Path planning with FW Offboard

PX4 Autopilot Fixed Wing 🛩️
1

Hi,
I want to implement a path tracking with VTOL FW mode in offboard mode I have a set of 350 Local points(x,y,z) that describe the path and I want to pass it to the autopilot to track the smooth path.

I tried offboard Setpoint with MAVSDK in SITL but from the observed behavior I think that a position set point for FW would mean a loiter point not as a way point to go through (similar to in mission mode).

  1. I want to make sure if I understand this in the right way as If I want to implement the whole path I’d need a feedback from telemetry to transit to the next way point assuming that it will be applicable.

  2. From my searching I couldn’t find resources for implementing a smooth obstacle avoidance path with FW in a simulation … All what I could find simulated is simple orbits. I’m not sure how the L1 Path follower controller really work ( I’m not expert in control at all ), but will it be actually able to follow a smooth trajectory like the one in the image or should I try to implement an external path following controller and send attitude set points to PX4. Is there any specific controller recommended?

I would really appreciate your advice on this issue as I think it’s somehow unimplemented before and it would be extremely exciting to get it done.

Screenshot from 2020-05-11 12-42-14
Screenshot from 2020-05-11 12-42-14508×528 400 KB

2 Likes
2

That would involve actually either sending attitude (e.g. roll / pitch / yaw) setpoint or so.

As you said, the native position control doesn’t treat waypoints, as fixed wing vehicles can’t take waypoints as a target (which is feasible for multirotors, as they can *stop on that waypoint), but should rather be given a path (as it always has to fly *somewhere, in the direction of the path).

This is how it is done in this project for example:

@Jaeyoung-Lim is the FW path following done via attitude setpoint?

3

Relevant thread message in discord, if you are interested: Discord