Usage Guide

This section provides instructions on how to use the simulation and control the real drone.

Building the Repository

To compile the repository:

colcon build --packages-select x4_description x4_bringup x4_interface x4_gazebo x4_vision x4_service_scripts

Launching the Simulation

To launch the Gazebo simulation with ArduPilot support:

ros2 launch x4_bringup x4_startup.launch.py

This command starts Gazebo and ArduPilot with SITL and a MAVROS bridge for ROS 2 commands. It also launches a MAVProxy terminal for communication. This launch file has two parameters: use_sim which defaults to true and use_real which defaults to false. For running the code on real hardware, make sure to flip these launch parameters.

ros2 launch x4_bringup x4_startup.launch.py use_sim:=false use_real:=true

Gazebo will not launch when usng real hardware.

Controlling the Drone

MAVROS Commands

In a new terminal:

Arm Throttle: ros2 service call /mavros/cmd/arming mavros_msgs/srv/CommandBool "{value: true}"
Set Mode: ros2 service call /mavros/set_mode mavros_msgs/srv/SetMode "{base_mode: 0, custom_mode: 'GUIDED'}"
Takeoff: ros2 service call /mavros/cmd/takeoff mavros_msgs/srv/CommandTOL "{min_pitch: 0.0, yaw: 0.0, latitude: 0.0, longitude: 0.0, altitude: 3.0}"
Land: ros2 service call /mavros/cmd/land mavros_msgs/srv/CommandTOL "{min_pitch: 0.0, yaw: 0.0, latitude: 0.0, longitude: 0.0, altitude: 0.0}"
Local Waypoint (Relative to Home): ros2 topic pub /mavros/setpoint_position/local geometry_msgs/msg/PoseStamped "{header: {frame_id: 'map'}, pose: {position: {x: 5.0, y: 5.0, z: 3.0}, orientation: {w: 1.0}}}"

These are just some examples but full documentation can be found here.

MAVProxy Commands:

In the MAVProxy terminal:

mode guided
arm throttle
takeoff 5
velocity x y z
mode land

ROS 2 DDS Commands:

NOTE: Not active by default. You can find methods to use this in the ardupilot.launch.py file and the x4_service_scripts package.

In a new terminal:

ros2 service call /ap/mode_switch ardupilot_msgs/srv/ModeSwitch "{mode: 4}"
ros2 service call /ap/arm_motors ardupilot_msgs/srv/ArmMotors "{arm: true}"
ros2 service call /ap/experimental/takeoff ardupilot_msgs/srv/Takeoff "{alt: 4}"

Available Topics

Some relevant DDS topics:

ros2 topic echo ap/imu/experimental/data
ros2 topic echo ap/pose/filtered