Starling gone rogue (uncontrollable) in Position flight mode

[muhammadbilal1]

Hi,
I started my ModalAI Starling and took off in "Position" flight mode.
After a few seconds of "Position" flight, the drone gone out of control and started taking altitude.
Fortunately, my roof is high enough. I bring the throttle stick to "0" (bottom) so it doesn't go up and come down but I don't know why but the drone kept going up, I tried to switch the flight mode to "Altitude" from the RC, but that didn't gave me the control and again kept going up and up.

It was an indoor flight (without GPS). I don't see any "invalid position" errors in the messages of log file.

At last I had to "Kill" it from the altitude of almost 14 meters.

Flight Log ==> https://review.px4.io/plot_app?log=6161205d-4982-4e9a-9dc6-5f868f048e38

How this can be fixed?

[muhammadbilal1]

@Moderator @Alex-Kushleyev Please help me, I am not sure how to make this thing stable.
I bought this drone by spending thousands of dollar, but I am not getting even very basic stable flight.

[muhammadbilal1]

@Moderator Your early response about the fix will be appreciated.

[Eric Katzfey]

@muhammadbilal1 The log shows that it was in position for the first half of the flight, switched into altitude mode for a short period, and then went back into position mode for the rest of the flight before the kill switch was engaged. I would do a complete flight in manual mode and verify that everything feels normal with that. Then I would try a complete flight in altitude mode and verify that everything works fine with that. Finally, if everything feels fine with manual and altitude modes try a flight with position mode. It's likely that you experienced a VIO "blowup" where VIO quality went to zero. Can you change the SDLOG_PROFILE parameter to 129 for your next position mode test? This will provide more information related to VIO input. Also, review our VIO debug tips here: https://docs.modalai.com/flying-with-vio/

[Shane Goodwin]

I am having the same problem with mine. One other thing I noticed is that the VOA point cloud in the portal seems to not be correctly oriented (I believe it's down and rotated). Once I fix this I plan to conduct more test flights - but with QGC open, when the Starling did as you describe, QGC announced that it had switched to Altitude mode. It apparently did this on its own because I had it just hovering in place in Position flight mode.

[Eric Katzfey]

@Shane-Goodwin Yes, then I would say follow the same guidance. VIO can fail. If it does, PX4 will drop back into altitude hold mode on it's own. The link to the troubleshooting guide explains common reasons why VIO can fail.

[Eric Katzfey]

@Shane-Goodwin But it's critical to start with the basics and make sure everything is solid before doing anything more complex. Always start with manual mode and verify that things look good. Then go to altitude hold mode and see if that is okay. Then move on to position mode. Finally add in VOA. Just go step by step to try help isolate where there may be issues.

[muhammadbilal1]

@Eric-Katzfey
Hi,
The first change of flight mode to "Altitude" was because of the loss of control of pilot (see it from the "Manual Control Output") on the drone.
This wasn't happened first time, I experienced the same before this flight too.

The steps you provided aren't suitable, I can't do the flights like "Manual" and then verify everything everytime, this is a random behavior, even if I try in the manual mode and get a good flight, I can still experience the bad flight afterwards.

When I get the bad VIO data, I get the message of "invalid setpoints" in the log and over the QGC too and the drone goes into the "altitude" mode.

But, the problem I shared here is the loss of control over the drone, drone kept going upwards and even pulling the throttle to "0" isn't bring the drone to ground.

You can clearly see, even in the altitude flight mode (2nd time), the drone still kept going upwards at "0" throttle.

Please get us a fix for this.