Duckiedrone Takeoff Demo (ROS2)#

This chapter describes the Takeoff demo (demonstration) for Duckiedrones using ROS2.

What you will need

  • A virtual Duckiedrone.

  • ROS2 stack installed and configured.

  • MAVROS2 interface properly set up.

What you will get

A Duckiedrone successfully arming and taking off autonomously.

Introduction to Duckiedrone takeoff#

Setup#

To set up the demo:

  1. Create a virtual Duckiedrone:

    dts duckiebot virtual create -t duckiedrone -c DD24 ROBOT_NAME

  2. Once the creation is complete, start it:

    dts duckiebot virtual start ROBOT_NAME

  3. Start the ROS2 stack on the drone:

    dts stack up -d -H ROBOT_NAME ros2/duckiedrone

  4. Start the matrix with the sandbox_drone map:

    dts matrix run --standalone -d --map sandbox_drone

  5. Attach the Duckiedrone to the matrix engine:

    dts matrix attach ROBOT_NAME map_0/vehicle_1

Note

Wait for all containers to be running before proceeding to the next step.

Start#

The code for the demo can be found in the dt-ros2-interface repository.

To clone the dt-ros2-interface repository, run:

git clone [email protected]:duckietown/dt-ros2-interface.git --branch ente

To build the dt-ros2-interface image on your Duckiedrone, run the following command from the newly created dt-ros2-interface directory:

dts devel build -H ROBOT_NAME

To run the demo on your Duckiedrone, run the following command from the newly created dt-ros2-interface directory:

dts devel run -H ROBOT_NAME -c bash -- -e ROS_DOMAIN_ID=42

Inside the bash prompt that appears:

  1. Set the drone to takeoff mode:

    ros2 service call /mavros/set_mode mavros_msgs/srv/SetMode "{base_mode: 0, custom_mode: 'AUTO.TAKEOFF'}"

    Expected output:

    response:
mavros_msgs.srv.SetMode_Response(mode_sent=True)

  2. Arm the drone to initiate takeoff:

    ros2 service call /mavros/cmd/arming mavros_msgs/srv/CommandBool "{value: true}"

    Expected output:

    requester: making request: mavros_msgs.srv.CommandBool_Request(value=True)
response:
mavros_msgs.srv.CommandBool_Response(success=True, result=0)

Your Duckiedrone should now arm and begin its takeoff sequence to a default height of 2.5m.

Stop#

To stop the demo:

  1. Land the drone by setting the drone into land mode:

    ros2 service call /mavros/set_mode mavros_msgs/srv/SetMode "{base_mode: 0, custom_mode: 'AUTO.LAND'}"

  2. Select the terminal from which the demo was run.

  3. Press Ctrl+D.

How it works#

The Takeoff demo consists of the following steps:

  1. MAVROS interface establishes communication between ROS2 and the PX4 flight controller via the MAVLink protocol.

  2. Mode setting configures the flight controller to AUTO.TAKEOFF mode, which prepares the drone for autonomous takeoff.

  3. Arming enables the motors, allowing the drone to generate thrust.

  4. Takeoff execution uses the flight controller’s autopilot to execute a controlled vertical ascent to a predefined altitude.

The MAVROS node acts as a bridge, translating ROS2 service calls and topic publications into MAVLink messages that the flight controller understands, and vice versa.

Debugging and parameter tuning#

If the performance of your Duckiedrone is inconsistent or the takeoff does not execute properly, consider the following debugging steps.

Verifying MAVROS connection#

Check that MAVROS is properly connected to the flight controller:

ros2 topic echo /mavros/state

You should see output indicating that the flight controller is connected and the mode is being reported.

Checking sensor data#

Verify that sensor data is being published:

ros2 topic list

Look for topics such as /mavros/imu/data, /mavros/battery, and /mavros/altitude and echo them to verify data flow.

Troubleshooting#

Troubleshooting

SYMPTOM

The drone does not arm.

RESOLUTION

Verify that the flight controller is in a safe state and that all pre-arm checks have passed. Check the /mavros/state topic to ensure the mode is set correctly.

Troubleshooting

SYMPTOM

MAVROS cannot connect to the flight controller.

RESOLUTION

Restart the virtual Duckiedrone using dts duckiebot virtual restart ROBOT_NAME.

Troubleshooting

SYMPTOM

The drone arms but does not take off.

RESOLUTION

Verify that the takeoff mode was set correctly before arming. Some flight controllers require the mode to be set before arming.

Troubleshooting

SYMPTOM

Service calls return errors.

RESOLUTION

Ensure that the ROS_DOMAIN_ID is set correctly (42) and that all containers in the ROS2 stack are running. Use docker ps or portainer (accessible through the dashboard or at ROBOT_NAME.local:9000) to verify container status.