VTOL "Turns" while transitioning after updating from 1.15.4 to 1.16

PX4 Autopilot
1

Exactly as title says. I’m flying 4 lift + 1 cruise standard VTOL (with single channel aileron and elevator, and no rudder) and after updating the firmware from 1.15.4 to 1.16, the aircraft started to behave strangely.

Whenever I transition from MC to FW, the aircraft would both roll and yaw right during the transition, which has never happened in 1.15.4. reverting the firmware back seemingly solved the issue. In between the update, I didn’t touch any parameter values that might affect fixed wing flight AFAIK.

I’m guessing if I get fixed wing tuned just right, the issue would disappear anyway, but I’m wondering if anyone else has experienced the same issue after the update and if so, has managed to solve it.

2

Let me mention @sfuhrer and could you provide a log where this happens (and maybe one where it does not as well), upload it to logs.px4.io and link it here?

3

Sure, it happened to two separate airframes too. Sorry I couldn’t upload more 1.16 logs with proper flights but I simply don’t have any. The issue happens just as I hit the transition switch so I hope it’s sufficient.

Also for some of these flights, I’ve changed some multirotor, fixed wing tuning values.

Standard VTOL with A tail

1.15.x

(mission mode)

https://review.px4.io/3d?log=8495b414-817e-4c87-8bcc-9f79386c8d1a

1.16

(position mode)

(mission mode attempt)

sorry I just removed the link b/c new user can only post 5 links in a post

Standard VTOL with single channel aileron and elevator

1.15.x

(position mode)

1.16

for some of these fligts below, the turn felt way too slow so I had to quickly transition back

(position mode)

fyi, I’m using clockwise rotating propeller for my 1 fixed wing motor (APC 14*10 P IIRC).

The wind wasn’t too strong on the ground afaik, but can’t really tell for sure. well it didn’t have any trouble aligning to the direction in multirotor mode, and the weird turn happens right after I hit the transition switch.

Thanks for your time

4

Yeah, I’ve seen something similar after moving to 1.16. The transition logic changed a bit, so roll/yaw coupling can show up if the FW isn’t re-tuned. Going back to 1.15 fixes it, but with some tuning on the FW side (ailerons/elevator and transition params) it should fly fine on 1.16. Worth checking the release notes too.