I'm preparing China aero design challenge competition .we have designed a fixedwing.and when work with the pixhawk we met several questions.
1.when we move the aireron the rudder will move with the aireron.how to disconnected the aileron and rudder
2.in manual mode and stabilize mode we just use 30% of elevator servo movement range.so we set channel 2 to 30% on our transmitter.but after radio calibration on mission planner .in fbwa mode we pull the elevator stick full downthe elevator servo still can move to 100%
So I used a stereo camera, a TX2 on top of Pixhawk to achieve fully autonomous drone flight and collision avoidance.
In case someone is also interested, here is how I have done it:https://github.com/generalized-intelligence/GAAS/tree/master/demo/tutorial_1