Make an optional launch arg for RViz, document it in README (#82)

* Avoid launching two RViz instances when MoveIt is launched

Co-authored-by: Denis Stogl <[email protected]>

Author: AndyZe

README.md

@@ -65,9 +65,9 @@ The most relevant arguments are the following:
 
 ### Example Commands for Testing the Driver
 
-1. To start the robot driver and controllers, use:
+- To start the robot driver and controllers, use:
    ```
-   ros2 launch ur_bringup ur_control.launch.py ur_type:=ur5e robot_ip:=yyy.yyy.yyy.yyy use_fake_hardware:=true
+   ros2 launch ur_bringup ur_control.launch.py ur_type:=ur5e robot_ip:=yyy.yyy.yyy.yyy use_fake_hardware:=true launch_rviz:=true
    ```
    For an offline test with the emulated hardware you can just copy-paste this line.
    To run on the hardware, write the IP address of your robot and omit the `use_fake_hardware` argument.
@@ -80,13 +80,13 @@ The most relevant arguments are the following:
 
    To check the controllers' state use `ros2 control list_controllers` command.
 
-2. Send some goal to the Joint Trajectory Controller by using a demo node from [ros2_control_demos](https://github.com/ros-controls/ros2_control_demos) package by starting  the following command in another terminal:
+- Send some goal to the Joint Trajectory Controller by using a demo node from [ros2_control_demos](https://github.com/ros-controls/ros2_control_demos) package by starting  the following command in another terminal:
    ```
    ros2 launch ur_bringup test_joint_trajectory_controller.launch.py
    ```
    After a few seconds the robot should move.
 
-3. To test another controller, simply define it using `robot_controller` argument:
+- To test another controller, simply define it using `robot_controller` argument:
    ```
    ros2 launch ur_bringup ur_control.launch.py ur_type:=ur5e robot_ip:=yyy.yyy.yyy.yyy robot_controller:=scaled_joint_trajectory_controller use_fake_hardware:=true
    ```
@@ -96,9 +96,11 @@ The most relevant arguments are the following:
    ```
    After a few seconds the robot should move (or jump when using emulation).
 
-4. To test the driver with example MoveIt-setup, start `ur_control` launch file and then start MoveIt using the following command:
+- To test the driver with example MoveIt-setup, first start the controllers then start MoveIt:
    ```
-   ros2 launch ur_bringup ur_moveit.launch.py ur_type:=ur5e robot_ip:="xxx.xxx" use_fake_hardware:=true
+   ros2 launch ur_bringup ur_control.launch.py ur_type:=ur5e robot_ip:=yyy.yyy.yyy.yyy use_fake_hardware:=true launch_rviz:=false
+
+   ros2 launch ur_bringup ur_moveit.launch.py ur_type:=ur5e robot_ip:="xxx.xxx" use_fake_hardware:=true launch_rviz:=true
    ```
    Now you should be able to use MoveIt Plugin in rviz2 to plan and execute trajectories with the robot.
    **NOTE**: This results in two instances of rviz2. You can safely close the one without *MotionPlanning* panel.

ur_bringup/launch/ur_control.launch.py

@@ -118,6 +118,9 @@ def generate_launch_description():
             description="Robot controller to start.",
         )
     )
+    declared_arguments.append(
+        DeclareLaunchArgument("launch_rviz", default_value="true", description="Launch RViz?")
+    )
 
     # Initialize Arguments
     ur_type = LaunchConfiguration("ur_type")
@@ -134,6 +137,7 @@ def generate_launch_description():
     use_fake_hardware = LaunchConfiguration("use_fake_hardware")
     fake_sensor_commands = LaunchConfiguration("fake_sensor_commands")
     robot_controller = LaunchConfiguration("robot_controller")
+    launch_rviz = LaunchConfiguration("launch_rviz")
 
     joint_limit_params = PathJoinSubstitution(
         [FindPackageShare(description_package), "config", ur_type, "joint_limits.yaml"]
@@ -236,8 +240,10 @@ def generate_launch_description():
         output="both",
         parameters=[robot_description],
     )
+
     rviz_node = Node(
         package="rviz2",
+        condition=IfCondition(LaunchConfiguration("launch_rviz")),
         executable="rviz2",
         name="rviz2",
         output="log",

ur_bringup/launch/ur_moveit.launch.py

@@ -148,6 +148,9 @@ def generate_launch_description():
             description="Robot controller to start.",
         )
     )
+    declared_arguments.append(
+        DeclareLaunchArgument("launch_rviz", default_value="true", description="Launch RViz?")
+    )
 
     # Initialize Arguments
     ur_type = LaunchConfiguration("ur_type")
@@ -166,6 +169,7 @@ def generate_launch_description():
     use_fake_hardware = LaunchConfiguration("use_fake_hardware")
     fake_sensor_commands = LaunchConfiguration("fake_sensor_commands")
     robot_controller = LaunchConfiguration("robot_controller")
+    launch_rviz = LaunchConfiguration("launch_rviz")
 
     joint_limit_params = PathJoinSubstitution(
         [FindPackageShare(description_package), "config", ur_type, "joint_limits.yaml"]
@@ -345,6 +349,7 @@ def generate_launch_description():
     )
     rviz_node = Node(
         package="rviz2",
+        condition=IfCondition(LaunchConfiguration("launch_rviz")),
         executable="rviz2",
         name="rviz2_moveit",
         output="log",