Props do not turn beyond idle in INS mode

[Carsten Böhme]

I ran into a strange problem with recent firmware, taulabs_next_20140202_210012_a6ecefe906_win32 and taulabs_next_20140207_140643_bd27ba6ff5_win32. No problems with the complementary algorithm, but in insoutdoor/insindoor modes, the props will not turn faster than idle regardless of throttle position.

On this copter I have successfully tested PH loiter from https://github.com/TauLabs/TauLabs/pull/1054 a while ago. The only thing I have done after that test flight was updating to taulabs_next_20140202_210012_a6ecefe906_win32 and then to taulabs_next_20140207_140643_bd27ba6ff5_win32 after I had encountered the problem. It happens whenever one of the INS algorithms is selected, regardless of flight mode, regardless whether pathfollower/planner modules are enabled. ManualThrottleCommand goes up as it should. (btw, the unit for that value should not be % if it goes from -1 to 1)

Short logfile attached (INSIndoor, arm, throttle from -1 to 1 in AttitudePlus mode, repeat in Rate mode)


Another note: the new defaults for altitude hold are likely much too high, quad shoots up ~10 m when switching to AH, then comes back to hold height.

[Carsten Böhme]

Trying to dig into that problem. I found that whenever the copter is armed and throttle above zero, ActuatorCommand becomes equal to the neutral setting for each channel and stays there, regardless of actual throttle position. Screenshots attached. I deliberately set different neutral positions to illustrate.

Screenshots were done in INSIndoor/INS with all other modules disabled.

I went back to rth from https://github.com/TauLabs/TauLabs/pull/1054 to test, same problem there.

[peabody124]

I still haven't had a chance to look at hte logs, but typically what you are describing happens when there is a NAN somewhere in the calculations. Check what the attitude estimate looks like. Also try erasing your home location (or all the settings) and reconfigure it.

[Carsten Böhme]

I have erased settings and manually entered the relevant settings from screenshots. It is working again.

I noticed that AccelBias, AccelScale (!), MagBias, MagScale were set to zero. Must have happened somewhere in the update process. A comparison between an older uav settings file and one taken from the logfile shows the scale and bias settings as the only significant difference (apart from VtolPathFollowerSettings and AltitudeHoldSettings where values have been changed in recent firmware). So it looks like this was the only source of the problem, which is a little strange since if I set those values to zero manually, the copter just becomes unflyable, but stills acts on throttle commands.

[peabody124]

Hmm.. Would be nice to know how those bad values got in there, but sounds like this is solved. It would be nice to have some kind of automatic analysis to catch those things but I can't think of an easy way to do that. It would be good to have an FAQ or troubleshooting page.

[Carsten Böhme]

I started a wiki page to collect such troubles https://github.com/TauLabs/TauLabs/wiki/FAQ:-things-that-can-go-wrong