Change mode from companion computer

PX4 Autopilot
1

Hi everyone,

i was looking at the offboard_control example for px4-ROS2. In order to switch to Offboard mode the following instruction is used:

this->publish_vehicle_command(VehicleCommand::VEHICLE_CMD_DO_SET_MODE, 1, 6);

Now i’m struggling on how i can switch back to some mode, for example to HOLD_MODE in order to let the vehicle hovering after finishing the operation in offboard. In the VehicleCommand.msg i’ve read that the numeration follows the ENUM MAV_MODE but i don’t where to find this information.

Any help is appreciated,
Thanks.

2

Make sure you are sending the right spelling for each mode, see the below link for the standard naming

http://docs.ros.org/en/api/mavros_msgs/html/msg/State.html

for example if you are using the mavros services to switch to mission mode

rosservice call /robot0/mavros/set_mode "base_mode: 0
custom_mode: 'AUTO.MISSION'"
3

I have developed a ROS2 node using MAVSDK to expose the basics of PX4 to do velocity based control from ROS2. Have a look at my code: https://github.com/slaghuis/drone_mavsdk

This node publishes a simple service to switch offboard mode. Depending on a parameter 1 or 0 the mode is either enabled or disabled. Look at linse 498-526.

I have never used PX4 ROS2 but will check it out.

Eric

4

Hi, Sorry for my second reply.

I now see what you mean. You are using Fast RTPS communication with PX4. Here is an example ROS1 node for that. Amongst other things, it does publish a service that you can call to switch to off board mode. Maybe this can help you.