I am working on a tail wheel fixed wing drone with Pixhawk Autopilot system.
Every time I turn it ON, the aircraft creates some error in leveling the control surfaces. Mostly it happens with the Elevator. So, when I turn it ON, the aircraft elevator will be slightly up or down. Anyhow it will not be level straight.
Is it necessary to level the aircraft before turning ON the Autopilot? If YES, can you explain the reason behind it?
If you are using Arduplane, in manual mode this should not happend, if in FBWA or FBWB modes it is normal since control surfaces are according to plane attitude.
I am using Pixhawk PX4 with Mission planner software.
This is happening right after connecting the battery. The elevator gets up position most of the times. So, when I get it leveled (pulling tail section up) it starts getting neutral position. That is why I thought it would be necessary to keep aircraft leveled every time before powering it up.
I understand that it should not happen. This is not right in manner. That’s why I am here to take your suggestions.
OK. Thank you for sharing this information. I would still like to get some answers on this. I want to see if someone else has got into such problem or not.
It has happened with me in Manual Mode. That is the reason I said I want to look for more answers. So that I can come to know if someone has come across a similar issue. I have no doubt on @lucamax. I am sorry if I have done anything wrong in saying that.
In MANUAL mode, if you do not move the TX sticks, the aircraft’s control surfaces, such as the elevator, will remain at the trim condition. The trim condition may be zero deflection, OR it may be not-zero deflection. For example, the elevator may be slightly up, it may be slightly down, OR it may be centered.
Above, you said:
In MANUAL mode, physically pitching the aircraft will not affect the elevator’s position. What you seem to be describing is behavior from FBWA, RTL, Auto, or FBWB mode.
So… now you have said:
Can you carefully describe WHAT has happened in Manual Mode that you want help with?
In manual mode servo positions are inherent to radio control , so if you have different position of control surfaces you should check if radio control output remain the same when switched on via Mission Planner’s radio calibration window.
@Harish_Patel How did you trim your control surfaces? Did u just use a standalone receiver to do it or did u do the trimming with the Pixhawk in the loop?
There was no need to apply sub trim to the control surfaces. Regarding trim, I have applied that with Pixhawk ON, while flying - as and when needed for the first time flight.