Px4 1.8.0 random glitches while flying (dangerous!)

Hi all,

i’m testing the 1.8.0 release with the Pixhawk 2.1 “cube”. My radios are Taranis (opentx 2.2.1) binded to an X8R with LBT FW.
I’m encountering a very strange beaviour: First days of flights, everything worked perfect. From one day to another, while in air it shows heavy glitches, in random directions, at point that it’s difficult to put back to ground (in every flight mode, i use Stabilized, Alt Hold and Position). It’s my second setup with same hardware and also the other one showed same, after some days. Then, back to normal for some flights (days after). I changed the FC in the old one, thinking the FC had faulty hardware. Now i think there’s something wrong not HW related.
Any suggestion?

downloading logs right now

Without logs or knowing all the components you have installed on your vehicle, then I can only suggest using a spectrum analyzers to make sure your frequencies are not being disrupted.

thanks AI_B for the answer.

I think i’m figuring out what’s the problem, and it’s going to be a OpenTX/FrSky RF FW issue with the “trainer” function enabled. I’m digging into it. As soon as i get it repeteable, i’ll do some updates or open an issue in the Git.

Hey @Steve_79 did you figure out what the problem was? Looking forward to your updates.

until now, all i can say is that if i enable trainer function on the taranis (opentx 2.2.0) even if there’s no cable connected to the dsc port, glitches come out. they go if i disable trainer function. i never had such issue with same tx and sw with other FCs i used before. as soon as i get some time to dig it, i will post logs etc

I have this issue as well. I send TAKEOFF command (using MAVLink command), and it will fly off in a different direction instead of merely up. But it does this seemingly randomly. When it does, I cannot get control with the various modes and many times need to use the kill switch to crash it. Maybe I will go back to 1.7X and see if it goes away. I don’t have any Trainer mode enabled on anything (Taranis controller)

do you send the actual lat/lon values?

other guess. two years ago there was a bug which flew the drone everytime you used the mavros command in direction von lon = 0 and lat = 0 --> somewhere in africa. you had no control until it crashed.

We send MAVLink TAKEOFF command, and there are no parameters. It takes off to the altitude that is set in PX4 paramters (2 meters). This take off position is the Home Position, set when it is Armed.