I have made a gazebo model for my costume UAV, and I when I run SITL, it shows up in gazebo. My next step is to modify the control so it can fly autonomously in simulation. I have modified the number of control channels in mavlink plugin in gazebo, but I have no idea how to start on the firmware end to output corresponding control command. I am currently looking through the src/modules/mavlink folder to see how the firmware sends and receives messages from gazebo, but have not gained any insights yet.
Can someone help me figure out how the firmware sends and receives messages from gazebo, and also is the mixer file the only file I need to change for control output since the output from att_control can be scaled and offset through mixer file?