Refactor battery demo

ros_gz_sim_demos/CMakeLists.txt

@@ -9,6 +9,12 @@ if(BUILD_TESTING)
   ament_lint_auto_find_test_dependencies()
 endif()
 
+install(
+  DIRECTORY
+    config/
+  DESTINATION share/${PROJECT_NAME}/config
+)
+
 install(
   DIRECTORY
     launch/

ros_gz_sim_demos/README.md

@@ -28,6 +28,18 @@ And
 
 ![](images/air_pressure_demo.png)
 
+## Battery
+
+Get the current state of a battery.
+
+    ros2 launch ros_gz_sim_demos battery.launch.py
+
+Then send a command so the vehicle moves and drains the battery.
+
+    ros2 topic pub /model/vehicle_blue/cmd_vel geometry_msgs/msg/Twist "{linear: {x: 5.0}, angular: {z: 0.5}}"
+
+![](images/battery_demo.png)
+
 ## Camera
 
 Publishes RGB camera image and info.
@@ -164,18 +176,6 @@ Using Gazebo Sim plugin:
 
 ![](images/rgbd_camera_demo.png)
 
-## Battery
-
-Get the current state of a battery.
-
-    ros2 launch ros_gz_sim_demos battery.launch.py
-
-Then send a command so the vehicle moves and drains the battery
-
-    ros2 topic pub /model/vehicle_blue/cmd_vel geometry_msgs/msg/Twist "{linear: {x: 5.0}, angular: {z: 0.5}}"
-
-![](images/battery_demo.png)
-
 ## Robot description publisher
 
 Leverage the robot description publisher to spawn a new urdf model in gazebo and

ros_gz_sim_demos/config/battery.yaml

@@ -0,0 +1,12 @@
+# Battery configuration.
+- topic_name: "/model/vehicle_blue/cmd_vel"
+  ros_type_name: "geometry_msgs/msg/Twist"
+  gz_type_name: "gz.msgs.Twist"
+  lazy: true
+  direction: ROS_TO_GZ
+
+- topic_name: "/model/vehicle_blue/battery/linear_battery/state"
+  ros_type_name: "sensor_msgs/msg/BatteryState"
+  gz_type_name: "gz.msgs.BatteryState"
+  lazy: true
+  direction: GZ_TO_ROS

ros_gz_sim_demos/launch/battery.launch.py

@@ -15,20 +15,20 @@
 import os
 
 from ament_index_python.packages import get_package_share_directory
-
 from launch import LaunchDescription
 from launch.actions import DeclareLaunchArgument
 from launch.actions import IncludeLaunchDescription
 from launch.conditions import IfCondition
 from launch.launch_description_sources import PythonLaunchDescriptionSource
 from launch.substitutions import LaunchConfiguration
-
 from launch_ros.actions import Node
+from ros_gz_bridge.actions import RosGzBridge
 
 
 def generate_launch_description():
 
     pkg_ros_gz_sim = get_package_share_directory('ros_gz_sim')
+    pkg_ros_gz_sim_demos = get_package_share_directory('ros_gz_sim_demos')
 
     # RQt
     rqt = Node(
@@ -40,6 +40,7 @@ def generate_launch_description():
         condition=IfCondition(LaunchConfiguration('rqt'))
     )
 
+    # Gazebo
     gz_sim = IncludeLaunchDescription(
         PythonLaunchDescriptionSource(
             os.path.join(pkg_ros_gz_sim, 'launch', 'gz_sim.launch.py')),
@@ -49,21 +50,15 @@ def generate_launch_description():
     )
 
     # Bridge
-    bridge = Node(
-        package='ros_gz_bridge',
-        executable='parameter_bridge',
-        arguments=[
-            '/model/vehicle_blue/cmd_vel@geometry_msgs/msg/[email protected]',
-            '/model/vehicle_blue/battery/linear_battery/state@sensor_msgs/msg/BatteryState@'
-            'gz.msgs.BatteryState'
-        ],
-        output='screen'
+    ros_gz_bridge = RosGzBridge(
+        bridge_name='ros_gz_bridge',
+        config_file=os.path.join(pkg_ros_gz_sim_demos, 'config', 'battery.yaml'),
     )
 
     return LaunchDescription([
         gz_sim,
         DeclareLaunchArgument('rqt', default_value='true',
                               description='Open RQt.'),
-        bridge,
+        ros_gz_bridge,
         rqt
     ])