I recently setup a ~400mm quad with a Pixhawk and 3DR external compass/GPS. Using all default values the quad flies pretty well, but I wanted to test out AutoTune to see how well it works. I noticed the AutoTune settings make the quad feel very twitchy, and unstable. When I went to land the quad immediately flipped over and despite throttle at full down, the motors continued to spin upside down, breaking props.
I thought possibly the AutoTune procedure didn't work properly, so I installed new props, restored PID values to default and tried again. After disarming and saving the new tune, and trying a flight with the new tune, again the quad flipped over in the same manner as before on landing, and again despite throttle down, the motors continued to spin.
I'm not sure what's causing this behavior, but I'm uploading the logs in hopes someone here has seen this problem before and knows how to resolve it. Please let me know if any additional information would be helpful.
Replies
I can fix my problem. I set the timing from medium to high on my hobbywing quattro 4in1 25A esc, and now after autotune the copter fly well :)
I have the same problem. Exactly the same. Is there a solution or at least a reason why is this happens? My first tought was that the motor-frame config is the problem 500mm carbon frame 3508 700kv motor, 11*47 props, maybe 600mm frame would be better. I think this because the autotune proces was very scareing in the first period, almost flip in the air, but till the end it becomes very good. With default values it is stable enough, and flys well, after autotune ends it flys great, but after landing, disarm, and restore the values, if i try to take off again with the new values it is sure it is starting to dance and flips in a moment. I only make it with the roll not tried all axes, because one pit is more than 10 minutes, 2.4.8 pixhawk 3.3.3 firmware. Thanks for any halp in advance! Roland
The frame is very stiff, and the Pixhawk is mounted using the self adhesive foam. I'm running V3.1.4 of firmware.