Simulation

3D simulation with Gazebo

Introduction to Gazebo world environments

PAL’s robots can be simulated with the Gazebo simulator, that offers a realistic 3D environment for simulating and testing our robots. It is integrated with ROS 2 providing features like accurate physics simulation, sensors emulation and customizable environments.

Several different world environments are provided with PAL’s robots:

• Empty world is loaded as default when the simulation is launched. The robot spawns in an empty world with no objects, as shown in Figure: Empty world simulated in Gazebo. In order to launch the simulation, the following instruction needs to be executed in a terminal:

  source /opt/pal/${PAL_DISTRO}/setup.bash
  ros2 launch robot_name_gazebo robot_name_gazebo.launch.py
  

  

  Figure: Empty world simulated in Gazebo

• Office world is a simple office world as shown in Figure: Small office world simulated in Gazebo can be launched with the following instruction:

  source /opt/pal/${PAL_DISTRO}/setup.bash
  ros2 launch robot_name_gazebo robot_name_gazebo.launch.py world_name:=small_office
  

  

  Figure: Small office world simulated in Gazebo

• PAL Gazebo worlds custom worlds are created by PAL Robotics and are also available in the humble distro or can be found at the following link: https://github.com/pal-robotics/pal_gazebo_worlds

PAL robots simulation

TIAGo ProKangarooTIAGoTIAGo++ARITALOSTRIAGo

To start TIAGo Pro using the Gazebo simulation, start your PAL developer Docker image and run the following command:

source /opt/pal/${PAL_DISTRO}/setup.bash
ros2 launch tiago_pro_gazebo tiago_pro_gazebo.launch.py

Figure: TIAGo Pro robot simulated in Gazebo

Autonomous Navigation simulation

To start the 🧭 Navigation functionalities along with the Gazebo simulation, the following command can be used:

source /opt/pal/${PAL_DISTRO}/setup.bash
ros2 launch <robot>_gazebo <robot>_gazebo.launch.py navigation:=True

Attention

Make sure to replace the <robot> placeholder with the name of your robot (e.g. tiago, omni_base, tiago_pro, etc.).

This starts the Autonomos Navigation along with the 📍 Localization and Rviz to interact with the robot. While in localization mode, the robot will use a map of the environment to localize itself and navigate autonomously. The pal_maps package offers several maps corresponding to the world environment loaded in Gazebo.

For example, to Navigate and Localize in the small_office world, it is enough to use the command:

source /opt/pal/${PAL_DISTRO}/setup.bash
ros2 launch <robot>_gazebo <robot>_gazebo.launch.py navigation:=True world_name:=small_office

And then change the current map with the command

ros2 service call /map_server/load_map nav2_msgs/srv/LoadMap "map_url: '<PAL_MAPS_DIR>/maps/small/office/map.yaml'"

Attention

Make sure to replace the <PAL_MAPS_DIR> placeholder with the full directory where you cloned ot installed the pal_maps package.

And the Localization will use the small_office map.

Otherwise, if you want to start the Autonomous Navigation with the 🗺️ Mapping to create a new map of a simulated environment, you can use the following command:

source /opt/pal/${PAL_DISTRO}/setup.bash
ros2 launch <robot>_gazebo <robot>_gazebo.launch.py navigation:=True slam:=True

Interaction simulation with PAL’s Interaction Simulator

See PAL Interaction simulator for more information.