Lading and waiting corrects the issue.
What could cause this. I had been flying an older version of the IMU this whole time. This version has an analogue filter for the gyros where the new hardware has it as an option. You must solder the pads around the gyros to enable them. I was also flying with two slightly tweaked motors giving off a lot of vibration. This could affect the accels.
My question is: If you have a problem like this, what is the vibration level on your copter, and do you have the filter pads soldered?
And notice I didn't say "loss of control" or "it didn't fly stable". I had control, and it flew perfectly. It just lost it's reference to the ground and I had to compensate with the stick. Had it been worse than 45° I would have lost control.
There are three pairs of pads, each with a white outline. (look for GYRO-XY near the relay).
Jani Solders his to enable the filter. I have never flown this board until now. I will solder them to test the filters this week.
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My fault for letting this discussion drift. The major noise induced drift issues have been addressed in software in the latest release and soldering the filter pads has been confirmed to help.
The DCM I term has been lowered to account for the faster loop speed.
The DCM p term has been raised to give faster recovery.
The accel cutoff has been reduced to limit the effect of accels in rapid accelerations.
If you have major drift issues, (not 1-2° slow drifts), please start a new thread.
There is a very interesting engineering centric thread going on now to analyze the effects of vibration and noise. It will probably inform future efforts, but the results are still unclear (and above my head). If you want to learn a lot about signals and noise, jump in.