VTOL DELTA QUAD problem at position mode


I am new with px4. Currently I am developing my VTOL based on skywalker X8 frame. My delta quad VTOL in copter at position mode very aggressive and at pitch/roll command it start shaking (e.g. oscillates at pitch axis if pilot injects pich command and the same with roll) and when it starts do pitch (somehow) the vector not pointed straight a head, but in stabilize and altitude modes it flies very well as a copter. I did the calibration as described in pixhawk documentation, have updated the firmware today, I have lowered to minimum the roll, pitch and position control sensitivities, have changed the gps/compass module.
Please advise. what i did wrong?


It sounds like a matter of tuning your PID’s
Are you using the standard parameters for generic quad delta airframe?


Thanks for quick replay.

Yes, I am using the standard parameters for generic quad delta airframe, just a little bit increased the P gain of YAW in section MC.

I have tried to tune some, but seems the standard parameters are the best.


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I’m facing the same problem with x6 frame
Very aggressive oscillations and uncontrolled yaw in whichever direction the correction is applied…
Used quad firmware and everything was smooth…

im also trying to setup a skywalker X6 VTOL.
i did some vtol flights as well but in every flight the plane did good in Qhover mode but in fbwa it nosedives randomly.
i then removed the quad motors and disabled Q_enable just to make sure it works well in fbwa.
i did some more test flights and it again randomly nosedives rolling…

what can be the problem?
if your setup works well can you send me the parameters that worked for you/


Hi Basit,

It seems like you ware using APM and not PX4.
This discussion forum only deals with PX4.

Please refer to the APM forums or give PX4 a try, that supports delta vtol’s out of the box.