I ran into this problem. When starting the quadcopter in position mode, it abruptly gave off the throttle, made a roll and fell down
More about my quadcopter:
It is a large quadcopter with 30 inches of propamy, power and control (via joystick) comes with a wire (Tethered drone).
Below I will provide a link to the log file that was recorded. Please disregard the errors until 4:14 - before that time the quadcopter was being positioned on the landing site and it was affected by interference.
Maybe I have some simple setup error here, because before that I was flying only on AP firmware.
It seems like it only shows 2 plots, and indicates that you probably have custom changes & are not logging all the topics that official PX4 releases do, is this a processed (certain topics removed) log by any chance?
We briefly discussed this during Community QnA call. There can be few possible issues:
Your Multirotor tuning parameters are default, but they should be reduced (as it’s not as agile), for example attitude P gain is 6.5, which is for sure too high for drone with 30 inches prop. So it could have been tuned improperly, leading to a crash.
Your PWM minimum output are all 1000 us, which could lead to motors coming to a stop mid-air, when it saturates to the minimum value, especially if your ESCs were not calibrated.
It seems like drone was in Hold mode, before switching to Position mode, why was that?