I am using PX4 to control a new custom fixed wing airframe. I’d like to create a Gazebo model that more closely matches the dynamics of my plane. In looking in the directory of Gazebo models, I see that there are two fixed wing models: rc_cessna and advanced_plane. I’m trying to better understand the assumptions made for each of these models so that I can make my own. I’m not sure if I should try to mimic the simpler rc_cessna model, or if I need to mimic the advanced_plane model for my plane, but I have some questions about each of them.
For the rc_cessna model, I see that there are lift-drag plugins for each of the control surfaces (e.g. PX4-gazebo-models/models/rc_cessna/model.sdf at fe3fe236e36a3ed5bce01a7501347d20a466c407 · PX4/PX4-gazebo-models · GitHub ). However, I am a little confused because I don’t see a separate plugin for the wing and for the elevon. Is the entire wing represented as a movable elevon, i.e. L764 is a wing that moves based on the servo joint? I also am trying to understand the parameters of this section. The “area” tag for the plugin is 0.6. However, when I look at the collision box for the overall wings in the model, it is 0.1 x 1.0, i.e. 0.1 m^2. I would therefore expect the surface area of each of the two wings to be ~0.05 m^2, not 0.6 m^2. Next, I see that there is another control surface on each side attached to the flap joints that appears to be identical, i.e. PX4-gazebo-models/models/rc_cessna/model.sdf at fe3fe236e36a3ed5bce01a7501347d20a466c407 · PX4/PX4-gazebo-models · GitHub matched the plugin defined in L764. Finally, I don’t see any lift-drag model plugin for the fuselage. Is that not modeled?
For the advanced plane model, I read the documentation on running AVL ( Advanced Lift Drag (AVL) Automation Tool | PX4 Guide (main) ), and I am working on putting together a model of my plane to use for this. The one question that I had is whether the example input file (i.e. PX4-gazebo-models/tools/avl_automation/input.yml at fe3fe236e36a3ed5bce01a7501347d20a466c407 · PX4/PX4-gazebo-models · GitHub ) for the AVL tool matches the advanced_plane model PX4-gazebo-models/models/advanced_plane/model.sdf at fe3fe236e36a3ed5bce01a7501347d20a466c407 · PX4/PX4-gazebo-models · GitHub . If not, is the input file used for generating that model checked into the repo anywhere? I think that it would be helpful as a reference so that I can double check that I am going through the AVL process correctly before I create my own model (i.e. have a known good input and output).
If there is any existing documentation / discussion around these models that I could read, I’d appreciate some links to them, or any other help / pointers that folks can provide.