S253809: /* Typical Usage */

2026-05-28T08:15:10Z

Typical Usage

← Older revision		Revision as of 10:15, 28 May 2026
Line 86:		Line 86:

	Basic simulator launch:		Basic simulator launch:


	ros2 launch fejemis_sim sim.launch.py		ros2 launch fejemis_sim sim.launch.py


	Use a different world:		Use a different world:


	ros2 launch fejemis_sim sim.launch.py world:=fejemis_sim::worlds/empty.world		ros2 launch fejemis_sim sim.launch.py world:=fejemis_sim::worlds/empty.world

	Disable the rover-command adapter and publish Twist directly:		Disable the rover-command adapter and publish Twist directly:
			ros2 launch fejemis_sim sim.launch.py rover_cmd_adapter:=False
	~~```bash~~
	ros2 launch fejemis_sim sim.launch.py rover_cmd_adapter:=False
	~~```~~

	Example RoverCommand input:		Example RoverCommand input:
			ros2 topic pub /fejemis/cmd_vel raubase_core/msg/RoverCommand "{source: 2, linear_vel: 0.2, turn_rate: 0.0}"
	~~```bash~~
	ros2 topic pub /fejemis/cmd_vel raubase_core/msg/RoverCommand "{source: 2, linear_vel: 0.2, turn_rate: 0.0}"
	~~```~~

	== Integration With The Rest Of The Stack ==		== Integration With The Rest Of The Stack ==

S253809: /* Typical Usage */

2026-05-28T08:14:29Z

Typical Usage

← Older revision		Revision as of 10:14, 28 May 2026
Line 87:		Line 87:
	Basic simulator launch:		Basic simulator launch:

	~~```bash~~
	ros2 launch fejemis_sim sim.launch.py		ros2 launch fejemis_sim sim.launch.py
	~~```~~

	Use a different world:		Use a different world:

	~~```bash~~
	ros2 launch fejemis_sim sim.launch.py world:=fejemis_sim::worlds/empty.world		ros2 launch fejemis_sim sim.launch.py world:=fejemis_sim::worlds/empty.world
	~~```~~

	Disable the rover-command adapter and publish Twist directly:		Disable the rover-command adapter and publish Twist directly:

S253809: Created page with "Back to Fejemis ROS2 Software == Purpose == ''fejemis_sim'' contains the Gazebo Sim bringup for Fejemis. It provides the world files, model assets, ROS-GZ bridge configuration, and launch file used to spawn the robot in simulation with the same control interface as the real robot. The package is used to: * Load a selectable Gazebo world for development and testing. * Publish the robot description from ''fejemis_description'' and spawn the model in Gazebo. * Bridg..."

2026-05-28T08:13:54Z

Created page with "Back to Fejemis ROS2 Software == Purpose == ''fejemis_sim'' contains the Gazebo Sim bringup for Fejemis. It provides the world files, model assets, ROS-GZ bridge configuration, and launch file used to spawn the robot in simulation with the same control interface as the real robot. The package is used to: * Load a selectable Gazebo world for development and testing. * Publish the robot description from ''fejemis_description'' and spawn the model in Gazebo. * Bridg..."

New page

Back to [[Fejemis ROS2 Software]]

== Purpose ==

''fejemis_sim'' contains the Gazebo Sim bringup for Fejemis. It provides the world files, model assets, ROS-GZ bridge configuration, and launch file used to spawn the robot in simulation with the same control interface as the real robot.

The package is used to:

* Load a selectable Gazebo world for development and testing.
* Publish the robot description from ''fejemis_description'' and spawn the model in Gazebo.
* Bridge robot state, sensors, and commands between ROS 2 and Gazebo.
* Optionally convert ''RoverCommand'' messages into Gazebo ''Twist'' commands so simulation matches the real control path.

== Package Layout ==

Important package folders:

* ''launch'' - simulation bringup entry point.
* ''config'' - Gazebo GUI configuration, bridge mappings, and RViz configuration.
* ''models'' - xacro fragments used to assemble Gazebo world templates.
* ''worlds'' - ready-made Gazebo worlds such as ''room.world'', ''empty.world'', and ''dynamic.world''.

== Main Launch File ==

The package is centered around ''launch/sim.launch.py''.

Launch sequence:

* Includes ''fejemis_description::launch/model.launch.py'' with ''use_sim_time=true'' so the robot description is available before spawning.
* Starts ''ros_gz_sim::launch/gz_sim.launch.py'' with the selected world file and ''config/gazebo.config'' GUI settings.
* Spawns the robot in Gazebo with ''ros_gz_sim/create'' using ''/robot_description'' and the Gazebo model name ''fejemis''.
* Starts ''ros_gz_bridge/parameter_bridge'' in the ''fejemis'' namespace using ''config/gz_bridge.yaml''.
* Optionally starts ''raubase_core/rover_2_twist'' when the rover-command adapter is enabled.

Launch arguments:

* ''world'' - selects the world to load. Default: ''fejemis_sim::worlds/room.world''.
* ''rover_cmd_adapter'' - enables the RoverCommand-to-Twist adapter. Default: ''True''.
* ''rviz'' - declared for launch consistency and GUI workflows.

== World Files ==

The default world is ''fejemis_sim::worlds/room.world'', which assembles the standard world template with the Fejemis simulation models.

Available world files:

* ''worlds/room.world'' - the main indoor test room used by the simulator.
* ''worlds/empty.world'' - a minimal empty world for lightweight testing.
* ''worlds/dynamic.world'' - a more active world variant for motion and interaction testing.

The world templates are built from the xacro fragments in ''models/worlds''.

== Gazebo Bridge ==

The bridge configuration in ''config/gz_bridge.yaml'' maps the robot command, state, and sensor topics between ROS 2 and Gazebo.

Bridged topics:

* ''/fejemis/cmd_vel_twist'' to ''/model/fejemis/cmd_vel'' - command input from ROS to Gazebo.
* ''/clock'' - simulation time from Gazebo to ROS.
* ''/joint_states'' to ''/world/demo/model/fejemis/joint_state'' - joint state feedback.
* ''/fejemis/odom'' to ''/model/fejemis/odom'' - simulated odometry.
* ''/fejemis/imu'' to ''/model/fejemis/imu'' - IMU output.
* ''/fejemis/mag'' to ''/model/fejemis/mag'' - magnetometer output.
* ''/fejemis/scan'' to ''/model/fejemis/scan'' - LiDAR scan.
* ''/fejemis/image_raw'' to ''/model/fejemis/image_raw'' - camera image stream.
* ''/fejemis/camera_info'' to ''/model/fejemis/camera_info'' - camera calibration data.

This bridge lets the simulator exercise the same downstream ROS 2 stack that runs on the real robot.

== Robot Control Path ==

By default, the simulator expects rover commands on ''/fejemis/cmd_vel'' in the ''raubase_core/msg/RoverCommand'' format. When ''rover_cmd_adapter'' is enabled, ''raubase_core/rover_2_twist'' converts that into ''geometry_msgs/Twist'' on ''/fejemis/cmd_vel_twist'', which is then forwarded to Gazebo.

This keeps the simulation control interface aligned with the real Fejemis command pipeline.

If the adapter is disabled, you can publish ''geometry_msgs/Twist'' directly to ''/fejemis/cmd_vel_twist''.

== Visualisation ==

The package also ships an RViz configuration in ''config/rviz2.rviz'' for simulator debugging and model inspection.

The Gazebo GUI settings are stored in ''config/gazebo.config''.

== Typical Usage ==

Basic simulator launch:

```bash
ros2 launch fejemis_sim sim.launch.py
```

Use a different world:

```bash
ros2 launch fejemis_sim sim.launch.py world:=fejemis_sim::worlds/empty.world
```

Disable the rover-command adapter and publish Twist directly:

```bash
ros2 launch fejemis_sim sim.launch.py rover_cmd_adapter:=False
```

Example RoverCommand input:

```bash
ros2 topic pub /fejemis/cmd_vel raubase_core/msg/RoverCommand "{source: 2, linear_vel: 0.2, turn_rate: 0.0}"
```

== Integration With The Rest Of The Stack ==

The simulation package is usually started together with ''fejemis'' and ''fejemis_maploc'' when testing the full ROS 2 stack in a desktop or lab environment.

In a simulated workflow, the same map, navigation, and behaviour layers can be exercised without running the physical bridge or Teensy hardware, while still keeping the robot description, command topics, and sensor topics aligned with the real system.

Fejemis Sim ROS2 - Revision history

S253809: /* Typical Usage */

S253809: /* Typical Usage */