Quadcopter unexpectedly rises in Altitude mode (indoors)


It would be very helpful if someone with more experience than me could look into my logs and comment on what can be found there. i did a flight without GPS connected, in altitude mode 2 times, one in smaller indoor space, and one in larger indoor space (just pointing out that the flight location was different).
First flight was ok for my standards. Just took off, hovered a little, while trying to compensate (with the sticks) some imbalance that makes the drone to drift in the front-right direction and landed. Logs can be seen here:

The second flight was not so lucky. While takeoff seemed ok, right after reaching the takeoff altitude (I assume) and hovering for less then a second, the drone flew up with with little to no additional throttle input. It then tangled in the safety net, somewhere at this point I hit the kill switch, after which the drone fell to the ground. Logs can be seen here:

Here is some video footage, if anybody is interested.

To sum up, It would be nice to hear what you think went wrong. In addition any comments on the vibration for example or any other topic are welcome, because I am new to this and cannot tell if the acc graphs look acceptable.

Hi Themaksiest!

I’m not used to fly without GPS and attitude mode, buy I will try to give you ideas that could help you.

1- I think that you drone is to light or your motors-ESC to powerfull. You are taking of with 20% throttle what usually is about 60%. Could be? Furthermore, you are hovering wtih 18% but the in the MPC_THR_HOVER your set-up is that you hover with 50% (this parameter is only for position control modes, not the case).

2- I think that the magnetic field is not stable enought. Check any power wire near to the pixhawk. Downgrading the motors and ESC can help to reduce de curren amount in the wires.

Something strange for me if that the throttle level is not equal in the joystick imput and the actuator controls, and I don’t know why.

The vibrations are acceptable. I have flew with worse ones.

I hope someone else could answer and give more information.