Low setpoint message frequency

[mhl787156]

For the drone to stay in offboard mode, setpoint messages must be sent at least 2hz. Currently when more than one vehicle is on the network, the setpoint frequency can drop below 2hz. Dropping below 2hz causes the autopilot on the vehicle to drop into failsafe mode (by default land). However because the drop is inconsistent, it can often recover half-way to landing causing a rather unsafe yo-yo effect.

With > 2 drones, they do not even get off the floor.

The sending of setpoint messages must be dependent of some external factor. This is odd as setpoint messages should only be transmitted between nodes on the same companion computer.

[mhl787156]

This may be relevant: https://discourse.ros.org/t/reducing-ros-2-cpu-overhead-by-simplifying-the-ros-2-layers/13808

[mhl787156]

Utilising onboard IPC may also be relevant: https://answers.ros.org/question/389596/ros2-docker-and-ipc/, and this example: https://github.com/ruffsl/ros2_docker_demos/blob/master/sros2/docker-compose.yml

As we are currently using UDP communication for all comms (including IPC on the same machine) it may be that the UDP connection is bottlenecking causing many packets to be dropped randomly, hence causing the drops in receive rate.