4. Keyboard Control and Autonomous Flight

Using this stack and espdrone-ros, the ESP-drone is able to:

• Use keyboard control in an assisted flight
• Fly autonomously following preprogrammed waypoints

The ArUco positioning system is required for both autonomous flight and keyboard control. Hence, the drone must be able to see at least 2 markers at a time throughout the entire flight, otherwise it will drift and crash.

Using Keyboard Control

This is not a "fully manual" control; the keyboard tells the drone which direction to go instead of controlling attitude and motor power, and the drone automatically stabilizes itself. You can think of this as autopilot, and the keyboard simply tells the autopilot where the drone should go.

Keyboard control is enabled by launching the drone with the -k or --keyboard flag after launch_espdrone_aruco as demonstrated in 3. Usage, e.g.:

launch_espdrone_aruco -d espdrone1 espdrone2 -e iot_lab -k

You can follow the instruction printed on the terminal screen for which keys are used.

Flying Autonomously

You have to specify the waypoints that the drone should follow before launching the drone in an autonomous flight. The waypoints are described in the drone configuration YAML file by the waypoints_list key. For instance:

drone_ip_addr   : "192.168.0.112"
camera_info_file: "espdrone1_640x480.yaml"
visualize_output: "true"
waypoints_list  : [[0.0, 0.0, 0.5, 0, 5.0], [1.0, 1.0, 0.5, 90, 5.0]]

Each waypoint is a list with the format [x, y, z, yaw, hover_time] in meters for x, y, z, degrees for yaw or orientation, and seconds for hover_time.

To fly the drone autonomously following the described waypoints, launch the drone using launch_espdrone_aruco with the -k or --keyboard flag, then press m to initiate autonomous flight.

During the flight, you can pause or resume the mission by pressing SPACE. When paused, you can control the drone manually using keyboard (assisted flight).

Using waypoint_recorder

Although you can manually input waypoints_list to the drone configuration file, you can use waypoint_recorder utility provided by the espdrone-ros ROS package. This utility records the position of the drone and automatically adds or updates waypoints_list inside the configuration file. To use the utility:

1. Launch the drone that you would like to record waypoints for.

   launch_espdrone_aruco -d espdrone_name -e env_name

2. Launch the waypoint_recorder utility, specifying the name of the drone.

   roslaunch espdrone_utils waypoint_recorder.launch drone_name:=replace_this_with_drone_name

   A new terminal should then appear, prompting you the duration of hover for each waypoint. Enter the desired hover time (in seconds). You can change this value later by pressing d.
3. You can now bring the drone by hand to the desired location and orientation, keeping at least 2 ArUco markers visible. Press SPACE to record that position and orientation as a waypoint. You can record as many waypoints as you like.
4. When you are done, press ENTER to save the recorded waypoints to the drone configuration file. No need for catkin build.
5. Finally, restart ROS so that the drone will follow the new waypoints.