SLAM

The SLAM (Simultaneous Localization and Mapping) is a technique to draw a map by estimating current location in an arbitrary space. Following the steps below, we can use Mini Pupper to draw a map of the surrounding area.

NOTE: Please run the SLAM node on Remote PC. Make sure to launch the Bringup from Mini Pupper before executing any operation.

1. Run SLAM Node

  1. If Bringup is not launched on Mini Pupper, launch Bringup first.

  • Open a terminal with Ctrl+Alt+T to connect Mini Pupper.

  • Look at monitor of Mini Pupper to obtain the IP address of it.

  • Use one of the terminals and run the following command to connect to the Mini Pupper. The default password is mangdang.

ssh ubuntu@{IP_ADDRESS_OF_MINI_PUPPER}

  • Bring up basic packages to start Mini Pupper applications.

. ~/ros2_ws/install/setup.bash
ros2 launch mini_pupper_bringup bringup.launch.py

  1. Open a new terminal from Remote PC with Ctrl + Alt + T and launch the SLAM node.

. ~/ros2_ws/install/setup.bash
ros2 launch mini_pupper_slam slam.launch.py

2. Teleoperation

Following the steps below, we can use teleoperation to explore unknown area of the map.

NOTE: Once SLAM node is successfully up and running. Vigorous change of the linear and angular speed might lower the smoothness of map generated. WARNING: Make sure to run the Bringup from the Mini Pupper before teleoperation. Be careful when testing the robot on the table as the robot might fall during teleoperation.

2.1 Keyboard

  1. Open a terminal with Ctrl+Alt+T on remote PC.

  2. Run teleoperation node using the following command.

. ~/ros2_ws/install/setup.bash
ros2 run teleop_twist_keyboard teleop_twist_keyboard

2.2 Joystick

  1. Open a terminal with Ctrl+Alt+T on remote PC.

  2. Run teleoperation node using the following command.

. ~/ros2_ws/install/setup.bash
ros2 launch teleop_twist_joy teleop-launch.py joy_dev:=/dev/input/{NAME_OF_JOYSTICK}

After teleoperation, a map with unknown area revealed will be shown as followed:

../_images/Map_generation.jpg

3. Save the map

Following the steps below, the files of the map will be saved.

  1. Open a terminal with Ctrl+Alt+T on remote PC.

  2. Use the following command to launch the map_saver_cli node in the nav2_map_server package to create map files.

The map file is saved in the directory where the map_saver_cli node is launched at.

. ~/ros2_ws/install/setup.bash
ros2 run nav2_map_server map_saver_cli -f ~/map

After running the above command, two files will be generated, namely map.pgm and map.yaml.

The following pictures shows the .pgm file to be saved.

../_images/map2.png